os_linux.cpp revision 8980:bba7a69f67c7
1/* 2 * Copyright (c) 1999, 2015, 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 "memory/allocation.inline.hpp" 36#include "memory/filemap.hpp" 37#include "mutex_linux.inline.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 109PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 110 111// if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 112// getrusage() is prepared to handle the associated failure. 113#ifndef RUSAGE_THREAD 114 #define RUSAGE_THREAD (1) /* only the calling thread */ 115#endif 116 117#define MAX_PATH (2 * K) 118 119#define MAX_SECS 100000000 120 121// for timer info max values which include all bits 122#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 123 124#define LARGEPAGES_BIT (1 << 6) 125//////////////////////////////////////////////////////////////////////////////// 126// global variables 127julong os::Linux::_physical_memory = 0; 128 129address os::Linux::_initial_thread_stack_bottom = NULL; 130uintptr_t os::Linux::_initial_thread_stack_size = 0; 131 132int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 133int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 134int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 135Mutex* os::Linux::_createThread_lock = NULL; 136pthread_t os::Linux::_main_thread; 137int os::Linux::_page_size = -1; 138const int os::Linux::_vm_default_page_size = (8 * K); 139bool os::Linux::_supports_fast_thread_cpu_time = false; 140const char * os::Linux::_glibc_version = NULL; 141const char * os::Linux::_libpthread_version = NULL; 142pthread_condattr_t os::Linux::_condattr[1]; 143 144static jlong initial_time_count=0; 145 146static int clock_tics_per_sec = 100; 147 148// For diagnostics to print a message once. see run_periodic_checks 149static sigset_t check_signal_done; 150static bool check_signals = true; 151 152// Signal number used to suspend/resume a thread 153 154// do not use any signal number less than SIGSEGV, see 4355769 155static int SR_signum = SIGUSR2; 156sigset_t SR_sigset; 157 158// Declarations 159static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 160 161// utility functions 162 163static int SR_initialize(); 164 165julong os::available_memory() { 166 return Linux::available_memory(); 167} 168 169julong os::Linux::available_memory() { 170 // values in struct sysinfo are "unsigned long" 171 struct sysinfo si; 172 sysinfo(&si); 173 174 return (julong)si.freeram * si.mem_unit; 175} 176 177julong os::physical_memory() { 178 return Linux::physical_memory(); 179} 180 181// Return true if user is running as root. 182 183bool os::have_special_privileges() { 184 static bool init = false; 185 static bool privileges = false; 186 if (!init) { 187 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 188 init = true; 189 } 190 return privileges; 191} 192 193 194#ifndef SYS_gettid 195// i386: 224, ia64: 1105, amd64: 186, sparc 143 196 #ifdef __ia64__ 197 #define SYS_gettid 1105 198 #else 199 #ifdef __i386__ 200 #define SYS_gettid 224 201 #else 202 #ifdef __amd64__ 203 #define SYS_gettid 186 204 #else 205 #ifdef __sparc__ 206 #define SYS_gettid 143 207 #else 208 #error define gettid for the arch 209 #endif 210 #endif 211 #endif 212 #endif 213#endif 214 215// Cpu architecture string 216static char cpu_arch[] = HOTSPOT_LIB_ARCH; 217 218 219// pid_t gettid() 220// 221// Returns the kernel thread id of the currently running thread. Kernel 222// thread id is used to access /proc. 223pid_t os::Linux::gettid() { 224 int rslt = syscall(SYS_gettid); 225 assert(rslt != -1, "must be."); // old linuxthreads implementation? 226 return (pid_t)rslt; 227} 228 229// Most versions of linux have a bug where the number of processors are 230// determined by looking at the /proc file system. In a chroot environment, 231// the system call returns 1. This causes the VM to act as if it is 232// a single processor and elide locking (see is_MP() call). 233static bool unsafe_chroot_detected = false; 234static const char *unstable_chroot_error = "/proc file system not found.\n" 235 "Java may be unstable running multithreaded in a chroot " 236 "environment on Linux when /proc filesystem is not mounted."; 237 238void os::Linux::initialize_system_info() { 239 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 240 if (processor_count() == 1) { 241 pid_t pid = os::Linux::gettid(); 242 char fname[32]; 243 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 244 FILE *fp = fopen(fname, "r"); 245 if (fp == NULL) { 246 unsafe_chroot_detected = true; 247 } else { 248 fclose(fp); 249 } 250 } 251 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 252 assert(processor_count() > 0, "linux error"); 253} 254 255void os::init_system_properties_values() { 256 // The next steps are taken in the product version: 257 // 258 // Obtain the JAVA_HOME value from the location of libjvm.so. 259 // This library should be located at: 260 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 261 // 262 // If "/jre/lib/" appears at the right place in the path, then we 263 // assume libjvm.so is installed in a JDK and we use this path. 264 // 265 // Otherwise exit with message: "Could not create the Java virtual machine." 266 // 267 // The following extra steps are taken in the debugging version: 268 // 269 // If "/jre/lib/" does NOT appear at the right place in the path 270 // instead of exit check for $JAVA_HOME environment variable. 271 // 272 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 273 // then we append a fake suffix "hotspot/libjvm.so" to this path so 274 // it looks like libjvm.so is installed there 275 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 276 // 277 // Otherwise exit. 278 // 279 // Important note: if the location of libjvm.so changes this 280 // code needs to be changed accordingly. 281 282 // See ld(1): 283 // The linker uses the following search paths to locate required 284 // shared libraries: 285 // 1: ... 286 // ... 287 // 7: The default directories, normally /lib and /usr/lib. 288#if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 289 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 290#else 291 #define DEFAULT_LIBPATH "/lib:/usr/lib" 292#endif 293 294// Base path of extensions installed on the system. 295#define SYS_EXT_DIR "/usr/java/packages" 296#define EXTENSIONS_DIR "/lib/ext" 297 298 // Buffer that fits several sprintfs. 299 // Note that the space for the colon and the trailing null are provided 300 // by the nulls included by the sizeof operator. 301 const size_t bufsize = 302 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 303 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 304 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 305 306 // sysclasspath, java_home, dll_dir 307 { 308 char *pslash; 309 os::jvm_path(buf, bufsize); 310 311 // Found the full path to libjvm.so. 312 // Now cut the path to <java_home>/jre if we can. 313 pslash = strrchr(buf, '/'); 314 if (pslash != NULL) { 315 *pslash = '\0'; // Get rid of /libjvm.so. 316 } 317 pslash = strrchr(buf, '/'); 318 if (pslash != NULL) { 319 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 320 } 321 Arguments::set_dll_dir(buf); 322 323 if (pslash != NULL) { 324 pslash = strrchr(buf, '/'); 325 if (pslash != NULL) { 326 *pslash = '\0'; // Get rid of /<arch>. 327 pslash = strrchr(buf, '/'); 328 if (pslash != NULL) { 329 *pslash = '\0'; // Get rid of /lib. 330 } 331 } 332 } 333 Arguments::set_java_home(buf); 334 set_boot_path('/', ':'); 335 } 336 337 // Where to look for native libraries. 338 // 339 // Note: Due to a legacy implementation, most of the library path 340 // is set in the launcher. This was to accomodate linking restrictions 341 // on legacy Linux implementations (which are no longer supported). 342 // Eventually, all the library path setting will be done here. 343 // 344 // However, to prevent the proliferation of improperly built native 345 // libraries, the new path component /usr/java/packages is added here. 346 // Eventually, all the library path setting will be done here. 347 { 348 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 349 // should always exist (until the legacy problem cited above is 350 // addressed). 351 const char *v = ::getenv("LD_LIBRARY_PATH"); 352 const char *v_colon = ":"; 353 if (v == NULL) { v = ""; v_colon = ""; } 354 // That's +1 for the colon and +1 for the trailing '\0'. 355 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 356 strlen(v) + 1 + 357 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1, 358 mtInternal); 359 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch); 360 Arguments::set_library_path(ld_library_path); 361 FREE_C_HEAP_ARRAY(char, ld_library_path); 362 } 363 364 // Extensions directories. 365 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 366 Arguments::set_ext_dirs(buf); 367 368 FREE_C_HEAP_ARRAY(char, buf); 369 370#undef DEFAULT_LIBPATH 371#undef SYS_EXT_DIR 372#undef EXTENSIONS_DIR 373} 374 375//////////////////////////////////////////////////////////////////////////////// 376// breakpoint support 377 378void os::breakpoint() { 379 BREAKPOINT; 380} 381 382extern "C" void breakpoint() { 383 // use debugger to set breakpoint here 384} 385 386//////////////////////////////////////////////////////////////////////////////// 387// signal support 388 389debug_only(static bool signal_sets_initialized = false); 390static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 391 392bool os::Linux::is_sig_ignored(int sig) { 393 struct sigaction oact; 394 sigaction(sig, (struct sigaction*)NULL, &oact); 395 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 396 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 397 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 398 return true; 399 } else { 400 return false; 401 } 402} 403 404void os::Linux::signal_sets_init() { 405 // Should also have an assertion stating we are still single-threaded. 406 assert(!signal_sets_initialized, "Already initialized"); 407 // Fill in signals that are necessarily unblocked for all threads in 408 // the VM. Currently, we unblock the following signals: 409 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 410 // by -Xrs (=ReduceSignalUsage)); 411 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 412 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 413 // the dispositions or masks wrt these signals. 414 // Programs embedding the VM that want to use the above signals for their 415 // own purposes must, at this time, use the "-Xrs" option to prevent 416 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 417 // (See bug 4345157, and other related bugs). 418 // In reality, though, unblocking these signals is really a nop, since 419 // these signals are not blocked by default. 420 sigemptyset(&unblocked_sigs); 421 sigemptyset(&allowdebug_blocked_sigs); 422 sigaddset(&unblocked_sigs, SIGILL); 423 sigaddset(&unblocked_sigs, SIGSEGV); 424 sigaddset(&unblocked_sigs, SIGBUS); 425 sigaddset(&unblocked_sigs, SIGFPE); 426#if defined(PPC64) 427 sigaddset(&unblocked_sigs, SIGTRAP); 428#endif 429 sigaddset(&unblocked_sigs, SR_signum); 430 431 if (!ReduceSignalUsage) { 432 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 433 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 434 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 435 } 436 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 437 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 438 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 439 } 440 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 441 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 442 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 443 } 444 } 445 // Fill in signals that are blocked by all but the VM thread. 446 sigemptyset(&vm_sigs); 447 if (!ReduceSignalUsage) { 448 sigaddset(&vm_sigs, BREAK_SIGNAL); 449 } 450 debug_only(signal_sets_initialized = true); 451 452} 453 454// These are signals that are unblocked while a thread is running Java. 455// (For some reason, they get blocked by default.) 456sigset_t* os::Linux::unblocked_signals() { 457 assert(signal_sets_initialized, "Not initialized"); 458 return &unblocked_sigs; 459} 460 461// These are the signals that are blocked while a (non-VM) thread is 462// running Java. Only the VM thread handles these signals. 463sigset_t* os::Linux::vm_signals() { 464 assert(signal_sets_initialized, "Not initialized"); 465 return &vm_sigs; 466} 467 468// These are signals that are blocked during cond_wait to allow debugger in 469sigset_t* os::Linux::allowdebug_blocked_signals() { 470 assert(signal_sets_initialized, "Not initialized"); 471 return &allowdebug_blocked_sigs; 472} 473 474void os::Linux::hotspot_sigmask(Thread* thread) { 475 476 //Save caller's signal mask before setting VM signal mask 477 sigset_t caller_sigmask; 478 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 479 480 OSThread* osthread = thread->osthread(); 481 osthread->set_caller_sigmask(caller_sigmask); 482 483 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 484 485 if (!ReduceSignalUsage) { 486 if (thread->is_VM_thread()) { 487 // Only the VM thread handles BREAK_SIGNAL ... 488 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 489 } else { 490 // ... all other threads block BREAK_SIGNAL 491 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 492 } 493 } 494} 495 496////////////////////////////////////////////////////////////////////////////// 497// detecting pthread library 498 499void os::Linux::libpthread_init() { 500 // Save glibc and pthread version strings. 501#if !defined(_CS_GNU_LIBC_VERSION) || \ 502 !defined(_CS_GNU_LIBPTHREAD_VERSION) 503 #error "glibc too old (< 2.3.2)" 504#endif 505 506 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 507 assert(n > 0, "cannot retrieve glibc version"); 508 char *str = (char *)malloc(n, mtInternal); 509 confstr(_CS_GNU_LIBC_VERSION, str, n); 510 os::Linux::set_glibc_version(str); 511 512 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 513 assert(n > 0, "cannot retrieve pthread version"); 514 str = (char *)malloc(n, mtInternal); 515 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 516 os::Linux::set_libpthread_version(str); 517} 518 519///////////////////////////////////////////////////////////////////////////// 520// thread stack expansion 521 522// os::Linux::manually_expand_stack() takes care of expanding the thread 523// stack. Note that this is normally not needed: pthread stacks allocate 524// thread stack using mmap() without MAP_NORESERVE, so the stack is already 525// committed. Therefore it is not necessary to expand the stack manually. 526// 527// Manually expanding the stack was historically needed on LinuxThreads 528// thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 529// it is kept to deal with very rare corner cases: 530// 531// For one, user may run the VM on an own implementation of threads 532// whose stacks are - like the old LinuxThreads - implemented using 533// mmap(MAP_GROWSDOWN). 534// 535// Also, this coding may be needed if the VM is running on the primordial 536// thread. Normally we avoid running on the primordial thread; however, 537// user may still invoke the VM on the primordial thread. 538// 539// The following historical comment describes the details about running 540// on a thread stack allocated with mmap(MAP_GROWSDOWN): 541 542 543// Force Linux kernel to expand current thread stack. If "bottom" is close 544// to the stack guard, caller should block all signals. 545// 546// MAP_GROWSDOWN: 547// A special mmap() flag that is used to implement thread stacks. It tells 548// kernel that the memory region should extend downwards when needed. This 549// allows early versions of LinuxThreads to only mmap the first few pages 550// when creating a new thread. Linux kernel will automatically expand thread 551// stack as needed (on page faults). 552// 553// However, because the memory region of a MAP_GROWSDOWN stack can grow on 554// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 555// region, it's hard to tell if the fault is due to a legitimate stack 556// access or because of reading/writing non-exist memory (e.g. buffer 557// overrun). As a rule, if the fault happens below current stack pointer, 558// Linux kernel does not expand stack, instead a SIGSEGV is sent to the 559// application (see Linux kernel fault.c). 560// 561// This Linux feature can cause SIGSEGV when VM bangs thread stack for 562// stack overflow detection. 563// 564// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 565// not use MAP_GROWSDOWN. 566// 567// To get around the problem and allow stack banging on Linux, we need to 568// manually expand thread stack after receiving the SIGSEGV. 569// 570// There are two ways to expand thread stack to address "bottom", we used 571// both of them in JVM before 1.5: 572// 1. adjust stack pointer first so that it is below "bottom", and then 573// touch "bottom" 574// 2. mmap() the page in question 575// 576// Now alternate signal stack is gone, it's harder to use 2. For instance, 577// if current sp is already near the lower end of page 101, and we need to 578// call mmap() to map page 100, it is possible that part of the mmap() frame 579// will be placed in page 100. When page 100 is mapped, it is zero-filled. 580// That will destroy the mmap() frame and cause VM to crash. 581// 582// The following code works by adjusting sp first, then accessing the "bottom" 583// page to force a page fault. Linux kernel will then automatically expand the 584// stack mapping. 585// 586// _expand_stack_to() assumes its frame size is less than page size, which 587// should always be true if the function is not inlined. 588 589#if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 590 #define NOINLINE 591#else 592 #define NOINLINE __attribute__ ((noinline)) 593#endif 594 595static void _expand_stack_to(address bottom) NOINLINE; 596 597static void _expand_stack_to(address bottom) { 598 address sp; 599 size_t size; 600 volatile char *p; 601 602 // Adjust bottom to point to the largest address within the same page, it 603 // gives us a one-page buffer if alloca() allocates slightly more memory. 604 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 605 bottom += os::Linux::page_size() - 1; 606 607 // sp might be slightly above current stack pointer; if that's the case, we 608 // will alloca() a little more space than necessary, which is OK. Don't use 609 // os::current_stack_pointer(), as its result can be slightly below current 610 // stack pointer, causing us to not alloca enough to reach "bottom". 611 sp = (address)&sp; 612 613 if (sp > bottom) { 614 size = sp - bottom; 615 p = (volatile char *)alloca(size); 616 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 617 p[0] = '\0'; 618 } 619} 620 621bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 622 assert(t!=NULL, "just checking"); 623 assert(t->osthread()->expanding_stack(), "expand should be set"); 624 assert(t->stack_base() != NULL, "stack_base was not initialized"); 625 626 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 627 sigset_t mask_all, old_sigset; 628 sigfillset(&mask_all); 629 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 630 _expand_stack_to(addr); 631 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 632 return true; 633 } 634 return false; 635} 636 637////////////////////////////////////////////////////////////////////////////// 638// create new thread 639 640// Thread start routine for all newly created threads 641static void *java_start(Thread *thread) { 642 // Try to randomize the cache line index of hot stack frames. 643 // This helps when threads of the same stack traces evict each other's 644 // cache lines. The threads can be either from the same JVM instance, or 645 // from different JVM instances. The benefit is especially true for 646 // processors with hyperthreading technology. 