os_linux.cpp revision 11658:8a5735c11a84
1/* 2 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25// no precompiled headers 26#include "classfile/classLoader.hpp" 27#include "classfile/systemDictionary.hpp" 28#include "classfile/vmSymbols.hpp" 29#include "code/icBuffer.hpp" 30#include "code/vtableStubs.hpp" 31#include "compiler/compileBroker.hpp" 32#include "compiler/disassembler.hpp" 33#include "interpreter/interpreter.hpp" 34#include "jvm_linux.h" 35#include "logging/log.hpp" 36#include "memory/allocation.inline.hpp" 37#include "memory/filemap.hpp" 38#include "oops/oop.inline.hpp" 39#include "os_linux.inline.hpp" 40#include "os_share_linux.hpp" 41#include "prims/jniFastGetField.hpp" 42#include "prims/jvm.h" 43#include "prims/jvm_misc.hpp" 44#include "runtime/arguments.hpp" 45#include "runtime/atomic.inline.hpp" 46#include "runtime/extendedPC.hpp" 47#include "runtime/globals.hpp" 48#include "runtime/interfaceSupport.hpp" 49#include "runtime/init.hpp" 50#include "runtime/java.hpp" 51#include "runtime/javaCalls.hpp" 52#include "runtime/mutexLocker.hpp" 53#include "runtime/objectMonitor.hpp" 54#include "runtime/orderAccess.inline.hpp" 55#include "runtime/osThread.hpp" 56#include "runtime/perfMemory.hpp" 57#include "runtime/sharedRuntime.hpp" 58#include "runtime/statSampler.hpp" 59#include "runtime/stubRoutines.hpp" 60#include "runtime/thread.inline.hpp" 61#include "runtime/threadCritical.hpp" 62#include "runtime/timer.hpp" 63#include "semaphore_posix.hpp" 64#include "services/attachListener.hpp" 65#include "services/memTracker.hpp" 66#include "services/runtimeService.hpp" 67#include "utilities/decoder.hpp" 68#include "utilities/defaultStream.hpp" 69#include "utilities/events.hpp" 70#include "utilities/elfFile.hpp" 71#include "utilities/growableArray.hpp" 72#include "utilities/macros.hpp" 73#include "utilities/vmError.hpp" 74 75// put OS-includes here 76# include <sys/types.h> 77# include <sys/mman.h> 78# include <sys/stat.h> 79# include <sys/select.h> 80# include <pthread.h> 81# include <signal.h> 82# include <errno.h> 83# include <dlfcn.h> 84# include <stdio.h> 85# include <unistd.h> 86# include <sys/resource.h> 87# include <pthread.h> 88# include <sys/stat.h> 89# include <sys/time.h> 90# include <sys/times.h> 91# include <sys/utsname.h> 92# include <sys/socket.h> 93# include <sys/wait.h> 94# include <pwd.h> 95# include <poll.h> 96# include <semaphore.h> 97# include <fcntl.h> 98# include <string.h> 99# include <syscall.h> 100# include <sys/sysinfo.h> 101# include <gnu/libc-version.h> 102# include <sys/ipc.h> 103# include <sys/shm.h> 104# include <link.h> 105# include <stdint.h> 106# include <inttypes.h> 107# include <sys/ioctl.h> 108 109#ifndef _GNU_SOURCE 110 #define _GNU_SOURCE 111 #include <sched.h> 112 #undef _GNU_SOURCE 113#else 114 #include <sched.h> 115#endif 116 117// if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 118// getrusage() is prepared to handle the associated failure. 119#ifndef RUSAGE_THREAD 120 #define RUSAGE_THREAD (1) /* only the calling thread */ 121#endif 122 123#define MAX_PATH (2 * K) 124 125#define MAX_SECS 100000000 126 127// for timer info max values which include all bits 128#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 129 130#define LARGEPAGES_BIT (1 << 6) 131//////////////////////////////////////////////////////////////////////////////// 132// global variables 133julong os::Linux::_physical_memory = 0; 134 135address os::Linux::_initial_thread_stack_bottom = NULL; 136uintptr_t os::Linux::_initial_thread_stack_size = 0; 137 138int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 139int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 140int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 141Mutex* os::Linux::_createThread_lock = NULL; 142pthread_t os::Linux::_main_thread; 143int os::Linux::_page_size = -1; 144bool os::Linux::_supports_fast_thread_cpu_time = false; 145uint32_t os::Linux::_os_version = 0; 146const char * os::Linux::_glibc_version = NULL; 147const char * os::Linux::_libpthread_version = NULL; 148pthread_condattr_t os::Linux::_condattr[1]; 149 150static jlong initial_time_count=0; 151 152static int clock_tics_per_sec = 100; 153 154// For diagnostics to print a message once. see run_periodic_checks 155static sigset_t check_signal_done; 156static bool check_signals = true; 157 158// Signal number used to suspend/resume a thread 159 160// do not use any signal number less than SIGSEGV, see 4355769 161static int SR_signum = SIGUSR2; 162sigset_t SR_sigset; 163 164// Declarations 165static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 166 167// utility functions 168 169static int SR_initialize(); 170 171julong os::available_memory() { 172 return Linux::available_memory(); 173} 174 175julong os::Linux::available_memory() { 176 // values in struct sysinfo are "unsigned long" 177 struct sysinfo si; 178 sysinfo(&si); 179 180 return (julong)si.freeram * si.mem_unit; 181} 182 183julong os::physical_memory() { 184 return Linux::physical_memory(); 185} 186 187// Return true if user is running as root. 188 189bool os::have_special_privileges() { 190 static bool init = false; 191 static bool privileges = false; 192 if (!init) { 193 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 194 init = true; 195 } 196 return privileges; 197} 198 199 200#ifndef SYS_gettid 201// i386: 224, ia64: 1105, amd64: 186, sparc 143 202 #ifdef __ia64__ 203 #define SYS_gettid 1105 204 #else 205 #ifdef __i386__ 206 #define SYS_gettid 224 207 #else 208 #ifdef __amd64__ 209 #define SYS_gettid 186 210 #else 211 #ifdef __sparc__ 212 #define SYS_gettid 143 213 #else 214 #error define gettid for the arch 215 #endif 216 #endif 217 #endif 218 #endif 219#endif 220 221// Cpu architecture string 222static char cpu_arch[] = HOTSPOT_LIB_ARCH; 223 224 225// pid_t gettid() 226// 227// Returns the kernel thread id of the currently running thread. Kernel 228// thread id is used to access /proc. 229pid_t os::Linux::gettid() { 230 int rslt = syscall(SYS_gettid); 231 assert(rslt != -1, "must be."); // old linuxthreads implementation? 232 return (pid_t)rslt; 233} 234 235// Most versions of linux have a bug where the number of processors are 236// determined by looking at the /proc file system. In a chroot environment, 237// the system call returns 1. This causes the VM to act as if it is 238// a single processor and elide locking (see is_MP() call). 239static bool unsafe_chroot_detected = false; 240static const char *unstable_chroot_error = "/proc file system not found.\n" 241 "Java may be unstable running multithreaded in a chroot " 242 "environment on Linux when /proc filesystem is not mounted."; 243 244void os::Linux::initialize_system_info() { 245 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 246 if (processor_count() == 1) { 247 pid_t pid = os::Linux::gettid(); 248 char fname[32]; 249 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 250 FILE *fp = fopen(fname, "r"); 251 if (fp == NULL) { 252 unsafe_chroot_detected = true; 253 } else { 254 fclose(fp); 255 } 256 } 257 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 258 assert(processor_count() > 0, "linux error"); 259} 260 261void os::init_system_properties_values() { 262 // The next steps are taken in the product version: 263 // 264 // Obtain the JAVA_HOME value from the location of libjvm.so. 265 // This library should be located at: 266 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 267 // 268 // If "/jre/lib/" appears at the right place in the path, then we 269 // assume libjvm.so is installed in a JDK and we use this path. 270 // 271 // Otherwise exit with message: "Could not create the Java virtual machine." 272 // 273 // The following extra steps are taken in the debugging version: 274 // 275 // If "/jre/lib/" does NOT appear at the right place in the path 276 // instead of exit check for $JAVA_HOME environment variable. 277 // 278 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 279 // then we append a fake suffix "hotspot/libjvm.so" to this path so 280 // it looks like libjvm.so is installed there 281 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 282 // 283 // Otherwise exit. 284 // 285 // Important note: if the location of libjvm.so changes this 286 // code needs to be changed accordingly. 287 288 // See ld(1): 289 // The linker uses the following search paths to locate required 290 // shared libraries: 291 // 1: ... 292 // ... 293 // 7: The default directories, normally /lib and /usr/lib. 294#if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 295 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 296#else 297 #define DEFAULT_LIBPATH "/lib:/usr/lib" 298#endif 299 300// Base path of extensions installed on the system. 301#define SYS_EXT_DIR "/usr/java/packages" 302#define EXTENSIONS_DIR "/lib/ext" 303 304 // Buffer that fits several sprintfs. 305 // Note that the space for the colon and the trailing null are provided 306 // by the nulls included by the sizeof operator. 307 const size_t bufsize = 308 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 309 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 310 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 311 312 // sysclasspath, java_home, dll_dir 313 { 314 char *pslash; 315 os::jvm_path(buf, bufsize); 316 317 // Found the full path to libjvm.so. 318 // Now cut the path to <java_home>/jre if we can. 319 pslash = strrchr(buf, '/'); 320 if (pslash != NULL) { 321 *pslash = '\0'; // Get rid of /libjvm.so. 322 } 323 pslash = strrchr(buf, '/'); 324 if (pslash != NULL) { 325 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 326 } 327 Arguments::set_dll_dir(buf); 328 329 if (pslash != NULL) { 330 pslash = strrchr(buf, '/'); 331 if (pslash != NULL) { 332 *pslash = '\0'; // Get rid of /<arch>. 333 pslash = strrchr(buf, '/'); 334 if (pslash != NULL) { 335 *pslash = '\0'; // Get rid of /lib. 336 } 337 } 338 } 339 Arguments::set_java_home(buf); 340 set_boot_path('/', ':'); 341 } 342 343 // Where to look for native libraries. 344 // 345 // Note: Due to a legacy implementation, most of the library path 346 // is set in the launcher. This was to accomodate linking restrictions 347 // on legacy Linux implementations (which are no longer supported). 348 // Eventually, all the library path setting will be done here. 349 // 350 // However, to prevent the proliferation of improperly built native 351 // libraries, the new path component /usr/java/packages is added here. 352 // Eventually, all the library path setting will be done here. 353 { 354 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 355 // should always exist (until the legacy problem cited above is 356 // addressed). 357 const char *v = ::getenv("LD_LIBRARY_PATH"); 358 const char *v_colon = ":"; 359 if (v == NULL) { v = ""; v_colon = ""; } 360 // That's +1 for the colon and +1 for the trailing '\0'. 361 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 362 strlen(v) + 1 + 363 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1, 364 mtInternal); 365 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch); 366 Arguments::set_library_path(ld_library_path); 367 FREE_C_HEAP_ARRAY(char, ld_library_path); 368 } 369 370 // Extensions directories. 371 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 372 Arguments::set_ext_dirs(buf); 373 374 FREE_C_HEAP_ARRAY(char, buf); 375 376#undef DEFAULT_LIBPATH 377#undef SYS_EXT_DIR 378#undef EXTENSIONS_DIR 379} 380 381//////////////////////////////////////////////////////////////////////////////// 382// breakpoint support 383 384void os::breakpoint() { 385 BREAKPOINT; 386} 387 388extern "C" void breakpoint() { 389 // use debugger to set breakpoint here 390} 391 392//////////////////////////////////////////////////////////////////////////////// 393// signal support 394 395debug_only(static bool signal_sets_initialized = false); 396static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 397 398bool os::Linux::is_sig_ignored(int sig) { 399 struct sigaction oact; 400 sigaction(sig, (struct sigaction*)NULL, &oact); 401 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 402 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 403 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 404 return true; 405 } else { 406 return false; 407 } 408} 409 410void os::Linux::signal_sets_init() { 411 // Should also have an assertion stating we are still single-threaded. 412 assert(!signal_sets_initialized, "Already initialized"); 413 // Fill in signals that are necessarily unblocked for all threads in 414 // the VM. Currently, we unblock the following signals: 415 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 416 // by -Xrs (=ReduceSignalUsage)); 417 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 418 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 419 // the dispositions or masks wrt these signals. 420 // Programs embedding the VM that want to use the above signals for their 421 // own purposes must, at this time, use the "-Xrs" option to prevent 422 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 423 // (See bug 4345157, and other related bugs). 424 // In reality, though, unblocking these signals is really a nop, since 425 // these signals are not blocked by default. 426 sigemptyset(&unblocked_sigs); 427 sigemptyset(&allowdebug_blocked_sigs); 428 sigaddset(&unblocked_sigs, SIGILL); 429 sigaddset(&unblocked_sigs, SIGSEGV); 430 sigaddset(&unblocked_sigs, SIGBUS); 431 sigaddset(&unblocked_sigs, SIGFPE); 432#if defined(PPC64) 433 sigaddset(&unblocked_sigs, SIGTRAP); 434#endif 435 sigaddset(&unblocked_sigs, SR_signum); 436 437 if (!ReduceSignalUsage) { 438 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 439 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 440 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 441 } 442 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 443 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 444 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 445 } 446 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 447 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 448 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 449 } 450 } 451 // Fill in signals that are blocked by all but the VM thread. 452 sigemptyset(&vm_sigs); 453 if (!ReduceSignalUsage) { 454 sigaddset(&vm_sigs, BREAK_SIGNAL); 455 } 456 debug_only(signal_sets_initialized = true); 457 458} 459 460// These are signals that are unblocked while a thread is running Java. 461// (For some reason, they get blocked by default.) 462sigset_t* os::Linux::unblocked_signals() { 463 assert(signal_sets_initialized, "Not initialized"); 464 return &unblocked_sigs; 465} 466 467// These are the signals that are blocked while a (non-VM) thread is 468// running Java. Only the VM thread handles these signals. 469sigset_t* os::Linux::vm_signals() { 470 assert(signal_sets_initialized, "Not initialized"); 471 return &vm_sigs; 472} 473 474// These are signals that are blocked during cond_wait to allow debugger in 475sigset_t* os::Linux::allowdebug_blocked_signals() { 476 assert(signal_sets_initialized, "Not initialized"); 477 return &allowdebug_blocked_sigs; 478} 479 480void os::Linux::hotspot_sigmask(Thread* thread) { 481 482 //Save caller's signal mask before setting VM signal mask 483 sigset_t caller_sigmask; 484 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 485 486 OSThread* osthread = thread->osthread(); 487 osthread->set_caller_sigmask(caller_sigmask); 488 489 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 490 491 if (!ReduceSignalUsage) { 492 if (thread->is_VM_thread()) { 493 // Only the VM thread handles BREAK_SIGNAL ... 494 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 495 } else { 496 // ... all other threads block BREAK_SIGNAL 497 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 498 } 499 } 500} 501 502////////////////////////////////////////////////////////////////////////////// 503// detecting pthread library 504 505void os::Linux::libpthread_init() { 506 // Save glibc and pthread version strings. 507#if !defined(_CS_GNU_LIBC_VERSION) || \ 508 !defined(_CS_GNU_LIBPTHREAD_VERSION) 509 #error "glibc too old (< 2.3.2)" 510#endif 511 512 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 513 assert(n > 0, "cannot retrieve glibc version"); 514 char *str = (char *)malloc(n, mtInternal); 515 confstr(_CS_GNU_LIBC_VERSION, str, n); 516 os::Linux::set_glibc_version(str); 517 518 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 519 assert(n > 0, "cannot retrieve pthread version"); 520 str = (char *)malloc(n, mtInternal); 521 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 522 os::Linux::set_libpthread_version(str); 523} 524 525///////////////////////////////////////////////////////////////////////////// 526// thread stack expansion 527 528// os::Linux::manually_expand_stack() takes care of expanding the thread 529// stack. Note that this is normally not needed: pthread stacks allocate 530// thread stack using mmap() without MAP_NORESERVE, so the stack is already 531// committed. Therefore it is not necessary to expand the stack manually. 532// 533// Manually expanding the stack was historically needed on LinuxThreads 534// thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 535// it is kept to deal with very rare corner cases: 536// 537// For one, user may run the VM on an own implementation of threads 538// whose stacks are - like the old LinuxThreads - implemented using 539// mmap(MAP_GROWSDOWN). 540// 541// Also, this coding may be needed if the VM is running on the primordial 542// thread. Normally we avoid running on the primordial thread; however, 543// user may still invoke the VM on the primordial thread. 544// 545// The following historical comment describes the details about running 546// on a thread stack allocated with mmap(MAP_GROWSDOWN): 547 548 549// Force Linux kernel to expand current thread stack. If "bottom" is close 550// to the stack guard, caller should block all signals. 551// 552// MAP_GROWSDOWN: 553// A special mmap() flag that is used to implement thread stacks. It tells 554// kernel that the memory region should extend downwards when needed. This 555// allows early versions of LinuxThreads to only mmap the first few pages 556// when creating a new thread. Linux kernel will automatically expand thread 557// stack as needed (on page faults). 558// 559// However, because the memory region of a MAP_GROWSDOWN stack can grow on 560// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 561// region, it's hard to tell if the fault is due to a legitimate stack 562// access or because of reading/writing non-exist memory (e.g. buffer 563// overrun). As a rule, if the fault happens below current stack pointer, 564// Linux kernel does not expand stack, instead a SIGSEGV is sent to the 565// application (see Linux kernel fault.c). 566// 567// This Linux feature can cause SIGSEGV when VM bangs thread stack for 568// stack overflow detection. 569// 570// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 571// not use MAP_GROWSDOWN. 572// 573// To get around the problem and allow stack banging on Linux, we need to 574// manually expand thread stack after receiving the SIGSEGV. 575// 576// There are two ways to expand thread stack to address "bottom", we used 577// both of them in JVM before 1.5: 578// 1. adjust stack pointer first so that it is below "bottom", and then 579// touch "bottom" 580// 2. mmap() the page in question 581// 582// Now alternate signal stack is gone, it's harder to use 2. For instance, 583// if current sp is already near the lower end of page 101, and we need to 584// call mmap() to map page 100, it is possible that part of the mmap() frame 585// will be placed in page 100. When page 100 is mapped, it is zero-filled. 586// That will destroy the mmap() frame and cause VM to crash. 587// 588// The following code works by adjusting sp first, then accessing the "bottom" 589// page to force a page fault. Linux kernel will then automatically expand the 590// stack mapping. 591// 592// _expand_stack_to() assumes its frame size is less than page size, which 593// should always be true if the function is not inlined. 594 595static void NOINLINE _expand_stack_to(address bottom) { 596 address sp; 597 size_t size; 598 volatile char *p; 599 600 // Adjust bottom to point to the largest address within the same page, it 601 // gives us a one-page buffer if alloca() allocates slightly more memory. 602 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 603 bottom += os::Linux::page_size() - 1; 604 605 // sp might be slightly above current stack pointer; if that's the case, we 606 // will alloca() a little more space than necessary, which is OK. Don't use 607 // os::current_stack_pointer(), as its result can be slightly below current 608 // stack pointer, causing us to not alloca enough to reach "bottom". 609 sp = (address)&sp; 610 611 if (sp > bottom) { 612 size = sp - bottom; 613 p = (volatile char *)alloca(size); 614 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 615 p[0] = '\0'; 616 } 617} 618 619bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 620 assert(t!=NULL, "just checking"); 621 assert(t->osthread()->expanding_stack(), "expand should be set"); 622 assert(t->stack_base() != NULL, "stack_base was not initialized"); 623 624 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 625 sigset_t mask_all, old_sigset; 626 sigfillset(&mask_all); 627 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 628 _expand_stack_to(addr); 629 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 630 return true; 631 } 632 return false; 633} 634 635////////////////////////////////////////////////////////////////////////////// 636// create new thread 637 638// Thread start routine for all newly created threads 639static void *thread_native_entry(Thread *thread) { 640 // Try to randomize the cache line index of hot stack frames. 641 // This helps when threads of the same stack traces evict each other's 642 // cache lines. The threads can be either from the same JVM instance, or 643 // from different JVM instances. The benefit is especially true for 644 // processors with hyperthreading technology. 645 static int counter = 0; 646 int pid = os::current_process_id(); 647 alloca(((pid ^ counter++) & 7) * 128); 648 649 thread->initialize_thread_current(); 650 651 OSThread* osthread = thread->osthread(); 652 Monitor* sync = osthread->startThread_lock(); 653 654 osthread->set_thread_id(os::current_thread_id()); 655 656 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 657 os::current_thread_id(), (uintx) pthread_self()); 658 659 if (UseNUMA) { 660 int lgrp_id = os::numa_get_group_id(); 661 if (lgrp_id != -1) { 662 thread->set_lgrp_id(lgrp_id); 663 } 664 } 665 // initialize signal mask for this thread 666 os::Linux::hotspot_sigmask(thread); 667 668 // initialize floating point control register 669 os::Linux::init_thread_fpu_state(); 670 671 // handshaking with parent thread 672 { 673 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 674 675 // notify parent thread 676 osthread->set_state(INITIALIZED); 677 sync->notify_all(); 678 679 // wait until os::start_thread() 680 while (osthread->get_state() == INITIALIZED) { 681 sync->wait(Mutex::_no_safepoint_check_flag); 682 } 683 } 684 685 // call one more level start routine 686 thread->run(); 687 688 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 689 os::current_thread_id(), (uintx) pthread_self()); 690 691 // If a thread has not deleted itself ("delete this") as part of its 692 // termination sequence, we have to ensure thread-local-storage is 693 // cleared before we actually terminate. No threads should ever be 694 // deleted asynchronously with respect to their termination. 695 if (Thread::current_or_null_safe() != NULL) { 696 assert(Thread::current_or_null_safe() == thread, "current thread is wrong"); 697 thread->clear_thread_current(); 698 } 699 700 return 0; 701} 702 703bool os::create_thread(Thread* thread, ThreadType thr_type, 704 size_t stack_size) { 705 assert(thread->osthread() == NULL, "caller responsible"); 706 707 // Allocate the OSThread object 708 OSThread* osthread = new OSThread(NULL, NULL); 709 if (osthread == NULL) { 710 return false; 711 } 712 713 // set the correct thread state 714 osthread->set_thread_type(thr_type); 715 716 // Initial state is ALLOCATED but not INITIALIZED 717 osthread->set_state(ALLOCATED); 718 719 thread->set_osthread(osthread); 720 721 // init thread attributes 722 pthread_attr_t attr; 723 pthread_attr_init(&attr); 724 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 725 726 // stack size 727 // calculate stack size if it's not specified by caller 728 if (stack_size == 0) { 729 stack_size = os::Linux::default_stack_size(thr_type); 730 731 switch (thr_type) { 732 case os::java_thread: 733 // Java threads use ThreadStackSize which default value can be 734 // changed with the flag -Xss 735 assert(JavaThread::stack_size_at_create() > 0, "this should be set"); 736 stack_size = JavaThread::stack_size_at_create(); 737 break; 738 case os::compiler_thread: 739 if (CompilerThreadStackSize > 0) { 740 stack_size = (size_t)(CompilerThreadStackSize * K); 741 break; 742 } // else fall through: 743 // use VMThreadStackSize if CompilerThreadStackSize is not defined 744 case os::vm_thread: 745 case os::pgc_thread: 746 case os::cgc_thread: 747 case os::watcher_thread: 748 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 749 break; 750 } 751 } 752 753 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 754 pthread_attr_setstacksize(&attr, stack_size); 755 756 // glibc guard page 757 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 758 759 ThreadState state; 760 761 { 762 pthread_t tid; 763 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 764 765 char buf[64]; 766 if (ret == 0) { 767 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 768 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 769 } else { 770 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 771 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 772 } 773 774 pthread_attr_destroy(&attr); 775 776 if (ret != 0) { 777 // Need to clean up stuff we've allocated so far 778 thread->set_osthread(NULL); 779 delete osthread; 780 return false; 781 } 782 783 // Store pthread info into the OSThread 784 osthread->set_pthread_id(tid); 785 786 // Wait until child thread is either initialized or aborted 787 { 788 Monitor* sync_with_child = osthread->startThread_lock(); 789 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 790 while ((state = osthread->get_state()) == ALLOCATED) { 791 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 792 } 793 } 794 } 795 796 // Aborted due to thread limit being reached 797 if (state == ZOMBIE) { 798 thread->set_osthread(NULL); 799 delete osthread; 800 return false; 801 } 802 803 // The thread is returned suspended (in state INITIALIZED), 804 // and is started higher up in the call chain 805 assert(state == INITIALIZED, "race condition"); 806 return true; 807} 808 809///////////////////////////////////////////////////////////////////////////// 810// attach existing thread 811 812// bootstrap the main thread 813bool os::create_main_thread(JavaThread* thread) { 814 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 815 return create_attached_thread(thread); 816} 817 818bool os::create_attached_thread(JavaThread* thread) { 819#ifdef ASSERT 820 thread->verify_not_published(); 821#endif 822 823 // Allocate the OSThread object 824 OSThread* osthread = new OSThread(NULL, NULL); 825 826 if (osthread == NULL) { 827 return false; 828 } 829 830 // Store pthread info into the OSThread 831 osthread->set_thread_id(os::Linux::gettid()); 832 osthread->set_pthread_id(::pthread_self()); 833 834 // initialize floating point control register 835 os::Linux::init_thread_fpu_state(); 836 837 // Initial thread state is RUNNABLE 838 osthread->set_state(RUNNABLE); 839 840 thread->set_osthread(osthread); 841 842 if (UseNUMA) { 843 int lgrp_id = os::numa_get_group_id(); 844 if (lgrp_id != -1) { 845 thread->set_lgrp_id(lgrp_id); 846 } 847 } 848 849 if (os::Linux::is_initial_thread()) { 850 // If current thread is initial thread, its stack is mapped on demand, 851 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 852 // the entire stack region to avoid SEGV in stack banging. 