647 static int counter = 0; 648 int pid = os::current_process_id(); 649 alloca(((pid ^ counter++) & 7) * 128); 650 651 ThreadLocalStorage::set_thread(thread); 652 653 OSThread* osthread = thread->osthread(); 654 Monitor* sync = osthread->startThread_lock(); 655 656 osthread->set_thread_id(os::current_thread_id()); 657 658 if (UseNUMA) { 659 int lgrp_id = os::numa_get_group_id(); 660 if (lgrp_id != -1) { 661 thread->set_lgrp_id(lgrp_id); 662 } 663 } 664 // initialize signal mask for this thread 665 os::Linux::hotspot_sigmask(thread); 666 667 // initialize floating point control register 668 os::Linux::init_thread_fpu_state(); 669 670 // handshaking with parent thread 671 { 672 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 673 674 // notify parent thread 675 osthread->set_state(INITIALIZED); 676 sync->notify_all(); 677 678 // wait until os::start_thread() 679 while (osthread->get_state() == INITIALIZED) { 680 sync->wait(Mutex::_no_safepoint_check_flag); 681 } 682 } 683 684 // call one more level start routine 685 thread->run(); 686 687 return 0; 688} 689 690bool os::create_thread(Thread* thread, ThreadType thr_type, 691 size_t stack_size) { 692 assert(thread->osthread() == NULL, "caller responsible"); 693 694 // Allocate the OSThread object 695 OSThread* osthread = new OSThread(NULL, NULL); 696 if (osthread == NULL) { 697 return false; 698 } 699 700 // set the correct thread state 701 osthread->set_thread_type(thr_type); 702 703 // Initial state is ALLOCATED but not INITIALIZED 704 osthread->set_state(ALLOCATED); 705 706 thread->set_osthread(osthread); 707 708 // init thread attributes 709 pthread_attr_t attr; 710 pthread_attr_init(&attr); 711 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 712 713 // stack size 714 // calculate stack size if it's not specified by caller 715 if (stack_size == 0) { 716 stack_size = os::Linux::default_stack_size(thr_type); 717 718 switch (thr_type) { 719 case os::java_thread: 720 // Java threads use ThreadStackSize which default value can be 721 // changed with the flag -Xss 722 assert(JavaThread::stack_size_at_create() > 0, "this should be set"); 723 stack_size = JavaThread::stack_size_at_create(); 724 break; 725 case os::compiler_thread: 726 if (CompilerThreadStackSize > 0) { 727 stack_size = (size_t)(CompilerThreadStackSize * K); 728 break; 729 } // else fall through: 730 // use VMThreadStackSize if CompilerThreadStackSize is not defined 731 case os::vm_thread: 732 case os::pgc_thread: 733 case os::cgc_thread: 734 case os::watcher_thread: 735 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 736 break; 737 } 738 } 739 740 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 741 pthread_attr_setstacksize(&attr, stack_size); 742 743 // glibc guard page 744 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 745 746 ThreadState state; 747 748 { 749 pthread_t tid; 750 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 751 752 pthread_attr_destroy(&attr); 753 754 if (ret != 0) { 755 if (PrintMiscellaneous && (Verbose || WizardMode)) { 756 perror("pthread_create()"); 757 } 758 // Need to clean up stuff we've allocated so far 759 thread->set_osthread(NULL); 760 delete osthread; 761 return false; 762 } 763 764 // Store pthread info into the OSThread 765 osthread->set_pthread_id(tid); 766 767 // Wait until child thread is either initialized or aborted 768 { 769 Monitor* sync_with_child = osthread->startThread_lock(); 770 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 771 while ((state = osthread->get_state()) == ALLOCATED) { 772 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 773 } 774 } 775 } 776 777 // Aborted due to thread limit being reached 778 if (state == ZOMBIE) { 779 thread->set_osthread(NULL); 780 delete osthread; 781 return false; 782 } 783 784 // The thread is returned suspended (in state INITIALIZED), 785 // and is started higher up in the call chain 786 assert(state == INITIALIZED, "race condition"); 787 return true; 788} 789 790///////////////////////////////////////////////////////////////////////////// 791// attach existing thread 792 793// bootstrap the main thread 794bool os::create_main_thread(JavaThread* thread) { 795 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 796 return create_attached_thread(thread); 797} 798 799bool os::create_attached_thread(JavaThread* thread) { 800#ifdef ASSERT 801 thread->verify_not_published(); 802#endif 803 804 // Allocate the OSThread object 805 OSThread* osthread = new OSThread(NULL, NULL); 806 807 if (osthread == NULL) { 808 return false; 809 } 810 811 // Store pthread info into the OSThread 812 osthread->set_thread_id(os::Linux::gettid()); 813 osthread->set_pthread_id(::pthread_self()); 814 815 // initialize floating point control register 816 os::Linux::init_thread_fpu_state(); 817 818 // Initial thread state is RUNNABLE 819 osthread->set_state(RUNNABLE); 820 821 thread->set_osthread(osthread); 822 823 if (UseNUMA) { 824 int lgrp_id = os::numa_get_group_id(); 825 if (lgrp_id != -1) { 826 thread->set_lgrp_id(lgrp_id); 827 } 828 } 829 830 if (os::Linux::is_initial_thread()) { 831 // If current thread is initial thread, its stack is mapped on demand, 832 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 833 // the entire stack region to avoid SEGV in stack banging. 834 // It is also useful to get around the heap-stack-gap problem on SuSE 835 // kernel (see 4821821 for details). We first expand stack to the top 836 // of yellow zone, then enable stack yellow zone (order is significant, 837 // enabling yellow zone first will crash JVM on SuSE Linux), so there 838 // is no gap between the last two virtual memory regions. 839 840 JavaThread *jt = (JavaThread *)thread; 841 address addr = jt->stack_yellow_zone_base(); 842 assert(addr != NULL, "initialization problem?"); 843 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 844 845 osthread->set_expanding_stack(); 846 os::Linux::manually_expand_stack(jt, addr); 847 osthread->clear_expanding_stack(); 848 } 849 850 // initialize signal mask for this thread 851 // and save the caller's signal mask 852 os::Linux::hotspot_sigmask(thread); 853 854 return true; 855} 856 857void os::pd_start_thread(Thread* thread) { 858 OSThread * osthread = thread->osthread(); 859 assert(osthread->get_state() != INITIALIZED, "just checking"); 860 Monitor* sync_with_child = osthread->startThread_lock(); 861 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 862 sync_with_child->notify(); 863} 864 865// Free Linux resources related to the OSThread 866void os::free_thread(OSThread* osthread) { 867 assert(osthread != NULL, "osthread not set"); 868 869 if (Thread::current()->osthread() == osthread) { 870 // Restore caller's signal mask 871 sigset_t sigmask = osthread->caller_sigmask(); 872 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 873 } 874 875 delete osthread; 876} 877 878////////////////////////////////////////////////////////////////////////////// 879// thread local storage 880 881// Restore the thread pointer if the destructor is called. This is in case 882// someone from JNI code sets up a destructor with pthread_key_create to run 883// detachCurrentThread on thread death. Unless we restore the thread pointer we 884// will hang or crash. When detachCurrentThread is called the key will be set 885// to null and we will not be called again. If detachCurrentThread is never 886// called we could loop forever depending on the pthread implementation. 887static void restore_thread_pointer(void* p) { 888 Thread* thread = (Thread*) p; 889 os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread); 890} 891 892int os::allocate_thread_local_storage() { 893 pthread_key_t key; 894 int rslt = pthread_key_create(&key, restore_thread_pointer); 895 assert(rslt == 0, "cannot allocate thread local storage"); 896 return (int)key; 897} 898 899// Note: This is currently not used by VM, as we don't destroy TLS key 900// on VM exit. 901void os::free_thread_local_storage(int index) { 902 int rslt = pthread_key_delete((pthread_key_t)index); 903 assert(rslt == 0, "invalid index"); 904} 905 906void os::thread_local_storage_at_put(int index, void* value) { 907 int rslt = pthread_setspecific((pthread_key_t)index, value); 908 assert(rslt == 0, "pthread_setspecific failed"); 909} 910 911extern "C" Thread* get_thread() { 912 return ThreadLocalStorage::thread(); 913} 914 915////////////////////////////////////////////////////////////////////////////// 916// initial thread 917 918// Check if current thread is the initial thread, similar to Solaris thr_main. 919bool os::Linux::is_initial_thread(void) { 920 char dummy; 921 // If called before init complete, thread stack bottom will be null. 922 // Can be called if fatal error occurs before initialization. 923 if (initial_thread_stack_bottom() == NULL) return false; 924 assert(initial_thread_stack_bottom() != NULL && 925 initial_thread_stack_size() != 0, 926 "os::init did not locate initial thread's stack region"); 927 if ((address)&dummy >= initial_thread_stack_bottom() && 928 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 929 return true; 930 } else { 931 return false; 932 } 933} 934 935// Find the virtual memory area that contains addr 936static bool find_vma(address addr, address* vma_low, address* vma_high) { 937 FILE *fp = fopen("/proc/self/maps", "r"); 938 if (fp) { 939 address low, high; 940 while (!feof(fp)) { 941 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 942 if (low <= addr && addr < high) { 943 if (vma_low) *vma_low = low; 944 if (vma_high) *vma_high = high; 945 fclose(fp); 946 return true; 947 } 948 } 949 for (;;) { 950 int ch = fgetc(fp); 951 if (ch == EOF || ch == (int)'\n') break; 952 } 953 } 954 fclose(fp); 955 } 956 return false; 957} 958 959// Locate initial thread stack. This special handling of initial thread stack 960// is needed because pthread_getattr_np() on most (all?) Linux distros returns 961// bogus value for initial thread. 962void os::Linux::capture_initial_stack(size_t max_size) { 963 // stack size is the easy part, get it from RLIMIT_STACK 964 size_t stack_size; 965 struct rlimit rlim; 966 getrlimit(RLIMIT_STACK, &rlim); 967 stack_size = rlim.rlim_cur; 968 969 // 6308388: a bug in ld.so will relocate its own .data section to the 970 // lower end of primordial stack; reduce ulimit -s value a little bit 971 // so we won't install guard page on ld.so's data section. 972 stack_size -= 2 * page_size(); 973 974 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 975 // 7.1, in both cases we will get 2G in return value. 976 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 977 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 978 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 979 // in case other parts in glibc still assumes 2M max stack size. 980 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 981 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 982 if (stack_size > 2 * K * K IA64_ONLY(*2)) { 983 stack_size = 2 * K * K IA64_ONLY(*2); 984 } 985 // Try to figure out where the stack base (top) is. This is harder. 986 // 987 // When an application is started, glibc saves the initial stack pointer in 988 // a global variable "__libc_stack_end", which is then used by system 989 // libraries. __libc_stack_end should be pretty close to stack top. The 990 // variable is available since the very early days. However, because it is 991 // a private interface, it could disappear in the future. 992 // 993 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 994 // to __libc_stack_end, it is very close to stack top, but isn't the real 995 // stack top. Note that /proc may not exist if VM is running as a chroot 996 // program, so reading /proc/<pid>/stat could fail. Also the contents of 997 // /proc/<pid>/stat could change in the future (though unlikely). 998 // 999 // We try __libc_stack_end first. If that doesn't work, look for 1000 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1001 // as a hint, which should work well in most cases. 1002 1003 uintptr_t stack_start; 1004 1005 // try __libc_stack_end first 1006 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1007 if (p && *p) { 1008 stack_start = *p; 1009 } else { 1010 // see if we can get the start_stack field from /proc/self/stat 1011 FILE *fp; 1012 int pid; 1013 char state; 1014 int ppid; 1015 int pgrp; 1016 int session; 1017 int nr; 1018 int tpgrp; 1019 unsigned long flags; 1020 unsigned long minflt; 1021 unsigned long cminflt; 1022 unsigned long majflt; 1023 unsigned long cmajflt; 1024 unsigned long utime; 1025 unsigned long stime; 1026 long cutime; 1027 long cstime; 1028 long prio; 1029 long nice; 1030 long junk; 1031 long it_real; 1032 uintptr_t start; 1033 uintptr_t vsize; 1034 intptr_t rss; 1035 uintptr_t rsslim; 1036 uintptr_t scodes; 1037 uintptr_t ecode; 1038 int i; 1039 1040 // Figure what the primordial thread stack base is. Code is inspired 1041 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1042 // followed by command name surrounded by parentheses, state, etc. 1043 char stat[2048]; 1044 int statlen; 1045 1046 fp = fopen("/proc/self/stat", "r"); 1047 if (fp) { 1048 statlen = fread(stat, 1, 2047, fp); 1049 stat[statlen] = '\0'; 1050 fclose(fp); 1051 1052 // Skip pid and the command string. Note that we could be dealing with 1053 // weird command names, e.g. user could decide to rename java launcher 1054 // to "java 1.4.2 :)", then the stat file would look like 1055 // 1234 (java 1.4.2 :)) R ... ... 1056 // We don't really need to know the command string, just find the last 1057 // occurrence of ")" and then start parsing from there. See bug 4726580. 1058 char * s = strrchr(stat, ')'); 1059 1060 i = 0; 1061 if (s) { 1062 // Skip blank chars 1063 do { s++; } while (s && isspace(*s)); 1064 1065#define _UFM UINTX_FORMAT 1066#define _DFM INTX_FORMAT 1067 1068 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1069 // 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 1070 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, 1071 &state, // 3 %c 1072 &ppid, // 4 %d 1073 &pgrp, // 5 %d 1074 &session, // 6 %d 1075 &nr, // 7 %d 1076 &tpgrp, // 8 %d 1077 &flags, // 9 %lu 1078 &minflt, // 10 %lu 1079 &cminflt, // 11 %lu 1080 &majflt, // 12 %lu 1081 &cmajflt, // 13 %lu 1082 &utime, // 14 %lu 1083 &stime, // 15 %lu 1084 &cutime, // 16 %ld 1085 &cstime, // 17 %ld 1086 &prio, // 18 %ld 1087 &nice, // 19 %ld 1088 &junk, // 20 %ld 1089 &it_real, // 21 %ld 1090 &start, // 22 UINTX_FORMAT 1091 &vsize, // 23 UINTX_FORMAT 1092 &rss, // 24 INTX_FORMAT 1093 &rsslim, // 25 UINTX_FORMAT 1094 &scodes, // 26 UINTX_FORMAT 1095 &ecode, // 27 UINTX_FORMAT 1096 &stack_start); // 28 UINTX_FORMAT 1097 } 1098 1099#undef _UFM 1100#undef _DFM 1101 1102 if (i != 28 - 2) { 1103 assert(false, "Bad conversion from /proc/self/stat"); 1104 // product mode - assume we are the initial thread, good luck in the 1105 // embedded case. 1106 warning("Can't detect initial thread stack location - bad conversion"); 1107 stack_start = (uintptr_t) &rlim; 1108 } 1109 } else { 1110 // For some reason we can't open /proc/self/stat (for example, running on 1111 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1112 // most cases, so don't abort: 1113 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1114 stack_start = (uintptr_t) &rlim; 1115 } 1116 } 1117 1118 // Now we have a pointer (stack_start) very close to the stack top, the 1119 // next thing to do is to figure out the exact location of stack top. We 1120 // can find out the virtual memory area that contains stack_start by 1121 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1122 // and its upper limit is the real stack top. (again, this would fail if 1123 // running inside chroot, because /proc may not exist.) 1124 1125 uintptr_t stack_top; 1126 address low, high; 1127 if (find_vma((address)stack_start, &low, &high)) { 1128 // success, "high" is the true stack top. (ignore "low", because initial 1129 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1130 stack_top = (uintptr_t)high; 1131 } else { 1132 // failed, likely because /proc/self/maps does not exist 1133 warning("Can't detect initial thread stack location - find_vma failed"); 1134 // best effort: stack_start is normally within a few pages below the real 1135 // stack top, use it as stack top, and reduce stack size so we won't put 1136 // guard page outside stack. 1137 stack_top = stack_start; 1138 stack_size -= 16 * page_size(); 1139 } 1140 1141 // stack_top could be partially down the page so align it 1142 stack_top = align_size_up(stack_top, page_size()); 1143 1144 if (max_size && stack_size > max_size) { 1145 _initial_thread_stack_size = max_size; 1146 } else { 1147 _initial_thread_stack_size = stack_size; 1148 } 1149 1150 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1151 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1152} 1153 1154//////////////////////////////////////////////////////////////////////////////// 1155// time support 1156 1157// Time since start-up in seconds to a fine granularity. 1158// Used by VMSelfDestructTimer and the MemProfiler. 1159double os::elapsedTime() { 1160 1161 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1162} 1163 1164jlong os::elapsed_counter() { 1165 return javaTimeNanos() - initial_time_count; 1166} 1167 1168jlong os::elapsed_frequency() { 1169 return NANOSECS_PER_SEC; // nanosecond resolution 1170} 1171 1172bool os::supports_vtime() { return true; } 1173bool os::enable_vtime() { return false; } 1174bool os::vtime_enabled() { return false; } 1175 1176double os::elapsedVTime() { 1177 struct rusage usage; 1178 int retval = getrusage(RUSAGE_THREAD, &usage); 1179 if (retval == 0) { 1180 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); 1181 } else { 1182 // better than nothing, but not much 1183 return elapsedTime(); 1184 } 1185} 1186 1187jlong os::javaTimeMillis() { 1188 timeval time; 1189 int status = gettimeofday(&time, NULL); 1190 assert(status != -1, "linux error"); 1191 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1192} 1193 1194void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1195 timeval time; 1196 int status = gettimeofday(&time, NULL); 1197 assert(status != -1, "linux error"); 1198 seconds = jlong(time.tv_sec); 1199 nanos = jlong(time.tv_usec) * 1000; 1200} 1201 1202 1203#ifndef CLOCK_MONOTONIC 1204 #define CLOCK_MONOTONIC (1) 1205#endif 1206 1207void os::Linux::clock_init() { 1208 // we do dlopen's in this particular order due to bug in linux 1209 // dynamical loader (see 6348968) leading to crash on exit 1210 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1211 if (handle == NULL) { 1212 handle = dlopen("librt.so", RTLD_LAZY); 1213 } 1214 1215 if (handle) { 1216 int (*clock_getres_func)(clockid_t, struct timespec*) = 1217 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1218 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1219 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1220 if (clock_getres_func && clock_gettime_func) { 1221 // See if monotonic clock is supported by the kernel. Note that some 1222 // early implementations simply return kernel jiffies (updated every 1223 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1224 // for nano time (though the monotonic property is still nice to have). 1225 // It's fixed in newer kernels, however clock_getres() still returns 1226 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1227 // resolution for now. Hopefully as people move to new kernels, this 1228 // won't be a problem. 1229 struct timespec res; 1230 struct timespec tp; 1231 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1232 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1233 // yes, monotonic clock is supported 1234 _clock_gettime = clock_gettime_func; 1235 return; 1236 } else { 1237 // close librt if there is no monotonic clock 1238 dlclose(handle); 1239 } 1240 } 1241 } 1242 warning("No monotonic clock was available - timed services may " \ 1243 "be adversely affected if the time-of-day clock changes"); 1244} 1245 1246#ifndef SYS_clock_getres 1247 #if defined(IA32) || defined(AMD64) 1248 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1249 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1250 #else 1251 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1252 #define sys_clock_getres(x,y) -1 1253 #endif 1254#else 1255 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1256#endif 1257 1258void os::Linux::fast_thread_clock_init() { 1259 if (!UseLinuxPosixThreadCPUClocks) { 1260 return; 1261 } 1262 clockid_t clockid; 1263 struct timespec tp; 1264 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1265 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1266 1267 // Switch to using fast clocks for thread cpu time if 1268 // the sys_clock_getres() returns 0 error code. 1269 // Note, that some kernels may support the current thread 1270 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1271 // returned by the pthread_getcpuclockid(). 1272 // If the fast Posix clocks are supported then the sys_clock_getres() 1273 // must return at least tp.tv_sec == 0 which means a resolution 1274 // better than 1 sec. This is extra check for reliability. 1275 1276 if (pthread_getcpuclockid_func && 1277 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1278 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1279 _supports_fast_thread_cpu_time = true; 1280 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1281 } 1282} 1283 1284jlong os::javaTimeNanos() { 1285 if (os::supports_monotonic_clock()) { 1286 struct timespec tp; 1287 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1288 assert(status == 0, "gettime error"); 1289 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1290 return result; 1291 } else { 1292 timeval time; 1293 int status = gettimeofday(&time, NULL); 1294 assert(status != -1, "linux error"); 1295 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1296 return 1000 * usecs; 1297 } 1298} 1299 1300void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1301 if (os::supports_monotonic_clock()) { 1302 info_ptr->max_value = ALL_64_BITS; 1303 1304 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1305 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1306 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1307 } else { 1308 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1309 info_ptr->max_value = ALL_64_BITS; 1310 1311 // gettimeofday is a real time clock so it skips 1312 info_ptr->may_skip_backward = true; 1313 info_ptr->may_skip_forward = true; 1314 } 1315 1316 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1317} 1318 1319// Return the real, user, and system times in seconds from an 1320// arbitrary fixed point in the past. 1321bool os::getTimesSecs(double* process_real_time, 1322 double* process_user_time, 1323 double* process_system_time) { 1324 struct tms ticks; 1325 clock_t real_ticks = times(&ticks); 1326 1327 if (real_ticks == (clock_t) (-1)) { 1328 return false; 1329 } else { 1330 double ticks_per_second = (double) clock_tics_per_sec; 1331 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1332 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1333 *process_real_time = ((double) real_ticks) / ticks_per_second; 1334 1335 return true; 1336 } 1337} 1338 1339 1340char * os::local_time_string(char *buf, size_t buflen) { 1341 struct tm t; 1342 time_t long_time; 1343 time(&long_time); 1344 localtime_r(&long_time, &t); 1345 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1346 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1347 t.tm_hour, t.tm_min, t.tm_sec); 1348 return buf; 1349} 1350 1351struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1352 return localtime_r(clock, res); 1353} 1354 1355//////////////////////////////////////////////////////////////////////////////// 1356// runtime exit support 1357 1358// Note: os::shutdown() might be called very early during initialization, or 1359// called from signal handler. Before adding something to os::shutdown(), make 1360// sure it is async-safe and can handle partially initialized VM. 1361void os::shutdown() { 1362 1363 // allow PerfMemory to attempt cleanup of any persistent resources 1364 perfMemory_exit(); 1365 1366 // needs to remove object in file system 1367 AttachListener::abort(); 1368 1369 // flush buffered output, finish log files 1370 ostream_abort(); 1371 1372 // Check for abort hook 1373 abort_hook_t abort_hook = Arguments::abort_hook(); 1374 if (abort_hook != NULL) { 1375 abort_hook(); 1376 } 1377 1378} 1379 1380// Note: os::abort() might be called very early during initialization, or 1381// called from signal handler. Before adding something to os::abort(), make 1382// sure it is async-safe and can handle partially initialized VM. 1383void os::abort(bool dump_core, void* siginfo, void* context) { 1384 os::shutdown(); 1385 if (dump_core) { 1386#ifndef PRODUCT 1387 fdStream out(defaultStream::output_fd()); 1388 out.print_raw("Current thread is "); 1389 char buf[16]; 1390 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1391 out.print_raw_cr(buf); 1392 out.print_raw_cr("Dumping core ..."); 1393#endif 1394 ::abort(); // dump core 1395 } 1396 1397 ::exit(1); 1398} 1399 1400// Die immediately, no exit hook, no abort hook, no cleanup. 1401void os::die() { 1402 ::abort(); 1403} 1404 1405 1406// This method is a copy of JDK's sysGetLastErrorString 1407// from src/solaris/hpi/src/system_md.c 1408 1409size_t os::lasterror(char *buf, size_t len) { 1410 if (errno == 0) return 0; 1411 1412 const char *s = ::strerror(errno); 1413 size_t n = ::strlen(s); 1414 if (n >= len) { 1415 n = len - 1; 1416 } 1417 ::strncpy(buf, s, n); 1418 buf[n] = '\0'; 1419 return n; 1420} 1421 1422// thread_id is kernel thread id (similar to Solaris LWP id) 1423intx os::current_thread_id() { return os::Linux::gettid(); } 1424int os::current_process_id() { 1425 return ::getpid(); 1426} 1427 1428// DLL functions 1429 1430const char* os::dll_file_extension() { return ".so"; } 1431 1432// This must be hard coded because it's the system's temporary 1433// directory not the java application's temp directory, ala java.io.tmpdir. 1434const char* os::get_temp_directory() { return "/tmp"; } 1435 1436static bool file_exists(const char* filename) { 1437 struct stat statbuf; 1438 if (filename == NULL || strlen(filename) == 0) { 1439 return false; 1440 } 1441 return os::stat(filename, &statbuf) == 0; 1442} 1443 1444bool os::dll_build_name(char* buffer, size_t buflen, 1445 const char* pname, const char* fname) { 1446 bool retval = false; 1447 // Copied from libhpi 1448 const size_t pnamelen = pname ? strlen(pname) : 0; 1449 1450 // Return error on buffer overflow. 1451 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1452 return retval; 1453 } 1454 1455 if (pnamelen == 0) { 1456 snprintf(buffer, buflen, "lib%s.so", fname); 1457 retval = true; 1458 } else if (strchr(pname, *os::path_separator()) != NULL) { 1459 int n; 1460 char** pelements = split_path(pname, &n); 1461 if (pelements == NULL) { 1462 return false; 1463 } 1464 for (int i = 0; i < n; i++) { 1465 // Really shouldn't be NULL, but check can't hurt 1466 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1467 continue; // skip the empty path values 1468 } 1469 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1470 if (file_exists(buffer)) { 1471 retval = true; 1472 break; 1473 } 1474 } 1475 // release the storage 1476 for (int i = 0; i < n; i++) { 1477 if (pelements[i] != NULL) { 1478 FREE_C_HEAP_ARRAY(char, pelements[i]); 1479 } 1480 } 1481 if (pelements != NULL) { 1482 FREE_C_HEAP_ARRAY(char*, pelements); 1483 } 1484 } else { 1485 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1486 retval = true; 1487 } 1488 return retval; 1489} 1490 1491// check if addr is inside libjvm.so 1492bool os::address_is_in_vm(address addr) { 1493 static address libjvm_base_addr; 1494 Dl_info dlinfo; 1495 1496 if (libjvm_base_addr == NULL) { 1497 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1498 libjvm_base_addr = (address)dlinfo.dli_fbase; 1499 } 1500 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1501 } 1502 1503 if (dladdr((void *)addr, &dlinfo) != 0) { 1504 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1505 } 1506 1507 return false; 1508} 1509 1510bool os::dll_address_to_function_name(address addr, char *buf, 1511 int buflen, int *offset, 1512 bool demangle) { 1513 // buf is not optional, but offset is optional 1514 assert(buf != NULL, "sanity check"); 1515 1516 Dl_info dlinfo; 1517 1518 if (dladdr((void*)addr, &dlinfo) != 0) { 1519 // see if we have a matching symbol 1520 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1521 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1522 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1523 } 1524 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1525 return true; 1526 } 1527 // no matching symbol so try for just file info 1528 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1529 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1530 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1531 return true; 1532 } 1533 } 1534 } 1535 1536 buf[0] = '\0'; 1537 if (offset != NULL) *offset = -1; 1538 return false; 1539} 1540 1541struct _address_to_library_name { 1542 address addr; // input : memory address 1543 size_t buflen; // size of fname 1544 char* fname; // output: library name 1545 address base; // library base addr 1546}; 1547 1548static int address_to_library_name_callback(struct dl_phdr_info *info, 1549 size_t size, void *data) { 1550 int i; 1551 bool found = false; 1552 address libbase = NULL; 1553 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1554 1555 // iterate through all loadable segments 1556 for (i = 0; i < info->dlpi_phnum; i++) { 1557 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1558 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1559 // base address of a library is the lowest address of its loaded 1560 // segments. 1561 if (libbase == NULL || libbase > segbase) { 1562 libbase = segbase; 1563 } 1564 // see if 'addr' is within current segment 1565 if (segbase <= d->addr && 1566 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1567 found = true; 1568 } 1569 } 1570 } 1571 1572 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1573 // so dll_address_to_library_name() can fall through to use dladdr() which 1574 // can figure out executable name from argv[0]. 1575 if (found && info->dlpi_name && info->dlpi_name[0]) { 1576 d->base = libbase; 1577 if (d->fname) { 1578 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1579 } 1580 return 1; 1581 } 1582 return 0; 1583} 1584 1585bool os::dll_address_to_library_name(address addr, char* buf, 1586 int buflen, int* offset) { 1587 // buf is not optional, but offset is optional 1588 assert(buf != NULL, "sanity check"); 1589 1590 Dl_info dlinfo; 1591 struct _address_to_library_name data; 1592 1593 // There is a bug in old glibc dladdr() implementation that it could resolve 1594 // to wrong library name if the .so file has a base address != NULL. Here 1595 // we iterate through the program headers of all loaded libraries to find 1596 // out which library 'addr' really belongs to. This workaround can be 1597 // removed once the minimum requirement for glibc is moved to 2.3.x. 1598 data.addr = addr; 1599 data.fname = buf; 1600 data.buflen = buflen; 1601 data.base = NULL; 1602 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1603 1604 if (rslt) { 1605 // buf already contains library name 1606 if (offset) *offset = addr - data.base; 1607 return true; 1608 } 1609 if (dladdr((void*)addr, &dlinfo) != 0) { 1610 if (dlinfo.dli_fname != NULL) { 1611 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1612 } 1613 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1614 *offset = addr - (address)dlinfo.dli_fbase; 1615 } 1616 return true; 1617 } 1618 1619 buf[0] = '\0'; 1620 if (offset) *offset = -1; 1621 return false; 1622} 1623 1624// Loads .dll/.so and 1625// in case of error it checks if .dll/.so was built for the 1626// same architecture as Hotspot is running on 1627 1628 1629// Remember the stack's state. The Linux dynamic linker will change 1630// the stack to 'executable' at most once, so we must safepoint only once. 1631bool os::Linux::_stack_is_executable = false; 1632 1633// VM operation that loads a library. This is necessary if stack protection 1634// of the Java stacks can be lost during loading the library. If we 1635// do not stop the Java threads, they can stack overflow before the stacks 1636// are protected again. 1637class VM_LinuxDllLoad: public VM_Operation { 1638 private: 1639 const char *_filename; 1640 char *_ebuf; 1641 int _ebuflen; 1642 void *_lib; 1643 public: 1644 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1645 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1646 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1647 void doit() { 1648 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1649 os::Linux::_stack_is_executable = true; 1650 } 1651 void* loaded_library() { return _lib; } 1652}; 1653 1654void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1655 void * result = NULL; 1656 bool load_attempted = false; 1657 1658 // Check whether the library to load might change execution rights 1659 // of the stack. If they are changed, the protection of the stack 1660 // guard pages will be lost. We need a safepoint to fix this. 1661 // 1662 // See Linux man page execstack(8) for more info. 1663 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1664 ElfFile ef(filename); 1665 if (!ef.specifies_noexecstack()) { 1666 if (!is_init_completed()) { 1667 os::Linux::_stack_is_executable = true; 1668 // This is OK - No Java threads have been created yet, and hence no 1669 // stack guard pages to fix. 1670 // 1671 // This should happen only when you are building JDK7 using a very 1672 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1673 // 1674 // Dynamic loader will make all stacks executable after 1675 // this function returns, and will not do that again. 1676 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1677 } else { 1678 warning("You have loaded library %s which might have disabled stack guard. " 1679 "The VM will try to fix the stack guard now.\n" 1680 "It's highly recommended that you fix the library with " 1681 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1682 filename); 1683 1684 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1685 JavaThread *jt = JavaThread::current(); 1686 if (jt->thread_state() != _thread_in_native) { 1687 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1688 // that requires ExecStack. Cannot enter safe point. Let's give up. 1689 warning("Unable to fix stack guard. Giving up."); 1690 } else { 1691 if (!LoadExecStackDllInVMThread) { 1692 // This is for the case where the DLL has an static 1693 // constructor function that executes JNI code. We cannot 1694 // load such DLLs in the VMThread. 1695 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1696 } 1697 1698 ThreadInVMfromNative tiv(jt); 1699 debug_only(VMNativeEntryWrapper vew;) 1700 1701 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1702 VMThread::execute(&op); 1703 if (LoadExecStackDllInVMThread) { 1704 result = op.loaded_library(); 1705 } 1706 load_attempted = true; 1707 } 1708 } 1709 } 1710 } 1711 1712 if (!load_attempted) { 1713 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1714 } 1715 1716 if (result != NULL) { 1717 // Successful loading 1718 return result; 1719 } 1720 1721 Elf32_Ehdr elf_head; 1722 int diag_msg_max_length=ebuflen-strlen(ebuf); 1723 char* diag_msg_buf=ebuf+strlen(ebuf); 1724 1725 if (diag_msg_max_length==0) { 1726 // No more space in ebuf for additional diagnostics message 1727 return NULL; 1728 } 1729 1730 1731 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1732 1733 if (file_descriptor < 0) { 1734 // Can't open library, report dlerror() message 1735 return NULL; 1736 } 1737 1738 bool failed_to_read_elf_head= 1739 (sizeof(elf_head)!= 1740 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1741 1742 ::close(file_descriptor); 1743 if (failed_to_read_elf_head) { 1744 // file i/o error - report dlerror() msg 1745 return NULL; 1746 } 1747 1748 typedef struct { 1749 Elf32_Half code; // Actual value as defined in elf.h 1750 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1751 char elf_class; // 32 or 64 bit 1752 char endianess; // MSB or LSB 1753 char* name; // String representation 1754 } arch_t; 1755 1756#ifndef EM_486 1757 #define EM_486 6 /* Intel 80486 */ 1758#endif 1759#ifndef EM_AARCH64 1760 #define EM_AARCH64 183 /* ARM AARCH64 */ 1761#endif 1762 1763 static const arch_t arch_array[]={ 1764 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1765 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1766 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1767 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1768 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1769 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1770 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1771 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1772#if defined(VM_LITTLE_ENDIAN) 1773 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1774#else 1775 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1776#endif 1777 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1778 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1779 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1780 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1781 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1782 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1783 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1784 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1785 }; 1786 1787#if (defined IA32) 1788 static Elf32_Half running_arch_code=EM_386; 1789#elif (defined AMD64) 1790 static Elf32_Half running_arch_code=EM_X86_64; 1791#elif (defined IA64) 1792 static Elf32_Half running_arch_code=EM_IA_64; 1793#elif (defined __sparc) && (defined _LP64) 1794 static Elf32_Half running_arch_code=EM_SPARCV9; 1795#elif (defined __sparc) && (!defined _LP64) 1796 static Elf32_Half running_arch_code=EM_SPARC; 1797#elif (defined __powerpc64__) 1798 static Elf32_Half running_arch_code=EM_PPC64; 1799#elif (defined __powerpc__) 1800 static Elf32_Half running_arch_code=EM_PPC; 1801#elif (defined ARM) 1802 static Elf32_Half running_arch_code=EM_ARM; 1803#elif (defined S390) 1804 static Elf32_Half running_arch_code=EM_S390; 1805#elif (defined ALPHA) 1806 static Elf32_Half running_arch_code=EM_ALPHA; 1807#elif (defined MIPSEL) 1808 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1809#elif (defined PARISC) 1810 static Elf32_Half running_arch_code=EM_PARISC; 1811#elif (defined MIPS) 1812 static Elf32_Half running_arch_code=EM_MIPS; 1813#elif (defined M68K) 1814 static Elf32_Half running_arch_code=EM_68K; 1815#elif (defined AARCH64) 1816 static Elf32_Half running_arch_code=EM_AARCH64; 1817#else 1818 #error Method os::dll_load requires that one of following is defined:\ 1819 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, AARCH64 1820#endif 1821 1822 // Identify compatability class for VM's architecture and library's architecture 1823 // Obtain string descriptions for architectures 1824 1825 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1826 int running_arch_index=-1; 1827 1828 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1829 if (running_arch_code == arch_array[i].code) { 1830 running_arch_index = i; 1831 } 1832 if (lib_arch.code == arch_array[i].code) { 1833 lib_arch.compat_class = arch_array[i].compat_class; 1834 lib_arch.name = arch_array[i].name; 1835 } 1836 } 1837 1838 assert(running_arch_index != -1, 1839 "Didn't find running architecture code (running_arch_code) in arch_array"); 1840 if (running_arch_index == -1) { 1841 // Even though running architecture detection failed 1842 // we may still continue with reporting dlerror() message 1843 return NULL; 1844 } 1845 1846 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1847 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1848 return NULL; 1849 } 1850 1851#ifndef S390 1852 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1853 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1854 return NULL; 1855 } 1856#endif // !S390 1857 1858 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1859 if (lib_arch.name!