853 // It is also useful to get around the heap-stack-gap problem on SuSE 854 // kernel (see 4821821 for details). We first expand stack to the top 855 // of yellow zone, then enable stack yellow zone (order is significant, 856 // enabling yellow zone first will crash JVM on SuSE Linux), so there 857 // is no gap between the last two virtual memory regions. 858 859 JavaThread *jt = (JavaThread *)thread; 860 address addr = jt->stack_reserved_zone_base(); 861 assert(addr != NULL, "initialization problem?"); 862 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 863 864 osthread->set_expanding_stack(); 865 os::Linux::manually_expand_stack(jt, addr); 866 osthread->clear_expanding_stack(); 867 } 868 869 // initialize signal mask for this thread 870 // and save the caller's signal mask 871 os::Linux::hotspot_sigmask(thread); 872 873 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 874 os::current_thread_id(), (uintx) pthread_self()); 875 876 return true; 877} 878 879void os::pd_start_thread(Thread* thread) { 880 OSThread * osthread = thread->osthread(); 881 assert(osthread->get_state() != INITIALIZED, "just checking"); 882 Monitor* sync_with_child = osthread->startThread_lock(); 883 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 884 sync_with_child->notify(); 885} 886 887// Free Linux resources related to the OSThread 888void os::free_thread(OSThread* osthread) { 889 assert(osthread != NULL, "osthread not set"); 890 891 // We are told to free resources of the argument thread, 892 // but we can only really operate on the current thread. 893 assert(Thread::current()->osthread() == osthread, 894 "os::free_thread but not current thread"); 895 896#ifdef ASSERT 897 sigset_t current; 898 sigemptyset(¤t); 899 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 900 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 901#endif 902 903 // Restore caller's signal mask 904 sigset_t sigmask = osthread->caller_sigmask(); 905 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 906 907 delete osthread; 908} 909 910////////////////////////////////////////////////////////////////////////////// 911// initial thread 912 913// Check if current thread is the initial thread, similar to Solaris thr_main. 914bool os::Linux::is_initial_thread(void) { 915 char dummy; 916 // If called before init complete, thread stack bottom will be null. 917 // Can be called if fatal error occurs before initialization. 918 if (initial_thread_stack_bottom() == NULL) return false; 919 assert(initial_thread_stack_bottom() != NULL && 920 initial_thread_stack_size() != 0, 921 "os::init did not locate initial thread's stack region"); 922 if ((address)&dummy >= initial_thread_stack_bottom() && 923 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 924 return true; 925 } else { 926 return false; 927 } 928} 929 930// Find the virtual memory area that contains addr 931static bool find_vma(address addr, address* vma_low, address* vma_high) { 932 FILE *fp = fopen("/proc/self/maps", "r"); 933 if (fp) { 934 address low, high; 935 while (!feof(fp)) { 936 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 937 if (low <= addr && addr < high) { 938 if (vma_low) *vma_low = low; 939 if (vma_high) *vma_high = high; 940 fclose(fp); 941 return true; 942 } 943 } 944 for (;;) { 945 int ch = fgetc(fp); 946 if (ch == EOF || ch == (int)'\n') break; 947 } 948 } 949 fclose(fp); 950 } 951 return false; 952} 953 954// Locate initial thread stack. This special handling of initial thread stack 955// is needed because pthread_getattr_np() on most (all?) Linux distros returns 956// bogus value for initial thread. 957void os::Linux::capture_initial_stack(size_t max_size) { 958 // stack size is the easy part, get it from RLIMIT_STACK 959 size_t stack_size; 960 struct rlimit rlim; 961 getrlimit(RLIMIT_STACK, &rlim); 962 stack_size = rlim.rlim_cur; 963 964 // 6308388: a bug in ld.so will relocate its own .data section to the 965 // lower end of primordial stack; reduce ulimit -s value a little bit 966 // so we won't install guard page on ld.so's data section. 967 stack_size -= 2 * page_size(); 968 969 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 970 // 7.1, in both cases we will get 2G in return value. 971 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 972 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 973 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 974 // in case other parts in glibc still assumes 2M max stack size. 975 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 976 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 977 if (stack_size > 2 * K * K IA64_ONLY(*2)) { 978 stack_size = 2 * K * K IA64_ONLY(*2); 979 } 980 // Try to figure out where the stack base (top) is. This is harder. 981 // 982 // When an application is started, glibc saves the initial stack pointer in 983 // a global variable "__libc_stack_end", which is then used by system 984 // libraries. __libc_stack_end should be pretty close to stack top. The 985 // variable is available since the very early days. However, because it is 986 // a private interface, it could disappear in the future. 987 // 988 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 989 // to __libc_stack_end, it is very close to stack top, but isn't the real 990 // stack top. Note that /proc may not exist if VM is running as a chroot 991 // program, so reading /proc/<pid>/stat could fail. Also the contents of 992 // /proc/<pid>/stat could change in the future (though unlikely). 993 // 994 // We try __libc_stack_end first. If that doesn't work, look for 995 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 996 // as a hint, which should work well in most cases. 997 998 uintptr_t stack_start; 999 1000 // try __libc_stack_end first 1001 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1002 if (p && *p) { 1003 stack_start = *p; 1004 } else { 1005 // see if we can get the start_stack field from /proc/self/stat 1006 FILE *fp; 1007 int pid; 1008 char state; 1009 int ppid; 1010 int pgrp; 1011 int session; 1012 int nr; 1013 int tpgrp; 1014 unsigned long flags; 1015 unsigned long minflt; 1016 unsigned long cminflt; 1017 unsigned long majflt; 1018 unsigned long cmajflt; 1019 unsigned long utime; 1020 unsigned long stime; 1021 long cutime; 1022 long cstime; 1023 long prio; 1024 long nice; 1025 long junk; 1026 long it_real; 1027 uintptr_t start; 1028 uintptr_t vsize; 1029 intptr_t rss; 1030 uintptr_t rsslim; 1031 uintptr_t scodes; 1032 uintptr_t ecode; 1033 int i; 1034 1035 // Figure what the primordial thread stack base is. Code is inspired 1036 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1037 // followed by command name surrounded by parentheses, state, etc. 1038 char stat[2048]; 1039 int statlen; 1040 1041 fp = fopen("/proc/self/stat", "r"); 1042 if (fp) { 1043 statlen = fread(stat, 1, 2047, fp); 1044 stat[statlen] = '\0'; 1045 fclose(fp); 1046 1047 // Skip pid and the command string. Note that we could be dealing with 1048 // weird command names, e.g. user could decide to rename java launcher 1049 // to "java 1.4.2 :)", then the stat file would look like 1050 // 1234 (java 1.4.2 :)) R ... ... 1051 // We don't really need to know the command string, just find the last 1052 // occurrence of ")" and then start parsing from there. See bug 4726580. 1053 char * s = strrchr(stat, ')'); 1054 1055 i = 0; 1056 if (s) { 1057 // Skip blank chars 1058 do { s++; } while (s && isspace(*s)); 1059 1060#define _UFM UINTX_FORMAT 1061#define _DFM INTX_FORMAT 1062 1063 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1064 // 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 1065 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM, 1066 &state, // 3 %c 1067 &ppid, // 4 %d 1068 &pgrp, // 5 %d 1069 &session, // 6 %d 1070 &nr, // 7 %d 1071 &tpgrp, // 8 %d 1072 &flags, // 9 %lu 1073 &minflt, // 10 %lu 1074 &cminflt, // 11 %lu 1075 &majflt, // 12 %lu 1076 &cmajflt, // 13 %lu 1077 &utime, // 14 %lu 1078 &stime, // 15 %lu 1079 &cutime, // 16 %ld 1080 &cstime, // 17 %ld 1081 &prio, // 18 %ld 1082 &nice, // 19 %ld 1083 &junk, // 20 %ld 1084 &it_real, // 21 %ld 1085 &start, // 22 UINTX_FORMAT 1086 &vsize, // 23 UINTX_FORMAT 1087 &rss, // 24 INTX_FORMAT 1088 &rsslim, // 25 UINTX_FORMAT 1089 &scodes, // 26 UINTX_FORMAT 1090 &ecode, // 27 UINTX_FORMAT 1091 &stack_start); // 28 UINTX_FORMAT 1092 } 1093 1094#undef _UFM 1095#undef _DFM 1096 1097 if (i != 28 - 2) { 1098 assert(false, "Bad conversion from /proc/self/stat"); 1099 // product mode - assume we are the initial thread, good luck in the 1100 // embedded case. 1101 warning("Can't detect initial thread stack location - bad conversion"); 1102 stack_start = (uintptr_t) &rlim; 1103 } 1104 } else { 1105 // For some reason we can't open /proc/self/stat (for example, running on 1106 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1107 // most cases, so don't abort: 1108 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1109 stack_start = (uintptr_t) &rlim; 1110 } 1111 } 1112 1113 // Now we have a pointer (stack_start) very close to the stack top, the 1114 // next thing to do is to figure out the exact location of stack top. We 1115 // can find out the virtual memory area that contains stack_start by 1116 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1117 // and its upper limit is the real stack top. (again, this would fail if 1118 // running inside chroot, because /proc may not exist.) 1119 1120 uintptr_t stack_top; 1121 address low, high; 1122 if (find_vma((address)stack_start, &low, &high)) { 1123 // success, "high" is the true stack top. (ignore "low", because initial 1124 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1125 stack_top = (uintptr_t)high; 1126 } else { 1127 // failed, likely because /proc/self/maps does not exist 1128 warning("Can't detect initial thread stack location - find_vma failed"); 1129 // best effort: stack_start is normally within a few pages below the real 1130 // stack top, use it as stack top, and reduce stack size so we won't put 1131 // guard page outside stack. 1132 stack_top = stack_start; 1133 stack_size -= 16 * page_size(); 1134 } 1135 1136 // stack_top could be partially down the page so align it 1137 stack_top = align_size_up(stack_top, page_size()); 1138 1139 if (max_size && stack_size > max_size) { 1140 _initial_thread_stack_size = max_size; 1141 } else { 1142 _initial_thread_stack_size = stack_size; 1143 } 1144 1145 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1146 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1147} 1148 1149//////////////////////////////////////////////////////////////////////////////// 1150// time support 1151 1152// Time since start-up in seconds to a fine granularity. 1153// Used by VMSelfDestructTimer and the MemProfiler. 1154double os::elapsedTime() { 1155 1156 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1157} 1158 1159jlong os::elapsed_counter() { 1160 return javaTimeNanos() - initial_time_count; 1161} 1162 1163jlong os::elapsed_frequency() { 1164 return NANOSECS_PER_SEC; // nanosecond resolution 1165} 1166 1167bool os::supports_vtime() { return true; } 1168bool os::enable_vtime() { return false; } 1169bool os::vtime_enabled() { return false; } 1170 1171double os::elapsedVTime() { 1172 struct rusage usage; 1173 int retval = getrusage(RUSAGE_THREAD, &usage); 1174 if (retval == 0) { 1175 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000); 1176 } else { 1177 // better than nothing, but not much 1178 return elapsedTime(); 1179 } 1180} 1181 1182jlong os::javaTimeMillis() { 1183 timeval time; 1184 int status = gettimeofday(&time, NULL); 1185 assert(status != -1, "linux error"); 1186 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1187} 1188 1189void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1190 timeval time; 1191 int status = gettimeofday(&time, NULL); 1192 assert(status != -1, "linux error"); 1193 seconds = jlong(time.tv_sec); 1194 nanos = jlong(time.tv_usec) * 1000; 1195} 1196 1197 1198#ifndef CLOCK_MONOTONIC 1199 #define CLOCK_MONOTONIC (1) 1200#endif 1201 1202void os::Linux::clock_init() { 1203 // we do dlopen's in this particular order due to bug in linux 1204 // dynamical loader (see 6348968) leading to crash on exit 1205 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1206 if (handle == NULL) { 1207 handle = dlopen("librt.so", RTLD_LAZY); 1208 } 1209 1210 if (handle) { 1211 int (*clock_getres_func)(clockid_t, struct timespec*) = 1212 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1213 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1214 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1215 if (clock_getres_func && clock_gettime_func) { 1216 // See if monotonic clock is supported by the kernel. Note that some 1217 // early implementations simply return kernel jiffies (updated every 1218 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1219 // for nano time (though the monotonic property is still nice to have). 1220 // It's fixed in newer kernels, however clock_getres() still returns 1221 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1222 // resolution for now. Hopefully as people move to new kernels, this 1223 // won't be a problem. 1224 struct timespec res; 1225 struct timespec tp; 1226 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1227 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1228 // yes, monotonic clock is supported 1229 _clock_gettime = clock_gettime_func; 1230 return; 1231 } else { 1232 // close librt if there is no monotonic clock 1233 dlclose(handle); 1234 } 1235 } 1236 } 1237 warning("No monotonic clock was available - timed services may " \ 1238 "be adversely affected if the time-of-day clock changes"); 1239} 1240 1241#ifndef SYS_clock_getres 1242 #if defined(IA32) || defined(AMD64) 1243 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1244 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1245 #else 1246 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1247 #define sys_clock_getres(x,y) -1 1248 #endif 1249#else 1250 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1251#endif 1252 1253void os::Linux::fast_thread_clock_init() { 1254 if (!UseLinuxPosixThreadCPUClocks) { 1255 return; 1256 } 1257 clockid_t clockid; 1258 struct timespec tp; 1259 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1260 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1261 1262 // Switch to using fast clocks for thread cpu time if 1263 // the sys_clock_getres() returns 0 error code. 1264 // Note, that some kernels may support the current thread 1265 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1266 // returned by the pthread_getcpuclockid(). 1267 // If the fast Posix clocks are supported then the sys_clock_getres() 1268 // must return at least tp.tv_sec == 0 which means a resolution 1269 // better than 1 sec. This is extra check for reliability. 1270 1271 if (pthread_getcpuclockid_func && 1272 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1273 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1274 _supports_fast_thread_cpu_time = true; 1275 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1276 } 1277} 1278 1279jlong os::javaTimeNanos() { 1280 if (os::supports_monotonic_clock()) { 1281 struct timespec tp; 1282 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1283 assert(status == 0, "gettime error"); 1284 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1285 return result; 1286 } else { 1287 timeval time; 1288 int status = gettimeofday(&time, NULL); 1289 assert(status != -1, "linux error"); 1290 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1291 return 1000 * usecs; 1292 } 1293} 1294 1295void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1296 if (os::supports_monotonic_clock()) { 1297 info_ptr->max_value = ALL_64_BITS; 1298 1299 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1300 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1301 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1302 } else { 1303 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1304 info_ptr->max_value = ALL_64_BITS; 1305 1306 // gettimeofday is a real time clock so it skips 1307 info_ptr->may_skip_backward = true; 1308 info_ptr->may_skip_forward = true; 1309 } 1310 1311 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1312} 1313 1314// Return the real, user, and system times in seconds from an 1315// arbitrary fixed point in the past. 1316bool os::getTimesSecs(double* process_real_time, 1317 double* process_user_time, 1318 double* process_system_time) { 1319 struct tms ticks; 1320 clock_t real_ticks = times(&ticks); 1321 1322 if (real_ticks == (clock_t) (-1)) { 1323 return false; 1324 } else { 1325 double ticks_per_second = (double) clock_tics_per_sec; 1326 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1327 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1328 *process_real_time = ((double) real_ticks) / ticks_per_second; 1329 1330 return true; 1331 } 1332} 1333 1334 1335char * os::local_time_string(char *buf, size_t buflen) { 1336 struct tm t; 1337 time_t long_time; 1338 time(&long_time); 1339 localtime_r(&long_time, &t); 1340 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1341 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1342 t.tm_hour, t.tm_min, t.tm_sec); 1343 return buf; 1344} 1345 1346struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1347 return localtime_r(clock, res); 1348} 1349 1350//////////////////////////////////////////////////////////////////////////////// 1351// runtime exit support 1352 1353// Note: os::shutdown() might be called very early during initialization, or 1354// called from signal handler. Before adding something to os::shutdown(), make 1355// sure it is async-safe and can handle partially initialized VM. 1356void os::shutdown() { 1357 1358 // allow PerfMemory to attempt cleanup of any persistent resources 1359 perfMemory_exit(); 1360 1361 // needs to remove object in file system 1362 AttachListener::abort(); 1363 1364 // flush buffered output, finish log files 1365 ostream_abort(); 1366 1367 // Check for abort hook 1368 abort_hook_t abort_hook = Arguments::abort_hook(); 1369 if (abort_hook != NULL) { 1370 abort_hook(); 1371 } 1372 1373} 1374 1375// Note: os::abort() might be called very early during initialization, or 1376// called from signal handler. Before adding something to os::abort(), make 1377// sure it is async-safe and can handle partially initialized VM. 1378void os::abort(bool dump_core, void* siginfo, const void* context) { 1379 os::shutdown(); 1380 if (dump_core) { 1381#ifndef PRODUCT 1382 fdStream out(defaultStream::output_fd()); 1383 out.print_raw("Current thread is "); 1384 char buf[16]; 1385 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1386 out.print_raw_cr(buf); 1387 out.print_raw_cr("Dumping core ..."); 1388#endif 1389 ::abort(); // dump core 1390 } 1391 1392 ::exit(1); 1393} 1394 1395// Die immediately, no exit hook, no abort hook, no cleanup. 1396void os::die() { 1397 ::abort(); 1398} 1399 1400 1401// This method is a copy of JDK's sysGetLastErrorString 1402// from src/solaris/hpi/src/system_md.c 1403 1404size_t os::lasterror(char *buf, size_t len) { 1405 if (errno == 0) return 0; 1406 1407 const char *s = os::strerror(errno); 1408 size_t n = ::strlen(s); 1409 if (n >= len) { 1410 n = len - 1; 1411 } 1412 ::strncpy(buf, s, n); 1413 buf[n] = '\0'; 1414 return n; 1415} 1416 1417// thread_id is kernel thread id (similar to Solaris LWP id) 1418intx os::current_thread_id() { return os::Linux::gettid(); } 1419int os::current_process_id() { 1420 return ::getpid(); 1421} 1422 1423// DLL functions 1424 1425const char* os::dll_file_extension() { return ".so"; } 1426 1427// This must be hard coded because it's the system's temporary 1428// directory not the java application's temp directory, ala java.io.tmpdir. 1429const char* os::get_temp_directory() { return "/tmp"; } 1430 1431static bool file_exists(const char* filename) { 1432 struct stat statbuf; 1433 if (filename == NULL || strlen(filename) == 0) { 1434 return false; 1435 } 1436 return os::stat(filename, &statbuf) == 0; 1437} 1438 1439bool os::dll_build_name(char* buffer, size_t buflen, 1440 const char* pname, const char* fname) { 1441 bool retval = false; 1442 // Copied from libhpi 1443 const size_t pnamelen = pname ? strlen(pname) : 0; 1444 1445 // Return error on buffer overflow. 1446 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1447 return retval; 1448 } 1449 1450 if (pnamelen == 0) { 1451 snprintf(buffer, buflen, "lib%s.so", fname); 1452 retval = true; 1453 } else if (strchr(pname, *os::path_separator()) != NULL) { 1454 int n; 1455 char** pelements = split_path(pname, &n); 1456 if (pelements == NULL) { 1457 return false; 1458 } 1459 for (int i = 0; i < n; i++) { 1460 // Really shouldn't be NULL, but check can't hurt 1461 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1462 continue; // skip the empty path values 1463 } 1464 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1465 if (file_exists(buffer)) { 1466 retval = true; 1467 break; 1468 } 1469 } 1470 // release the storage 1471 for (int i = 0; i < n; i++) { 1472 if (pelements[i] != NULL) { 1473 FREE_C_HEAP_ARRAY(char, pelements[i]); 1474 } 1475 } 1476 if (pelements != NULL) { 1477 FREE_C_HEAP_ARRAY(char*, pelements); 1478 } 1479 } else { 1480 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1481 retval = true; 1482 } 1483 return retval; 1484} 1485 1486// check if addr is inside libjvm.so 1487bool os::address_is_in_vm(address addr) { 1488 static address libjvm_base_addr; 1489 Dl_info dlinfo; 1490 1491 if (libjvm_base_addr == NULL) { 1492 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1493 libjvm_base_addr = (address)dlinfo.dli_fbase; 1494 } 1495 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1496 } 1497 1498 if (dladdr((void *)addr, &dlinfo) != 0) { 1499 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1500 } 1501 1502 return false; 1503} 1504 1505bool os::dll_address_to_function_name(address addr, char *buf, 1506 int buflen, int *offset, 1507 bool demangle) { 1508 // buf is not optional, but offset is optional 1509 assert(buf != NULL, "sanity check"); 1510 1511 Dl_info dlinfo; 1512 1513 if (dladdr((void*)addr, &dlinfo) != 0) { 1514 // see if we have a matching symbol 1515 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1516 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1517 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1518 } 1519 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1520 return true; 1521 } 1522 // no matching symbol so try for just file info 1523 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1524 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1525 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1526 return true; 1527 } 1528 } 1529 } 1530 1531 buf[0] = '\0'; 1532 if (offset != NULL) *offset = -1; 1533 return false; 1534} 1535 1536struct _address_to_library_name { 1537 address addr; // input : memory address 1538 size_t buflen; // size of fname 1539 char* fname; // output: library name 1540 address base; // library base addr 1541}; 1542 1543static int address_to_library_name_callback(struct dl_phdr_info *info, 1544 size_t size, void *data) { 1545 int i; 1546 bool found = false; 1547 address libbase = NULL; 1548 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1549 1550 // iterate through all loadable segments 1551 for (i = 0; i < info->dlpi_phnum; i++) { 1552 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1553 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1554 // base address of a library is the lowest address of its loaded 1555 // segments. 1556 if (libbase == NULL || libbase > segbase) { 1557 libbase = segbase; 1558 } 1559 // see if 'addr' is within current segment 1560 if (segbase <= d->addr && 1561 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1562 found = true; 1563 } 1564 } 1565 } 1566 1567 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1568 // so dll_address_to_library_name() can fall through to use dladdr() which 1569 // can figure out executable name from argv[0]. 