=NULL) { 1860 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1861 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1862 lib_arch.name, arch_array[running_arch_index].name); 1863 } else { 1864 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1865 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1866 lib_arch.code, 1867 arch_array[running_arch_index].name); 1868 } 1869 } 1870 1871 return NULL; 1872} 1873 1874void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1875 int ebuflen) { 1876 void * result = ::dlopen(filename, RTLD_LAZY); 1877 if (result == NULL) { 1878 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1879 ebuf[ebuflen-1] = '\0'; 1880 } 1881 return result; 1882} 1883 1884void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1885 int ebuflen) { 1886 void * result = NULL; 1887 if (LoadExecStackDllInVMThread) { 1888 result = dlopen_helper(filename, ebuf, ebuflen); 1889 } 1890 1891 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1892 // library that requires an executable stack, or which does not have this 1893 // stack attribute set, dlopen changes the stack attribute to executable. The 1894 // read protection of the guard pages gets lost. 1895 // 1896 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1897 // may have been queued at the same time. 1898 1899 if (!_stack_is_executable) { 1900 JavaThread *jt = Threads::first(); 1901 1902 while (jt) { 1903 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1904 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions 1905 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(), 1906 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) { 1907 warning("Attempt to reguard stack yellow zone failed."); 1908 } 1909 } 1910 jt = jt->next(); 1911 } 1912 } 1913 1914 return result; 1915} 1916 1917void* os::dll_lookup(void* handle, const char* name) { 1918 void* res = dlsym(handle, name); 1919 return res; 1920} 1921 1922void* os::get_default_process_handle() { 1923 return (void*)::dlopen(NULL, RTLD_LAZY); 1924} 1925 1926static bool _print_ascii_file(const char* filename, outputStream* st) { 1927 int fd = ::open(filename, O_RDONLY); 1928 if (fd == -1) { 1929 return false; 1930 } 1931 1932 char buf[32]; 1933 int bytes; 1934 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 1935 st->print_raw(buf, bytes); 1936 } 1937 1938 ::close(fd); 1939 1940 return true; 1941} 1942 1943void os::print_dll_info(outputStream *st) { 1944 st->print_cr("Dynamic libraries:"); 1945 1946 char fname[32]; 1947 pid_t pid = os::Linux::gettid(); 1948 1949 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1950 1951 if (!_print_ascii_file(fname, st)) { 1952 st->print("Can not get library information for pid = %d\n", pid); 1953 } 1954} 1955 1956int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1957 FILE *procmapsFile = NULL; 1958 1959 // Open the procfs maps file for the current process 1960 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1961 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1962 char line[PATH_MAX + 100]; 1963 1964 // Read line by line from 'file' 1965 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1966 u8 base, top, offset, inode; 1967 char permissions[5]; 1968 char device[6]; 1969 char name[PATH_MAX + 1]; 1970 1971 // Parse fields from line 1972 sscanf(line, "%lx-%lx %4s %lx %5s %ld %s", &base, &top, permissions, &offset, device, &inode, name); 1973 1974 // Filter by device id '00:00' so that we only get file system mapped files. 1975 if (strcmp(device, "00:00") != 0) { 1976 1977 // Call callback with the fields of interest 1978 if(callback(name, (address)base, (address)top, param)) { 1979 // Oops abort, callback aborted 1980 fclose(procmapsFile); 1981 return 1; 1982 } 1983 } 1984 } 1985 fclose(procmapsFile); 1986 } 1987 return 0; 1988} 1989 1990void os::print_os_info_brief(outputStream* st) { 1991 os::Linux::print_distro_info(st); 1992 1993 os::Posix::print_uname_info(st); 1994 1995 os::Linux::print_libversion_info(st); 1996 1997} 1998 1999void os::print_os_info(outputStream* st) { 2000 st->print("OS:"); 2001 2002 os::Linux::print_distro_info(st); 2003 2004 os::Posix::print_uname_info(st); 2005 2006 // Print warning if unsafe chroot environment detected 2007 if (unsafe_chroot_detected) { 2008 st->print("WARNING!! "); 2009 st->print_cr("%s", unstable_chroot_error); 2010 } 2011 2012 os::Linux::print_libversion_info(st); 2013 2014 os::Posix::print_rlimit_info(st); 2015 2016 os::Posix::print_load_average(st); 2017 2018 os::Linux::print_full_memory_info(st); 2019} 2020 2021// Try to identify popular distros. 2022// Most Linux distributions have a /etc/XXX-release file, which contains 2023// the OS version string. Newer Linux distributions have a /etc/lsb-release 2024// file that also contains the OS version string. Some have more than one 2025// /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2026// /etc/redhat-release.), so the order is important. 2027// Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2028// their own specific XXX-release file as well as a redhat-release file. 2029// Because of this the XXX-release file needs to be searched for before the 2030// redhat-release file. 2031// Since Red Hat has a lsb-release file that is not very descriptive the 2032// search for redhat-release needs to be before lsb-release. 2033// Since the lsb-release file is the new standard it needs to be searched 2034// before the older style release files. 2035// Searching system-release (Red Hat) and os-release (other Linuxes) are a 2036// next to last resort. The os-release file is a new standard that contains 2037// distribution information and the system-release file seems to be an old 2038// standard that has been replaced by the lsb-release and os-release files. 2039// Searching for the debian_version file is the last resort. It contains 2040// an informative string like "6.0.6" or "wheezy/sid". Because of this 2041// "Debian " is printed before the contents of the debian_version file. 2042 2043const char* distro_files[] = { 2044 "/etc/oracle-release", 2045 "/etc/mandriva-release", 2046 "/etc/mandrake-release", 2047 "/etc/sun-release", 2048 "/etc/redhat-release", 2049 "/etc/lsb-release", 2050 "/etc/SuSE-release", 2051 "/etc/turbolinux-release", 2052 "/etc/gentoo-release", 2053 "/etc/ltib-release", 2054 "/etc/angstrom-version", 2055 "/etc/system-release", 2056 "/etc/os-release", 2057 NULL }; 2058 2059void os::Linux::print_distro_info(outputStream* st) { 2060 for (int i = 0;; i++) { 2061 const char* file = distro_files[i]; 2062 if (file == NULL) { 2063 break; // done 2064 } 2065 // If file prints, we found it. 2066 if (_print_ascii_file(file, st)) { 2067 return; 2068 } 2069 } 2070 2071 if (file_exists("/etc/debian_version")) { 2072 st->print("Debian "); 2073 _print_ascii_file("/etc/debian_version", st); 2074 } else { 2075 st->print("Linux"); 2076 } 2077 st->cr(); 2078} 2079 2080static void parse_os_info(char* distro, size_t length, const char* file) { 2081 FILE* fp = fopen(file, "r"); 2082 if (fp != NULL) { 2083 char buf[256]; 2084 // get last line of the file. 2085 while (fgets(buf, sizeof(buf), fp)) { } 2086 // Edit out extra stuff in expected ubuntu format 2087 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL) { 2088 char* ptr = strstr(buf, "\""); // the name is in quotes 2089 if (ptr != NULL) { 2090 ptr++; // go beyond first quote 2091 char* nl = strchr(ptr, '\"'); 2092 if (nl != NULL) *nl = '\0'; 2093 strncpy(distro, ptr, length); 2094 } else { 2095 ptr = strstr(buf, "="); 2096 ptr++; // go beyond equals then 2097 char* nl = strchr(ptr, '\n'); 2098 if (nl != NULL) *nl = '\0'; 2099 strncpy(distro, ptr, length); 2100 } 2101 } else { 2102 // if not in expected Ubuntu format, print out whole line minus \n 2103 char* nl = strchr(buf, '\n'); 2104 if (nl != NULL) *nl = '\0'; 2105 strncpy(distro, buf, length); 2106 } 2107 // close distro file 2108 fclose(fp); 2109 } 2110} 2111 2112void os::get_summary_os_info(char* buf, size_t buflen) { 2113 for (int i = 0;; i++) { 2114 const char* file = distro_files[i]; 2115 if (file == NULL) { 2116 break; // ran out of distro_files 2117 } 2118 if (file_exists(file)) { 2119 parse_os_info(buf, buflen, file); 2120 return; 2121 } 2122 } 2123 // special case for debian 2124 if (file_exists("/etc/debian_version")) { 2125 strncpy(buf, "Debian ", buflen); 2126 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2127 } else { 2128 strncpy(buf, "Linux", buflen); 2129 } 2130} 2131 2132void os::Linux::print_libversion_info(outputStream* st) { 2133 // libc, pthread 2134 st->print("libc:"); 2135 st->print("%s ", os::Linux::glibc_version()); 2136 st->print("%s ", os::Linux::libpthread_version()); 2137 st->cr(); 2138} 2139 2140void os::Linux::print_full_memory_info(outputStream* st) { 2141 st->print("\n/proc/meminfo:\n"); 2142 _print_ascii_file("/proc/meminfo", st); 2143 st->cr(); 2144} 2145 2146void os::print_memory_info(outputStream* st) { 2147 2148 st->print("Memory:"); 2149 st->print(" %dk page", os::vm_page_size()>>10); 2150 2151 // values in struct sysinfo are "unsigned long" 2152 struct sysinfo si; 2153 sysinfo(&si); 2154 2155 st->print(", physical " UINT64_FORMAT "k", 2156 os::physical_memory() >> 10); 2157 st->print("(" UINT64_FORMAT "k free)", 2158 os::available_memory() >> 10); 2159 st->print(", swap " UINT64_FORMAT "k", 2160 ((jlong)si.totalswap * si.mem_unit) >> 10); 2161 st->print("(" UINT64_FORMAT "k free)", 2162 ((jlong)si.freeswap * si.mem_unit) >> 10); 2163 st->cr(); 2164} 2165 2166// Print the first "model name" line and the first "flags" line 2167// that we find and nothing more. We assume "model name" comes 2168// before "flags" so if we find a second "model name", then the 2169// "flags" field is considered missing. 2170static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2171#if defined(IA32) || defined(AMD64) 2172 // Other platforms have less repetitive cpuinfo files 2173 FILE *fp = fopen("/proc/cpuinfo", "r"); 2174 if (fp) { 2175 while (!feof(fp)) { 2176 if (fgets(buf, buflen, fp)) { 2177 // Assume model name comes before flags 2178 bool model_name_printed = false; 2179 if (strstr(buf, "model name") != NULL) { 2180 if (!model_name_printed) { 2181 st->print_raw("\nCPU Model and flags from /proc/cpuinfo:\n"); 2182 st->print_raw(buf); 2183 model_name_printed = true; 2184 } else { 2185 // model name printed but not flags? Odd, just return 2186 fclose(fp); 2187 return true; 2188 } 2189 } 2190 // print the flags line too 2191 if (strstr(buf, "flags") != NULL) { 2192 st->print_raw(buf); 2193 fclose(fp); 2194 return true; 2195 } 2196 } 2197 } 2198 fclose(fp); 2199 } 2200#endif // x86 platforms 2201 return false; 2202} 2203 2204void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2205 // Only print the model name if the platform provides this as a summary 2206 if (!print_model_name_and_flags(st, buf, buflen)) { 2207 st->print("\n/proc/cpuinfo:\n"); 2208 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2209 st->print_cr(" <Not Available>"); 2210 } 2211 } 2212} 2213 2214#if defined(AMD64) || defined(IA32) || defined(X32) 2215const char* search_string = "model name"; 2216#elif defined(SPARC) 2217const char* search_string = "cpu"; 2218#else 2219const char* search_string = "Processor"; 2220#endif 2221 2222// Parses the cpuinfo file for string representing the model name. 2223void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2224 FILE* fp = fopen("/proc/cpuinfo", "r"); 2225 if (fp != NULL) { 2226 while (!feof(fp)) { 2227 char buf[256]; 2228 if (fgets(buf, sizeof(buf), fp)) { 2229 char* start = strstr(buf, search_string); 2230 if (start != NULL) { 2231 char *ptr = start + strlen(search_string); 2232 char *end = buf + strlen(buf); 2233 while (ptr != end) { 2234 // skip whitespace and colon for the rest of the name. 2235 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2236 break; 2237 } 2238 ptr++; 2239 } 2240 if (ptr != end) { 2241 // reasonable string, get rid of newline and keep the rest 2242 char* nl = strchr(buf, '\n'); 2243 if (nl != NULL) *nl = '\0'; 2244 strncpy(cpuinfo, ptr, length); 2245 fclose(fp); 2246 return; 2247 } 2248 } 2249 } 2250 } 2251 fclose(fp); 2252 } 2253 // cpuinfo not found or parsing failed, just print generic string. The entire 2254 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2255#if defined(AMD64) 2256 strncpy(cpuinfo, "x86_64", length); 2257#elif defined(IA32) 2258 strncpy(cpuinfo, "x86_32", length); 2259#elif defined(IA64) 2260 strncpy(cpuinfo, "IA64", length); 2261#elif defined(SPARC) 2262 strncpy(cpuinfo, "sparcv9", length); 2263#elif defined(AARCH64) 2264 strncpy(cpuinfo, "AArch64", length); 2265#elif defined(ARM) 2266 strncpy(cpuinfo, "ARM", length); 2267#elif defined(PPC) 2268 strncpy(cpuinfo, "PPC64", length); 2269#elif defined(ZERO_LIBARCH) 2270 strncpy(cpuinfo, ZERO_LIBARCH, length); 2271#else 2272 strncpy(cpuinfo, "unknown", length); 2273#endif 2274} 2275 2276void os::print_siginfo(outputStream* st, void* siginfo) { 2277 const siginfo_t* si = (const siginfo_t*)siginfo; 2278 2279 os::Posix::print_siginfo_brief(st, si); 2280#if INCLUDE_CDS 2281 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2282 UseSharedSpaces) { 2283 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2284 if (mapinfo->is_in_shared_space(si->si_addr)) { 2285 st->print("\n\nError accessing class data sharing archive." \ 2286 " Mapped file inaccessible during execution, " \ 2287 " possible disk/network problem."); 2288 } 2289 } 2290#endif 2291 st->cr(); 2292} 2293 2294 2295static void print_signal_handler(outputStream* st, int sig, 2296 char* buf, size_t buflen); 2297 2298void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2299 st->print_cr("Signal Handlers:"); 2300 print_signal_handler(st, SIGSEGV, buf, buflen); 2301 print_signal_handler(st, SIGBUS , buf, buflen); 2302 print_signal_handler(st, SIGFPE , buf, buflen); 2303 print_signal_handler(st, SIGPIPE, buf, buflen); 2304 print_signal_handler(st, SIGXFSZ, buf, buflen); 2305 print_signal_handler(st, SIGILL , buf, buflen); 2306 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2307 print_signal_handler(st, SR_signum, buf, buflen); 2308 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2309 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2310 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2311 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2312#if defined(PPC64) 2313 print_signal_handler(st, SIGTRAP, buf, buflen); 2314#endif 2315} 2316 2317static char saved_jvm_path[MAXPATHLEN] = {0}; 2318 2319// Find the full path to the current module, libjvm.so 2320void os::jvm_path(char *buf, jint buflen) { 2321 // Error checking. 2322 if (buflen < MAXPATHLEN) { 2323 assert(false, "must use a large-enough buffer"); 2324 buf[0] = '\0'; 2325 return; 2326 } 2327 // Lazy resolve the path to current module. 2328 if (saved_jvm_path[0] != 0) { 2329 strcpy(buf, saved_jvm_path); 2330 return; 2331 } 2332 2333 char dli_fname[MAXPATHLEN]; 2334 bool ret = dll_address_to_library_name( 2335 CAST_FROM_FN_PTR(address, os::jvm_path), 2336 dli_fname, sizeof(dli_fname), NULL); 2337 assert(ret, "cannot locate libjvm"); 2338 char *rp = NULL; 2339 if (ret && dli_fname[0] != '\0') { 2340 rp = realpath(dli_fname, buf); 2341 } 2342 if (rp == NULL) { 2343 return; 2344 } 2345 2346 if (Arguments::sun_java_launcher_is_altjvm()) { 2347 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2348 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". 2349 // If "/jre/lib/" appears at the right place in the string, then 2350 // assume we are installed in a JDK and we're done. Otherwise, check 2351 // for a JAVA_HOME environment variable and fix up the path so it 2352 // looks like libjvm.so is installed there (append a fake suffix 2353 // hotspot/libjvm.so). 2354 const char *p = buf + strlen(buf) - 1; 2355 for (int count = 0; p > buf && count < 5; ++count) { 2356 for (--p; p > buf && *p != '/'; --p) 2357 /* empty */ ; 2358 } 2359 2360 if (strncmp(p, "/jre/lib/", 9) != 0) { 2361 // Look for JAVA_HOME in the environment. 2362 char* java_home_var = ::getenv("JAVA_HOME"); 2363 if (java_home_var != NULL && java_home_var[0] != 0) { 2364 char* jrelib_p; 2365 int len; 2366 2367 // Check the current module name "libjvm.so". 2368 p = strrchr(buf, '/'); 2369 if (p == NULL) { 2370 return; 2371 } 2372 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2373 2374 rp = realpath(java_home_var, buf); 2375 if (rp == NULL) { 2376 return; 2377 } 2378 2379 // determine if this is a legacy image or modules image 2380 // modules image doesn't have "jre" subdirectory 2381 len = strlen(buf); 2382 assert(len < buflen, "Ran out of buffer room"); 2383 jrelib_p = buf + len; 2384 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2385 if (0 != access(buf, F_OK)) { 2386 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2387 } 2388 2389 if (0 == access(buf, F_OK)) { 2390 // Use current module name "libjvm.so" 2391 len = strlen(buf); 2392 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2393 } else { 2394 // Go back to path of .so 2395 rp = realpath(dli_fname, buf); 2396 if (rp == NULL) { 2397 return; 2398 } 2399 } 2400 } 2401 } 2402 } 2403 2404 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2405 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2406} 2407 2408void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2409 // no prefix required, not even "_" 2410} 2411 2412void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2413 // no suffix required 2414} 2415 2416//////////////////////////////////////////////////////////////////////////////// 2417// sun.misc.Signal support 2418 2419static volatile jint sigint_count = 0; 2420 2421static void UserHandler(int sig, void *siginfo, void *context) { 2422 // 4511530 - sem_post is serialized and handled by the manager thread. When 2423 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2424 // don't want to flood the manager thread with sem_post requests. 2425 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2426 return; 2427 } 2428 2429 // Ctrl-C is pressed during error reporting, likely because the error 2430 // handler fails to abort. Let VM die immediately. 2431 if (sig == SIGINT && is_error_reported()) { 2432 os::die(); 2433 } 2434 2435 os::signal_notify(sig); 2436} 2437 2438void* os::user_handler() { 2439 return CAST_FROM_FN_PTR(void*, UserHandler); 2440} 2441 2442struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2443 struct timespec ts; 2444 // Semaphore's are always associated with CLOCK_REALTIME 2445 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2446 // see unpackTime for discussion on overflow checking 2447 if (sec >= MAX_SECS) { 2448 ts.tv_sec += MAX_SECS; 2449 ts.tv_nsec = 0; 2450 } else { 2451 ts.tv_sec += sec; 2452 ts.tv_nsec += nsec; 2453 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2454 ts.tv_nsec -= NANOSECS_PER_SEC; 2455 ++ts.tv_sec; // note: this must be <= max_secs 2456 } 2457 } 2458 2459 return ts; 2460} 2461 2462extern "C" { 2463 typedef void (*sa_handler_t)(int); 2464 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2465} 2466 2467void* os::signal(int signal_number, void* handler) { 2468 struct sigaction sigAct, oldSigAct; 2469 2470 sigfillset(&(sigAct.sa_mask)); 2471 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2472 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2473 2474 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2475 // -1 means registration failed 2476 return (void *)-1; 2477 } 2478 2479 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2480} 2481 2482void os::signal_raise(int signal_number) { 2483 ::raise(signal_number); 2484} 2485 2486// The following code is moved from os.cpp for making this 2487// code platform specific, which it is by its very nature. 2488 2489// Will be modified when max signal is changed to be dynamic 2490int os::sigexitnum_pd() { 2491 return NSIG; 2492} 2493 2494// a counter for each possible signal value 2495static volatile jint pending_signals[NSIG+1] = { 0 }; 2496 2497// Linux(POSIX) specific hand shaking semaphore. 2498static sem_t sig_sem; 2499static PosixSemaphore sr_semaphore; 2500 2501void os::signal_init_pd() { 2502 // Initialize signal structures 2503 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2504 2505 // Initialize signal semaphore 2506 ::sem_init(&sig_sem, 0, 0); 2507} 2508 2509void os::signal_notify(int sig) { 2510 Atomic::inc(&pending_signals[sig]); 2511 ::sem_post(&sig_sem); 2512} 2513 2514static int check_pending_signals(bool wait) { 2515 Atomic::store(0, &sigint_count); 2516 for (;;) { 2517 for (int i = 0; i < NSIG + 1; i++) { 2518 jint n = pending_signals[i]; 2519 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2520 return i; 2521 } 2522 } 2523 if (!wait) { 2524 return -1; 2525 } 2526 JavaThread *thread = JavaThread::current(); 2527 ThreadBlockInVM tbivm(thread); 2528 2529 bool threadIsSuspended; 2530 do { 2531 thread->set_suspend_equivalent(); 2532 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2533 ::sem_wait(&sig_sem); 2534 2535 // were we externally suspended while we were waiting? 2536 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2537 if (threadIsSuspended) { 2538 // The semaphore has been incremented, but while we were waiting 2539 // another thread suspended us. We don't want to continue running 2540 // while suspended because that would surprise the thread that 2541 // suspended us. 2542 ::sem_post(&sig_sem); 2543 2544 thread->java_suspend_self(); 2545 } 2546 } while (threadIsSuspended); 2547 } 2548} 2549 2550int os::signal_lookup() { 2551 return check_pending_signals(false); 2552} 2553 2554int os::signal_wait() { 2555 return check_pending_signals(true); 2556} 2557 2558//////////////////////////////////////////////////////////////////////////////// 2559// Virtual Memory 2560 2561int os::vm_page_size() { 2562 // Seems redundant as all get out 2563 assert(os::Linux::page_size() != -1, "must call os::init"); 2564 return os::Linux::page_size(); 2565} 2566 2567// Solaris allocates memory by pages. 2568int os::vm_allocation_granularity() { 2569 assert(os::Linux::page_size() != -1, "must call os::init"); 2570 return os::Linux::page_size(); 2571} 2572 2573// Rationale behind this function: 2574// current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2575// mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2576// samples for JITted code. Here we create private executable mapping over the code cache 2577// and then we can use standard (well, almost, as mapping can change) way to provide 2578// info for the reporting script by storing timestamp and location of symbol 2579void linux_wrap_code(char* base, size_t size) { 2580 static volatile jint cnt = 0; 2581 2582 if (!UseOprofile) { 2583 return; 2584 } 2585 2586 char buf[PATH_MAX+1]; 2587 int num = Atomic::add(1, &cnt); 2588 2589 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2590 os::get_temp_directory(), os::current_process_id(), num); 2591 unlink(buf); 2592 2593 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2594 2595 if (fd != -1) { 2596 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2597 if (rv != (off_t)-1) { 2598 if (::write(fd, "", 1) == 1) { 2599 mmap(base, size, 2600 PROT_READ|PROT_WRITE|PROT_EXEC, 2601 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2602 } 2603 } 2604 ::close(fd); 2605 unlink(buf); 2606 } 2607} 2608 2609static bool recoverable_mmap_error(int err) { 2610 // See if the error is one we can let the caller handle. This 2611 // list of errno values comes from JBS-6843484. I can't find a 2612 // Linux man page that documents this specific set of errno 2613 // values so while this list currently matches Solaris, it may 2614 // change as we gain experience with this failure mode. 2615 switch (err) { 2616 case EBADF: 2617 case EINVAL: 2618 case ENOTSUP: 2619 // let the caller deal with these errors 2620 return true; 2621 2622 default: 2623 // Any remaining errors on this OS can cause our reserved mapping 2624 // to be lost. That can cause confusion where different data 2625 // structures think they have the same memory mapped. The worst 2626 // scenario is if both the VM and a library think they have the 2627 // same memory mapped. 2628 return false; 2629 } 2630} 2631 2632static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2633 int err) { 2634 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2635 ", %d) failed; error='%s' (errno=%d)", addr, size, exec, 2636 strerror(err), err); 2637} 2638 2639static void warn_fail_commit_memory(char* addr, size_t size, 2640 size_t alignment_hint, bool exec, 2641 int err) { 2642 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2643 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size, 2644 alignment_hint, exec, strerror(err), err); 2645} 2646 2647// NOTE: Linux kernel does not really reserve the pages for us. 2648// All it does is to check if there are enough free pages 2649// left at the time of mmap(). This could be a potential 2650// problem. 2651int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2652 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2653 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2654 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2655 if (res != (uintptr_t) MAP_FAILED) { 2656 if (UseNUMAInterleaving) { 2657 numa_make_global(addr, size); 2658 } 2659 return 0; 2660 } 2661 2662 int err = errno; // save errno from mmap() call above 2663 2664 if (!recoverable_mmap_error(err)) { 2665 warn_fail_commit_memory(addr, size, exec, err); 2666 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2667 } 2668 2669 return err; 2670} 2671 2672bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2673 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2674} 2675 2676void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2677 const char* mesg) { 2678 assert(mesg != NULL, "mesg must be specified"); 2679 int err = os::Linux::commit_memory_impl(addr, size, exec); 2680 if (err != 0) { 2681 // the caller wants all commit errors to exit with the specified mesg: 2682 warn_fail_commit_memory(addr, size, exec, err); 2683 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg); 2684 } 2685} 2686 2687// Define MAP_HUGETLB here so we can build HotSpot on old systems. 2688#ifndef MAP_HUGETLB 2689 #define MAP_HUGETLB 0x40000 2690#endif 2691 2692// Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2693#ifndef MADV_HUGEPAGE 2694 #define MADV_HUGEPAGE 14 2695#endif 2696 2697int os::Linux::commit_memory_impl(char* addr, size_t size, 2698 size_t alignment_hint, bool exec) { 2699 int err = os::Linux::commit_memory_impl(addr, size, exec); 2700 if (err == 0) { 2701 realign_memory(addr, size, alignment_hint); 2702 } 2703 return err; 2704} 2705 2706bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2707 bool exec) { 2708 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2709} 2710 2711void os::pd_commit_memory_or_exit(char* addr, size_t size, 2712 size_t alignment_hint, bool exec, 2713 const char* mesg) { 2714 assert(mesg != NULL, "mesg must be specified"); 2715 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2716 if (err != 0) { 2717 // the caller wants all commit errors to exit with the specified mesg: 2718 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2719 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg); 2720 } 2721} 2722 2723void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2724 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2725 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2726 // be supported or the memory may already be backed by huge pages. 2727 ::madvise(addr, bytes, MADV_HUGEPAGE); 2728 } 2729} 2730 2731void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2732 // This method works by doing an mmap over an existing mmaping and effectively discarding 2733 // the existing pages. However it won't work for SHM-based large pages that cannot be 2734 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2735 // small pages on top of the SHM segment. This method always works for small pages, so we 2736 // allow that in any case. 2737 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2738 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2739 } 2740} 2741 2742void os::numa_make_global(char *addr, size_t bytes) { 2743 Linux::numa_interleave_memory(addr, bytes); 2744} 2745 2746// Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2747// bind policy to MPOL_PREFERRED for the current thread. 2748#define USE_MPOL_PREFERRED 0 2749 2750void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2751 // To make NUMA and large pages more robust when both enabled, we need to ease 2752 // the requirements on where the memory should be allocated. MPOL_BIND is the 2753 // default policy and it will force memory to be allocated on the specified 2754 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2755 // the specified node, but will not force it. Using this policy will prevent 2756 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2757 // free large pages. 2758 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2759 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2760} 2761 2762bool os::numa_topology_changed() { return false; } 2763 2764size_t os::numa_get_groups_num() { 2765 int max_node = Linux::numa_max_node(); 2766 return max_node > 0 ? max_node + 1 : 1; 2767} 2768 2769int os::numa_get_group_id() { 2770 int cpu_id = Linux::sched_getcpu(); 2771 if (cpu_id != -1) { 2772 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2773 if (lgrp_id != -1) { 2774 return lgrp_id; 2775 } 2776 } 2777 return 0; 2778} 2779 2780size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2781 for (size_t i = 0; i < size; i++) { 2782 ids[i] = i; 2783 } 2784 return size; 2785} 2786 2787bool os::get_page_info(char *start, page_info* info) { 2788 return false; 2789} 2790 2791char *os::scan_pages(char *start, char* end, page_info* page_expected, 2792 page_info* page_found) { 2793 return end; 2794} 2795 2796 2797int os::Linux::sched_getcpu_syscall(void) { 2798 unsigned int cpu; 2799 int retval = -1; 2800 2801#if defined(IA32) 2802 #ifndef SYS_getcpu 2803 #define SYS_getcpu 318 2804 #endif 2805 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2806#elif defined(AMD64) 2807// Unfortunately we have to bring all these macros here from vsyscall.h 2808// to be able to compile on old linuxes. 2809 #define __NR_vgetcpu 2 2810 #define VSYSCALL_START (-10UL << 20) 2811 #define VSYSCALL_SIZE 1024 2812 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2813 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2814 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2815 retval = vgetcpu(&cpu, NULL, NULL); 2816#endif 2817 2818 return (retval == -1) ? retval : cpu; 2819} 2820 2821// Something to do with the numa-aware allocator needs these symbols 2822extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2823extern "C" JNIEXPORT void numa_error(char *where) { } 2824extern "C" JNIEXPORT int fork1() { return fork(); } 2825 2826 2827// If we are running with libnuma version > 2, then we should 2828// be trying to use symbols with versions 1.1 2829// If we are running with earlier version, which did not have symbol versions, 2830// we should use the base version. 2831void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2832 void *f = dlvsym(handle, name, "libnuma_1.1"); 2833 if (f == NULL) { 2834 f = dlsym(handle, name); 2835 } 2836 return f; 2837} 2838 2839bool os::Linux::libnuma_init() { 2840 // sched_getcpu() should be in libc. 2841 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2842 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2843 2844 // If it's not, try a direct syscall. 2845 if (sched_getcpu() == -1) { 2846 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2847 (void*)&sched_getcpu_syscall)); 2848 } 2849 2850 if (sched_getcpu() != -1) { // Does it work? 2851 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2852 if (handle != NULL) { 2853 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2854 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2855 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2856 libnuma_dlsym(handle, "numa_max_node"))); 2857 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2858 libnuma_dlsym(handle, "numa_available"))); 2859 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2860 libnuma_dlsym(handle, "numa_tonode_memory"))); 2861 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2862 libnuma_dlsym(handle, "numa_interleave_memory"))); 2863 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2864 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2865 2866 2867 if (numa_available() != -1) { 2868 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2869 // Create a cpu -> node mapping 2870 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2871 rebuild_cpu_to_node_map(); 2872 return true; 2873 } 2874 } 2875 } 2876 return false; 2877} 2878 2879// rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2880// The table is later used in get_node_by_cpu(). 2881void os::Linux::rebuild_cpu_to_node_map() { 2882 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2883 // in libnuma (possible values are starting from 16, 2884 // and continuing up with every other power of 2, but less 2885 // than the maximum number of CPUs supported by kernel), and 2886 // is a subject to change (in libnuma version 2 the requirements 2887 // are more reasonable) we'll just hardcode the number they use 2888 // in the library. 2889 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2890 2891 size_t cpu_num = os::active_processor_count(); 2892 size_t cpu_map_size = NCPUS / BitsPerCLong; 2893 size_t cpu_map_valid_size = 2894 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2895 2896 cpu_to_node()->clear(); 2897 cpu_to_node()->at_grow(cpu_num - 1); 2898 size_t node_num = numa_get_groups_num(); 2899 2900 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2901 for (size_t i = 0; i < node_num; i++) { 2902 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2903 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2904 if (cpu_map[j] != 0) { 2905 for (size_t k = 0; k < BitsPerCLong; k++) { 2906 if (cpu_map[j] & (1UL << k)) { 2907 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2908 } 2909 } 2910 } 2911 } 2912 } 2913 } 2914 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2915} 2916 2917int os::Linux::get_node_by_cpu(int cpu_id) { 2918 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2919 return cpu_to_node()->at(cpu_id); 2920 } 2921 return -1; 2922} 2923 2924GrowableArray<int>* os::Linux::_cpu_to_node; 2925os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2926os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2927os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2928os::Linux::numa_available_func_t os::Linux::_numa_available; 2929os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2930os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2931os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2932unsigned long* os::Linux::_numa_all_nodes; 2933 2934bool os::pd_uncommit_memory(char* addr, size_t size) { 2935 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2936 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2937 return res != (uintptr_t) MAP_FAILED; 2938} 2939 2940static address get_stack_commited_bottom(address bottom, size_t size) { 2941 address nbot = bottom; 2942 address ntop = bottom + size; 2943 2944 size_t page_sz = os::vm_page_size(); 2945 unsigned pages = size / page_sz; 2946 2947 unsigned char vec[1]; 2948 unsigned imin = 1, imax = pages + 1, imid; 2949 int mincore_return_value = 0; 2950 2951 assert(imin <= imax, "Unexpected page size"); 2952 2953 while (imin < imax) { 2954 imid = (imax + imin) / 2; 2955 nbot = ntop - (imid * page_sz); 2956 2957 // Use a trick with mincore to check whether the page is mapped or not. 2958 // mincore sets vec to 1 if page resides in memory and to 0 if page 2959 // is swapped output but if page we are asking for is unmapped 2960 // it returns -1,ENOMEM 2961 mincore_return_value = mincore(nbot, page_sz, vec); 2962 2963 if (mincore_return_value == -1) { 2964 // Page is not mapped go up 2965 // to find first mapped page 2966 if (errno != EAGAIN) { 2967 assert(errno == ENOMEM, "Unexpected mincore errno"); 2968 imax = imid; 2969 } 2970 } else { 2971 // Page is mapped go down 2972 // to find first not mapped page 2973 imin = imid + 1; 2974 } 2975 } 2976 2977 nbot = nbot + page_sz; 2978 2979 // Adjust stack bottom one page up if last checked page is not mapped 2980 if (mincore_return_value == -1) { 2981 nbot = nbot + page_sz; 2982 } 2983 2984 return nbot; 2985} 2986 2987 2988// Linux uses a growable mapping for the stack, and if the mapping for 2989// the stack guard pages is not removed when we detach a thread the 2990// stack cannot grow beyond the pages where the stack guard was 2991// mapped. If at some point later in the process the stack expands to 2992// that point, the Linux kernel cannot expand the stack any further 2993// because the guard pages are in the way, and a segfault occurs. 2994// 2995// However, it's essential not to split the stack region by unmapping 2996// a region (leaving a hole) that's already part of the stack mapping, 2997// so if the stack mapping has already grown beyond the guard pages at 2998// the time we create them, we have to truncate the stack mapping. 2999// So, we need to know the extent of the stack mapping when 3000// create_stack_guard_pages() is called. 3001 3002// We only need this for stacks that are growable: at the time of 3003// writing thread stacks don't use growable mappings (i.e. those 3004// creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3005// only applies to the main thread. 3006 3007// If the (growable) stack mapping already extends beyond the point 3008// where we're going to put our guard pages, truncate the mapping at 3009// that point by munmap()ping it. This ensures that when we later 3010// munmap() the guard pages we don't leave a hole in the stack 3011// mapping. This only affects the main/initial thread 3012 3013bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3014 if (os::Linux::is_initial_thread()) { 3015 // As we manually grow stack up to bottom inside create_attached_thread(), 3016 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3017 // we don't need to do anything special. 3018 // Check it first, before calling heavy function. 3019 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3020 unsigned char vec[1]; 3021 3022 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3023 // Fallback to slow path on all errors, including EAGAIN 3024 stack_extent = (uintptr_t) get_stack_commited_bottom( 3025 os::Linux::initial_thread_stack_bottom(), 3026 (size_t)addr - stack_extent); 3027 } 3028 3029 if (stack_extent < (uintptr_t)addr) { 3030 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3031 } 3032 } 3033 3034 return os::commit_memory(addr, size, !ExecMem); 3035} 3036 3037// If this is a growable mapping, remove the guard pages entirely by 3038// munmap()ping them. If not, just call uncommit_memory(). This only 3039// affects the main/initial thread, but guard against future OS changes 3040// It's safe to always unmap guard pages for initial thread because we 3041// always place it right after end of the mapped region 3042 3043bool os::remove_stack_guard_pages(char* addr, size_t size) { 3044 uintptr_t stack_extent, stack_base; 3045 3046 if (os::Linux::is_initial_thread()) { 3047 return ::munmap(addr, size) == 0; 3048 } 3049 3050 return os::uncommit_memory(addr, size); 3051} 3052 3053// If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3054// at 'requested_addr'. If there are existing memory mappings at the same 3055// location, however, they will be overwritten. If 'fixed' is false, 3056// 'requested_addr' is only treated as a hint, the return value may or 3057// may not start from the requested address. Unlike Linux mmap(), this 3058// function returns NULL to indicate failure. 3059static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3060 char * addr; 3061 int flags; 3062 3063 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3064 if (fixed) { 3065 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3066 flags |= MAP_FIXED; 3067 } 3068 3069 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3070 // touch an uncommitted page. Otherwise, the read/write might 3071 // succeed if we have enough swap space to back the physical page. 3072 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3073 flags, -1, 0); 3074 3075 return addr == MAP_FAILED ? NULL : addr; 3076} 3077 3078static int anon_munmap(char * addr, size_t size) { 3079 return ::munmap(addr, size) == 0; 3080} 3081 3082char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3083 size_t alignment_hint) { 3084 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3085} 3086 3087bool os::pd_release_memory(char* addr, size_t size) { 3088 return anon_munmap(addr, size); 3089} 3090 3091static bool linux_mprotect(char* addr, size_t size, int prot) { 3092 // Linux wants the mprotect address argument to be page aligned. 