1570 if (found && info->dlpi_name && info->dlpi_name[0]) { 1571 d->base = libbase; 1572 if (d->fname) { 1573 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1574 } 1575 return 1; 1576 } 1577 return 0; 1578} 1579 1580bool os::dll_address_to_library_name(address addr, char* buf, 1581 int buflen, int* offset) { 1582 // buf is not optional, but offset is optional 1583 assert(buf != NULL, "sanity check"); 1584 1585 Dl_info dlinfo; 1586 struct _address_to_library_name data; 1587 1588 // There is a bug in old glibc dladdr() implementation that it could resolve 1589 // to wrong library name if the .so file has a base address != NULL. Here 1590 // we iterate through the program headers of all loaded libraries to find 1591 // out which library 'addr' really belongs to. This workaround can be 1592 // removed once the minimum requirement for glibc is moved to 2.3.x. 1593 data.addr = addr; 1594 data.fname = buf; 1595 data.buflen = buflen; 1596 data.base = NULL; 1597 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1598 1599 if (rslt) { 1600 // buf already contains library name 1601 if (offset) *offset = addr - data.base; 1602 return true; 1603 } 1604 if (dladdr((void*)addr, &dlinfo) != 0) { 1605 if (dlinfo.dli_fname != NULL) { 1606 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1607 } 1608 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1609 *offset = addr - (address)dlinfo.dli_fbase; 1610 } 1611 return true; 1612 } 1613 1614 buf[0] = '\0'; 1615 if (offset) *offset = -1; 1616 return false; 1617} 1618 1619// Loads .dll/.so and 1620// in case of error it checks if .dll/.so was built for the 1621// same architecture as Hotspot is running on 1622 1623 1624// Remember the stack's state. The Linux dynamic linker will change 1625// the stack to 'executable' at most once, so we must safepoint only once. 1626bool os::Linux::_stack_is_executable = false; 1627 1628// VM operation that loads a library. This is necessary if stack protection 1629// of the Java stacks can be lost during loading the library. If we 1630// do not stop the Java threads, they can stack overflow before the stacks 1631// are protected again. 1632class VM_LinuxDllLoad: public VM_Operation { 1633 private: 1634 const char *_filename; 1635 char *_ebuf; 1636 int _ebuflen; 1637 void *_lib; 1638 public: 1639 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1640 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1641 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1642 void doit() { 1643 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1644 os::Linux::_stack_is_executable = true; 1645 } 1646 void* loaded_library() { return _lib; } 1647}; 1648 1649void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1650 void * result = NULL; 1651 bool load_attempted = false; 1652 1653 // Check whether the library to load might change execution rights 1654 // of the stack. If they are changed, the protection of the stack 1655 // guard pages will be lost. We need a safepoint to fix this. 1656 // 1657 // See Linux man page execstack(8) for more info. 1658 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1659 ElfFile ef(filename); 1660 if (!ef.specifies_noexecstack()) { 1661 if (!is_init_completed()) { 1662 os::Linux::_stack_is_executable = true; 1663 // This is OK - No Java threads have been created yet, and hence no 1664 // stack guard pages to fix. 1665 // 1666 // This should happen only when you are building JDK7 using a very 1667 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1668 // 1669 // Dynamic loader will make all stacks executable after 1670 // this function returns, and will not do that again. 1671 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1672 } else { 1673 warning("You have loaded library %s which might have disabled stack guard. " 1674 "The VM will try to fix the stack guard now.\n" 1675 "It's highly recommended that you fix the library with " 1676 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1677 filename); 1678 1679 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1680 JavaThread *jt = JavaThread::current(); 1681 if (jt->thread_state() != _thread_in_native) { 1682 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1683 // that requires ExecStack. Cannot enter safe point. Let's give up. 1684 warning("Unable to fix stack guard. Giving up."); 1685 } else { 1686 if (!LoadExecStackDllInVMThread) { 1687 // This is for the case where the DLL has an static 1688 // constructor function that executes JNI code. We cannot 1689 // load such DLLs in the VMThread. 1690 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1691 } 1692 1693 ThreadInVMfromNative tiv(jt); 1694 debug_only(VMNativeEntryWrapper vew;) 1695 1696 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1697 VMThread::execute(&op); 1698 if (LoadExecStackDllInVMThread) { 1699 result = op.loaded_library(); 1700 } 1701 load_attempted = true; 1702 } 1703 } 1704 } 1705 } 1706 1707 if (!load_attempted) { 1708 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1709 } 1710 1711 if (result != NULL) { 1712 // Successful loading 1713 return result; 1714 } 1715 1716 Elf32_Ehdr elf_head; 1717 int diag_msg_max_length=ebuflen-strlen(ebuf); 1718 char* diag_msg_buf=ebuf+strlen(ebuf); 1719 1720 if (diag_msg_max_length==0) { 1721 // No more space in ebuf for additional diagnostics message 1722 return NULL; 1723 } 1724 1725 1726 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1727 1728 if (file_descriptor < 0) { 1729 // Can't open library, report dlerror() message 1730 return NULL; 1731 } 1732 1733 bool failed_to_read_elf_head= 1734 (sizeof(elf_head)!= 1735 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1736 1737 ::close(file_descriptor); 1738 if (failed_to_read_elf_head) { 1739 // file i/o error - report dlerror() msg 1740 return NULL; 1741 } 1742 1743 typedef struct { 1744 Elf32_Half code; // Actual value as defined in elf.h 1745 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1746 unsigned char elf_class; // 32 or 64 bit 1747 unsigned char endianess; // MSB or LSB 1748 char* name; // String representation 1749 } arch_t; 1750 1751#ifndef EM_486 1752 #define EM_486 6 /* Intel 80486 */ 1753#endif 1754#ifndef EM_AARCH64 1755 #define EM_AARCH64 183 /* ARM AARCH64 */ 1756#endif 1757 1758 static const arch_t arch_array[]={ 1759 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1760 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1761 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1762 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1763 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1764 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1765 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1766 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1767#if defined(VM_LITTLE_ENDIAN) 1768 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1769#else 1770 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"}, 1771#endif 1772 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1773 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1774 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1775 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1776 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1777 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1778 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1779 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1780 }; 1781 1782#if (defined IA32) 1783 static Elf32_Half running_arch_code=EM_386; 1784#elif (defined AMD64) 1785 static Elf32_Half running_arch_code=EM_X86_64; 1786#elif (defined IA64) 1787 static Elf32_Half running_arch_code=EM_IA_64; 1788#elif (defined __sparc) && (defined _LP64) 1789 static Elf32_Half running_arch_code=EM_SPARCV9; 1790#elif (defined __sparc) && (!defined _LP64) 1791 static Elf32_Half running_arch_code=EM_SPARC; 1792#elif (defined __powerpc64__) 1793 static Elf32_Half running_arch_code=EM_PPC64; 1794#elif (defined __powerpc__) 1795 static Elf32_Half running_arch_code=EM_PPC; 1796#elif (defined ARM) 1797 static Elf32_Half running_arch_code=EM_ARM; 1798#elif (defined S390) 1799 static Elf32_Half running_arch_code=EM_S390; 1800#elif (defined ALPHA) 1801 static Elf32_Half running_arch_code=EM_ALPHA; 1802#elif (defined MIPSEL) 1803 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1804#elif (defined PARISC) 1805 static Elf32_Half running_arch_code=EM_PARISC; 1806#elif (defined MIPS) 1807 static Elf32_Half running_arch_code=EM_MIPS; 1808#elif (defined M68K) 1809 static Elf32_Half running_arch_code=EM_68K; 1810#elif (defined AARCH64) 1811 static Elf32_Half running_arch_code=EM_AARCH64; 1812#else 1813 #error Method os::dll_load requires that one of following is defined:\ 1814 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, AARCH64 1815#endif 1816 1817 // Identify compatability class for VM's architecture and library's architecture 1818 // Obtain string descriptions for architectures 1819 1820 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1821 int running_arch_index=-1; 1822 1823 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1824 if (running_arch_code == arch_array[i].code) { 1825 running_arch_index = i; 1826 } 1827 if (lib_arch.code == arch_array[i].code) { 1828 lib_arch.compat_class = arch_array[i].compat_class; 1829 lib_arch.name = arch_array[i].name; 1830 } 1831 } 1832 1833 assert(running_arch_index != -1, 1834 "Didn't find running architecture code (running_arch_code) in arch_array"); 1835 if (running_arch_index == -1) { 1836 // Even though running architecture detection failed 1837 // we may still continue with reporting dlerror() message 1838 return NULL; 1839 } 1840 1841 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1842 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1843 return NULL; 1844 } 1845 1846#ifndef S390 1847 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1848 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1849 return NULL; 1850 } 1851#endif // !S390 1852 1853 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1854 if (lib_arch.name!=NULL) { 1855 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1856 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1857 lib_arch.name, arch_array[running_arch_index].name); 1858 } else { 1859 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1860 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1861 lib_arch.code, 1862 arch_array[running_arch_index].name); 1863 } 1864 } 1865 1866 return NULL; 1867} 1868 1869void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1870 int ebuflen) { 1871 void * result = ::dlopen(filename, RTLD_LAZY); 1872 if (result == NULL) { 1873 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1874 ebuf[ebuflen-1] = '\0'; 1875 } 1876 return result; 1877} 1878 1879void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1880 int ebuflen) { 1881 void * result = NULL; 1882 if (LoadExecStackDllInVMThread) { 1883 result = dlopen_helper(filename, ebuf, ebuflen); 1884 } 1885 1886 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1887 // library that requires an executable stack, or which does not have this 1888 // stack attribute set, dlopen changes the stack attribute to executable. The 1889 // read protection of the guard pages gets lost. 1890 // 1891 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1892 // may have been queued at the same time. 1893 1894 if (!_stack_is_executable) { 1895 JavaThread *jt = Threads::first(); 1896 1897 while (jt) { 1898 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1899 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1900 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1901 warning("Attempt to reguard stack yellow zone failed."); 1902 } 1903 } 1904 jt = jt->next(); 1905 } 1906 } 1907 1908 return result; 1909} 1910 1911void* os::dll_lookup(void* handle, const char* name) { 1912 void* res = dlsym(handle, name); 1913 return res; 1914} 1915 1916void* os::get_default_process_handle() { 1917 return (void*)::dlopen(NULL, RTLD_LAZY); 1918} 1919 1920static bool _print_ascii_file(const char* filename, outputStream* st) { 1921 int fd = ::open(filename, O_RDONLY); 1922 if (fd == -1) { 1923 return false; 1924 } 1925 1926 char buf[33]; 1927 int bytes; 1928 buf[32] = '\0'; 1929 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1930 st->print_raw(buf, bytes); 1931 } 1932 1933 ::close(fd); 1934 1935 return true; 1936} 1937 1938void os::print_dll_info(outputStream *st) { 1939 st->print_cr("Dynamic libraries:"); 1940 1941 char fname[32]; 1942 pid_t pid = os::Linux::gettid(); 1943 1944 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1945 1946 if (!_print_ascii_file(fname, st)) { 1947 st->print("Can not get library information for pid = %d\n", pid); 1948 } 1949} 1950 1951int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1952 FILE *procmapsFile = NULL; 1953 1954 // Open the procfs maps file for the current process 1955 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1956 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1957 char line[PATH_MAX + 100]; 1958 1959 // Read line by line from 'file' 1960 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1961 u8 base, top, offset, inode; 1962 char permissions[5]; 1963 char device[6]; 1964 char name[PATH_MAX + 1]; 1965 1966 // Parse fields from line 1967 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1968 &base, &top, permissions, &offset, device, &inode, name); 1969 1970 // Filter by device id '00:00' so that we only get file system mapped files. 1971 if (strcmp(device, "00:00") != 0) { 1972 1973 // Call callback with the fields of interest 1974 if(callback(name, (address)base, (address)top, param)) { 1975 // Oops abort, callback aborted 1976 fclose(procmapsFile); 1977 return 1; 1978 } 1979 } 1980 } 1981 fclose(procmapsFile); 1982 } 1983 return 0; 1984} 1985 1986void os::print_os_info_brief(outputStream* st) { 1987 os::Linux::print_distro_info(st); 1988 1989 os::Posix::print_uname_info(st); 1990 1991 os::Linux::print_libversion_info(st); 1992 1993} 1994 1995void os::print_os_info(outputStream* st) { 1996 st->print("OS:"); 1997 1998 os::Linux::print_distro_info(st); 1999 2000 os::Posix::print_uname_info(st); 2001 2002 // Print warning if unsafe chroot environment detected 2003 if (unsafe_chroot_detected) { 2004 st->print("WARNING!! "); 2005 st->print_cr("%s", unstable_chroot_error); 2006 } 2007 2008 os::Linux::print_libversion_info(st); 2009 2010 os::Posix::print_rlimit_info(st); 2011 2012 os::Posix::print_load_average(st); 2013 2014 os::Linux::print_full_memory_info(st); 2015} 2016 2017// Try to identify popular distros. 2018// Most Linux distributions have a /etc/XXX-release file, which contains 2019// the OS version string. Newer Linux distributions have a /etc/lsb-release 2020// file that also contains the OS version string. Some have more than one 2021// /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2022// /etc/redhat-release.), so the order is important. 2023// Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2024// their own specific XXX-release file as well as a redhat-release file. 2025// Because of this the XXX-release file needs to be searched for before the 2026// redhat-release file. 2027// Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 2028// search for redhat-release / SuSE-release needs to be before lsb-release. 2029// Since the lsb-release file is the new standard it needs to be searched 2030// before the older style release files. 2031// Searching system-release (Red Hat) and os-release (other Linuxes) are a 2032// next to last resort. The os-release file is a new standard that contains 2033// distribution information and the system-release file seems to be an old 2034// standard that has been replaced by the lsb-release and os-release files. 2035// Searching for the debian_version file is the last resort. It contains 2036// an informative string like "6.0.6" or "wheezy/sid". Because of this 2037// "Debian " is printed before the contents of the debian_version file. 2038 2039const char* distro_files[] = { 2040 "/etc/oracle-release", 2041 "/etc/mandriva-release", 2042 "/etc/mandrake-release", 2043 "/etc/sun-release", 2044 "/etc/redhat-release", 2045 "/etc/SuSE-release", 2046 "/etc/lsb-release", 2047 "/etc/turbolinux-release", 2048 "/etc/gentoo-release", 2049 "/etc/ltib-release", 2050 "/etc/angstrom-version", 2051 "/etc/system-release", 2052 "/etc/os-release", 2053 NULL }; 2054 2055void os::Linux::print_distro_info(outputStream* st) { 2056 for (int i = 0;; i++) { 2057 const char* file = distro_files[i]; 2058 if (file == NULL) { 2059 break; // done 2060 } 2061 // If file prints, we found it. 2062 if (_print_ascii_file(file, st)) { 2063 return; 2064 } 2065 } 2066 2067 if (file_exists("/etc/debian_version")) { 2068 st->print("Debian "); 2069 _print_ascii_file("/etc/debian_version", st); 2070 } else { 2071 st->print("Linux"); 2072 } 2073 st->cr(); 2074} 2075 2076static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2077 char buf[256]; 2078 while (fgets(buf, sizeof(buf), fp)) { 2079 // Edit out extra stuff in expected format 2080 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2081 char* ptr = strstr(buf, "\""); // the name is in quotes 2082 if (ptr != NULL) { 2083 ptr++; // go beyond first quote 2084 char* nl = strchr(ptr, '\"'); 2085 if (nl != NULL) *nl = '\0'; 2086 strncpy(distro, ptr, length); 2087 } else { 2088 ptr = strstr(buf, "="); 2089 ptr++; // go beyond equals then 2090 char* nl = strchr(ptr, '\n'); 2091 if (nl != NULL) *nl = '\0'; 2092 strncpy(distro, ptr, length); 2093 } 2094 return; 2095 } else if (get_first_line) { 2096 char* nl = strchr(buf, '\n'); 2097 if (nl != NULL) *nl = '\0'; 2098 strncpy(distro, buf, length); 2099 return; 2100 } 2101 } 2102 // print last line and close 2103 char* nl = strchr(buf, '\n'); 2104 if (nl != NULL) *nl = '\0'; 2105 strncpy(distro, buf, length); 2106} 2107 2108static void parse_os_info(char* distro, size_t length, const char* file) { 2109 FILE* fp = fopen(file, "r"); 2110 if (fp != NULL) { 2111 // if suse format, print out first line 2112 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2113 parse_os_info_helper(fp, distro, length, get_first_line); 2114 fclose(fp); 2115 } 2116} 2117 2118void os::get_summary_os_info(char* buf, size_t buflen) { 2119 for (int i = 0;; i++) { 2120 const char* file = distro_files[i]; 2121 if (file == NULL) { 2122 break; // ran out of distro_files 2123 } 2124 if (file_exists(file)) { 2125 parse_os_info(buf, buflen, file); 2126 return; 2127 } 2128 } 2129 // special case for debian 2130 if (file_exists("/etc/debian_version")) { 2131 strncpy(buf, "Debian ", buflen); 2132 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2133 } else { 2134 strncpy(buf, "Linux", buflen); 2135 } 2136} 2137 2138void os::Linux::print_libversion_info(outputStream* st) { 2139 // libc, pthread 2140 st->print("libc:"); 2141 st->print("%s ", os::Linux::glibc_version()); 2142 st->print("%s ", os::Linux::libpthread_version()); 2143 st->cr(); 2144} 2145 2146void os::Linux::print_full_memory_info(outputStream* st) { 2147 st->print("\n/proc/meminfo:\n"); 2148 _print_ascii_file("/proc/meminfo", st); 2149 st->cr(); 2150} 2151 2152void os::print_memory_info(outputStream* st) { 2153 2154 st->print("Memory:"); 2155 st->print(" %dk page", os::vm_page_size()>>10); 2156 2157 // values in struct sysinfo are "unsigned long" 2158 struct sysinfo si; 2159 sysinfo(&si); 2160 2161 st->print(", physical " UINT64_FORMAT "k", 2162 os::physical_memory() >> 10); 2163 st->print("(" UINT64_FORMAT "k free)", 2164 os::available_memory() >> 10); 2165 st->print(", swap " UINT64_FORMAT "k", 2166 ((jlong)si.totalswap * si.mem_unit) >> 10); 2167 st->print("(" UINT64_FORMAT "k free)", 2168 ((jlong)si.freeswap * si.mem_unit) >> 10); 2169 st->cr(); 2170} 2171 2172// Print the first "model name" line and the first "flags" line 2173// that we find and nothing more. We assume "model name" comes 2174// before "flags" so if we find a second "model name", then the 2175// "flags" field is considered missing. 2176static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2177#if defined(IA32) || defined(AMD64) 2178 // Other platforms have less repetitive cpuinfo files 2179 FILE *fp = fopen("/proc/cpuinfo", "r"); 2180 if (fp) { 2181 while (!feof(fp)) { 2182 if (fgets(buf, buflen, fp)) { 2183 // Assume model name comes before flags 2184 bool model_name_printed = false; 2185 if (strstr(buf, "model name") != NULL) { 2186 if (!model_name_printed) { 2187 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2188 st->print_raw(buf); 2189 model_name_printed = true; 2190 } else { 2191 // model name printed but not flags? Odd, just return 2192 fclose(fp); 2193 return true; 2194 } 2195 } 2196 // print the flags line too 2197 if (strstr(buf, "flags") != NULL) { 2198 st->print_raw(buf); 2199 fclose(fp); 2200 return true; 2201 } 2202 } 2203 } 2204 fclose(fp); 2205 } 2206#endif // x86 platforms 2207 return false; 2208} 2209 2210void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2211 // Only print the model name if the platform provides this as a summary 2212 if (!print_model_name_and_flags(st, buf, buflen)) { 2213 st->print("\n/proc/cpuinfo:\n"); 2214 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2215 st->print_cr(" <Not Available>"); 2216 } 2217 } 2218} 2219 2220#if defined(AMD64) || defined(IA32) || defined(X32) 2221const char* search_string = "model name"; 2222#elif defined(SPARC) 2223const char* search_string = "cpu"; 2224#elif defined(PPC64) 2225const char* search_string = "cpu"; 2226#else 2227const char* search_string = "Processor"; 2228#endif 2229 2230// Parses the cpuinfo file for string representing the model name. 2231void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2232 FILE* fp = fopen("/proc/cpuinfo", "r"); 2233 if (fp != NULL) { 2234 while (!feof(fp)) { 2235 char buf[256]; 2236 if (fgets(buf, sizeof(buf), fp)) { 2237 char* start = strstr(buf, search_string); 2238 if (start != NULL) { 2239 char *ptr = start + strlen(search_string); 2240 char *end = buf + strlen(buf); 2241 while (ptr != end) { 2242 // skip whitespace and colon for the rest of the name. 2243 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2244 break; 2245 } 2246 ptr++; 2247 } 2248 if (ptr != end) { 2249 // reasonable string, get rid of newline and keep the rest 2250 char* nl = strchr(buf, '\n'); 2251 if (nl != NULL) *nl = '\0'; 2252 strncpy(cpuinfo, ptr, length); 2253 fclose(fp); 2254 return; 2255 } 2256 } 2257 } 2258 } 2259 fclose(fp); 2260 } 2261 // cpuinfo not found or parsing failed, just print generic string. The entire 2262 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2263#if defined(AMD64) 2264 strncpy(cpuinfo, "x86_64", length); 2265#elif defined(IA32) 2266 strncpy(cpuinfo, "x86_32", length); 2267#elif defined(IA64) 2268 strncpy(cpuinfo, "IA64", length); 2269#elif defined(SPARC) 2270 strncpy(cpuinfo, "sparcv9", length); 2271#elif defined(AARCH64) 2272 strncpy(cpuinfo, "AArch64", length); 2273#elif defined(ARM) 2274 strncpy(cpuinfo, "ARM", length); 2275#elif defined(PPC) 2276 strncpy(cpuinfo, "PPC64", length); 2277#elif defined(ZERO_LIBARCH) 2278 strncpy(cpuinfo, ZERO_LIBARCH, length); 2279#else 2280 strncpy(cpuinfo, "unknown", length); 2281#endif 2282} 2283 2284static void print_signal_handler(outputStream* st, int sig, 2285 char* buf, size_t buflen); 2286 2287void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2288 st->print_cr("Signal Handlers:"); 2289 print_signal_handler(st, SIGSEGV, buf, buflen); 2290 print_signal_handler(st, SIGBUS , buf, buflen); 2291 print_signal_handler(st, SIGFPE , buf, buflen); 2292 print_signal_handler(st, SIGPIPE, buf, buflen); 2293 print_signal_handler(st, SIGXFSZ, buf, buflen); 2294 print_signal_handler(st, SIGILL , buf, buflen); 2295 print_signal_handler(st, SR_signum, buf, buflen); 2296 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2297 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2298 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2299 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2300#if defined(PPC64) 2301 print_signal_handler(st, SIGTRAP, buf, buflen); 2302#endif 2303} 2304 2305static char saved_jvm_path[MAXPATHLEN] = {0}; 2306 2307// Find the full path to the current module, libjvm.so 2308void os::jvm_path(char *buf, jint buflen) { 2309 // Error checking. 2310 if (buflen < MAXPATHLEN) { 2311 assert(false, "must use a large-enough buffer"); 2312 buf[0] = '\0'; 2313 return; 2314 } 2315 // Lazy resolve the path to current module. 2316 if (saved_jvm_path[0] != 0) { 2317 strcpy(buf, saved_jvm_path); 2318 return; 2319 } 2320 2321 char dli_fname[MAXPATHLEN]; 2322 bool ret = dll_address_to_library_name( 2323 CAST_FROM_FN_PTR(address, os::jvm_path), 2324 dli_fname, sizeof(dli_fname), NULL); 2325 assert(ret, "cannot locate libjvm"); 2326 char *rp = NULL; 2327 if (ret && dli_fname[0] != '\0') { 2328 rp = realpath(dli_fname, buf); 2329 } 2330 if (rp == NULL) { 2331 return; 2332 } 2333 2334 if (Arguments::sun_java_launcher_is_altjvm()) { 2335 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2336 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". 2337 // If "/jre/lib/" appears at the right place in the string, then 2338 // assume we are installed in a JDK and we're done. Otherwise, check 2339 // for a JAVA_HOME environment variable and fix up the path so it 2340 // looks like libjvm.so is installed there (append a fake suffix 2341 // hotspot/libjvm.so). 2342 const char *p = buf + strlen(buf) - 1; 2343 for (int count = 0; p > buf && count < 5; ++count) { 2344 for (--p; p > buf && *p != '/'; --p) 2345 /* empty */ ; 2346 } 2347 2348 if (strncmp(p, "/jre/lib/", 9) != 0) { 2349 // Look for JAVA_HOME in the environment. 2350 char* java_home_var = ::getenv("JAVA_HOME"); 2351 if (java_home_var != NULL && java_home_var[0] != 0) { 2352 char* jrelib_p; 2353 int len; 2354 2355 // Check the current module name "libjvm.so". 