3093 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3094 3095 // According to SUSv3, mprotect() should only be used with mappings 3096 // established by mmap(), and mmap() always maps whole pages. Unaligned 3097 // 'addr' likely indicates problem in the VM (e.g. trying to change 3098 // protection of malloc'ed or statically allocated memory). Check the 3099 // caller if you hit this assert. 3100 assert(addr == bottom, "sanity check"); 3101 3102 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3103 return ::mprotect(bottom, size, prot) == 0; 3104} 3105 3106// Set protections specified 3107bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3108 bool is_committed) { 3109 unsigned int p = 0; 3110 switch (prot) { 3111 case MEM_PROT_NONE: p = PROT_NONE; break; 3112 case MEM_PROT_READ: p = PROT_READ; break; 3113 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3114 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3115 default: 3116 ShouldNotReachHere(); 3117 } 3118 // is_committed is unused. 3119 return linux_mprotect(addr, bytes, p); 3120} 3121 3122bool os::guard_memory(char* addr, size_t size) { 3123 return linux_mprotect(addr, size, PROT_NONE); 3124} 3125 3126bool os::unguard_memory(char* addr, size_t size) { 3127 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3128} 3129 3130bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3131 size_t page_size) { 3132 bool result = false; 3133 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3134 MAP_ANONYMOUS|MAP_PRIVATE, 3135 -1, 0); 3136 if (p != MAP_FAILED) { 3137 void *aligned_p = align_ptr_up(p, page_size); 3138 3139 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3140 3141 munmap(p, page_size * 2); 3142 } 3143 3144 if (warn && !result) { 3145 warning("TransparentHugePages is not supported by the operating system."); 3146 } 3147 3148 return result; 3149} 3150 3151bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3152 bool result = false; 3153 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3154 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3155 -1, 0); 3156 3157 if (p != MAP_FAILED) { 3158 // We don't know if this really is a huge page or not. 3159 FILE *fp = fopen("/proc/self/maps", "r"); 3160 if (fp) { 3161 while (!feof(fp)) { 3162 char chars[257]; 3163 long x = 0; 3164 if (fgets(chars, sizeof(chars), fp)) { 3165 if (sscanf(chars, "%lx-%*x", &x) == 1 3166 && x == (long)p) { 3167 if (strstr (chars, "hugepage")) { 3168 result = true; 3169 break; 3170 } 3171 } 3172 } 3173 } 3174 fclose(fp); 3175 } 3176 munmap(p, page_size); 3177 } 3178 3179 if (warn && !result) { 3180 warning("HugeTLBFS is not supported by the operating system."); 3181 } 3182 3183 return result; 3184} 3185 3186// Set the coredump_filter bits to include largepages in core dump (bit 6) 3187// 3188// From the coredump_filter documentation: 3189// 3190// - (bit 0) anonymous private memory 3191// - (bit 1) anonymous shared memory 3192// - (bit 2) file-backed private memory 3193// - (bit 3) file-backed shared memory 3194// - (bit 4) ELF header pages in file-backed private memory areas (it is 3195// effective only if the bit 2 is cleared) 3196// - (bit 5) hugetlb private memory 3197// - (bit 6) hugetlb shared memory 3198// 3199static void set_coredump_filter(void) { 3200 FILE *f; 3201 long cdm; 3202 3203 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3204 return; 3205 } 3206 3207 if (fscanf(f, "%lx", &cdm) != 1) { 3208 fclose(f); 3209 return; 3210 } 3211 3212 rewind(f); 3213 3214 if ((cdm & LARGEPAGES_BIT) == 0) { 3215 cdm |= LARGEPAGES_BIT; 3216 fprintf(f, "%#lx", cdm); 3217 } 3218 3219 fclose(f); 3220} 3221 3222// Large page support 3223 3224static size_t _large_page_size = 0; 3225 3226size_t os::Linux::find_large_page_size() { 3227 size_t large_page_size = 0; 3228 3229 // large_page_size on Linux is used to round up heap size. x86 uses either 3230 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3231 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3232 // page as large as 256M. 3233 // 3234 // Here we try to figure out page size by parsing /proc/meminfo and looking 3235 // for a line with the following format: 3236 // Hugepagesize: 2048 kB 3237 // 3238 // If we can't determine the value (e.g. /proc is not mounted, or the text 3239 // format has been changed), we'll use the largest page size supported by 3240 // the processor. 3241 3242#ifndef ZERO 3243 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3244 ARM32_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M); 3245#endif // ZERO 3246 3247 FILE *fp = fopen("/proc/meminfo", "r"); 3248 if (fp) { 3249 while (!feof(fp)) { 3250 int x = 0; 3251 char buf[16]; 3252 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3253 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3254 large_page_size = x * K; 3255 break; 3256 } 3257 } else { 3258 // skip to next line 3259 for (;;) { 3260 int ch = fgetc(fp); 3261 if (ch == EOF || ch == (int)'\n') break; 3262 } 3263 } 3264 } 3265 fclose(fp); 3266 } 3267 3268 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3269 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3270 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3271 proper_unit_for_byte_size(large_page_size)); 3272 } 3273 3274 return large_page_size; 3275} 3276 3277size_t os::Linux::setup_large_page_size() { 3278 _large_page_size = Linux::find_large_page_size(); 3279 const size_t default_page_size = (size_t)Linux::page_size(); 3280 if (_large_page_size > default_page_size) { 3281 _page_sizes[0] = _large_page_size; 3282 _page_sizes[1] = default_page_size; 3283 _page_sizes[2] = 0; 3284 } 3285 3286 return _large_page_size; 3287} 3288 3289bool os::Linux::setup_large_page_type(size_t page_size) { 3290 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3291 FLAG_IS_DEFAULT(UseSHM) && 3292 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3293 3294 // The type of large pages has not been specified by the user. 3295 3296 // Try UseHugeTLBFS and then UseSHM. 3297 UseHugeTLBFS = UseSHM = true; 3298 3299 // Don't try UseTransparentHugePages since there are known 3300 // performance issues with it turned on. This might change in the future. 3301 UseTransparentHugePages = false; 3302 } 3303 3304 if (UseTransparentHugePages) { 3305 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3306 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3307 UseHugeTLBFS = false; 3308 UseSHM = false; 3309 return true; 3310 } 3311 UseTransparentHugePages = false; 3312 } 3313 3314 if (UseHugeTLBFS) { 3315 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3316 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3317 UseSHM = false; 3318 return true; 3319 } 3320 UseHugeTLBFS = false; 3321 } 3322 3323 return UseSHM; 3324} 3325 3326void os::large_page_init() { 3327 if (!UseLargePages && 3328 !UseTransparentHugePages && 3329 !UseHugeTLBFS && 3330 !UseSHM) { 3331 // Not using large pages. 3332 return; 3333 } 3334 3335 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3336 // The user explicitly turned off large pages. 3337 // Ignore the rest of the large pages flags. 3338 UseTransparentHugePages = false; 3339 UseHugeTLBFS = false; 3340 UseSHM = false; 3341 return; 3342 } 3343 3344 size_t large_page_size = Linux::setup_large_page_size(); 3345 UseLargePages = Linux::setup_large_page_type(large_page_size); 3346 3347 set_coredump_filter(); 3348} 3349 3350#ifndef SHM_HUGETLB 3351 #define SHM_HUGETLB 04000 3352#endif 3353 3354char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3355 char* req_addr, bool exec) { 3356 // "exec" is passed in but not used. Creating the shared image for 3357 // the code cache doesn't have an SHM_X executable permission to check. 3358 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3359 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3360 3361 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) { 3362 return NULL; // Fallback to small pages. 3363 } 3364 3365 key_t key = IPC_PRIVATE; 3366 char *addr; 3367 3368 bool warn_on_failure = UseLargePages && 3369 (!FLAG_IS_DEFAULT(UseLargePages) || 3370 !FLAG_IS_DEFAULT(UseSHM) || 3371 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3372 char msg[128]; 3373 3374 // Create a large shared memory region to attach to based on size. 3375 // Currently, size is the total size of the heap 3376 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3377 if (shmid == -1) { 3378 // Possible reasons for shmget failure: 3379 // 1. shmmax is too small for Java heap. 3380 // > check shmmax value: cat /proc/sys/kernel/shmmax 3381 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3382 // 2. not enough large page memory. 3383 // > check available large pages: cat /proc/meminfo 3384 // > increase amount of large pages: 3385 // echo new_value > /proc/sys/vm/nr_hugepages 3386 // Note 1: different Linux may use different name for this property, 3387 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3388 // Note 2: it's possible there's enough physical memory available but 3389 // they are so fragmented after a long run that they can't 3390 // coalesce into large pages. Try to reserve large pages when 3391 // the system is still "fresh". 3392 if (warn_on_failure) { 3393 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3394 warning("%s", msg); 3395 } 3396 return NULL; 3397 } 3398 3399 // attach to the region 3400 addr = (char*)shmat(shmid, req_addr, 0); 3401 int err = errno; 3402 3403 // Remove shmid. If shmat() is successful, the actual shared memory segment 3404 // will be deleted when it's detached by shmdt() or when the process 3405 // terminates. If shmat() is not successful this will remove the shared 3406 // segment immediately. 3407 shmctl(shmid, IPC_RMID, NULL); 3408 3409 if ((intptr_t)addr == -1) { 3410 if (warn_on_failure) { 3411 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3412 warning("%s", msg); 3413 } 3414 return NULL; 3415 } 3416 3417 return addr; 3418} 3419 3420static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3421 int error) { 3422 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3423 3424 bool warn_on_failure = UseLargePages && 3425 (!FLAG_IS_DEFAULT(UseLargePages) || 3426 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3427 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3428 3429 if (warn_on_failure) { 3430 char msg[128]; 3431 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3432 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3433 warning("%s", msg); 3434 } 3435} 3436 3437char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3438 char* req_addr, 3439 bool exec) { 3440 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3441 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3442 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3443 3444 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3445 char* addr = (char*)::mmap(req_addr, bytes, prot, 3446 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3447 -1, 0); 3448 3449 if (addr == MAP_FAILED) { 3450 warn_on_large_pages_failure(req_addr, bytes, errno); 3451 return NULL; 3452 } 3453 3454 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3455 3456 return addr; 3457} 3458 3459// Helper for os::Linux::reserve_memory_special_huge_tlbfs_mixed(). 3460// Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3461// (req_addr != NULL) or with a given alignment. 3462// - bytes shall be a multiple of alignment. 3463// - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3464// - alignment sets the alignment at which memory shall be allocated. 3465// It must be a multiple of allocation granularity. 3466// Returns address of memory or NULL. If req_addr was not NULL, will only return 3467// req_addr or NULL. 3468static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3469 3470 size_t extra_size = bytes; 3471 if (req_addr == NULL && alignment > 0) { 3472 extra_size += alignment; 3473 } 3474 3475 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3476 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3477 -1, 0); 3478 if (start == MAP_FAILED) { 3479 start = NULL; 3480 } else { 3481 if (req_addr != NULL) { 3482 if (start != req_addr) { 3483 ::munmap(start, extra_size); 3484 start = NULL; 3485 } 3486 } else { 3487 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3488 char* const end_aligned = start_aligned + bytes; 3489 char* const end = start + extra_size; 3490 if (start_aligned > start) { 3491 ::munmap(start, start_aligned - start); 3492 } 3493 if (end_aligned < end) { 3494 ::munmap(end_aligned, end - end_aligned); 3495 } 3496 start = start_aligned; 3497 } 3498 } 3499 return start; 3500 3501} 3502 3503// Reserve memory using mmap(MAP_HUGETLB). 3504// - bytes shall be a multiple of alignment. 3505// - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3506// - alignment sets the alignment at which memory shall be allocated. 3507// It must be a multiple of allocation granularity. 3508// Returns address of memory or NULL. If req_addr was not NULL, will only return 3509// req_addr or NULL. 3510char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3511 size_t alignment, 3512 char* req_addr, 3513 bool exec) { 3514 size_t large_page_size = os::large_page_size(); 3515 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3516 3517 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3518 assert(is_size_aligned(bytes, alignment), "Must be"); 3519 3520 // First reserve - but not commit - the address range in small pages. 3521 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3522 3523 if (start == NULL) { 3524 return NULL; 3525 } 3526 3527 assert(is_ptr_aligned(start, alignment), "Must be"); 3528 3529 char* end = start + bytes; 3530 3531 // Find the regions of the allocated chunk that can be promoted to large pages. 3532 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3533 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3534 3535 size_t lp_bytes = lp_end - lp_start; 3536 3537 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3538 3539 if (lp_bytes == 0) { 3540 // The mapped region doesn't even span the start and the end of a large page. 3541 // Fall back to allocate a non-special area. 3542 ::munmap(start, end - start); 3543 return NULL; 3544 } 3545 3546 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3547 3548 void* result; 3549 3550 // Commit small-paged leading area. 3551 if (start != lp_start) { 3552 result = ::mmap(start, lp_start - start, prot, 3553 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3554 -1, 0); 3555 if (result == MAP_FAILED) { 3556 ::munmap(lp_start, end - lp_start); 3557 return NULL; 3558 } 3559 } 3560 3561 // Commit large-paged area. 3562 result = ::mmap(lp_start, lp_bytes, prot, 3563 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3564 -1, 0); 3565 if (result == MAP_FAILED) { 3566 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3567 // If the mmap above fails, the large pages region will be unmapped and we 3568 // have regions before and after with small pages. Release these regions. 3569 // 3570 // | mapped | unmapped | mapped | 3571 // ^ ^ ^ ^ 3572 // start lp_start lp_end end 3573 // 3574 ::munmap(start, lp_start - start); 3575 ::munmap(lp_end, end - lp_end); 3576 return NULL; 3577 } 3578 3579 // Commit small-paged trailing area. 3580 if (lp_end != end) { 3581 result = ::mmap(lp_end, end - lp_end, prot, 3582 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3583 -1, 0); 3584 if (result == MAP_FAILED) { 3585 ::munmap(start, lp_end - start); 3586 return NULL; 3587 } 3588 } 3589 3590 return start; 3591} 3592 3593char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3594 size_t alignment, 3595 char* req_addr, 3596 bool exec) { 3597 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3598 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3599 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3600 assert(is_power_of_2(os::large_page_size()), "Must be"); 3601 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3602 3603 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3604 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3605 } else { 3606 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3607 } 3608} 3609 3610char* os::reserve_memory_special(size_t bytes, size_t alignment, 3611 char* req_addr, bool exec) { 3612 assert(UseLargePages, "only for large pages"); 3613 3614 char* addr; 3615 if (UseSHM) { 3616 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3617 } else { 3618 assert(UseHugeTLBFS, "must be"); 3619 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3620 } 3621 3622 if (addr != NULL) { 3623 if (UseNUMAInterleaving) { 3624 numa_make_global(addr, bytes); 3625 } 3626 3627 // The memory is committed 3628 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3629 } 3630 3631 return addr; 3632} 3633 3634bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3635 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3636 return shmdt(base) == 0; 3637} 3638 3639bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3640 return pd_release_memory(base, bytes); 3641} 3642 3643bool os::release_memory_special(char* base, size_t bytes) { 3644 bool res; 3645 if (MemTracker::tracking_level() > NMT_minimal) { 3646 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3647 res = os::Linux::release_memory_special_impl(base, bytes); 3648 if (res) { 3649 tkr.record((address)base, bytes); 3650 } 3651 3652 } else { 3653 res = os::Linux::release_memory_special_impl(base, bytes); 3654 } 3655 return res; 3656} 3657 3658bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3659 assert(UseLargePages, "only for large pages"); 3660 bool res; 3661 3662 if (UseSHM) { 3663 res = os::Linux::release_memory_special_shm(base, bytes); 3664 } else { 3665 assert(UseHugeTLBFS, "must be"); 3666 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3667 } 3668 return res; 3669} 3670 3671size_t os::large_page_size() { 3672 return _large_page_size; 3673} 3674 3675// With SysV SHM the entire memory region must be allocated as shared 3676// memory. 3677// HugeTLBFS allows application to commit large page memory on demand. 3678// However, when committing memory with HugeTLBFS fails, the region 3679// that was supposed to be committed will lose the old reservation 3680// and allow other threads to steal that memory region. Because of this 3681// behavior we can't commit HugeTLBFS memory. 3682bool os::can_commit_large_page_memory() { 3683 return UseTransparentHugePages; 3684} 3685 3686bool os::can_execute_large_page_memory() { 3687 return UseTransparentHugePages || UseHugeTLBFS; 3688} 3689 3690// Reserve memory at an arbitrary address, only if that area is 3691// available (and not reserved for something else). 3692 3693char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3694 const int max_tries = 10; 3695 char* base[max_tries]; 3696 size_t size[max_tries]; 3697 const size_t gap = 0x000000; 3698 3699 // Assert only that the size is a multiple of the page size, since 3700 // that's all that mmap requires, and since that's all we really know 3701 // about at this low abstraction level. If we need higher alignment, 3702 // we can either pass an alignment to this method or verify alignment 3703 // in one of the methods further up the call chain. See bug 5044738. 3704 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3705 3706 // Repeatedly allocate blocks until the block is allocated at the 3707 // right spot. 3708 3709 // Linux mmap allows caller to pass an address as hint; give it a try first, 3710 // if kernel honors the hint then we can return immediately. 3711 char * addr = anon_mmap(requested_addr, bytes, false); 3712 if (addr == requested_addr) { 3713 return requested_addr; 3714 } 3715 3716 if (addr != NULL) { 3717 // mmap() is successful but it fails to reserve at the requested address 3718 anon_munmap(addr, bytes); 3719 } 3720 3721 int i; 3722 for (i = 0; i < max_tries; ++i) { 3723 base[i] = reserve_memory(bytes); 3724 3725 if (base[i] != NULL) { 3726 // Is this the block we wanted? 3727 if (base[i] == requested_addr) { 3728 size[i] = bytes; 3729 break; 3730 } 3731 3732 // Does this overlap the block we wanted? Give back the overlapped 3733 // parts and try again. 3734 3735 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3736 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3737 unmap_memory(base[i], top_overlap); 3738 base[i] += top_overlap; 3739 size[i] = bytes - top_overlap; 3740 } else { 3741 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3742 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3743 unmap_memory(requested_addr, bottom_overlap); 3744 size[i] = bytes - bottom_overlap; 3745 } else { 3746 size[i] = bytes; 3747 } 3748 } 3749 } 3750 } 3751 3752 // Give back the unused reserved pieces. 