2356 p = strrchr(buf, '/'); 2357 if (p == NULL) { 2358 return; 2359 } 2360 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2361 2362 rp = realpath(java_home_var, buf); 2363 if (rp == NULL) { 2364 return; 2365 } 2366 2367 // determine if this is a legacy image or modules image 2368 // modules image doesn't have "jre" subdirectory 2369 len = strlen(buf); 2370 assert(len < buflen, "Ran out of buffer room"); 2371 jrelib_p = buf + len; 2372 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2373 if (0 != access(buf, F_OK)) { 2374 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2375 } 2376 2377 if (0 == access(buf, F_OK)) { 2378 // Use current module name "libjvm.so" 2379 len = strlen(buf); 2380 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2381 } else { 2382 // Go back to path of .so 2383 rp = realpath(dli_fname, buf); 2384 if (rp == NULL) { 2385 return; 2386 } 2387 } 2388 } 2389 } 2390 } 2391 2392 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2393 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2394} 2395 2396void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2397 // no prefix required, not even "_" 2398} 2399 2400void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2401 // no suffix required 2402} 2403 2404//////////////////////////////////////////////////////////////////////////////// 2405// sun.misc.Signal support 2406 2407static volatile jint sigint_count = 0; 2408 2409static void UserHandler(int sig, void *siginfo, void *context) { 2410 // 4511530 - sem_post is serialized and handled by the manager thread. When 2411 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2412 // don't want to flood the manager thread with sem_post requests. 2413 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2414 return; 2415 } 2416 2417 // Ctrl-C is pressed during error reporting, likely because the error 2418 // handler fails to abort. Let VM die immediately. 2419 if (sig == SIGINT && is_error_reported()) { 2420 os::die(); 2421 } 2422 2423 os::signal_notify(sig); 2424} 2425 2426void* os::user_handler() { 2427 return CAST_FROM_FN_PTR(void*, UserHandler); 2428} 2429 2430struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2431 struct timespec ts; 2432 // Semaphore's are always associated with CLOCK_REALTIME 2433 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2434 // see unpackTime for discussion on overflow checking 2435 if (sec >= MAX_SECS) { 2436 ts.tv_sec += MAX_SECS; 2437 ts.tv_nsec = 0; 2438 } else { 2439 ts.tv_sec += sec; 2440 ts.tv_nsec += nsec; 2441 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2442 ts.tv_nsec -= NANOSECS_PER_SEC; 2443 ++ts.tv_sec; // note: this must be <= max_secs 2444 } 2445 } 2446 2447 return ts; 2448} 2449 2450extern "C" { 2451 typedef void (*sa_handler_t)(int); 2452 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2453} 2454 2455void* os::signal(int signal_number, void* handler) { 2456 struct sigaction sigAct, oldSigAct; 2457 2458 sigfillset(&(sigAct.sa_mask)); 2459 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2460 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2461 2462 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2463 // -1 means registration failed 2464 return (void *)-1; 2465 } 2466 2467 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2468} 2469 2470void os::signal_raise(int signal_number) { 2471 ::raise(signal_number); 2472} 2473 2474// The following code is moved from os.cpp for making this 2475// code platform specific, which it is by its very nature. 2476 2477// Will be modified when max signal is changed to be dynamic 2478int os::sigexitnum_pd() { 2479 return NSIG; 2480} 2481 2482// a counter for each possible signal value 2483static volatile jint pending_signals[NSIG+1] = { 0 }; 2484 2485// Linux(POSIX) specific hand shaking semaphore. 2486static sem_t sig_sem; 2487static PosixSemaphore sr_semaphore; 2488 2489void os::signal_init_pd() { 2490 // Initialize signal structures 2491 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2492 2493 // Initialize signal semaphore 2494 ::sem_init(&sig_sem, 0, 0); 2495} 2496 2497void os::signal_notify(int sig) { 2498 Atomic::inc(&pending_signals[sig]); 2499 ::sem_post(&sig_sem); 2500} 2501 2502static int check_pending_signals(bool wait) { 2503 Atomic::store(0, &sigint_count); 2504 for (;;) { 2505 for (int i = 0; i < NSIG + 1; i++) { 2506 jint n = pending_signals[i]; 2507 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2508 return i; 2509 } 2510 } 2511 if (!wait) { 2512 return -1; 2513 } 2514 JavaThread *thread = JavaThread::current(); 2515 ThreadBlockInVM tbivm(thread); 2516 2517 bool threadIsSuspended; 2518 do { 2519 thread->set_suspend_equivalent(); 2520 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2521 ::sem_wait(&sig_sem); 2522 2523 // were we externally suspended while we were waiting? 2524 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2525 if (threadIsSuspended) { 2526 // The semaphore has been incremented, but while we were waiting 2527 // another thread suspended us. We don't want to continue running 2528 // while suspended because that would surprise the thread that 2529 // suspended us. 2530 ::sem_post(&sig_sem); 2531 2532 thread->java_suspend_self(); 2533 } 2534 } while (threadIsSuspended); 2535 } 2536} 2537 2538int os::signal_lookup() { 2539 return check_pending_signals(false); 2540} 2541 2542int os::signal_wait() { 2543 return check_pending_signals(true); 2544} 2545 2546//////////////////////////////////////////////////////////////////////////////// 2547// Virtual Memory 2548 2549int os::vm_page_size() { 2550 // Seems redundant as all get out 2551 assert(os::Linux::page_size() != -1, "must call os::init"); 2552 return os::Linux::page_size(); 2553} 2554 2555// Solaris allocates memory by pages. 2556int os::vm_allocation_granularity() { 2557 assert(os::Linux::page_size() != -1, "must call os::init"); 2558 return os::Linux::page_size(); 2559} 2560 2561// Rationale behind this function: 2562// current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2563// mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2564// samples for JITted code. Here we create private executable mapping over the code cache 2565// and then we can use standard (well, almost, as mapping can change) way to provide 2566// info for the reporting script by storing timestamp and location of symbol 2567void linux_wrap_code(char* base, size_t size) { 2568 static volatile jint cnt = 0; 2569 2570 if (!UseOprofile) { 2571 return; 2572 } 2573 2574 char buf[PATH_MAX+1]; 2575 int num = Atomic::add(1, &cnt); 2576 2577 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2578 os::get_temp_directory(), os::current_process_id(), num); 2579 unlink(buf); 2580 2581 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2582 2583 if (fd != -1) { 2584 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2585 if (rv != (off_t)-1) { 2586 if (::write(fd, "", 1) == 1) { 2587 mmap(base, size, 2588 PROT_READ|PROT_WRITE|PROT_EXEC, 2589 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2590 } 2591 } 2592 ::close(fd); 2593 unlink(buf); 2594 } 2595} 2596 2597static bool recoverable_mmap_error(int err) { 2598 // See if the error is one we can let the caller handle. This 2599 // list of errno values comes from JBS-6843484. I can't find a 2600 // Linux man page that documents this specific set of errno 2601 // values so while this list currently matches Solaris, it may 2602 // change as we gain experience with this failure mode. 2603 switch (err) { 2604 case EBADF: 2605 case EINVAL: 2606 case ENOTSUP: 2607 // let the caller deal with these errors 2608 return true; 2609 2610 default: 2611 // Any remaining errors on this OS can cause our reserved mapping 2612 // to be lost. That can cause confusion where different data 2613 // structures think they have the same memory mapped. The worst 2614 // scenario is if both the VM and a library think they have the 2615 // same memory mapped. 2616 return false; 2617 } 2618} 2619 2620static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2621 int err) { 2622 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2623 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2624 os::strerror(err), err); 2625} 2626 2627static void warn_fail_commit_memory(char* addr, size_t size, 2628 size_t alignment_hint, bool exec, 2629 int err) { 2630 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2631 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2632 alignment_hint, exec, os::strerror(err), err); 2633} 2634 2635// NOTE: Linux kernel does not really reserve the pages for us. 2636// All it does is to check if there are enough free pages 2637// left at the time of mmap(). This could be a potential 2638// problem. 2639int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2640 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2641 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2642 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2643 if (res != (uintptr_t) MAP_FAILED) { 2644 if (UseNUMAInterleaving) { 2645 numa_make_global(addr, size); 2646 } 2647 return 0; 2648 } 2649 2650 int err = errno; // save errno from mmap() call above 2651 2652 if (!recoverable_mmap_error(err)) { 2653 warn_fail_commit_memory(addr, size, exec, err); 2654 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2655 } 2656 2657 return err; 2658} 2659 2660bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2661 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2662} 2663 2664void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2665 const char* mesg) { 2666 assert(mesg != NULL, "mesg must be specified"); 2667 int err = os::Linux::commit_memory_impl(addr, size, exec); 2668 if (err != 0) { 2669 // the caller wants all commit errors to exit with the specified mesg: 2670 warn_fail_commit_memory(addr, size, exec, err); 2671 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2672 } 2673} 2674 2675// Define MAP_HUGETLB here so we can build HotSpot on old systems. 2676#ifndef MAP_HUGETLB 2677 #define MAP_HUGETLB 0x40000 2678#endif 2679 2680// Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2681#ifndef MADV_HUGEPAGE 2682 #define MADV_HUGEPAGE 14 2683#endif 2684 2685int os::Linux::commit_memory_impl(char* addr, size_t size, 2686 size_t alignment_hint, bool exec) { 2687 int err = os::Linux::commit_memory_impl(addr, size, exec); 2688 if (err == 0) { 2689 realign_memory(addr, size, alignment_hint); 2690 } 2691 return err; 2692} 2693 2694bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2695 bool exec) { 2696 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2697} 2698 2699void os::pd_commit_memory_or_exit(char* addr, size_t size, 2700 size_t alignment_hint, bool exec, 2701 const char* mesg) { 2702 assert(mesg != NULL, "mesg must be specified"); 2703 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2704 if (err != 0) { 2705 // the caller wants all commit errors to exit with the specified mesg: 2706 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2707 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2708 } 2709} 2710 2711void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2712 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2713 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2714 // be supported or the memory may already be backed by huge pages. 2715 ::madvise(addr, bytes, MADV_HUGEPAGE); 2716 } 2717} 2718 2719void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2720 // This method works by doing an mmap over an existing mmaping and effectively discarding 2721 // the existing pages. However it won't work for SHM-based large pages that cannot be 2722 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2723 // small pages on top of the SHM segment. This method always works for small pages, so we 2724 // allow that in any case. 2725 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2726 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2727 } 2728} 2729 2730void os::numa_make_global(char *addr, size_t bytes) { 2731 Linux::numa_interleave_memory(addr, bytes); 2732} 2733 2734// Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2735// bind policy to MPOL_PREFERRED for the current thread. 2736#define USE_MPOL_PREFERRED 0 2737 2738void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2739 // To make NUMA and large pages more robust when both enabled, we need to ease 2740 // the requirements on where the memory should be allocated. MPOL_BIND is the 2741 // default policy and it will force memory to be allocated on the specified 2742 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2743 // the specified node, but will not force it. Using this policy will prevent 2744 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2745 // free large pages. 2746 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2747 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2748} 2749 2750bool os::numa_topology_changed() { return false; } 2751 2752size_t os::numa_get_groups_num() { 2753 int max_node = Linux::numa_max_node(); 2754 return max_node > 0 ? max_node + 1 : 1; 2755} 2756 2757int os::numa_get_group_id() { 2758 int cpu_id = Linux::sched_getcpu(); 2759 if (cpu_id != -1) { 2760 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2761 if (lgrp_id != -1) { 2762 return lgrp_id; 2763 } 2764 } 2765 return 0; 2766} 2767 2768size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2769 for (size_t i = 0; i < size; i++) { 2770 ids[i] = i; 2771 } 2772 return size; 2773} 2774 2775bool os::get_page_info(char *start, page_info* info) { 2776 return false; 2777} 2778 2779char *os::scan_pages(char *start, char* end, page_info* page_expected, 2780 page_info* page_found) { 2781 return end; 2782} 2783 2784 2785int os::Linux::sched_getcpu_syscall(void) { 2786 unsigned int cpu = 0; 2787 int retval = -1; 2788 2789#if defined(IA32) 2790 #ifndef SYS_getcpu 2791 #define SYS_getcpu 318 2792 #endif 2793 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2794#elif defined(AMD64) 2795// Unfortunately we have to bring all these macros here from vsyscall.h 2796// to be able to compile on old linuxes. 2797 #define __NR_vgetcpu 2 2798 #define VSYSCALL_START (-10UL << 20) 2799 #define VSYSCALL_SIZE 1024 2800 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2801 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2802 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2803 retval = vgetcpu(&cpu, NULL, NULL); 2804#endif 2805 2806 return (retval == -1) ? retval : cpu; 2807} 2808 2809// Something to do with the numa-aware allocator needs these symbols 2810extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2811extern "C" JNIEXPORT void numa_error(char *where) { } 2812 2813 2814// If we are running with libnuma version > 2, then we should 2815// be trying to use symbols with versions 1.1 2816// If we are running with earlier version, which did not have symbol versions, 2817// we should use the base version. 2818void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2819 void *f = dlvsym(handle, name, "libnuma_1.1"); 2820 if (f == NULL) { 2821 f = dlsym(handle, name); 2822 } 2823 return f; 2824} 2825 2826bool os::Linux::libnuma_init() { 2827 // sched_getcpu() should be in libc. 2828 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2829 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2830 2831 // If it's not, try a direct syscall. 2832 if (sched_getcpu() == -1) { 2833 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2834 (void*)&sched_getcpu_syscall)); 2835 } 2836 2837 if (sched_getcpu() != -1) { // Does it work? 2838 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2839 if (handle != NULL) { 2840 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2841 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2842 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2843 libnuma_dlsym(handle, "numa_max_node"))); 2844 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2845 libnuma_dlsym(handle, "numa_available"))); 2846 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2847 libnuma_dlsym(handle, "numa_tonode_memory"))); 2848 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2849 libnuma_dlsym(handle, "numa_interleave_memory"))); 2850 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2851 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2852 2853 2854 if (numa_available() != -1) { 2855 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2856 // Create a cpu -> node mapping 2857 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2858 rebuild_cpu_to_node_map(); 2859 return true; 2860 } 2861 } 2862 } 2863 return false; 2864} 2865 2866// rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2867// The table is later used in get_node_by_cpu(). 2868void os::Linux::rebuild_cpu_to_node_map() { 2869 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2870 // in libnuma (possible values are starting from 16, 2871 // and continuing up with every other power of 2, but less 2872 // than the maximum number of CPUs supported by kernel), and 2873 // is a subject to change (in libnuma version 2 the requirements 2874 // are more reasonable) we'll just hardcode the number they use 2875 // in the library. 2876 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2877 2878 size_t cpu_num = os::active_processor_count(); 2879 size_t cpu_map_size = NCPUS / BitsPerCLong; 2880 size_t cpu_map_valid_size = 2881 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2882 2883 cpu_to_node()->clear(); 2884 cpu_to_node()->at_grow(cpu_num - 1); 2885 size_t node_num = numa_get_groups_num(); 2886 2887 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2888 for (size_t i = 0; i < node_num; i++) { 2889 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2890 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2891 if (cpu_map[j] != 0) { 2892 for (size_t k = 0; k < BitsPerCLong; k++) { 2893 if (cpu_map[j] & (1UL << k)) { 2894 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2895 } 2896 } 2897 } 2898 } 2899 } 2900 } 2901 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2902} 2903 2904int os::Linux::get_node_by_cpu(int cpu_id) { 2905 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2906 return cpu_to_node()->at(cpu_id); 2907 } 2908 return -1; 2909} 2910 2911GrowableArray<int>* os::Linux::_cpu_to_node; 2912os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2913os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2914os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2915os::Linux::numa_available_func_t os::Linux::_numa_available; 2916os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2917os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2918os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2919unsigned long* os::Linux::_numa_all_nodes; 2920 2921bool os::pd_uncommit_memory(char* addr, size_t size) { 2922 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2923 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2924 return res != (uintptr_t) MAP_FAILED; 2925} 2926 2927static address get_stack_commited_bottom(address bottom, size_t size) { 2928 address nbot = bottom; 2929 address ntop = bottom + size; 2930 2931 size_t page_sz = os::vm_page_size(); 2932 unsigned pages = size / page_sz; 2933 2934 unsigned char vec[1]; 2935 unsigned imin = 1, imax = pages + 1, imid; 2936 int mincore_return_value = 0; 2937 2938 assert(imin <= imax, "Unexpected page size"); 2939 2940 while (imin < imax) { 2941 imid = (imax + imin) / 2; 2942 nbot = ntop - (imid * page_sz); 2943 2944 // Use a trick with mincore to check whether the page is mapped or not. 2945 // mincore sets vec to 1 if page resides in memory and to 0 if page 2946 // is swapped output but if page we are asking for is unmapped 2947 // it returns -1,ENOMEM 2948 mincore_return_value = mincore(nbot, page_sz, vec); 2949 2950 if (mincore_return_value == -1) { 2951 // Page is not mapped go up 2952 // to find first mapped page 2953 if (errno != EAGAIN) { 2954 assert(errno == ENOMEM, "Unexpected mincore errno"); 2955 imax = imid; 2956 } 2957 } else { 2958 // Page is mapped go down 2959 // to find first not mapped page 2960 imin = imid + 1; 2961 } 2962 } 2963 2964 nbot = nbot + page_sz; 2965 2966 // Adjust stack bottom one page up if last checked page is not mapped 2967 if (mincore_return_value == -1) { 2968 nbot = nbot + page_sz; 2969 } 2970 2971 return nbot; 2972} 2973 2974 2975// Linux uses a growable mapping for the stack, and if the mapping for 2976// the stack guard pages is not removed when we detach a thread the 2977// stack cannot grow beyond the pages where the stack guard was 2978// mapped. If at some point later in the process the stack expands to 2979// that point, the Linux kernel cannot expand the stack any further 2980// because the guard pages are in the way, and a segfault occurs. 2981// 2982// However, it's essential not to split the stack region by unmapping 2983// a region (leaving a hole) that's already part of the stack mapping, 2984// so if the stack mapping has already grown beyond the guard pages at 2985// the time we create them, we have to truncate the stack mapping. 2986// So, we need to know the extent of the stack mapping when 2987// create_stack_guard_pages() is called. 2988 2989// We only need this for stacks that are growable: at the time of 2990// writing thread stacks don't use growable mappings (i.e. those 2991// creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2992// only applies to the main thread. 2993 2994// If the (growable) stack mapping already extends beyond the point 2995// where we're going to put our guard pages, truncate the mapping at 2996// that point by munmap()ping it. This ensures that when we later 2997// munmap() the guard pages we don't leave a hole in the stack 2998// mapping. This only affects the main/initial thread 2999 3000bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3001 if (os::Linux::is_initial_thread()) { 3002 // As we manually grow stack up to bottom inside create_attached_thread(), 3003 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3004 // we don't need to do anything special. 3005 // Check it first, before calling heavy function. 3006 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3007 unsigned char vec[1]; 3008 3009 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3010 // Fallback to slow path on all errors, including EAGAIN 3011 stack_extent = (uintptr_t) get_stack_commited_bottom( 3012 os::Linux::initial_thread_stack_bottom(), 3013 (size_t)addr - stack_extent); 3014 } 3015 3016 if (stack_extent < (uintptr_t)addr) { 3017 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3018 } 3019 } 3020 3021 return os::commit_memory(addr, size, !ExecMem); 3022} 3023 3024// If this is a growable mapping, remove the guard pages entirely by 3025// munmap()ping them. If not, just call uncommit_memory(). This only 3026// affects the main/initial thread, but guard against future OS changes 3027// It's safe to always unmap guard pages for initial thread because we 3028// always place it right after end of the mapped region 3029 3030bool os::remove_stack_guard_pages(char* addr, size_t size) { 3031 uintptr_t stack_extent, stack_base; 3032 3033 if (os::Linux::is_initial_thread()) { 3034 return ::munmap(addr, size) == 0; 3035 } 3036 3037 return os::uncommit_memory(addr, size); 3038} 3039 3040// If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3041// at 'requested_addr'. If there are existing memory mappings at the same 3042// location, however, they will be overwritten. If 'fixed' is false, 3043// 'requested_addr' is only treated as a hint, the return value may or 3044// may not start from the requested address. Unlike Linux mmap(), this 3045// function returns NULL to indicate failure. 3046static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3047 char * addr; 3048 int flags; 3049 3050 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3051 if (fixed) { 3052 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3053 flags |= MAP_FIXED; 3054 } 3055 3056 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3057 // touch an uncommitted page. Otherwise, the read/write might 3058 // succeed if we have enough swap space to back the physical page. 3059 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3060 flags, -1, 0); 3061 3062 return addr == MAP_FAILED ? NULL : addr; 3063} 3064 3065// Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3066// (req_addr != NULL) or with a given alignment. 3067// - bytes shall be a multiple of alignment. 3068// - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3069// - alignment sets the alignment at which memory shall be allocated. 3070// It must be a multiple of allocation granularity. 3071// Returns address of memory or NULL. If req_addr was not NULL, will only return 3072// req_addr or NULL. 3073static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3074 3075 size_t extra_size = bytes; 3076 if (req_addr == NULL && alignment > 0) { 3077 extra_size += alignment; 3078 } 3079 3080 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3081 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3082 -1, 0); 3083 if (start == MAP_FAILED) { 3084 start = NULL; 3085 } else { 3086 if (req_addr != NULL) { 3087 if (start != req_addr) { 3088 ::munmap(start, extra_size); 3089 start = NULL; 3090 } 3091 } else { 3092 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3093 char* const end_aligned = start_aligned + bytes; 3094 char* const end = start + extra_size; 3095 if (start_aligned > start) { 3096 ::munmap(start, start_aligned - start); 3097 } 3098 if (end_aligned < end) { 3099 ::munmap(end_aligned, end - end_aligned); 3100 } 3101 start = start_aligned; 3102 } 3103 } 3104 return start; 3105} 3106 3107static int anon_munmap(char * addr, size_t size) { 3108 return ::munmap(addr, size) == 0; 3109} 3110 3111char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3112 size_t alignment_hint) { 3113 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3114} 3115 3116bool os::pd_release_memory(char* addr, size_t size) { 3117 return anon_munmap(addr, size); 3118} 3119 3120static bool linux_mprotect(char* addr, size_t size, int prot) { 3121 // Linux wants the mprotect address argument to be page aligned. 3122 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3123 3124 // According to SUSv3, mprotect() should only be used with mappings 3125 // established by mmap(), and mmap() always maps whole pages. Unaligned 3126 // 'addr' likely indicates problem in the VM (e.g. trying to change 3127 // protection of malloc'ed or statically allocated memory). Check the 3128 // caller if you hit this assert. 3129 assert(addr == bottom, "sanity check"); 3130 3131 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3132 return ::mprotect(bottom, size, prot) == 0; 3133} 3134 3135// Set protections specified 3136bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3137 bool is_committed) { 3138 unsigned int p = 0; 3139 switch (prot) { 3140 case MEM_PROT_NONE: p = PROT_NONE; break; 3141 case MEM_PROT_READ: p = PROT_READ; break; 3142 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3143 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3144 default: 3145 ShouldNotReachHere(); 3146 } 3147 // is_committed is unused. 3148 return linux_mprotect(addr, bytes, p); 3149} 3150 3151bool os::guard_memory(char* addr, size_t size) { 3152 return linux_mprotect(addr, size, PROT_NONE); 3153} 3154 3155bool os::unguard_memory(char* addr, size_t size) { 3156 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3157} 3158 3159bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3160 size_t page_size) { 3161 bool result = false; 3162 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3163 MAP_ANONYMOUS|MAP_PRIVATE, 3164 -1, 0); 3165 if (p != MAP_FAILED) { 3166 void *aligned_p = align_ptr_up(p, page_size); 3167 3168 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3169 3170 munmap(p, page_size * 2); 3171 } 3172 3173 if (warn && !result) { 3174 warning("TransparentHugePages is not supported by the operating system."); 3175 } 3176 3177 return result; 3178} 3179 3180bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3181 bool result = false; 3182 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3183 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3184 -1, 0); 3185 3186 if (p != MAP_FAILED) { 3187 // We don't know if this really is a huge page or not. 3188 FILE *fp = fopen("/proc/self/maps", "r"); 3189 if (fp) { 3190 while (!feof(fp)) { 3191 char chars[257]; 3192 long x = 0; 3193 if (fgets(chars, sizeof(chars), fp)) { 3194 if (sscanf(chars, "%lx-%*x", &x) == 1 3195 && x == (long)p) { 3196 if (strstr (chars, "hugepage")) { 3197 result = true; 3198 break; 3199 } 3200 } 3201 } 3202 } 3203 fclose(fp); 3204 } 3205 munmap(p, page_size); 3206 } 3207 3208 if (warn && !result) { 3209 warning("HugeTLBFS is not supported by the operating system."); 3210 } 3211 3212 return result; 3213} 3214 3215// Set the coredump_filter bits to include largepages in core dump (bit 6) 3216// 3217// From the coredump_filter documentation: 3218// 3219// - (bit 0) anonymous private memory 3220// - (bit 1) anonymous shared memory 3221// - (bit 2) file-backed private memory 3222// - (bit 3) file-backed shared memory 3223// - (bit 4) ELF header pages in file-backed private memory areas (it is 3224// effective only if the bit 2 is cleared) 3225// - (bit 5) hugetlb private memory 3226// - (bit 6) hugetlb shared memory 3227// 3228static void set_coredump_filter(void) { 3229 FILE *f; 3230 long cdm; 3231 3232 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3233 return; 3234 } 3235 3236 if (fscanf(f, "%lx", &cdm) != 1) { 3237 fclose(f); 3238 return; 3239 } 3240 3241 rewind(f); 3242 3243 if ((cdm & LARGEPAGES_BIT) == 0) { 3244 cdm |= LARGEPAGES_BIT; 3245 fprintf(f, "%#lx", cdm); 3246 } 3247 3248 fclose(f); 3249} 3250 3251// Large page support 3252 3253static size_t _large_page_size = 0; 3254 3255size_t os::Linux::find_large_page_size() { 3256 size_t large_page_size = 0; 3257 3258 // large_page_size on Linux is used to round up heap size. x86 uses either 3259 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3260 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3261 // page as large as 256M. 3262 // 3263 // Here we try to figure out page size by parsing /proc/meminfo and looking 3264 // for a line with the following format: 3265 // Hugepagesize: 2048 kB 3266 // 3267 // If we can't determine the value (e.g. /proc is not mounted, or the text 3268 // format has been changed), we'll use the largest page size supported by 3269 // the processor. 3270 3271#ifndef ZERO 3272 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3273 ARM32_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M); 3274#endif // ZERO 3275 3276 FILE *fp = fopen("/proc/meminfo", "r"); 3277 if (fp) { 3278 while (!feof(fp)) { 3279 int x = 0; 3280 char buf[16]; 3281 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3282 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3283 large_page_size = x * K; 3284 break; 3285 } 3286 } else { 3287 // skip to next line 3288 for (;;) { 3289 int ch = fgetc(fp); 3290 if (ch == EOF || ch == (int)'\n') break; 3291 } 3292 } 3293 } 3294 fclose(fp); 3295 } 3296 3297 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3298 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3299 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3300 proper_unit_for_byte_size(large_page_size)); 3301 } 3302 3303 return large_page_size; 3304} 3305 3306size_t os::Linux::setup_large_page_size() { 3307 _large_page_size = Linux::find_large_page_size(); 3308 const size_t default_page_size = (size_t)Linux::page_size(); 3309 if (_large_page_size > default_page_size) { 3310 _page_sizes[0] = _large_page_size; 3311 _page_sizes[1] = default_page_size; 3312 _page_sizes[2] = 0; 3313 } 3314 3315 return _large_page_size; 3316} 3317 3318bool os::Linux::setup_large_page_type(size_t page_size) { 3319 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3320 FLAG_IS_DEFAULT(UseSHM) && 3321 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3322 3323 // The type of large pages has not been specified by the user. 3324 3325 // Try UseHugeTLBFS and then UseSHM. 3326 UseHugeTLBFS = UseSHM = true; 3327 3328 // Don't try UseTransparentHugePages since there are known 3329 // performance issues with it turned on. This might change in the future. 3330 UseTransparentHugePages = false; 3331 } 3332 3333 if (UseTransparentHugePages) { 3334 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3335 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3336 UseHugeTLBFS = false; 3337 UseSHM = false; 3338 return true; 3339 } 3340 UseTransparentHugePages = false; 3341 } 3342 3343 if (UseHugeTLBFS) { 3344 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3345 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3346 UseSHM = false; 3347 return true; 3348 } 3349 UseHugeTLBFS = false; 3350 } 3351 3352 return UseSHM; 3353} 3354 3355void os::large_page_init() { 3356 if (!UseLargePages && 3357 !UseTransparentHugePages && 3358 !UseHugeTLBFS && 3359 !UseSHM) { 3360 // Not using large pages. 3361 return; 3362 } 3363 3364 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3365 // The user explicitly turned off large pages. 3366 // Ignore the rest of the large pages flags. 3367 UseTransparentHugePages = false; 3368 UseHugeTLBFS = false; 3369 UseSHM = false; 3370 return; 3371 } 3372 3373 size_t large_page_size = Linux::setup_large_page_size(); 3374 UseLargePages = Linux::setup_large_page_type(large_page_size); 3375 3376 set_coredump_filter(); 3377} 3378 3379#ifndef SHM_HUGETLB 3380 #define SHM_HUGETLB 04000 3381#endif 3382 3383#define shm_warning_format(format, ...) \ 3384 do { \ 3385 if (UseLargePages && \ 3386 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3387 !FLAG_IS_DEFAULT(UseSHM) || \ 3388 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3389 warning(format, __VA_ARGS__); \ 3390 } \ 3391 } while (0) 3392 3393#define shm_warning(str) shm_warning_format("%s", str) 3394 3395#define shm_warning_with_errno(str) \ 3396 do { \ 3397 int err = errno; \ 3398 shm_warning_format(str " (error = %d)", err); \ 3399 } while (0) 3400 3401static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3402 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment"); 3403 3404 if (!is_size_aligned(alignment, SHMLBA)) { 3405 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3406 return NULL; 3407 } 3408 3409 // To ensure that we get 'alignment' aligned memory from shmat, 3410 // we pre-reserve aligned virtual memory and then attach to that. 3411 3412 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3413 if (pre_reserved_addr == NULL) { 3414 // Couldn't pre-reserve aligned memory. 3415 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3416 return NULL; 3417 } 3418 3419 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3420 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3421 3422 if ((intptr_t)addr == -1) { 3423 int err = errno; 3424 shm_warning_with_errno("Failed to attach shared memory."); 3425 3426 assert(err != EACCES, "Unexpected error"); 3427 assert(err != EIDRM, "Unexpected error"); 3428 assert(err != EINVAL, "Unexpected error"); 3429 3430 // Since we don't know if the kernel unmapped the pre-reserved memory area 3431 // we can't unmap it, since that would potentially unmap memory that was 3432 // mapped from other threads. 3433 return NULL; 3434 } 3435 3436 return addr; 3437} 3438 3439static char* shmat_at_address(int shmid, char* req_addr) { 3440 if (!is_ptr_aligned(req_addr, SHMLBA)) { 3441 assert(false, "Requested address needs to be SHMLBA aligned"); 3442 return NULL; 3443 } 3444 3445 char* addr = (char*)shmat(shmid, req_addr, 0); 3446 3447 if ((intptr_t)addr == -1) { 3448 shm_warning_with_errno("Failed to attach shared memory."); 3449 return NULL; 3450 } 3451 3452 return addr; 3453} 3454 3455static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3456 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3457 if (req_addr != NULL) { 3458 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3459 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3460 return shmat_at_address(shmid, req_addr); 3461 } 3462 3463 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3464 // return large page size aligned memory addresses when req_addr == NULL. 3465 // However, if the alignment is larger than the large page size, we have 3466 // to manually ensure that the memory returned is 'alignment' aligned. 3467 if (alignment > os::large_page_size()) { 3468 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3469 return shmat_with_alignment(shmid, bytes, alignment); 3470 } else { 3471 return shmat_at_address(shmid, NULL); 3472 } 3473} 3474 3475char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3476 char* req_addr, bool exec) { 3477 // "exec" is passed in but not used. Creating the shared image for 3478 // the code cache doesn't have an SHM_X executable permission to check. 3479 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3480 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3481 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address"); 3482 3483 if (!is_size_aligned(bytes, os::large_page_size())) { 3484 return NULL; // Fallback to small pages. 3485 } 3486 3487 // Create a large shared memory region to attach to based on size. 3488 // Currently, size is the total size of the heap. 3489 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3490 if (shmid == -1) { 3491 // Possible reasons for shmget failure: 3492 // 1. shmmax is too small for Java heap. 3493 // > check shmmax value: cat /proc/sys/kernel/shmmax 3494 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3495 // 2. not enough large page memory. 3496 // > check available large pages: cat /proc/meminfo 3497 // > increase amount of large pages: 3498 // echo new_value > /proc/sys/vm/nr_hugepages 3499 // Note 1: different Linux may use different name for this property, 3500 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3501 // Note 2: it's possible there's enough physical memory available but 3502 // they are so fragmented after a long run that they can't 3503 // coalesce into large pages. Try to reserve large pages when 3504 // the system is still "fresh". 3505 shm_warning_with_errno("Failed to reserve shared memory."); 3506 return NULL; 3507 } 3508 3509 // Attach to the region. 3510 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3511 3512 // Remove shmid. If shmat() is successful, the actual shared memory segment 3513 // will be deleted when it's detached by shmdt() or when the process 3514 // terminates. If shmat() is not successful this will remove the shared 3515 // segment immediately. 3516 shmctl(shmid, IPC_RMID, NULL); 3517 3518 return addr; 3519} 3520 3521static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3522 int error) { 3523 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3524 3525 bool warn_on_failure = UseLargePages && 3526 (!FLAG_IS_DEFAULT(UseLargePages) || 3527 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3528 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3529 3530 if (warn_on_failure) { 3531 char msg[128]; 3532 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3533 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3534 warning("%s", msg); 3535 } 3536} 3537 3538char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3539 char* req_addr, 3540 bool exec) { 3541 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3542 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3543 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3544 3545 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3546 char* addr = (char*)::mmap(req_addr, bytes, prot, 3547 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3548 -1, 0); 3549 3550 if (addr == MAP_FAILED) { 3551 warn_on_large_pages_failure(req_addr, bytes, errno); 3552 return NULL; 3553 } 3554 3555 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3556 3557 return addr; 3558} 3559 3560// Reserve memory using mmap(MAP_HUGETLB). 3561// - bytes shall be a multiple of alignment. 3562// - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3563// - alignment sets the alignment at which memory shall be allocated. 3564// It must be a multiple of allocation granularity. 3565// Returns address of memory or NULL. If req_addr was not NULL, will only return 3566// req_addr or NULL. 3567char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3568 size_t alignment, 3569 char* req_addr, 3570 bool exec) { 3571 size_t large_page_size = os::large_page_size(); 3572 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3573 3574 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3575 assert(is_size_aligned(bytes, alignment), "Must be"); 3576 3577 // First reserve - but not commit - the address range in small pages. 3578 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3579 3580 if (start == NULL) { 3581 return NULL; 3582 } 3583 3584 assert(is_ptr_aligned(start, alignment), "Must be"); 3585 3586 char* end = start + bytes; 3587 3588 // Find the regions of the allocated chunk that can be promoted to large pages. 3589 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3590 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3591 3592 size_t lp_bytes = lp_end - lp_start; 3593 3594 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3595 3596 if (lp_bytes == 0) { 3597 // The mapped region doesn't even span the start and the end of a large page. 3598 // Fall back to allocate a non-special area. 3599 ::munmap(start, end - start); 3600 return NULL; 3601 } 3602 3603 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3604 3605 void* result; 3606 3607 // Commit small-paged leading area. 3608 if (start != lp_start) { 3609 result = ::mmap(start, lp_start - start, prot, 3610 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3611 -1, 0); 3612 if (result == MAP_FAILED) { 3613 ::munmap(lp_start, end - lp_start); 3614 return NULL; 3615 } 3616 } 3617 3618 // Commit large-paged area. 3619 result = ::mmap(lp_start, lp_bytes, prot, 3620 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3621 -1, 0); 3622 if (result == MAP_FAILED) { 3623 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3624 // If the mmap above fails, the large pages region will be unmapped and we 3625 // have regions before and after with small pages. Release these regions. 3626 // 3627 // | mapped | unmapped | mapped | 3628 // ^ ^ ^ ^ 3629 // start lp_start lp_end end 3630 // 3631 ::munmap(start, lp_start - start); 3632 ::munmap(lp_end, end - lp_end); 3633 return NULL; 3634 } 3635 3636 // Commit small-paged trailing area. 3637 if (lp_end != end) { 3638 result = ::mmap(lp_end, end - lp_end, prot, 3639 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3640 -1, 0); 3641 if (result == MAP_FAILED) { 3642 ::munmap(start, lp_end - start); 3643 return NULL; 3644 } 3645 } 3646 3647 return start; 3648} 3649 3650char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3651 size_t alignment, 3652 char* req_addr, 3653 bool exec) { 3654 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3655 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3656 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3657 assert(is_power_of_2(os::large_page_size()), "Must be"); 3658 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3659 3660 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3661 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3662 } else { 3663 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3664 } 3665} 3666 3667char* os::reserve_memory_special(size_t bytes, size_t alignment, 3668 char* req_addr, bool exec) { 3669 assert(UseLargePages, "only for large pages"); 3670 3671 char* addr; 3672 if (UseSHM) { 3673 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3674 } else { 3675 assert(UseHugeTLBFS, "must be"); 3676 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3677 } 3678 3679 if (addr != NULL) { 3680 if (UseNUMAInterleaving) { 3681 numa_make_global(addr, bytes); 3682 } 3683 3684 // The memory is committed 3685 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3686 } 3687 3688 return addr; 3689} 3690 3691bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3692 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3693 return shmdt(base) == 0; 3694} 3695 3696bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3697 return pd_release_memory(base, bytes); 3698} 3699 3700bool os::release_memory_special(char* base, size_t bytes) { 3701 bool res; 3702 if (MemTracker::tracking_level() > NMT_minimal) { 3703 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3704 res = os::Linux::release_memory_special_impl(base, bytes); 3705 if (res) { 3706 tkr.record((address)base, bytes); 3707 } 3708 3709 } else { 3710 res = os::Linux::release_memory_special_impl(base, bytes); 3711 } 3712 return res; 3713} 3714 3715bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3716 assert(UseLargePages, "only for large pages"); 3717 bool res; 3718 3719 if (UseSHM) { 3720 res = os::Linux::release_memory_special_shm(base, bytes); 3721 } else { 3722 assert(UseHugeTLBFS, "must be"); 3723 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3724 } 3725 return res; 3726} 3727 3728size_t os::large_page_size() { 3729 return _large_page_size; 3730} 3731 3732// With SysV SHM the entire memory region must be allocated as shared 3733// memory. 3734// HugeTLBFS allows application to commit large page memory on demand. 3735// However, when committing memory with HugeTLBFS fails, the region 3736// that was supposed to be committed will lose the old reservation 3737// and allow other threads to steal that memory region. Because of this 3738// behavior we can't commit HugeTLBFS memory. 3739bool os::can_commit_large_page_memory() { 3740 return UseTransparentHugePages; 3741} 3742 3743bool os::can_execute_large_page_memory() { 3744 return UseTransparentHugePages || UseHugeTLBFS; 3745} 3746 3747// Reserve memory at an arbitrary address, only if that area is 3748// available (and not reserved for something else). 3749 3750char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3751 const int max_tries = 10; 3752 char* base[max_tries]; 3753 size_t size[max_tries]; 3754 const size_t gap = 0x000000; 3755 3756 // Assert only that the size is a multiple of the page size, since 3757 // that's all that mmap requires, and since that's all we really know 3758 // about at this low abstraction level. If we need higher alignment, 3759 // we can either pass an alignment to this method or verify alignment 3760 // in one of the methods further up the call chain. See bug 5044738. 3761 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3762 3763 // Repeatedly allocate blocks until the block is allocated at the 3764 // right spot. 3765 3766 // Linux mmap allows caller to pass an address as hint; give it a try first, 3767 // if kernel honors the hint then we can return immediately. 3768 char * addr = anon_mmap(requested_addr, bytes, false); 3769 if (addr == requested_addr) { 3770 return requested_addr; 3771 } 3772 3773 if (addr != NULL) { 3774 // mmap() is successful but it fails to reserve at the requested address 3775 anon_munmap(addr, bytes); 3776 } 3777 3778 int i; 3779 for (i = 0; i < max_tries; ++i) { 3780 base[i] = reserve_memory(bytes); 3781 3782 if (base[i] != NULL) { 3783 // Is this the block we wanted? 3784 if (base[i] == requested_addr) { 3785 size[i] = bytes; 3786 break; 3787 } 3788 3789 // Does this overlap the block we wanted? Give back the overlapped 3790 // parts and try again. 3791 3792 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3793 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3794 unmap_memory(base[i], top_overlap); 3795 base[i] += top_overlap; 3796 size[i] = bytes - top_overlap; 3797 } else { 3798 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3799 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3800 unmap_memory(requested_addr, bottom_overlap); 3801 size[i] = bytes - bottom_overlap; 3802 } else { 3803 size[i] = bytes; 3804 } 3805 } 3806 } 3807 } 3808 3809 // Give back the unused reserved pieces. 3810 3811 for (int j = 0; j < i; ++j) { 3812 if (base[j] != NULL) { 3813 unmap_memory(base[j], size[j]); 3814 } 3815 } 3816 3817 if (i < max_tries) { 3818 return requested_addr; 3819 } else { 3820 return NULL; 3821 } 3822} 3823 3824size_t os::read(int fd, void *buf, unsigned int nBytes) { 3825 return ::read(fd, buf, nBytes); 3826} 3827 3828size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3829 return ::pread(fd, buf, nBytes, offset); 3830} 3831 3832// Short sleep, direct OS call. 3833// 3834// Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3835// sched_yield(2) will actually give up the CPU: 3836// 3837// * Alone on this pariticular CPU, keeps running. 3838// * Before the introduction of "skip_buddy" with "compat_yield" disabled 3839// (pre 2.6.39). 3840// 3841// So calling this with 0 is an alternative. 3842// 3843void os::naked_short_sleep(jlong ms) { 3844 struct timespec req; 3845 3846 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3847 req.tv_sec = 0; 3848 if (ms > 0) { 3849 req.tv_nsec = (ms % 1000) * 1000000; 3850 } else { 3851 req.tv_nsec = 1; 3852 } 3853 3854 nanosleep(&req, NULL); 3855 3856 return; 3857} 3858 3859// Sleep forever; naked call to OS-specific sleep; use with CAUTION 3860void os::infinite_sleep() { 3861 while (true) { // sleep forever ... 3862 ::sleep(100); // ... 100 seconds at a time 3863 } 3864} 3865 3866// Used to convert frequent JVM_Yield() to nops 3867bool os::dont_yield() { 3868 return DontYieldALot; 3869} 3870 3871void os::naked_yield() { 3872 sched_yield(); 3873} 3874 3875//////////////////////////////////////////////////////////////////////////////// 3876// thread priority support 3877 3878// Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3879// only supports dynamic priority, static priority must be zero. For real-time 3880// applications, Linux supports SCHED_RR which allows static priority (1-99). 3881// However, for large multi-threaded applications, SCHED_RR is not only slower 3882// than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3883// of 5 runs - Sep 2005). 3884// 3885// The following code actually changes the niceness of kernel-thread/LWP. It 3886// has an assumption that setpriority() only modifies one kernel-thread/LWP, 3887// not the entire user process, and user level threads are 1:1 mapped to kernel 3888// threads. It has always been the case, but could change in the future. For 3889// this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3890// It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3891 3892int os::java_to_os_priority[CriticalPriority + 1] = { 3893 19, // 0 Entry should never be used 3894 3895 4, // 1 MinPriority 3896 3, // 2 3897 2, // 3 3898 3899 1, // 4 3900 0, // 5 NormPriority 3901 -1, // 6 3902 3903 -2, // 7 3904 -3, // 8 3905 -4, // 9 NearMaxPriority 3906 3907 -5, // 10 MaxPriority 3908 3909 -5 // 11 CriticalPriority 3910}; 3911 3912static int prio_init() { 3913 if (ThreadPriorityPolicy == 1) { 3914 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3915 // if effective uid is not root. Perhaps, a more elegant way of doing 3916 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3917 if (geteuid() != 0) { 3918 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3919 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3920 } 3921 ThreadPriorityPolicy = 0; 3922 } 3923 } 3924 if (UseCriticalJavaThreadPriority) { 3925 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3926 } 3927 return 0; 3928} 3929 3930OSReturn os::set_native_priority(Thread* thread, int newpri) { 3931 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3932 3933 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3934 return (ret == 0) ? OS_OK : OS_ERR; 3935} 3936 3937OSReturn os::get_native_priority(const Thread* const thread, 3938 int *priority_ptr) { 3939 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3940 *priority_ptr = java_to_os_priority[NormPriority]; 3941 return OS_OK; 3942 } 3943 3944 errno = 0; 3945 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3946 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3947} 3948 3949// Hint to the underlying OS that a task switch would not be good. 3950// Void return because it's a hint and can fail. 3951void os::hint_no_preempt() {} 3952 3953//////////////////////////////////////////////////////////////////////////////// 3954// suspend/resume support 3955 3956// the low-level signal-based suspend/resume support is a remnant from the 3957// old VM-suspension that used to be for java-suspension, safepoints etc, 3958// within hotspot. Now there is a single use-case for this: 3959// - calling get_thread_pc() on the VMThread by the flat-profiler task 3960// that runs in the watcher thread. 