3753 3754 for (int j = 0; j < i; ++j) { 3755 if (base[j] != NULL) { 3756 unmap_memory(base[j], size[j]); 3757 } 3758 } 3759 3760 if (i < max_tries) { 3761 return requested_addr; 3762 } else { 3763 return NULL; 3764 } 3765} 3766 3767size_t os::read(int fd, void *buf, unsigned int nBytes) { 3768 return ::read(fd, buf, nBytes); 3769} 3770 3771size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3772 return ::pread(fd, buf, nBytes, offset); 3773} 3774 3775// Short sleep, direct OS call. 3776// 3777// Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3778// sched_yield(2) will actually give up the CPU: 3779// 3780// * Alone on this pariticular CPU, keeps running. 3781// * Before the introduction of "skip_buddy" with "compat_yield" disabled 3782// (pre 2.6.39). 3783// 3784// So calling this with 0 is an alternative. 3785// 3786void os::naked_short_sleep(jlong ms) { 3787 struct timespec req; 3788 3789 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3790 req.tv_sec = 0; 3791 if (ms > 0) { 3792 req.tv_nsec = (ms % 1000) * 1000000; 3793 } else { 3794 req.tv_nsec = 1; 3795 } 3796 3797 nanosleep(&req, NULL); 3798 3799 return; 3800} 3801 3802// Sleep forever; naked call to OS-specific sleep; use with CAUTION 3803void os::infinite_sleep() { 3804 while (true) { // sleep forever ... 3805 ::sleep(100); // ... 100 seconds at a time 3806 } 3807} 3808 3809// Used to convert frequent JVM_Yield() to nops 3810bool os::dont_yield() { 3811 return DontYieldALot; 3812} 3813 3814void os::naked_yield() { 3815 sched_yield(); 3816} 3817 3818//////////////////////////////////////////////////////////////////////////////// 3819// thread priority support 3820 3821// Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3822// only supports dynamic priority, static priority must be zero. For real-time 3823// applications, Linux supports SCHED_RR which allows static priority (1-99). 3824// However, for large multi-threaded applications, SCHED_RR is not only slower 3825// than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3826// of 5 runs - Sep 2005). 3827// 3828// The following code actually changes the niceness of kernel-thread/LWP. It 3829// has an assumption that setpriority() only modifies one kernel-thread/LWP, 3830// not the entire user process, and user level threads are 1:1 mapped to kernel 3831// threads. It has always been the case, but could change in the future. For 3832// this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3833// It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3834 3835int os::java_to_os_priority[CriticalPriority + 1] = { 3836 19, // 0 Entry should never be used 3837 3838 4, // 1 MinPriority 3839 3, // 2 3840 2, // 3 3841 3842 1, // 4 3843 0, // 5 NormPriority 3844 -1, // 6 3845 3846 -2, // 7 3847 -3, // 8 3848 -4, // 9 NearMaxPriority 3849 3850 -5, // 10 MaxPriority 3851 3852 -5 // 11 CriticalPriority 3853}; 3854 3855static int prio_init() { 3856 if (ThreadPriorityPolicy == 1) { 3857 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3858 // if effective uid is not root. Perhaps, a more elegant way of doing 3859 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3860 if (geteuid() != 0) { 3861 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3862 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3863 } 3864 ThreadPriorityPolicy = 0; 3865 } 3866 } 3867 if (UseCriticalJavaThreadPriority) { 3868 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3869 } 3870 return 0; 3871} 3872 3873OSReturn os::set_native_priority(Thread* thread, int newpri) { 3874 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3875 3876 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3877 return (ret == 0) ? OS_OK : OS_ERR; 3878} 3879 3880OSReturn os::get_native_priority(const Thread* const thread, 3881 int *priority_ptr) { 3882 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3883 *priority_ptr = java_to_os_priority[NormPriority]; 3884 return OS_OK; 3885 } 3886 3887 errno = 0; 3888 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3889 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3890} 3891 3892// Hint to the underlying OS that a task switch would not be good. 3893// Void return because it's a hint and can fail. 3894void os::hint_no_preempt() {} 3895 3896//////////////////////////////////////////////////////////////////////////////// 3897// suspend/resume support 3898 3899// the low-level signal-based suspend/resume support is a remnant from the 3900// old VM-suspension that used to be for java-suspension, safepoints etc, 3901// within hotspot. Now there is a single use-case for this: 3902// - calling get_thread_pc() on the VMThread by the flat-profiler task 3903// that runs in the watcher thread. 3904// The remaining code is greatly simplified from the more general suspension 3905// code that used to be used. 3906// 3907// The protocol is quite simple: 3908// - suspend: 3909// - sends a signal to the target thread 3910// - polls the suspend state of the osthread using a yield loop 3911// - target thread signal handler (SR_handler) sets suspend state 3912// and blocks in sigsuspend until continued 3913// - resume: 3914// - sets target osthread state to continue 3915// - sends signal to end the sigsuspend loop in the SR_handler 3916// 3917// Note that the SR_lock plays no role in this suspend/resume protocol. 3918 3919static void resume_clear_context(OSThread *osthread) { 3920 osthread->set_ucontext(NULL); 3921 osthread->set_siginfo(NULL); 3922} 3923 3924static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 3925 ucontext_t* context) { 3926 osthread->set_ucontext(context); 3927 osthread->set_siginfo(siginfo); 3928} 3929 3930// Handler function invoked when a thread's execution is suspended or 3931// resumed. We have to be careful that only async-safe functions are 3932// called here (Note: most pthread functions are not async safe and 3933// should be avoided.) 3934// 3935// Note: sigwait() is a more natural fit than sigsuspend() from an 3936// interface point of view, but sigwait() prevents the signal hander 3937// from being run. libpthread would get very confused by not having 3938// its signal handlers run and prevents sigwait()'s use with the 3939// mutex granting granting signal. 3940// 3941// Currently only ever called on the VMThread and JavaThreads (PC sampling) 3942// 3943static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3944 // Save and restore errno to avoid confusing native code with EINTR 3945 // after sigsuspend. 3946 int old_errno = errno; 3947 3948 Thread* thread = Thread::current(); 3949 OSThread* osthread = thread->osthread(); 3950 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 3951 3952 os::SuspendResume::State current = osthread->sr.state(); 3953 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 3954 suspend_save_context(osthread, siginfo, context); 3955 3956 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 3957 os::SuspendResume::State state = osthread->sr.suspended(); 3958 if (state == os::SuspendResume::SR_SUSPENDED) { 3959 sigset_t suspend_set; // signals for sigsuspend() 3960 3961 // get current set of blocked signals and unblock resume signal 3962 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3963 sigdelset(&suspend_set, SR_signum); 3964 3965 sr_semaphore.signal(); 3966 // wait here until we are resumed 3967 while (1) { 3968 sigsuspend(&suspend_set); 3969 3970 os::SuspendResume::State result = osthread->sr.running(); 3971 if (result == os::SuspendResume::SR_RUNNING) { 3972 sr_semaphore.signal(); 3973 break; 3974 } 3975 } 3976 3977 } else if (state == os::SuspendResume::SR_RUNNING) { 3978 // request was cancelled, continue 3979 } else { 3980 ShouldNotReachHere(); 3981 } 3982 3983 resume_clear_context(osthread); 3984 } else if (current == os::SuspendResume::SR_RUNNING) { 3985 // request was cancelled, continue 3986 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 3987 // ignore 3988 } else { 3989 // ignore 3990 } 3991 3992 errno = old_errno; 3993} 3994 3995 3996static int SR_initialize() { 3997 struct sigaction act; 3998 char *s; 3999 // Get signal number to use for suspend/resume 4000 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4001 int sig = ::strtol(s, 0, 10); 4002 if (sig > 0 || sig < _NSIG) { 4003 SR_signum = sig; 4004 } 4005 } 4006 4007 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4008 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4009 4010 sigemptyset(&SR_sigset); 4011 sigaddset(&SR_sigset, SR_signum); 4012 4013 // Set up signal handler for suspend/resume 4014 act.sa_flags = SA_RESTART|SA_SIGINFO; 4015 act.sa_handler = (void (*)(int)) SR_handler; 4016 4017 // SR_signum is blocked by default. 4018 // 4528190 - We also need to block pthread restart signal (32 on all 4019 // supported Linux platforms). Note that LinuxThreads need to block 4020 // this signal for all threads to work properly. So we don't have 4021 // to use hard-coded signal number when setting up the mask. 4022 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4023 4024 if (sigaction(SR_signum, &act, 0) == -1) { 4025 return -1; 4026 } 4027 4028 // Save signal flag 4029 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4030 return 0; 4031} 4032 4033static int sr_notify(OSThread* osthread) { 4034 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4035 assert_status(status == 0, status, "pthread_kill"); 4036 return status; 4037} 4038 4039// "Randomly" selected value for how long we want to spin 4040// before bailing out on suspending a thread, also how often 4041// we send a signal to a thread we want to resume 4042static const int RANDOMLY_LARGE_INTEGER = 1000000; 4043static const int RANDOMLY_LARGE_INTEGER2 = 100; 4044 4045// returns true on success and false on error - really an error is fatal 4046// but this seems the normal response to library errors 4047static bool do_suspend(OSThread* osthread) { 4048 assert(osthread->sr.is_running(), "thread should be running"); 4049 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4050 4051 // mark as suspended and send signal 4052 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4053 // failed to switch, state wasn't running? 4054 ShouldNotReachHere(); 4055 return false; 4056 } 4057 4058 if (sr_notify(osthread) != 0) { 4059 ShouldNotReachHere(); 4060 } 4061 4062 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4063 while (true) { 4064 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4065 break; 4066 } else { 4067 // timeout 4068 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4069 if (cancelled == os::SuspendResume::SR_RUNNING) { 4070 return false; 4071 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4072 // make sure that we consume the signal on the semaphore as well 4073 sr_semaphore.wait(); 4074 break; 4075 } else { 4076 ShouldNotReachHere(); 4077 return false; 4078 } 4079 } 4080 } 4081 4082 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4083 return true; 4084} 4085 4086static void do_resume(OSThread* osthread) { 4087 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4088 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4089 4090 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4091 // failed to switch to WAKEUP_REQUEST 4092 ShouldNotReachHere(); 4093 return; 4094 } 4095 4096 while (true) { 4097 if (sr_notify(osthread) == 0) { 4098 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4099 if (osthread->sr.is_running()) { 4100 return; 4101 } 4102 } 4103 } else { 4104 ShouldNotReachHere(); 4105 } 4106 } 4107 4108 guarantee(osthread->sr.is_running(), "Must be running!"); 4109} 4110 4111/////////////////////////////////////////////////////////////////////////////////// 4112// signal handling (except suspend/resume) 4113 4114// This routine may be used by user applications as a "hook" to catch signals. 4115// The user-defined signal handler must pass unrecognized signals to this 4116// routine, and if it returns true (non-zero), then the signal handler must 4117// return immediately. If the flag "abort_if_unrecognized" is true, then this 4118// routine will never retun false (zero), but instead will execute a VM panic 4119// routine kill the process. 4120// 4121// If this routine returns false, it is OK to call it again. This allows 4122// the user-defined signal handler to perform checks either before or after 4123// the VM performs its own checks. Naturally, the user code would be making 4124// a serious error if it tried to handle an exception (such as a null check 4125// or breakpoint) that the VM was generating for its own correct operation. 4126// 4127// This routine may recognize any of the following kinds of signals: 4128// SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4129// It should be consulted by handlers for any of those signals. 4130// 4131// The caller of this routine must pass in the three arguments supplied 4132// to the function referred to in the "sa_sigaction" (not the "sa_handler") 4133// field of the structure passed to sigaction(). This routine assumes that 4134// the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4135// 4136// Note that the VM will print warnings if it detects conflicting signal 4137// handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4138// 4139extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4140 siginfo_t* siginfo, 4141 void* ucontext, 4142 int abort_if_unrecognized); 4143 4144void signalHandler(int sig, siginfo_t* info, void* uc) { 4145 assert(info != NULL && uc != NULL, "it must be old kernel"); 4146 int orig_errno = errno; // Preserve errno value over signal handler. 4147 JVM_handle_linux_signal(sig, info, uc, true); 4148 errno = orig_errno; 4149} 4150 4151 4152// This boolean allows users to forward their own non-matching signals 4153// to JVM_handle_linux_signal, harmlessly. 4154bool os::Linux::signal_handlers_are_installed = false; 4155 4156// For signal-chaining 4157struct sigaction os::Linux::sigact[MAXSIGNUM]; 4158unsigned int os::Linux::sigs = 0; 4159bool os::Linux::libjsig_is_loaded = false; 4160typedef struct sigaction *(*get_signal_t)(int); 4161get_signal_t os::Linux::get_signal_action = NULL; 4162 4163struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4164 struct sigaction *actp = NULL; 4165 4166 if (libjsig_is_loaded) { 4167 // Retrieve the old signal handler from libjsig 4168 actp = (*get_signal_action)(sig); 4169 } 4170 if (actp == NULL) { 4171 // Retrieve the preinstalled signal handler from jvm 4172 actp = get_preinstalled_handler(sig); 4173 } 4174 4175 return actp; 4176} 4177 4178static bool call_chained_handler(struct sigaction *actp, int sig, 4179 siginfo_t *siginfo, void *context) { 4180 // Call the old signal handler 4181 if (actp->sa_handler == SIG_DFL) { 4182 // It's more reasonable to let jvm treat it as an unexpected exception 4183 // instead of taking the default action. 4184 return false; 4185 } else if (actp->sa_handler != SIG_IGN) { 4186 if ((actp->sa_flags & SA_NODEFER) == 0) { 4187 // automaticlly block the signal 4188 sigaddset(&(actp->sa_mask), sig); 4189 } 4190 4191 sa_handler_t hand; 4192 sa_sigaction_t sa; 4193 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4194 // retrieve the chained handler 4195 if (siginfo_flag_set) { 4196 sa = actp->sa_sigaction; 4197 } else { 4198 hand = actp->sa_handler; 4199 } 4200 4201 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4202 actp->sa_handler = SIG_DFL; 4203 } 4204 4205 // try to honor the signal mask 4206 sigset_t oset; 4207 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4208 4209 // call into the chained handler 4210 if (siginfo_flag_set) { 4211 (*sa)(sig, siginfo, context); 4212 } else { 4213 (*hand)(sig); 4214 } 4215 4216 // restore the signal mask 4217 pthread_sigmask(SIG_SETMASK, &oset, 0); 4218 } 4219 // Tell jvm's signal handler the signal is taken care of. 4220 return true; 4221} 4222 4223bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4224 bool chained = false; 4225 // signal-chaining 4226 if (UseSignalChaining) { 4227 struct sigaction *actp = get_chained_signal_action(sig); 4228 if (actp != NULL) { 4229 chained = call_chained_handler(actp, sig, siginfo, context); 4230 } 4231 } 4232 return chained; 4233} 4234 4235struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4236 if ((((unsigned int)1 << sig) & sigs) != 0) { 4237 return &sigact[sig]; 4238 } 4239 return NULL; 4240} 4241 4242void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4243 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4244 sigact[sig] = oldAct; 4245 sigs |= (unsigned int)1 << sig; 4246} 4247 4248// for diagnostic 4249int os::Linux::sigflags[MAXSIGNUM]; 4250 4251int os::Linux::get_our_sigflags(int sig) { 4252 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4253 return sigflags[sig]; 4254} 4255 4256void os::Linux::set_our_sigflags(int sig, int flags) { 4257 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4258 sigflags[sig] = flags; 4259} 4260 4261void os::Linux::set_signal_handler(int sig, bool set_installed) { 4262 // Check for overwrite. 4263 struct sigaction oldAct; 4264 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4265 4266 void* oldhand = oldAct.sa_sigaction 4267 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4268 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4269 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4270 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4271 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4272 if (AllowUserSignalHandlers || !set_installed) { 4273 // Do not overwrite; user takes responsibility to forward to us. 4274 return; 4275 } else if (UseSignalChaining) { 4276 // save the old handler in jvm 4277 save_preinstalled_handler(sig, oldAct); 4278 // libjsig also interposes the sigaction() call below and saves the 4279 // old sigaction on it own. 4280 } else { 4281 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 4282 "%#lx for signal %d.", (long)oldhand, sig)); 4283 } 4284 } 4285 4286 struct sigaction sigAct; 4287 sigfillset(&(sigAct.sa_mask)); 4288 sigAct.sa_handler = SIG_DFL; 4289 if (!set_installed) { 4290 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4291 } else { 4292 sigAct.sa_sigaction = signalHandler; 4293 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4294 } 4295 // Save flags, which are set by ours 4296 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4297 sigflags[sig] = sigAct.sa_flags; 4298 4299 int ret = sigaction(sig, &sigAct, &oldAct); 4300 assert(ret == 0, "check"); 4301 4302 void* oldhand2 = oldAct.sa_sigaction 4303 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4304 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4305 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4306} 4307 4308// install signal handlers for signals that HotSpot needs to 4309// handle in order to support Java-level exception handling. 4310 4311void os::Linux::install_signal_handlers() { 4312 if (!signal_handlers_are_installed) { 4313 signal_handlers_are_installed = true; 4314 4315 // signal-chaining 4316 typedef void (*signal_setting_t)(); 4317 signal_setting_t begin_signal_setting = NULL; 4318 signal_setting_t end_signal_setting = NULL; 4319 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4320 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4321 if (begin_signal_setting != NULL) { 4322 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4323 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4324 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4325 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4326 libjsig_is_loaded = true; 4327 assert(UseSignalChaining, "should enable signal-chaining"); 4328 } 4329 if (libjsig_is_loaded) { 4330 // Tell libjsig jvm is setting signal handlers 4331 (*begin_signal_setting)(); 4332 } 4333 4334 set_signal_handler(SIGSEGV, true); 4335 set_signal_handler(SIGPIPE, true); 4336 set_signal_handler(SIGBUS, true); 4337 set_signal_handler(SIGILL, true); 4338 set_signal_handler(SIGFPE, true); 4339#if defined(PPC64) 4340 set_signal_handler(SIGTRAP, true); 4341#endif 4342 set_signal_handler(SIGXFSZ, true); 4343 4344 if (libjsig_is_loaded) { 4345 // Tell libjsig jvm finishes setting signal handlers 4346 (*end_signal_setting)(); 4347 } 4348 4349 // We don't activate signal checker if libjsig is in place, we trust ourselves 4350 // and if UserSignalHandler is installed all bets are off. 4351 // Log that signal checking is off only if -verbose:jni is specified. 