3961// The remaining code is greatly simplified from the more general suspension 3962// code that used to be used. 3963// 3964// The protocol is quite simple: 3965// - suspend: 3966// - sends a signal to the target thread 3967// - polls the suspend state of the osthread using a yield loop 3968// - target thread signal handler (SR_handler) sets suspend state 3969// and blocks in sigsuspend until continued 3970// - resume: 3971// - sets target osthread state to continue 3972// - sends signal to end the sigsuspend loop in the SR_handler 3973// 3974// Note that the SR_lock plays no role in this suspend/resume protocol. 3975 3976static void resume_clear_context(OSThread *osthread) { 3977 osthread->set_ucontext(NULL); 3978 osthread->set_siginfo(NULL); 3979} 3980 3981static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 3982 ucontext_t* context) { 3983 osthread->set_ucontext(context); 3984 osthread->set_siginfo(siginfo); 3985} 3986 3987// Handler function invoked when a thread's execution is suspended or 3988// resumed. We have to be careful that only async-safe functions are 3989// called here (Note: most pthread functions are not async safe and 3990// should be avoided.) 3991// 3992// Note: sigwait() is a more natural fit than sigsuspend() from an 3993// interface point of view, but sigwait() prevents the signal hander 3994// from being run. libpthread would get very confused by not having 3995// its signal handlers run and prevents sigwait()'s use with the 3996// mutex granting granting signal. 3997// 3998// Currently only ever called on the VMThread and JavaThreads (PC sampling) 3999// 4000static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4001 // Save and restore errno to avoid confusing native code with EINTR 4002 // after sigsuspend. 4003 int old_errno = errno; 4004 4005 Thread* thread = Thread::current_or_null_safe(); 4006 assert(thread != NULL, "Missing current thread in SR_handler"); 4007 OSThread* osthread = thread->osthread(); 4008 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4009 4010 os::SuspendResume::State current = osthread->sr.state(); 4011 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4012 suspend_save_context(osthread, siginfo, context); 4013 4014 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4015 os::SuspendResume::State state = osthread->sr.suspended(); 4016 if (state == os::SuspendResume::SR_SUSPENDED) { 4017 sigset_t suspend_set; // signals for sigsuspend() 4018 sigemptyset(&suspend_set); 4019 // get current set of blocked signals and unblock resume signal 4020 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4021 sigdelset(&suspend_set, SR_signum); 4022 4023 sr_semaphore.signal(); 4024 // wait here until we are resumed 4025 while (1) { 4026 sigsuspend(&suspend_set); 4027 4028 os::SuspendResume::State result = osthread->sr.running(); 4029 if (result == os::SuspendResume::SR_RUNNING) { 4030 sr_semaphore.signal(); 4031 break; 4032 } 4033 } 4034 4035 } else if (state == os::SuspendResume::SR_RUNNING) { 4036 // request was cancelled, continue 4037 } else { 4038 ShouldNotReachHere(); 4039 } 4040 4041 resume_clear_context(osthread); 4042 } else if (current == os::SuspendResume::SR_RUNNING) { 4043 // request was cancelled, continue 4044 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4045 // ignore 4046 } else { 4047 // ignore 4048 } 4049 4050 errno = old_errno; 4051} 4052 4053static int SR_initialize() { 4054 struct sigaction act; 4055 char *s; 4056 4057 // Get signal number to use for suspend/resume 4058 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4059 int sig = ::strtol(s, 0, 10); 4060 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4061 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4062 SR_signum = sig; 4063 } else { 4064 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4065 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4066 } 4067 } 4068 4069 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4070 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4071 4072 sigemptyset(&SR_sigset); 4073 sigaddset(&SR_sigset, SR_signum); 4074 4075 // Set up signal handler for suspend/resume 4076 act.sa_flags = SA_RESTART|SA_SIGINFO; 4077 act.sa_handler = (void (*)(int)) SR_handler; 4078 4079 // SR_signum is blocked by default. 4080 // 4528190 - We also need to block pthread restart signal (32 on all 4081 // supported Linux platforms). Note that LinuxThreads need to block 4082 // this signal for all threads to work properly. So we don't have 4083 // to use hard-coded signal number when setting up the mask. 4084 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4085 4086 if (sigaction(SR_signum, &act, 0) == -1) { 4087 return -1; 4088 } 4089 4090 // Save signal flag 4091 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4092 return 0; 4093} 4094 4095static int sr_notify(OSThread* osthread) { 4096 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4097 assert_status(status == 0, status, "pthread_kill"); 4098 return status; 4099} 4100 4101// "Randomly" selected value for how long we want to spin 4102// before bailing out on suspending a thread, also how often 4103// we send a signal to a thread we want to resume 4104static const int RANDOMLY_LARGE_INTEGER = 1000000; 4105static const int RANDOMLY_LARGE_INTEGER2 = 100; 4106 4107// returns true on success and false on error - really an error is fatal 4108// but this seems the normal response to library errors 4109static bool do_suspend(OSThread* osthread) { 4110 assert(osthread->sr.is_running(), "thread should be running"); 4111 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4112 4113 // mark as suspended and send signal 4114 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4115 // failed to switch, state wasn't running? 4116 ShouldNotReachHere(); 4117 return false; 4118 } 4119 4120 if (sr_notify(osthread) != 0) { 4121 ShouldNotReachHere(); 4122 } 4123 4124 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4125 while (true) { 4126 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4127 break; 4128 } else { 4129 // timeout 4130 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4131 if (cancelled == os::SuspendResume::SR_RUNNING) { 4132 return false; 4133 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4134 // make sure that we consume the signal on the semaphore as well 4135 sr_semaphore.wait(); 4136 break; 4137 } else { 4138 ShouldNotReachHere(); 4139 return false; 4140 } 4141 } 4142 } 4143 4144 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4145 return true; 4146} 4147 4148static void do_resume(OSThread* osthread) { 4149 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4150 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4151 4152 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4153 // failed to switch to WAKEUP_REQUEST 4154 ShouldNotReachHere(); 4155 return; 4156 } 4157 4158 while (true) { 4159 if (sr_notify(osthread) == 0) { 4160 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4161 if (osthread->sr.is_running()) { 4162 return; 4163 } 4164 } 4165 } else { 4166 ShouldNotReachHere(); 4167 } 4168 } 4169 4170 guarantee(osthread->sr.is_running(), "Must be running!"); 4171} 4172 4173/////////////////////////////////////////////////////////////////////////////////// 4174// signal handling (except suspend/resume) 4175 4176// This routine may be used by user applications as a "hook" to catch signals. 4177// The user-defined signal handler must pass unrecognized signals to this 4178// routine, and if it returns true (non-zero), then the signal handler must 4179// return immediately. If the flag "abort_if_unrecognized" is true, then this 4180// routine will never retun false (zero), but instead will execute a VM panic 4181// routine kill the process. 4182// 4183// If this routine returns false, it is OK to call it again. This allows 4184// the user-defined signal handler to perform checks either before or after 4185// the VM performs its own checks. Naturally, the user code would be making 4186// a serious error if it tried to handle an exception (such as a null check 4187// or breakpoint) that the VM was generating for its own correct operation. 4188// 4189// This routine may recognize any of the following kinds of signals: 4190// SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4191// It should be consulted by handlers for any of those signals. 4192// 4193// The caller of this routine must pass in the three arguments supplied 4194// to the function referred to in the "sa_sigaction" (not the "sa_handler") 4195// field of the structure passed to sigaction(). This routine assumes that 4196// the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4197// 4198// Note that the VM will print warnings if it detects conflicting signal 4199// handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4200// 4201extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4202 siginfo_t* siginfo, 4203 void* ucontext, 4204 int abort_if_unrecognized); 4205 4206void signalHandler(int sig, siginfo_t* info, void* uc) { 4207 assert(info != NULL && uc != NULL, "it must be old kernel"); 4208 int orig_errno = errno; // Preserve errno value over signal handler. 4209 JVM_handle_linux_signal(sig, info, uc, true); 4210 errno = orig_errno; 4211} 4212 4213 4214// This boolean allows users to forward their own non-matching signals 4215// to JVM_handle_linux_signal, harmlessly. 4216bool os::Linux::signal_handlers_are_installed = false; 4217 4218// For signal-chaining 4219struct sigaction sigact[NSIG]; 4220uint64_t sigs = 0; 4221#if (64 < NSIG-1) 4222#error "Not all signals can be encoded in sigs. Adapt its type!" 4223#endif 4224bool os::Linux::libjsig_is_loaded = false; 4225typedef struct sigaction *(*get_signal_t)(int); 4226get_signal_t os::Linux::get_signal_action = NULL; 4227 4228struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4229 struct sigaction *actp = NULL; 4230 4231 if (libjsig_is_loaded) { 4232 // Retrieve the old signal handler from libjsig 4233 actp = (*get_signal_action)(sig); 4234 } 4235 if (actp == NULL) { 4236 // Retrieve the preinstalled signal handler from jvm 4237 actp = get_preinstalled_handler(sig); 4238 } 4239 4240 return actp; 4241} 4242 4243static bool call_chained_handler(struct sigaction *actp, int sig, 4244 siginfo_t *siginfo, void *context) { 4245 // Call the old signal handler 4246 if (actp->sa_handler == SIG_DFL) { 4247 // It's more reasonable to let jvm treat it as an unexpected exception 4248 // instead of taking the default action. 4249 return false; 4250 } else if (actp->sa_handler != SIG_IGN) { 4251 if ((actp->sa_flags & SA_NODEFER) == 0) { 4252 // automaticlly block the signal 4253 sigaddset(&(actp->sa_mask), sig); 4254 } 4255 4256 sa_handler_t hand = NULL; 4257 sa_sigaction_t sa = NULL; 4258 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4259 // retrieve the chained handler 4260 if (siginfo_flag_set) { 4261 sa = actp->sa_sigaction; 4262 } else { 4263 hand = actp->sa_handler; 4264 } 4265 4266 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4267 actp->sa_handler = SIG_DFL; 4268 } 4269 4270 // try to honor the signal mask 4271 sigset_t oset; 4272 sigemptyset(&oset); 4273 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4274 4275 // call into the chained handler 4276 if (siginfo_flag_set) { 4277 (*sa)(sig, siginfo, context); 4278 } else { 4279 (*hand)(sig); 4280 } 4281 4282 // restore the signal mask 4283 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4284 } 4285 // Tell jvm's signal handler the signal is taken care of. 4286 return true; 4287} 4288 4289bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4290 bool chained = false; 4291 // signal-chaining 4292 if (UseSignalChaining) { 4293 struct sigaction *actp = get_chained_signal_action(sig); 4294 if (actp != NULL) { 4295 chained = call_chained_handler(actp, sig, siginfo, context); 4296 } 4297 } 4298 return chained; 4299} 4300 4301struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4302 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4303 return &sigact[sig]; 4304 } 4305 return NULL; 4306} 4307 4308void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4309 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4310 sigact[sig] = oldAct; 4311 sigs |= (uint64_t)1 << (sig-1); 4312} 4313 4314// for diagnostic 4315int sigflags[NSIG]; 4316 4317int os::Linux::get_our_sigflags(int sig) { 4318 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4319 return sigflags[sig]; 4320} 4321 4322void os::Linux::set_our_sigflags(int sig, int flags) { 4323 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4324 if (sig > 0 && sig < NSIG) { 4325 sigflags[sig] = flags; 4326 } 4327} 4328 4329void os::Linux::set_signal_handler(int sig, bool set_installed) { 4330 // Check for overwrite. 4331 struct sigaction oldAct; 4332 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4333 4334 void* oldhand = oldAct.sa_sigaction 4335 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4336 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4337 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4338 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4339 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4340 if (AllowUserSignalHandlers || !set_installed) { 4341 // Do not overwrite; user takes responsibility to forward to us. 4342 return; 4343 } else if (UseSignalChaining) { 4344 // save the old handler in jvm 4345 save_preinstalled_handler(sig, oldAct); 4346 // libjsig also interposes the sigaction() call below and saves the 4347 // old sigaction on it own. 4348 } else { 4349 fatal("Encountered unexpected pre-existing sigaction handler " 4350 "%#lx for signal %d.", (long)oldhand, sig); 4351 } 4352 } 4353 4354 struct sigaction sigAct; 4355 sigfillset(&(sigAct.sa_mask)); 4356 sigAct.sa_handler = SIG_DFL; 4357 if (!set_installed) { 4358 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4359 } else { 4360 sigAct.sa_sigaction = signalHandler; 4361 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4362 } 4363 // Save flags, which are set by ours 4364 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4365 sigflags[sig] = sigAct.sa_flags; 4366 4367 int ret = sigaction(sig, &sigAct, &oldAct); 4368 assert(ret == 0, "check"); 4369 4370 void* oldhand2 = oldAct.sa_sigaction 4371 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4372 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4373 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4374} 4375 4376// install signal handlers for signals that HotSpot needs to 4377// handle in order to support Java-level exception handling. 4378 4379void os::Linux::install_signal_handlers() { 4380 if (!signal_handlers_are_installed) { 4381 signal_handlers_are_installed = true; 4382 4383 // signal-chaining 4384 typedef void (*signal_setting_t)(); 4385 signal_setting_t begin_signal_setting = NULL; 4386 signal_setting_t end_signal_setting = NULL; 4387 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4388 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4389 if (begin_signal_setting != NULL) { 4390 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4391 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4392 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4393 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4394 libjsig_is_loaded = true; 4395 assert(UseSignalChaining, "should enable signal-chaining"); 4396 } 4397 if (libjsig_is_loaded) { 4398 // Tell libjsig jvm is setting signal handlers 4399 (*begin_signal_setting)(); 4400 } 4401 4402 set_signal_handler(SIGSEGV, true); 4403 set_signal_handler(SIGPIPE, true); 4404 set_signal_handler(SIGBUS, true); 4405 set_signal_handler(SIGILL, true); 4406 set_signal_handler(SIGFPE, true); 4407#if defined(PPC64) 4408 set_signal_handler(SIGTRAP, true); 4409#endif 4410 set_signal_handler(SIGXFSZ, true); 4411 4412 if (libjsig_is_loaded) { 4413 // Tell libjsig jvm finishes setting signal handlers 4414 (*end_signal_setting)(); 4415 } 4416 4417 // We don't activate signal checker if libjsig is in place, we trust ourselves 4418 // and if UserSignalHandler is installed all bets are off. 4419 // Log that signal checking is off only if -verbose:jni is specified. 4420 if (CheckJNICalls) { 4421 if (libjsig_is_loaded) { 4422 if (PrintJNIResolving) { 4423 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4424 } 4425 check_signals = false; 4426 } 4427 if (AllowUserSignalHandlers) { 4428 if (PrintJNIResolving) { 4429 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4430 } 4431 check_signals = false; 4432 } 4433 } 4434 } 4435} 4436 4437// This is the fastest way to get thread cpu time on Linux. 4438// Returns cpu time (user+sys) for any thread, not only for current. 4439// POSIX compliant clocks are implemented in the kernels 2.6.16+. 4440// It might work on 2.6.10+ with a special kernel/glibc patch. 4441// For reference, please, see IEEE Std 1003.1-2004: 4442// http://www.unix.org/single_unix_specification 4443 4444jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4445 struct timespec tp; 4446 int rc = os::Linux::clock_gettime(clockid, &tp); 4447 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4448 4449 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4450} 4451 4452void os::Linux::initialize_os_info() { 4453 assert(_os_version == 0, "OS info already initialized"); 4454 4455 struct utsname _uname; 4456 4457 uint32_t major; 4458 uint32_t minor; 4459 uint32_t fix; 4460 4461 int rc; 4462 4463 // Kernel version is unknown if 4464 // verification below fails. 4465 _os_version = 0x01000000; 4466 4467 rc = uname(&_uname); 4468 if (rc != -1) { 4469 4470 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4471 if (rc == 3) { 4472 4473 if (major < 256 && minor < 256 && fix < 256) { 4474 // Kernel version format is as expected, 4475 // set it overriding unknown state. 4476 _os_version = (major << 16) | 4477 (minor << 8 ) | 4478 (fix << 0 ) ; 4479 } 4480 } 4481 } 4482} 4483 4484uint32_t os::Linux::os_version() { 4485 assert(_os_version != 0, "not initialized"); 4486 return _os_version & 0x00FFFFFF; 4487} 4488 4489bool os::Linux::os_version_is_known() { 4490 assert(_os_version != 0, "not initialized"); 4491 return _os_version & 0x01000000 ? false : true; 4492} 4493 4494///// 4495// glibc on Linux platform uses non-documented flag 4496// to indicate, that some special sort of signal 4497// trampoline is used. 4498// We will never set this flag, and we should 4499// ignore this flag in our diagnostic 4500#ifdef SIGNIFICANT_SIGNAL_MASK 4501 #undef SIGNIFICANT_SIGNAL_MASK 4502#endif 4503#define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4504 4505static const char* get_signal_handler_name(address handler, 4506 char* buf, int buflen) { 4507 int offset = 0; 4508 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4509 if (found) { 4510 // skip directory names 4511 const char *p1, *p2; 4512 p1 = buf; 4513 size_t len = strlen(os::file_separator()); 4514 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4515 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4516 } else { 4517 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4518 } 4519 return buf; 4520} 4521 4522static void print_signal_handler(outputStream* st, int sig, 4523 char* buf, size_t buflen) { 4524 struct sigaction sa; 4525 4526 sigaction(sig, NULL, &sa); 4527 4528 // See comment for SIGNIFICANT_SIGNAL_MASK define 4529 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4530 4531 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4532 4533 address handler = (sa.sa_flags & SA_SIGINFO) 4534 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4535 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4536 4537 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4538 st->print("SIG_DFL"); 4539 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4540 st->print("SIG_IGN"); 4541 } else { 4542 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4543 } 4544 4545 st->print(", sa_mask[0]="); 4546 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4547 4548 address rh = VMError::get_resetted_sighandler(sig); 4549 // May be, handler was resetted by VMError? 4550 if (rh != NULL) { 4551 handler = rh; 4552 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4553 } 4554 4555 st->print(", sa_flags="); 4556 os::Posix::print_sa_flags(st, sa.sa_flags); 4557 4558 // Check: is it our handler? 4559 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4560 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4561 // It is our signal handler 4562 // check for flags, reset system-used one! 4563 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4564 st->print( 4565 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4566 os::Linux::get_our_sigflags(sig)); 4567 } 4568 } 4569 st->cr(); 4570} 4571 4572 4573#define DO_SIGNAL_CHECK(sig) \ 4574 do { \ 4575 if (!sigismember(&check_signal_done, sig)) { \ 4576 os::Linux::check_signal_handler(sig); \ 4577 } \ 4578 } while (0) 4579 4580// This method is a periodic task to check for misbehaving JNI applications 4581// under CheckJNI, we can add any periodic checks here 4582 4583void os::run_periodic_checks() { 4584 if (check_signals == false) return; 4585 4586 // SEGV and BUS if overridden could potentially prevent 4587 // generation of hs*.log in the event of a crash, debugging 4588 // such a case can be very challenging, so we absolutely 4589 // check the following for a good measure: 4590 DO_SIGNAL_CHECK(SIGSEGV); 4591 DO_SIGNAL_CHECK(SIGILL); 4592 DO_SIGNAL_CHECK(SIGFPE); 4593 DO_SIGNAL_CHECK(SIGBUS); 4594 DO_SIGNAL_CHECK(SIGPIPE); 4595 DO_SIGNAL_CHECK(SIGXFSZ); 4596#if defined(PPC64) 4597 DO_SIGNAL_CHECK(SIGTRAP); 4598#endif 4599 4600 // ReduceSignalUsage allows the user to override these handlers 4601 // see comments at the very top and jvm_solaris.h 4602 if (!ReduceSignalUsage) { 4603 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4604 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4605 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4606 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4607 } 4608 4609 DO_SIGNAL_CHECK(SR_signum); 4610} 4611 4612typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4613 4614static os_sigaction_t os_sigaction = NULL; 4615 4616void os::Linux::check_signal_handler(int sig) { 4617 char buf[O_BUFLEN]; 4618 address jvmHandler = NULL; 4619 4620 4621 struct sigaction act; 4622 if (os_sigaction == NULL) { 4623 // only trust the default sigaction, in case it has been interposed 4624 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4625 if (os_sigaction == NULL) return; 4626 } 4627 4628 os_sigaction(sig, (struct sigaction*)NULL, &act); 4629 4630 4631 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4632 4633 address thisHandler = (act.sa_flags & SA_SIGINFO) 4634 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4635 : CAST_FROM_FN_PTR(address, act.sa_handler); 4636 4637 4638 switch (sig) { 4639 case SIGSEGV: 4640 case SIGBUS: 4641 case SIGFPE: 4642 case SIGPIPE: 4643 case SIGILL: 4644 case SIGXFSZ: 4645 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4646 break; 4647 4648 case SHUTDOWN1_SIGNAL: 4649 case SHUTDOWN2_SIGNAL: 4650 case SHUTDOWN3_SIGNAL: 4651 case BREAK_SIGNAL: 4652 jvmHandler = (address)user_handler(); 4653 break; 4654 4655 default: 4656 if (sig == SR_signum) { 4657 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4658 } else { 4659 return; 4660 } 4661 break; 4662 } 4663 4664 if (thisHandler != jvmHandler) { 4665 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4666 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4667 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4668 // No need to check this sig any longer 4669 sigaddset(&check_signal_done, sig); 4670 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4671 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4672 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4673 exception_name(sig, buf, O_BUFLEN)); 4674 } 4675 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4676 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4677 tty->print("expected:"); 4678 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4679 tty->cr(); 4680 tty->print(" found:"); 4681 os::Posix::print_sa_flags(tty, act.sa_flags); 4682 tty->cr(); 4683 // No need to check this sig any longer 4684 sigaddset(&check_signal_done, sig); 4685 } 4686 4687 // Dump all the signal 4688 if (sigismember(&check_signal_done, sig)) { 4689 print_signal_handlers(tty, buf, O_BUFLEN); 4690 } 4691} 4692 4693extern void report_error(char* file_name, int line_no, char* title, 4694 char* format, ...); 4695 4696// this is called _before_ the most of global arguments have been parsed 4697void os::init(void) { 4698 char dummy; // used to get a guess on initial stack address 4699// first_hrtime = gethrtime(); 4700 4701 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4702 4703 init_random(1234567); 4704 4705 ThreadCritical::initialize(); 4706 4707 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4708 if (Linux::page_size() == -1) { 4709 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4710 os::strerror(errno)); 4711 } 4712 init_page_sizes((size_t) Linux::page_size()); 4713 4714 Linux::initialize_system_info(); 4715 4716 Linux::initialize_os_info(); 4717 4718 // main_thread points to the aboriginal thread 4719 Linux::_main_thread = pthread_self(); 4720 4721 Linux::clock_init(); 4722 initial_time_count = javaTimeNanos(); 4723 4724 // pthread_condattr initialization for monotonic clock 4725 int status; 4726 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4727 if ((status = pthread_condattr_init(_condattr)) != 0) { 4728 fatal("pthread_condattr_init: %s", os::strerror(status)); 4729 } 4730 // Only set the clock if CLOCK_MONOTONIC is available 4731 if (os::supports_monotonic_clock()) { 4732 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4733 if (status == EINVAL) { 4734 warning("Unable to use monotonic clock with relative timed-waits" \ 4735 " - changes to the time-of-day clock may have adverse affects"); 4736 } else { 4737 fatal("pthread_condattr_setclock: %s", os::strerror(status)); 4738 } 4739 } 4740 } 4741 // else it defaults to CLOCK_REALTIME 4742 4743 // retrieve entry point for pthread_setname_np 4744 Linux::_pthread_setname_np = 4745 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4746 4747} 4748 4749// To install functions for atexit system call 4750extern "C" { 4751 static void perfMemory_exit_helper() { 4752 perfMemory_exit(); 4753 } 4754} 4755 4756// this is called _after_ the global arguments have been parsed 4757jint os::init_2(void) { 4758 Linux::fast_thread_clock_init(); 4759 4760 // Allocate a single page and mark it as readable for safepoint polling 4761 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4762 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4763 4764 os::set_polling_page(polling_page); 4765 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page)); 4766 4767 if (!UseMembar) { 4768 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4769 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4770 os::set_memory_serialize_page(mem_serialize_page); 4771 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page)); 4772 } 4773 4774 // initialize suspend/resume support - must do this before signal_sets_init() 4775 if (SR_initialize() != 0) { 4776 perror("SR_initialize failed"); 4777 return JNI_ERR; 4778 } 4779 4780 Linux::signal_sets_init(); 4781 Linux::install_signal_handlers(); 4782 4783 // Check minimum allowable stack size for thread creation and to initialize 4784 // the java system classes, including StackOverflowError - depends on page 4785 // size. Add two 4K pages for compiler2 recursion in main thread. 4786 // Add in 4*BytesPerWord 4K pages to account for VM stack during 4787 // class initialization depending on 32 or 64 bit VM. 4788 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4789 JavaThread::stack_guard_zone_size() + 4790 JavaThread::stack_shadow_zone_size() + 4791 (4*BytesPerWord COMPILER2_PRESENT(+2)) * 4 * K); 4792 4793 os::Linux::min_stack_allowed = align_size_up(os::Linux::min_stack_allowed, os::vm_page_size()); 4794 4795 size_t threadStackSizeInBytes = ThreadStackSize * K; 4796 if (threadStackSizeInBytes != 0 && 4797 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4798 tty->print_cr("\nThe stack size specified is too small, " 4799 "Specify at least " SIZE_FORMAT "k", 4800 os::Linux::min_stack_allowed/ K); 4801 return JNI_ERR; 4802 } 4803 4804 // Make the stack size a multiple of the page size so that 4805 // the yellow/red zones can be guarded. 4806 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4807 vm_page_size())); 4808 4809 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4810 4811#if defined(IA32) 4812 workaround_expand_exec_shield_cs_limit(); 4813#endif 4814 4815 Linux::libpthread_init(); 4816 log_info(os)("HotSpot is running with %s, %s", 4817 Linux::glibc_version(), Linux::libpthread_version()); 4818 4819 if (UseNUMA) { 4820 if (!Linux::libnuma_init()) { 4821 UseNUMA = false; 4822 } else { 4823 if ((Linux::numa_max_node() < 1)) { 4824 // There's only one node(they start from 0), disable NUMA. 4825 UseNUMA = false; 4826 } 4827 } 4828 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4829 // we can make the adaptive lgrp chunk resizing work. If the user specified 4830 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4831 // disable adaptive resizing. 4832 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4833 if (FLAG_IS_DEFAULT(UseNUMA)) { 4834 UseNUMA = false; 4835 } else { 4836 if (FLAG_IS_DEFAULT(UseLargePages) && 4837 FLAG_IS_DEFAULT(UseSHM) && 4838 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4839 UseLargePages = false; 4840 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4841 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4842 UseAdaptiveSizePolicy = false; 4843 UseAdaptiveNUMAChunkSizing = false; 4844 } 4845 } 4846 } 4847 if (!UseNUMA && ForceNUMA) { 4848 UseNUMA = true; 4849 } 4850 } 4851 4852 if (MaxFDLimit) { 4853 // set the number of file descriptors to max. print out error 4854 // if getrlimit/setrlimit fails but continue regardless. 4855 struct rlimit nbr_files; 4856 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4857 if (status != 0) { 4858 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 4859 } else { 4860 nbr_files.rlim_cur = nbr_files.rlim_max; 4861 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4862 if (status != 0) { 4863 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 4864 } 4865 } 4866 } 4867 4868 // Initialize lock used to serialize thread creation (see os::create_thread) 4869 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4870 4871 // at-exit methods are called in the reverse order of their registration. 4872 // atexit functions are called on return from main or as a result of a 4873 // call to exit(3C). There can be only 32 of these functions registered 4874 // and atexit() does not set errno. 4875 4876 if (PerfAllowAtExitRegistration) { 4877 // only register atexit functions if PerfAllowAtExitRegistration is set. 4878 // atexit functions can be delayed until process exit time, which 4879 // can be problematic for embedded VM situations. Embedded VMs should 4880 // call DestroyJavaVM() to assure that VM resources are released. 4881 4882 // note: perfMemory_exit_helper atexit function may be removed in 4883 // the future if the appropriate cleanup code can be added to the 4884 // VM_Exit VMOperation's doit method. 4885 if (atexit(perfMemory_exit_helper) != 0) { 4886 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4887 } 4888 } 4889 4890 // initialize thread priority policy 4891 prio_init(); 4892 4893 return JNI_OK; 4894} 4895 4896// Mark the polling page as unreadable 4897void os::make_polling_page_unreadable(void) { 4898 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4899 fatal("Could not disable polling page"); 4900 } 4901} 4902 4903// Mark the polling page as readable 4904void os::make_polling_page_readable(void) { 4905 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4906 fatal("Could not enable polling page"); 4907 } 4908} 4909 4910// older glibc versions don't have this macro (which expands to 4911// an optimized bit-counting function) so we have to roll our own 4912#ifndef CPU_COUNT 4913 4914static int _cpu_count(const cpu_set_t* cpus) { 4915 int count = 0; 4916 // only look up to the number of configured processors 4917 for (int i = 0; i < os::processor_count(); i++) { 4918 if (CPU_ISSET(i, cpus)) { 4919 count++; 4920 } 4921 } 4922 return count; 4923} 4924 4925#define CPU_COUNT(cpus) _cpu_count(cpus) 4926 4927#endif // CPU_COUNT 4928 4929// Get the current number of available processors for this process. 4930// This value can change at any time during a process's lifetime. 4931// sched_getaffinity gives an accurate answer as it accounts for cpusets. 4932// If it appears there may be more than 1024 processors then we do a 4933// dynamic check - see 6515172 for details. 4934// If anything goes wrong we fallback to returning the number of online 4935// processors - which can be greater than the number available to the process. 4936int os::active_processor_count() { 4937 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 4938 cpu_set_t* cpus_p = &cpus; 4939 int cpus_size = sizeof(cpu_set_t); 4940 4941 int configured_cpus = processor_count(); // upper bound on available cpus 4942 int cpu_count = 0; 4943 4944// old build platforms may not support dynamic cpu sets 4945#ifdef CPU_ALLOC 4946 4947 // To enable easy testing of the dynamic path on different platforms we 4948 // introduce a diagnostic flag: UseCpuAllocPath 4949 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 4950 // kernel may use a mask bigger than cpu_set_t 4951 log_trace(os)("active_processor_count: using dynamic path %s" 4952 "- configured processors: %d", 4953 UseCpuAllocPath ? "(forced) " : "", 4954 configured_cpus); 4955 cpus_p = CPU_ALLOC(configured_cpus); 4956 if (cpus_p != NULL) { 4957 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 4958 // zero it just to be safe 4959 CPU_ZERO_S(cpus_size, cpus_p); 4960 } 4961 else { 4962 // failed to allocate so fallback to online cpus 4963 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4964 log_trace(os)("active_processor_count: " 4965 "CPU_ALLOC failed (%s) - using " 4966 "online processor count: %d", 4967 os::strerror(errno), online_cpus); 4968 return online_cpus; 4969 } 4970 } 4971 else { 4972 log_trace(os)("active_processor_count: using static path - configured processors: %d", 4973 configured_cpus); 4974 } 4975#else // CPU_ALLOC 4976// these stubs won't be executed 4977#define CPU_COUNT_S(size, cpus) -1 4978#define CPU_FREE(cpus) 4979 4980 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 4981 configured_cpus); 4982#endif // CPU_ALLOC 4983 4984 // pid 0 means the current thread - which we have to assume represents the process 4985 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 4986 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 4987 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 4988 } 4989 else { 4990 cpu_count = CPU_COUNT(cpus_p); 4991 } 4992 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 4993 } 4994 else { 4995 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 4996 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 4997 "which may exceed available processors", os::strerror(errno), cpu_count); 4998 } 4999 5000 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5001 CPU_FREE(cpus_p); 5002 } 5003 5004 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check"); 5005 return cpu_count; 5006} 5007 5008void os::set_native_thread_name(const char *name) { 5009 if (Linux::_pthread_setname_np) { 5010 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5011 snprintf(buf, sizeof(buf), "%s", name); 5012 buf[sizeof(buf) - 1] = '\0'; 5013 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5014 // ERANGE should not happen; all other errors should just be ignored. 5015 assert(rc != ERANGE, "pthread_setname_np failed"); 5016 } 5017} 5018 5019bool os::distribute_processes(uint length, uint* distribution) { 5020 // Not yet implemented. 5021 return false; 5022} 5023 5024bool os::bind_to_processor(uint processor_id) { 5025 // Not yet implemented. 5026 return false; 5027} 5028 5029/// 5030 5031void os::SuspendedThreadTask::internal_do_task() { 5032 if (do_suspend(_thread->osthread())) { 5033 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5034 do_task(context); 5035 do_resume(_thread->osthread()); 5036 } 5037} 5038 5039class PcFetcher : public os::SuspendedThreadTask { 5040 public: 5041 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 5042 ExtendedPC result(); 5043 protected: 5044 void do_task(const os::SuspendedThreadTaskContext& context); 5045 private: 5046 ExtendedPC _epc; 5047}; 5048 5049ExtendedPC PcFetcher::result() { 5050 guarantee(is_done(), "task is not done yet."); 5051 return _epc; 5052} 5053 5054void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 5055 Thread* thread = context.thread(); 5056 OSThread* osthread = thread->osthread(); 5057 if (osthread->ucontext() != NULL) { 5058 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext()); 5059 } else { 5060 // NULL context is unexpected, double-check this is the VMThread 5061 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 5062 } 5063} 5064 5065// Suspends the target using the signal mechanism and then grabs the PC before 5066// resuming the target. Used by the flat-profiler only 5067ExtendedPC os::get_thread_pc(Thread* thread) { 5068 // Make sure that it is called by the watcher for the VMThread 5069 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 5070 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 5071 5072 PcFetcher fetcher(thread); 5073 fetcher.run(); 5074 return fetcher.result(); 5075} 5076 5077//////////////////////////////////////////////////////////////////////////////// 5078// debug support 5079 5080bool os::find(address addr, outputStream* st) { 5081 Dl_info dlinfo; 5082 memset(&dlinfo, 0, sizeof(dlinfo)); 5083 if (dladdr(addr, &dlinfo) != 0) { 5084 st->print(PTR_FORMAT ": ", p2i(addr)); 5085 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5086 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5087 p2i(addr) - p2i(dlinfo.dli_saddr)); 5088 } else if (dlinfo.dli_fbase != NULL) { 5089 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5090 } else { 5091 st->print("<absolute address>"); 5092 } 5093 if (dlinfo.dli_fname != NULL) { 5094 st->print(" in %s", dlinfo.dli_fname); 5095 } 5096 if (dlinfo.dli_fbase != NULL) { 5097 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5098 } 5099 st->cr(); 5100 5101 if (Verbose) { 5102 // decode some bytes around the PC 5103 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5104 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5105 address lowest = (address) dlinfo.dli_sname; 5106 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5107 if (begin < lowest) begin = lowest; 5108 Dl_info dlinfo2; 5109 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5110 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5111 end = (address) dlinfo2.dli_saddr; 5112 } 5113 Disassembler::decode(begin, end, st); 5114 } 5115 return true; 5116 } 5117 return false; 5118} 5119 5120//////////////////////////////////////////////////////////////////////////////// 5121// misc 5122 5123// This does not do anything on Linux. This is basically a hook for being 5124// able to use structured exception handling (thread-local exception filters) 5125// on, e.g., Win32. 5126void 5127os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5128 JavaCallArguments* args, Thread* thread) { 5129 f(value, method, args, thread); 5130} 5131 5132void os::print_statistics() { 5133} 5134 5135bool os::message_box(const char* title, const char* message) { 5136 int i; 5137 fdStream err(defaultStream::error_fd()); 5138 for (i = 0; i < 78; i++) err.print_raw("="); 5139 err.cr(); 5140 err.print_raw_cr(title); 5141 for (i = 0; i < 78; i++) err.print_raw("-"); 5142 err.cr(); 5143 err.print_raw_cr(message); 5144 for (i = 0; i < 78; i++) err.print_raw("="); 5145 err.cr(); 5146 5147 char buf[16]; 5148 // Prevent process from exiting upon "read error" without consuming all CPU 5149 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5150 5151 return buf[0] == 'y' || buf[0] == 'Y'; 5152} 5153 5154int os::stat(const char *path, struct stat *sbuf) { 5155 char pathbuf[MAX_PATH]; 5156 if (strlen(path) > MAX_PATH - 1) { 5157 errno = ENAMETOOLONG; 5158 return -1; 5159 } 5160 os::native_path(strcpy(pathbuf, path)); 5161 return ::stat(pathbuf, sbuf); 5162} 5163 5164bool os::check_heap(bool force) { 5165 return true; 5166} 5167 5168// Is a (classpath) directory empty? 5169bool os::dir_is_empty(const char* path) { 5170 DIR *dir = NULL; 5171 struct dirent *ptr; 5172 5173 dir = opendir(path); 5174 if (dir == NULL) return true; 5175 5176 // Scan the directory 5177 bool result = true; 5178 char buf[sizeof(struct dirent) + MAX_PATH]; 5179 while (result && (ptr = ::readdir(dir)) != NULL) { 5180 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5181 result = false; 5182 } 5183 } 5184 closedir(dir); 5185 return result; 5186} 5187 5188// This code originates from JDK's sysOpen and open64_w 5189// from src/solaris/hpi/src/system_md.c 5190 5191int os::open(const char *path, int oflag, int mode) { 5192 if (strlen(path) > MAX_PATH - 1) { 5193 errno = ENAMETOOLONG; 5194 return -1; 5195 } 5196 5197 // All file descriptors that are opened in the Java process and not 5198 // specifically destined for a subprocess should have the close-on-exec 5199 // flag set. If we don't set it, then careless 3rd party native code 5200 // might fork and exec without closing all appropriate file descriptors 5201 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5202 // turn might: 5203 // 5204 // - cause end-of-file to fail to be detected on some file 5205 // descriptors, resulting in mysterious hangs, or 5206 // 5207 // - might cause an fopen in the subprocess to fail on a system 5208 // suffering from bug 1085341. 5209 // 5210 // (Yes, the default setting of the close-on-exec flag is a Unix 5211 // design flaw) 5212 // 5213 // See: 5214 // 1085341: 32-bit stdio routines should support file descriptors >255 5215 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5216 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5217 // 5218 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5219 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5220 // because it saves a system call and removes a small window where the flag 5221 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5222 // and we fall back to using FD_CLOEXEC (see below). 5223#ifdef O_CLOEXEC 5224 oflag |= O_CLOEXEC; 5225#endif 5226 5227 int fd = ::open64(path, oflag, mode); 5228 if (fd == -1) return -1; 5229 5230 //If the open succeeded, the file might still be a directory 5231 { 5232 struct stat64 buf64; 5233 int ret = ::fstat64(fd, &buf64); 5234 int st_mode = buf64.st_mode; 5235 5236 if (ret != -1) { 5237 if ((st_mode & S_IFMT) == S_IFDIR) { 5238 errno = EISDIR; 5239 ::close(fd); 5240 return -1; 5241 } 5242 } else { 5243 ::close(fd); 5244 return -1; 5245 } 5246 } 5247 5248#ifdef FD_CLOEXEC 5249 // Validate that the use of the O_CLOEXEC flag on open above worked. 5250 // With recent kernels, we will perform this check exactly once. 5251 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5252 if (!O_CLOEXEC_is_known_to_work) { 5253 int flags = ::fcntl(fd, F_GETFD); 5254 if (flags != -1) { 5255 if ((flags & FD_CLOEXEC) != 0) 5256 O_CLOEXEC_is_known_to_work = 1; 5257 else 5258 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5259 } 5260 } 5261#endif 5262 5263 return fd; 5264} 5265 5266 5267// create binary file, rewriting existing file if required 5268int os::create_binary_file(const char* path, bool rewrite_existing) { 5269 int oflags = O_WRONLY | O_CREAT; 5270 if (!rewrite_existing) { 5271 oflags |= O_EXCL; 5272 } 5273 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5274} 5275 5276// return current position of file pointer 5277jlong os::current_file_offset(int fd) { 5278 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5279} 5280 5281// move file pointer to the specified offset 5282jlong os::seek_to_file_offset(int fd, jlong offset) { 5283 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5284} 5285 5286// This code originates from JDK's sysAvailable 5287// from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5288 5289int os::available(int fd, jlong *bytes) { 5290 jlong cur, end; 5291 int mode; 5292 struct stat64 buf64; 5293 5294 if (::fstat64(fd, &buf64) >= 0) { 5295 mode = buf64.st_mode; 5296 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5297 int n; 5298 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5299 *bytes = n; 5300 return 1; 5301 } 5302 } 5303 } 5304 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5305 return 0; 5306 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5307 return 0; 5308 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5309 return 0; 5310 } 5311 *bytes = end - cur; 5312 return 1; 5313} 5314 5315// Map a block of memory. 5316char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5317 char *addr, size_t bytes, bool read_only, 5318 bool allow_exec) { 5319 int prot; 5320 int flags = MAP_PRIVATE; 5321 5322 if (read_only) { 5323 prot = PROT_READ; 5324 } else { 5325 prot = PROT_READ | PROT_WRITE; 5326 } 5327 5328 if (allow_exec) { 5329 prot |= PROT_EXEC; 5330 } 5331 5332 if (addr != NULL) { 5333 flags |= MAP_FIXED; 5334 } 5335 5336 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5337 fd, file_offset); 5338 if (mapped_address == MAP_FAILED) { 5339 return NULL; 5340 } 5341 return mapped_address; 5342} 5343 5344 5345// Remap a block of memory. 5346char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5347 char *addr, size_t bytes, bool read_only, 5348 bool allow_exec) { 5349 // same as map_memory() on this OS 5350 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5351 allow_exec); 5352} 5353 5354 5355// Unmap a block of memory. 5356bool os::pd_unmap_memory(char* addr, size_t bytes) { 5357 return munmap(addr, bytes) == 0; 5358} 5359 5360static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5361 5362static clockid_t thread_cpu_clockid(Thread* thread) { 5363 pthread_t tid = thread->osthread()->pthread_id(); 5364 clockid_t clockid; 5365 5366 // Get thread clockid 5367 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5368 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5369 return clockid; 5370} 5371 5372// current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5373// are used by JVM M&M and JVMTI to get user+sys or user CPU time 5374// of a thread. 5375// 5376// current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5377// the fast estimate available on the platform. 5378 5379jlong os::current_thread_cpu_time() { 5380 if (os::Linux::supports_fast_thread_cpu_time()) { 5381 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5382 } else { 5383 // return user + sys since the cost is the same 5384 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5385 } 5386} 5387 5388jlong os::thread_cpu_time(Thread* thread) { 5389 // consistent with what current_thread_cpu_time() returns 5390 if (os::Linux::supports_fast_thread_cpu_time()) { 5391 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5392 } else { 5393 return slow_thread_cpu_time(thread, true /* user + sys */); 5394 } 5395} 5396 5397jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5398 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5399 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5400 } else { 5401 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5402 } 5403} 5404 5405jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5406 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5407 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5408 } else { 5409 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5410 } 5411} 5412 5413// -1 on error. 5414static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5415 pid_t tid = thread->osthread()->thread_id(); 5416 char *s; 5417 char stat[2048]; 5418 int statlen; 5419 char proc_name[64]; 5420 int count; 5421 long sys_time, user_time; 5422 char cdummy; 5423 int idummy; 5424 long ldummy; 5425 FILE *fp; 5426 5427 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5428 fp = fopen(proc_name, "r"); 5429 if (fp == NULL) return -1; 5430 statlen = fread(stat, 1, 2047, fp); 5431 stat[statlen] = '\0'; 5432 fclose(fp); 5433 5434 // Skip pid and the command string. Note that we could be dealing with 5435 // weird command names, e.g. user could decide to rename java launcher 5436 // to "java 1.4.2 :)", then the stat file would look like 5437 // 1234 (java 1.4.2 :)) R ... ... 5438 // We don't really need to know the command string, just find the last 5439 // occurrence of ")" and then start parsing from there. See bug 4726580. 5440 s = strrchr(stat, ')'); 5441 if (s == NULL) return -1; 5442 5443 // Skip blank chars 5444 do { s++; } while (s && isspace(*s)); 5445 5446 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5447 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5448 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5449 &user_time, &sys_time); 5450 if (count != 13) return -1; 5451 if (user_sys_cpu_time) { 5452 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5453 } else { 5454 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5455 } 5456} 5457 5458void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5459 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5460 info_ptr->may_skip_backward = false; // elapsed time not wall time 5461 info_ptr->may_skip_forward = false; // elapsed time not wall time 5462 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5463} 5464 5465void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5466 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5467 info_ptr->may_skip_backward = false; // elapsed time not wall time 5468 info_ptr->may_skip_forward = false; // elapsed time not wall time 5469 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5470} 5471 5472bool os::is_thread_cpu_time_supported() { 5473 return true; 5474} 5475 5476// System loadavg support. Returns -1 if load average cannot be obtained. 5477// Linux doesn't yet have a (official) notion of processor sets, 5478// so just return the system wide load average. 5479int os::loadavg(double loadavg[], int nelem) { 5480 return ::getloadavg(loadavg, nelem); 5481} 5482 5483void os::pause() { 5484 char filename[MAX_PATH]; 5485 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5486 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5487 } else { 5488 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5489 } 5490 5491 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5492 if (fd != -1) { 5493 struct stat buf; 5494 ::close(fd); 5495 while (::stat(filename, &buf) == 0) { 5496 (void)::poll(NULL, 0, 100); 5497 } 5498 } else { 5499 jio_fprintf(stderr, 5500 "Could not open pause file '%s', continuing immediately.\n", filename); 5501 } 5502} 5503 5504 5505// Refer to the comments in os_solaris.cpp park-unpark. The next two 5506// comment paragraphs are worth repeating here: 5507// 5508// Assumption: 5509// Only one parker can exist on an event, which is why we allocate 5510// them per-thread. Multiple unparkers can coexist. 5511// 5512// _Event serves as a restricted-range semaphore. 5513// -1 : thread is blocked, i.e. there is a waiter 5514// 0 : neutral: thread is running or ready, 5515// could have been signaled after a wait started 5516// 1 : signaled - thread is running or ready 5517// 5518 5519// utility to compute the abstime argument to timedwait: 5520// millis is the relative timeout time 5521// abstime will be the absolute timeout time 5522// TODO: replace compute_abstime() with unpackTime() 5523 5524static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5525 if (millis < 0) millis = 0; 5526 5527 jlong seconds = millis / 1000; 5528 millis %= 1000; 5529 if (seconds > 50000000) { // see man cond_timedwait(3T) 5530 seconds = 50000000; 5531 } 5532 5533 if (os::supports_monotonic_clock()) { 5534 struct timespec now; 5535 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5536 assert_status(status == 0, status, "clock_gettime"); 5537 abstime->tv_sec = now.tv_sec + seconds; 5538 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5539 if (nanos >= NANOSECS_PER_SEC) { 5540 abstime->tv_sec += 1; 5541 nanos -= NANOSECS_PER_SEC; 5542 } 5543 abstime->tv_nsec = nanos; 5544 } else { 5545 struct timeval now; 5546 int status = gettimeofday(&now, NULL); 5547 assert(status == 0, "gettimeofday"); 5548 abstime->tv_sec = now.tv_sec + seconds; 5549 long usec = now.tv_usec + millis * 1000; 5550 if (usec >= 1000000) { 5551 abstime->tv_sec += 1; 5552 usec -= 1000000; 5553 } 5554 abstime->tv_nsec = usec * 1000; 5555 } 5556 return abstime; 5557} 5558 5559void os::PlatformEvent::park() { // AKA "down()" 5560 // Transitions for _Event: 5561 // -1 => -1 : illegal 5562 // 1 => 0 : pass - return immediately 5563 // 0 => -1 : block; then set _Event to 0 before returning 5564 5565 // Invariant: Only the thread associated with the Event/PlatformEvent 5566 // may call park(). 5567 // TODO: assert that _Assoc != NULL or _Assoc == Self 5568 assert(_nParked == 0, "invariant"); 5569 5570 int v; 5571 for (;;) { 5572 v = _Event; 5573 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5574 } 5575 guarantee(v >= 0, "invariant"); 5576 if (v == 0) { 5577 // Do this the hard way by blocking ... 5578 int status = pthread_mutex_lock(_mutex); 5579 assert_status(status == 0, status, "mutex_lock"); 5580 guarantee(_nParked == 0, "invariant"); 5581 ++_nParked; 5582 while (_Event < 0) { 5583 status = pthread_cond_wait(_cond, _mutex); 5584 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5585 // Treat this the same as if the wait was interrupted 5586 if (status == ETIME) { status = EINTR; } 5587 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5588 } 5589 --_nParked; 5590 5591 _Event = 0; 5592 status = pthread_mutex_unlock(_mutex); 5593 assert_status(status == 0, status, "mutex_unlock"); 5594 // Paranoia to ensure our locked and lock-free paths interact 5595 // correctly with each other. 5596 OrderAccess::fence(); 5597 } 5598 guarantee(_Event >= 0, "invariant"); 5599} 5600 5601int os::PlatformEvent::park(jlong millis) { 5602 // Transitions for _Event: 5603 // -1 => -1 : illegal 5604 // 1 => 0 : pass - return immediately 5605 // 0 => -1 : block; then set _Event to 0 before returning 5606 5607 guarantee(_nParked == 0, "invariant"); 5608 5609 int v; 5610 for (;;) { 5611 v = _Event; 5612 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5613 } 5614 guarantee(v >= 0, "invariant"); 5615 if (v != 0) return OS_OK; 5616 5617 // We do this the hard way, by blocking the thread. 5618 // Consider enforcing a minimum timeout value. 5619 struct timespec abst; 5620 compute_abstime(&abst, millis); 5621 5622 int ret = OS_TIMEOUT; 5623 int status = pthread_mutex_lock(_mutex); 5624 assert_status(status == 0, status, "mutex_lock"); 5625 guarantee(_nParked == 0, "invariant"); 5626 ++_nParked; 5627 5628 // Object.wait(timo) will return because of 5629 // (a) notification 5630 // (b) timeout 5631 // (c) thread.interrupt 5632 // 5633 // Thread.interrupt and object.notify{All} both call Event::set. 5634 // That is, we treat thread.interrupt as a special case of notification. 5635 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5636 // We assume all ETIME returns are valid. 5637 // 5638 // TODO: properly differentiate simultaneous notify+interrupt. 5639 // In that case, we should propagate the notify to another waiter. 5640 5641 while (_Event < 0) { 5642 status = pthread_cond_timedwait(_cond, _mutex, &abst); 5643 assert_status(status == 0 || status == EINTR || 5644 status == ETIME || status == ETIMEDOUT, 5645 status, "cond_timedwait"); 5646 if (!FilterSpuriousWakeups) break; // previous semantics 5647 if (status == ETIME || status == ETIMEDOUT) break; 5648 // We consume and ignore EINTR and spurious wakeups. 5649 } 5650 --_nParked; 5651 if (_Event >= 0) { 5652 ret = OS_OK; 5653 } 5654 _Event = 0; 5655 status = pthread_mutex_unlock(_mutex); 5656 assert_status(status == 0, status, "mutex_unlock"); 5657 assert(_nParked == 0, "invariant"); 5658 // Paranoia to ensure our locked and lock-free paths interact 5659 // correctly with each other. 5660 OrderAccess::fence(); 5661 return ret; 5662} 5663 5664void os::PlatformEvent::unpark() { 5665 // Transitions for _Event: 5666 // 0 => 1 : just return 5667 // 1 => 1 : just return 5668 // -1 => either 0 or 1; must signal target thread 5669 // That is, we can safely transition _Event from -1 to either 5670 // 0 or 1. 5671 // See also: "Semaphores in Plan 9" by Mullender & Cox 5672 // 5673 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5674 // that it will take two back-to-back park() calls for the owning 5675 // thread to block. This has the benefit of forcing a spurious return 5676 // from the first park() call after an unpark() call which will help 5677 // shake out uses of park() and unpark() without condition variables. 5678 5679 if (Atomic::xchg(1, &_Event) >= 0) return; 5680 5681 // Wait for the thread associated with the event to vacate 5682 int status = pthread_mutex_lock(_mutex); 5683 assert_status(status == 0, status, "mutex_lock"); 5684 int AnyWaiters = _nParked; 5685 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5686 status = pthread_mutex_unlock(_mutex); 5687 assert_status(status == 0, status, "mutex_unlock"); 5688 if (AnyWaiters != 0) { 5689 // Note that we signal() *after* dropping the lock for "immortal" Events. 5690 // This is safe and avoids a common class of futile wakeups. In rare 5691 // circumstances this can cause a thread to return prematurely from 5692 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5693 // will simply re-test the condition and re-park itself. 5694 // This provides particular benefit if the underlying platform does not 5695 // provide wait morphing. 5696 status = pthread_cond_signal(_cond); 5697 assert_status(status == 0, status, "cond_signal"); 5698 } 5699} 5700 5701 5702// JSR166 5703// ------------------------------------------------------- 5704 5705// The solaris and linux implementations of park/unpark are fairly 5706// conservative for now, but can be improved. They currently use a 5707// mutex/condvar pair, plus a a count. 5708// Park decrements count if > 0, else does a condvar wait. Unpark 5709// sets count to 1 and signals condvar. Only one thread ever waits 5710// on the condvar. Contention seen when trying to park implies that someone 5711// is unparking you, so don't wait. And spurious returns are fine, so there 5712// is no need to track notifications. 5713 5714// This code is common to linux and solaris and will be moved to a 5715// common place in dolphin. 5716// 5717// The passed in time value is either a relative time in nanoseconds 5718// or an absolute time in milliseconds. Either way it has to be unpacked 5719// into suitable seconds and nanoseconds components and stored in the 5720// given timespec structure. 5721// Given time is a 64-bit value and the time_t used in the timespec is only 5722// a signed-32-bit value (except on 64-bit Linux) we have to watch for 5723// overflow if times way in the future are given. Further on Solaris versions 5724// prior to 10 there is a restriction (see cond_timedwait) that the specified 5725// number of seconds, in abstime, is less than current_time + 100,000,000. 5726// As it will be 28 years before "now + 100000000" will overflow we can 5727// ignore overflow and just impose a hard-limit on seconds using the value 5728// of "now + 100,000,000". This places a limit on the timeout of about 3.17 5729// years from "now". 5730 5731static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5732 assert(time > 0, "convertTime"); 5733 time_t max_secs = 0; 5734 5735 if (!os::supports_monotonic_clock() || isAbsolute) { 5736 struct timeval now; 5737 int status = gettimeofday(&now, NULL); 5738 assert(status == 0, "gettimeofday"); 5739 5740 max_secs = now.tv_sec + MAX_SECS; 5741 5742 if (isAbsolute) { 5743 jlong secs = time / 1000; 5744 if (secs > max_secs) { 5745 absTime->tv_sec = max_secs; 5746 } else { 5747 absTime->tv_sec = secs; 5748 } 5749 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5750 } else { 5751 jlong secs = time / NANOSECS_PER_SEC; 5752 if (secs >= MAX_SECS) { 5753 absTime->tv_sec = max_secs; 5754 absTime->tv_nsec = 0; 5755 } else { 5756 absTime->tv_sec = now.tv_sec + secs; 5757 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5758 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5759 absTime->tv_nsec -= NANOSECS_PER_SEC; 5760 ++absTime->tv_sec; // note: this must be <= max_secs 5761 } 5762 } 5763 } 5764 } else { 5765 // must be relative using monotonic clock 5766 struct timespec now; 5767 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5768 assert_status(status == 0, status, "clock_gettime"); 5769 max_secs = now.tv_sec + MAX_SECS; 5770 jlong secs = time / NANOSECS_PER_SEC; 5771 if (secs >= MAX_SECS) { 5772 absTime->tv_sec = max_secs; 5773 absTime->tv_nsec = 0; 5774 } else { 5775 absTime->tv_sec = now.tv_sec + secs; 5776 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5777 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5778 absTime->tv_nsec -= NANOSECS_PER_SEC; 5779 ++absTime->tv_sec; // note: this must be <= max_secs 5780 } 5781 } 5782 } 5783 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5784 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5785 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5786 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5787} 5788 5789void Parker::park(bool isAbsolute, jlong time) { 5790 // Ideally we'd do something useful while spinning, such 5791 // as calling unpackTime(). 5792 5793 // Optional fast-path check: 5794 // Return immediately if a permit is available. 5795 // We depend on Atomic::xchg() having full barrier semantics 5796 // since we are doing a lock-free update to _counter. 5797 if (Atomic::xchg(0, &_counter) > 0) return; 5798 5799 Thread* thread = Thread::current(); 5800 assert(thread->is_Java_thread(), "Must be JavaThread"); 5801 JavaThread *jt = (JavaThread *)thread; 5802 5803 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5804 // Check interrupt before trying to wait 5805 if (Thread::is_interrupted(thread, false)) { 5806 return; 5807 } 5808 5809 // Next, demultiplex/decode time arguments 5810 timespec absTime; 5811 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5812 return; 5813 } 5814 if (time > 0) { 5815 unpackTime(&absTime, isAbsolute, time); 5816 } 5817 5818 5819 // Enter safepoint region 5820 // Beware of deadlocks such as 6317397. 5821 // The per-thread Parker:: mutex is a classic leaf-lock. 5822 // In particular a thread must never block on the Threads_lock while 5823 // holding the Parker:: mutex. If safepoints are pending both the 5824 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5825 ThreadBlockInVM tbivm(jt); 5826 5827 // Don't wait if cannot get lock since interference arises from 5828 // unblocking. Also. check interrupt before trying wait 5829 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5830 return; 5831 } 5832 5833 int status; 5834 if (_counter > 0) { // no wait needed 5835 _counter = 0; 5836 status = pthread_mutex_unlock(_mutex); 5837 assert_status(status == 0, status, "invariant"); 5838 // Paranoia to ensure our locked and lock-free paths interact 5839 // correctly with each other and Java-level accesses. 5840 OrderAccess::fence(); 5841 return; 5842 } 5843 5844#ifdef ASSERT 5845 // Don't catch signals while blocked; let the running threads have the signals. 5846 // (This allows a debugger to break into the running thread.) 5847 sigset_t oldsigs; 5848 sigemptyset(&oldsigs); 5849 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5850 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5851#endif 5852 5853 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5854 jt->set_suspend_equivalent(); 5855 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5856 5857 assert(_cur_index == -1, "invariant"); 5858 if (time == 0) { 5859 _cur_index = REL_INDEX; // arbitrary choice when not timed 5860 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5861 } else { 5862 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5863 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5864 } 5865 _cur_index = -1; 5866 assert_status(status == 0 || status == EINTR || 5867 status == ETIME || status == ETIMEDOUT, 5868 status, "cond_timedwait"); 5869 5870#ifdef ASSERT 5871 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5872#endif 5873 5874 _counter = 0; 5875 status = pthread_mutex_unlock(_mutex); 5876 assert_status(status == 0, status, "invariant"); 5877 // Paranoia to ensure our locked and lock-free paths interact 5878 // correctly with each other and Java-level accesses. 5879 OrderAccess::fence(); 5880 5881 // If externally suspended while waiting, re-suspend 5882 if (jt->handle_special_suspend_equivalent_condition()) { 5883 jt->java_suspend_self(); 5884 } 5885} 5886 5887void Parker::unpark() { 5888 int status = pthread_mutex_lock(_mutex); 5889 assert_status(status == 0, status, "invariant"); 5890 const int s = _counter; 5891 _counter = 1; 5892 // must capture correct index before unlocking 5893 int index = _cur_index; 5894 status = pthread_mutex_unlock(_mutex); 5895 assert_status(status == 0, status, "invariant"); 5896 if (s < 1 && index != -1) { 5897 // thread is definitely parked 5898 status = pthread_cond_signal(&_cond[index]); 5899 assert_status(status == 0, status, "invariant"); 5900 } 5901} 5902 5903 5904extern char** environ; 5905 5906// Run the specified command in a separate process. Return its exit value, 5907// or -1 on failure (e.g. can't fork a new process). 5908// Unlike system(), this function can be called from signal handler. It 5909// doesn't block SIGINT et al. 5910int os::fork_and_exec(char* cmd) { 5911 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5912 5913 pid_t pid = fork(); 5914 5915 if (pid < 0) { 5916 // fork failed 5917 return -1; 5918 5919 } else if (pid == 0) { 5920 // child process 5921 5922 execve("/bin/sh", (char* const*)argv, environ); 5923 5924 // execve failed 5925 _exit(-1); 5926 5927 } else { 5928 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5929 // care about the actual exit code, for now. 5930 5931 int status; 5932 5933 // Wait for the child process to exit. This returns immediately if 5934 // the child has already exited. */ 5935 while (waitpid(pid, &status, 0) < 0) { 5936 switch (errno) { 5937 case ECHILD: return 0; 5938 case EINTR: break; 5939 default: return -1; 5940 } 5941 } 5942 5943 if (WIFEXITED(status)) { 5944 // The child exited normally; get its exit code. 5945 return WEXITSTATUS(status); 5946 } else if (WIFSIGNALED(status)) { 5947 // The child exited because of a signal 5948 // The best value to return is 0x80 + signal number, 5949 // because that is what all Unix shells do, and because 5950 // it allows callers to distinguish between process exit and 5951 // process death by signal. 5952 return 0x80 + WTERMSIG(status); 5953 } else { 5954 // Unknown exit code; pass it through 5955 return status; 5956 } 5957 } 5958} 5959 5960// is_headless_jre() 5961// 5962// Test for the existence of xawt/libmawt.so or libawt_xawt.so 5963// in order to report if we are running in a headless jre 5964// 5965// Since JDK8 xawt/libmawt.so was moved into the same directory 5966// as libawt.so, and renamed libawt_xawt.so 5967// 5968bool os::is_headless_jre() { 5969 struct stat statbuf; 5970 char buf[MAXPATHLEN]; 5971 char libmawtpath[MAXPATHLEN]; 5972 const char *xawtstr = "/xawt/libmawt.so"; 5973 const char *new_xawtstr = "/libawt_xawt.so"; 5974 char *p; 5975 5976 // Get path to libjvm.so 5977 os::jvm_path(buf, sizeof(buf)); 5978 5979 // Get rid of libjvm.so 5980 p = strrchr(buf, '/'); 5981 if (p == NULL) { 5982 return false; 5983 } else { 5984 *p = '\0'; 5985 } 5986 5987 // Get rid of client or server 5988 p = strrchr(buf, '/'); 5989 if (p == NULL) { 5990 return false; 5991 } else { 5992 *p = '\0'; 5993 } 5994 5995 // check xawt/libmawt.so 5996 strcpy(libmawtpath, buf); 5997 strcat(libmawtpath, xawtstr); 5998 if (::stat(libmawtpath, &statbuf) == 0) return false; 5999 6000 // check libawt_xawt.so 6001 strcpy(libmawtpath, buf); 6002 strcat(libmawtpath, new_xawtstr); 6003 if (::stat(libmawtpath, &statbuf) == 0) return false; 6004 6005 return true; 6006} 6007 6008// Get the default path to the core file 6009// Returns the length of the string 6010int os::get_core_path(char* buffer, size_t bufferSize) { 6011 /* 6012 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 6013 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 6014 */ 6015 const int core_pattern_len = 129; 6016 char core_pattern[core_pattern_len] = {0}; 6017 6018 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 6019 if (core_pattern_file == -1) { 6020 return -1; 6021 } 6022 6023 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 6024 ::close(core_pattern_file); 6025 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 6026 return -1; 6027 } 6028 if (core_pattern[ret-1] == '\n') { 6029 core_pattern[ret-1] = '\0'; 6030 } else { 6031 core_pattern[ret] = '\0'; 6032 } 6033 6034 char *pid_pos = strstr(core_pattern, "%p"); 6035 int written; 6036 6037 if (core_pattern[0] == '/') { 6038 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 6039 } else { 6040 char cwd[PATH_MAX]; 6041 6042 const char* p = get_current_directory(cwd, PATH_MAX); 6043 if (p == NULL) { 6044 return -1; 6045 } 6046 6047 if (core_pattern[0] == '|') { 6048 written = jio_snprintf(buffer, bufferSize, 6049 "\"%s\" (or dumping to %s/core.%d)", 6050 &core_pattern[1], p, current_process_id()); 6051 } else { 6052 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 6053 } 6054 } 6055 6056 if (written < 0) { 6057 return -1; 6058 } 6059 6060 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 6061 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 6062 6063 if (core_uses_pid_file != -1) { 6064 char core_uses_pid = 0; 6065 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 6066 ::close(core_uses_pid_file); 6067 6068 if (core_uses_pid == '1') { 6069 jio_snprintf(buffer + written, bufferSize - written, 6070 ".%d", current_process_id()); 6071 } 6072 } 6073 } 6074 6075 return strlen(buffer); 6076} 6077 6078bool os::start_debugging(char *buf, int buflen) { 6079 int len = (int)strlen(buf); 6080 char *p = &buf[len]; 6081 6082 jio_snprintf(p, buflen-len, 6083 "\n\n" 6084 "Do you want to debug the problem?\n\n" 6085 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 6086 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 6087 "Otherwise, press RETURN to abort...", 6088 os::current_process_id(), os::current_process_id(), 6089 os::current_thread_id(), os::current_thread_id()); 6090 6091 bool yes = os::message_box("Unexpected Error", buf); 6092 6093 if (yes) { 6094 // yes, user asked VM to launch debugger 6095 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 6096 os::current_process_id(), os::current_process_id()); 6097 6098 os::fork_and_exec(buf); 6099 yes = false; 6100 } 6101 return yes; 6102} 6103 6104static inline struct timespec get_mtime(const char* filename) { 6105 struct stat st; 6106 int ret = os::stat(filename, &st); 6107 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno)); 6108 return st.st_mtim; 6109} 6110 6111int os::compare_file_modified_times(const char* file1, const char* file2) { 6112 struct timespec filetime1 = get_mtime(file1); 6113 struct timespec filetime2 = get_mtime(file2); 6114 int diff = filetime1.tv_sec - filetime2.tv_sec; 6115 if (diff == 0) { 6116 return filetime1.tv_nsec - filetime2.tv_nsec; 6117 } 6118 return diff; 6119} 6120 6121/////////////// Unit tests /////////////// 6122 6123#ifndef PRODUCT 6124 6125#define test_log(...) \ 6126 do { \ 6127 if (VerboseInternalVMTests) { \ 6128 tty->print_cr(__VA_ARGS__); \ 6129 tty->flush(); \ 6130 } \ 6131 } while (false) 6132 6133class TestReserveMemorySpecial : AllStatic { 6134 public: 6135 static void small_page_write(void* addr, size_t size) { 6136 size_t page_size = os::vm_page_size(); 6137 6138 char* end = (char*)addr + size; 6139 for (char* p = (char*)addr; p < end; p += page_size) { 6140 *p = 1; 6141 } 6142 } 6143 6144 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6145 if (!UseHugeTLBFS) { 6146 return; 6147 } 6148 6149 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6150 6151 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6152 6153 if (addr != NULL) { 6154 small_page_write(addr, size); 6155 6156 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6157 } 6158 } 6159 6160 static void test_reserve_memory_special_huge_tlbfs_only() { 6161 if (!UseHugeTLBFS) { 6162 return; 6163 } 6164 6165 size_t lp = os::large_page_size(); 6166 6167 for (size_t size = lp; size <= lp * 10; size += lp) { 6168 test_reserve_memory_special_huge_tlbfs_only(size); 6169 } 6170 } 6171 6172 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6173 size_t lp = os::large_page_size(); 6174 size_t ag = os::vm_allocation_granularity(); 6175 6176 // sizes to test 6177 const size_t sizes[] = { 6178 lp, lp + ag, lp + lp / 2, lp * 2, 6179 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6180 lp * 10, lp * 10 + lp / 2 6181 }; 6182 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6183 6184 // For each size/alignment combination, we test three scenarios: 6185 // 1) with req_addr == NULL 6186 // 2) with a non-null req_addr at which we expect to successfully allocate 6187 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6188 // expect the allocation to either fail or to ignore req_addr 6189 6190 // Pre-allocate two areas; they shall be as large as the largest allocation 6191 // and aligned to the largest alignment we will be testing. 6192 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6193 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6194 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6195 -1, 0); 6196 assert(mapping1 != MAP_FAILED, "should work"); 6197 6198 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6199 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6200 -1, 0); 6201 assert(mapping2 != MAP_FAILED, "should work"); 6202 6203 // Unmap the first mapping, but leave the second mapping intact: the first 6204 // mapping will serve as a value for a "good" req_addr (case 2). The second 6205 // mapping, still intact, as "bad" req_addr (case 3). 6206 ::munmap(mapping1, mapping_size); 6207 6208 // Case 1 6209 test_log("%s, req_addr NULL:", __FUNCTION__); 6210 test_log("size align result"); 6211 6212 for (int i = 0; i < num_sizes; i++) { 6213 const size_t size = sizes[i]; 6214 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6215 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6216 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6217 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6218 if (p != NULL) { 6219 assert(is_ptr_aligned(p, alignment), "must be"); 6220 small_page_write(p, size); 6221 os::Linux::release_memory_special_huge_tlbfs(p, size); 6222 } 6223 } 6224 } 6225 6226 // Case 2 6227 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6228 test_log("size align req_addr result"); 6229 6230 for (int i = 0; i < num_sizes; i++) { 6231 const size_t size = sizes[i]; 6232 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6233 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 6234 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6235 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6236 size, alignment, p2i(req_addr), p2i(p), 6237 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6238 if (p != NULL) { 6239 assert(p == req_addr, "must be"); 6240 small_page_write(p, size); 6241 os::Linux::release_memory_special_huge_tlbfs(p, size); 6242 } 6243 } 6244 } 6245 6246 // Case 3 6247 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6248 test_log("size align req_addr result"); 6249 6250 for (int i = 0; i < num_sizes; i++) { 6251 const size_t size = sizes[i]; 6252 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6253 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6254 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6255 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6256 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6257 // as the area around req_addr contains already existing mappings, the API should always 6258 // return NULL (as per contract, it cannot return another address) 6259 assert(p == NULL, "must be"); 6260 } 6261 } 6262 6263 ::munmap(mapping2, mapping_size); 6264 6265 } 6266 6267 static void test_reserve_memory_special_huge_tlbfs() { 6268 if (!UseHugeTLBFS) { 6269 return; 6270 } 6271 6272 test_reserve_memory_special_huge_tlbfs_only(); 6273 test_reserve_memory_special_huge_tlbfs_mixed(); 6274 } 6275 6276 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6277 if (!UseSHM) { 6278 return; 6279 } 6280 6281 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6282 6283 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6284 6285 if (addr != NULL) { 6286 assert(is_ptr_aligned(addr, alignment), "Check"); 6287 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6288 6289 small_page_write(addr, size); 6290 6291 os::Linux::release_memory_special_shm(addr, size); 6292 } 6293 } 6294 6295 static void test_reserve_memory_special_shm() { 6296 size_t lp = os::large_page_size(); 6297 size_t ag = os::vm_allocation_granularity(); 6298 6299 for (size_t size = ag; size < lp * 3; size += ag) { 6300 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6301 test_reserve_memory_special_shm(size, alignment); 6302 } 6303 } 6304 } 6305 6306 static void test() { 6307 test_reserve_memory_special_huge_tlbfs(); 6308 test_reserve_memory_special_shm(); 6309 } 6310}; 6311 6312void TestReserveMemorySpecial_test() { 6313 TestReserveMemorySpecial::test(); 6314} 6315 6316#endif 6317