4352 if (CheckJNICalls) { 4353 if (libjsig_is_loaded) { 4354 if (PrintJNIResolving) { 4355 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4356 } 4357 check_signals = false; 4358 } 4359 if (AllowUserSignalHandlers) { 4360 if (PrintJNIResolving) { 4361 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4362 } 4363 check_signals = false; 4364 } 4365 } 4366 } 4367} 4368 4369// This is the fastest way to get thread cpu time on Linux. 4370// Returns cpu time (user+sys) for any thread, not only for current. 4371// POSIX compliant clocks are implemented in the kernels 2.6.16+. 4372// It might work on 2.6.10+ with a special kernel/glibc patch. 4373// For reference, please, see IEEE Std 1003.1-2004: 4374// http://www.unix.org/single_unix_specification 4375 4376jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4377 struct timespec tp; 4378 int rc = os::Linux::clock_gettime(clockid, &tp); 4379 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4380 4381 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4382} 4383 4384///// 4385// glibc on Linux platform uses non-documented flag 4386// to indicate, that some special sort of signal 4387// trampoline is used. 4388// We will never set this flag, and we should 4389// ignore this flag in our diagnostic 4390#ifdef SIGNIFICANT_SIGNAL_MASK 4391 #undef SIGNIFICANT_SIGNAL_MASK 4392#endif 4393#define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4394 4395static const char* get_signal_handler_name(address handler, 4396 char* buf, int buflen) { 4397 int offset; 4398 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4399 if (found) { 4400 // skip directory names 4401 const char *p1, *p2; 4402 p1 = buf; 4403 size_t len = strlen(os::file_separator()); 4404 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4405 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4406 } else { 4407 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4408 } 4409 return buf; 4410} 4411 4412static void print_signal_handler(outputStream* st, int sig, 4413 char* buf, size_t buflen) { 4414 struct sigaction sa; 4415 4416 sigaction(sig, NULL, &sa); 4417 4418 // See comment for SIGNIFICANT_SIGNAL_MASK define 4419 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4420 4421 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4422 4423 address handler = (sa.sa_flags & SA_SIGINFO) 4424 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4425 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4426 4427 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4428 st->print("SIG_DFL"); 4429 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4430 st->print("SIG_IGN"); 4431 } else { 4432 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4433 } 4434 4435 st->print(", sa_mask[0]="); 4436 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4437 4438 address rh = VMError::get_resetted_sighandler(sig); 4439 // May be, handler was resetted by VMError? 4440 if (rh != NULL) { 4441 handler = rh; 4442 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4443 } 4444 4445 st->print(", sa_flags="); 4446 os::Posix::print_sa_flags(st, sa.sa_flags); 4447 4448 // Check: is it our handler? 4449 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4450 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4451 // It is our signal handler 4452 // check for flags, reset system-used one! 4453 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4454 st->print( 4455 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4456 os::Linux::get_our_sigflags(sig)); 4457 } 4458 } 4459 st->cr(); 4460} 4461 4462 4463#define DO_SIGNAL_CHECK(sig) \ 4464 do { \ 4465 if (!sigismember(&check_signal_done, sig)) { \ 4466 os::Linux::check_signal_handler(sig); \ 4467 } \ 4468 } while (0) 4469 4470// This method is a periodic task to check for misbehaving JNI applications 4471// under CheckJNI, we can add any periodic checks here 4472 4473void os::run_periodic_checks() { 4474 if (check_signals == false) return; 4475 4476 // SEGV and BUS if overridden could potentially prevent 4477 // generation of hs*.log in the event of a crash, debugging 4478 // such a case can be very challenging, so we absolutely 4479 // check the following for a good measure: 4480 DO_SIGNAL_CHECK(SIGSEGV); 4481 DO_SIGNAL_CHECK(SIGILL); 4482 DO_SIGNAL_CHECK(SIGFPE); 4483 DO_SIGNAL_CHECK(SIGBUS); 4484 DO_SIGNAL_CHECK(SIGPIPE); 4485 DO_SIGNAL_CHECK(SIGXFSZ); 4486#if defined(PPC64) 4487 DO_SIGNAL_CHECK(SIGTRAP); 4488#endif 4489 4490 // ReduceSignalUsage allows the user to override these handlers 4491 // see comments at the very top and jvm_solaris.h 4492 if (!ReduceSignalUsage) { 4493 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4494 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4495 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4496 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4497 } 4498 4499 DO_SIGNAL_CHECK(SR_signum); 4500 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 4501} 4502 4503typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4504 4505static os_sigaction_t os_sigaction = NULL; 4506 4507void os::Linux::check_signal_handler(int sig) { 4508 char buf[O_BUFLEN]; 4509 address jvmHandler = NULL; 4510 4511 4512 struct sigaction act; 4513 if (os_sigaction == NULL) { 4514 // only trust the default sigaction, in case it has been interposed 4515 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4516 if (os_sigaction == NULL) return; 4517 } 4518 4519 os_sigaction(sig, (struct sigaction*)NULL, &act); 4520 4521 4522 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4523 4524 address thisHandler = (act.sa_flags & SA_SIGINFO) 4525 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4526 : CAST_FROM_FN_PTR(address, act.sa_handler); 4527 4528 4529 switch (sig) { 4530 case SIGSEGV: 4531 case SIGBUS: 4532 case SIGFPE: 4533 case SIGPIPE: 4534 case SIGILL: 4535 case SIGXFSZ: 4536 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4537 break; 4538 4539 case SHUTDOWN1_SIGNAL: 4540 case SHUTDOWN2_SIGNAL: 4541 case SHUTDOWN3_SIGNAL: 4542 case BREAK_SIGNAL: 4543 jvmHandler = (address)user_handler(); 4544 break; 4545 4546 case INTERRUPT_SIGNAL: 4547 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4548 break; 4549 4550 default: 4551 if (sig == SR_signum) { 4552 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4553 } else { 4554 return; 4555 } 4556 break; 4557 } 4558 4559 if (thisHandler != jvmHandler) { 4560 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4561 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4562 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4563 // No need to check this sig any longer 4564 sigaddset(&check_signal_done, sig); 4565 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4566 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4567 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4568 exception_name(sig, buf, O_BUFLEN)); 4569 } 4570 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4571 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4572 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4573 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4574 // No need to check this sig any longer 4575 sigaddset(&check_signal_done, sig); 4576 } 4577 4578 // Dump all the signal 4579 if (sigismember(&check_signal_done, sig)) { 4580 print_signal_handlers(tty, buf, O_BUFLEN); 4581 } 4582} 4583 4584extern void report_error(char* file_name, int line_no, char* title, 4585 char* format, ...); 4586 4587extern bool signal_name(int signo, char* buf, size_t len); 4588 4589const char* os::exception_name(int exception_code, char* buf, size_t size) { 4590 if (0 < exception_code && exception_code <= SIGRTMAX) { 4591 // signal 4592 if (!signal_name(exception_code, buf, size)) { 4593 jio_snprintf(buf, size, "SIG%d", exception_code); 4594 } 4595 return buf; 4596 } else { 4597 return NULL; 4598 } 4599} 4600 4601// this is called _before_ the most of global arguments have been parsed 4602void os::init(void) { 4603 char dummy; // used to get a guess on initial stack address 4604// first_hrtime = gethrtime(); 4605 4606 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4607 4608 init_random(1234567); 4609 4610 ThreadCritical::initialize(); 4611 4612 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4613 if (Linux::page_size() == -1) { 4614 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 4615 strerror(errno))); 4616 } 4617 init_page_sizes((size_t) Linux::page_size()); 4618 4619 Linux::initialize_system_info(); 4620 4621 // main_thread points to the aboriginal thread 4622 Linux::_main_thread = pthread_self(); 4623 4624 Linux::clock_init(); 4625 initial_time_count = javaTimeNanos(); 4626 4627 // pthread_condattr initialization for monotonic clock 4628 int status; 4629 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4630 if ((status = pthread_condattr_init(_condattr)) != 0) { 4631 fatal(err_msg("pthread_condattr_init: %s", strerror(status))); 4632 } 4633 // Only set the clock if CLOCK_MONOTONIC is available 4634 if (os::supports_monotonic_clock()) { 4635 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4636 if (status == EINVAL) { 4637 warning("Unable to use monotonic clock with relative timed-waits" \ 4638 " - changes to the time-of-day clock may have adverse affects"); 4639 } else { 4640 fatal(err_msg("pthread_condattr_setclock: %s", strerror(status))); 4641 } 4642 } 4643 } 4644 // else it defaults to CLOCK_REALTIME 4645 4646 // If the pagesize of the VM is greater than 8K determine the appropriate 4647 // number of initial guard pages. The user can change this with the 4648 // command line arguments, if needed. 4649 if (vm_page_size() > (int)Linux::vm_default_page_size()) { 4650 StackYellowPages = 1; 4651 StackRedPages = 1; 4652 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size(); 4653 } 4654 4655 // retrieve entry point for pthread_setname_np 4656 Linux::_pthread_setname_np = 4657 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4658 4659} 4660 4661// To install functions for atexit system call 4662extern "C" { 4663 static void perfMemory_exit_helper() { 4664 perfMemory_exit(); 4665 } 4666} 4667 4668// this is called _after_ the global arguments have been parsed 4669jint os::init_2(void) { 4670 Linux::fast_thread_clock_init(); 4671 4672 // Allocate a single page and mark it as readable for safepoint polling 4673 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4674 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4675 4676 os::set_polling_page(polling_page); 4677 4678#ifndef PRODUCT 4679 if (Verbose && PrintMiscellaneous) { 4680 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", 4681 (intptr_t)polling_page); 4682 } 4683#endif 4684 4685 if (!UseMembar) { 4686 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4687 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4688 os::set_memory_serialize_page(mem_serialize_page); 4689 4690#ifndef PRODUCT 4691 if (Verbose && PrintMiscellaneous) { 4692 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", 4693 (intptr_t)mem_serialize_page); 4694 } 4695#endif 4696 } 4697 4698 // initialize suspend/resume support - must do this before signal_sets_init() 4699 if (SR_initialize() != 0) { 4700 perror("SR_initialize failed"); 4701 return JNI_ERR; 4702 } 4703 4704 Linux::signal_sets_init(); 4705 Linux::install_signal_handlers(); 4706 4707 // Check minimum allowable stack size for thread creation and to initialize 4708 // the java system classes, including StackOverflowError - depends on page 4709 // size. Add a page for compiler2 recursion in main thread. 4710 // Add in 2*BytesPerWord times page size to account for VM stack during 4711 // class initialization depending on 32 or 64 bit VM. 4712 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4713 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() + 4714 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size()); 4715 4716 size_t threadStackSizeInBytes = ThreadStackSize * K; 4717 if (threadStackSizeInBytes != 0 && 4718 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4719 tty->print_cr("\nThe stack size specified is too small, " 4720 "Specify at least %dk", 4721 os::Linux::min_stack_allowed/ K); 4722 return JNI_ERR; 4723 } 4724 4725 // Make the stack size a multiple of the page size so that 4726 // the yellow/red zones can be guarded. 4727 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4728 vm_page_size())); 4729 4730 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4731 4732#if defined(IA32) 4733 workaround_expand_exec_shield_cs_limit(); 4734#endif 4735 4736 Linux::libpthread_init(); 4737 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4738 tty->print_cr("[HotSpot is running with %s, %s]\n", 4739 Linux::glibc_version(), Linux::libpthread_version()); 4740 } 4741 4742 if (UseNUMA) { 4743 if (!Linux::libnuma_init()) { 4744 UseNUMA = false; 4745 } else { 4746 if ((Linux::numa_max_node() < 1)) { 4747 // There's only one node(they start from 0), disable NUMA. 4748 UseNUMA = false; 4749 } 4750 } 4751 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4752 // we can make the adaptive lgrp chunk resizing work. If the user specified 4753 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4754 // disable adaptive resizing. 4755 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4756 if (FLAG_IS_DEFAULT(UseNUMA)) { 4757 UseNUMA = false; 4758 } else { 4759 if (FLAG_IS_DEFAULT(UseLargePages) && 4760 FLAG_IS_DEFAULT(UseSHM) && 4761 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4762 UseLargePages = false; 4763 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4764 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4765 UseAdaptiveSizePolicy = false; 4766 UseAdaptiveNUMAChunkSizing = false; 4767 } 4768 } 4769 } 4770 if (!UseNUMA && ForceNUMA) { 4771 UseNUMA = true; 4772 } 4773 } 4774 4775 if (MaxFDLimit) { 4776 // set the number of file descriptors to max. print out error 4777 // if getrlimit/setrlimit fails but continue regardless. 4778 struct rlimit nbr_files; 4779 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4780 if (status != 0) { 4781 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4782 perror("os::init_2 getrlimit failed"); 4783 } 4784 } else { 4785 nbr_files.rlim_cur = nbr_files.rlim_max; 4786 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4787 if (status != 0) { 4788 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4789 perror("os::init_2 setrlimit failed"); 4790 } 4791 } 4792 } 4793 } 4794 4795 // Initialize lock used to serialize thread creation (see os::create_thread) 4796 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4797 4798 // at-exit methods are called in the reverse order of their registration. 4799 // atexit functions are called on return from main or as a result of a 4800 // call to exit(3C). There can be only 32 of these functions registered 4801 // and atexit() does not set errno. 4802 4803 if (PerfAllowAtExitRegistration) { 4804 // only register atexit functions if PerfAllowAtExitRegistration is set. 4805 // atexit functions can be delayed until process exit time, which 4806 // can be problematic for embedded VM situations. Embedded VMs should 4807 // call DestroyJavaVM() to assure that VM resources are released. 4808 4809 // note: perfMemory_exit_helper atexit function may be removed in 4810 // the future if the appropriate cleanup code can be added to the 4811 // VM_Exit VMOperation's doit method. 4812 if (atexit(perfMemory_exit_helper) != 0) { 4813 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4814 } 4815 } 4816 4817 // initialize thread priority policy 4818 prio_init(); 4819 4820 return JNI_OK; 4821} 4822 4823// Mark the polling page as unreadable 4824void os::make_polling_page_unreadable(void) { 4825 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4826 fatal("Could not disable polling page"); 4827 } 4828} 4829 4830// Mark the polling page as readable 4831void os::make_polling_page_readable(void) { 4832 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4833 fatal("Could not enable polling page"); 4834 } 4835} 4836 4837int os::active_processor_count() { 4838 // Linux doesn't yet have a (official) notion of processor sets, 4839 // so just return the number of online processors. 4840 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4841 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4842 return online_cpus; 4843} 4844 4845void os::set_native_thread_name(const char *name) { 4846 if (Linux::_pthread_setname_np) { 4847 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 4848 snprintf(buf, sizeof(buf), "%s", name); 4849 buf[sizeof(buf) - 1] = '\0'; 4850 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 4851 // ERANGE should not happen; all other errors should just be ignored. 4852 assert(rc != ERANGE, "pthread_setname_np failed"); 4853 } 4854} 4855 4856bool os::distribute_processes(uint length, uint* distribution) { 4857 // Not yet implemented. 4858 return false; 4859} 4860 4861bool os::bind_to_processor(uint processor_id) { 4862 // Not yet implemented. 4863 return false; 4864} 4865 4866/// 4867 4868void os::SuspendedThreadTask::internal_do_task() { 4869 if (do_suspend(_thread->osthread())) { 4870 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 4871 do_task(context); 4872 do_resume(_thread->osthread()); 4873 } 4874} 4875 4876class PcFetcher : public os::SuspendedThreadTask { 4877 public: 4878 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 4879 ExtendedPC result(); 4880 protected: 4881 void do_task(const os::SuspendedThreadTaskContext& context); 4882 private: 4883 ExtendedPC _epc; 4884}; 4885 4886ExtendedPC PcFetcher::result() { 4887 guarantee(is_done(), "task is not done yet."); 4888 return _epc; 4889} 4890 4891void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 4892 Thread* thread = context.thread(); 4893 OSThread* osthread = thread->osthread(); 4894 if (osthread->ucontext() != NULL) { 4895 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext()); 4896 } else { 4897 // NULL context is unexpected, double-check this is the VMThread 4898 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4899 } 4900} 4901 4902// Suspends the target using the signal mechanism and then grabs the PC before 4903// resuming the target. Used by the flat-profiler only 4904ExtendedPC os::get_thread_pc(Thread* thread) { 4905 // Make sure that it is called by the watcher for the VMThread 4906 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4907 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4908 4909 PcFetcher fetcher(thread); 4910 fetcher.run(); 4911 return fetcher.result(); 4912} 4913 4914//////////////////////////////////////////////////////////////////////////////// 4915// debug support 4916 4917bool os::find(address addr, outputStream* st) { 4918 Dl_info dlinfo; 4919 memset(&dlinfo, 0, sizeof(dlinfo)); 4920 if (dladdr(addr, &dlinfo) != 0) { 4921 st->print(PTR_FORMAT ": ", addr); 4922 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 4923 st->print("%s+%#x", dlinfo.dli_sname, 4924 addr - (intptr_t)dlinfo.dli_saddr); 4925 } else if (dlinfo.dli_fbase != NULL) { 4926 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4927 } else { 4928 st->print("<absolute address>"); 4929 } 4930 if (dlinfo.dli_fname != NULL) { 4931 st->print(" in %s", dlinfo.dli_fname); 4932 } 4933 if (dlinfo.dli_fbase != NULL) { 4934 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4935 } 4936 st->cr(); 4937 4938 if (Verbose) { 4939 // decode some bytes around the PC 4940 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 4941 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 4942 address lowest = (address) dlinfo.dli_sname; 4943 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4944 if (begin < lowest) begin = lowest; 4945 Dl_info dlinfo2; 4946 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 4947 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 4948 end = (address) dlinfo2.dli_saddr; 4949 } 4950 Disassembler::decode(begin, end, st); 4951 } 4952 return true; 4953 } 4954 return false; 4955} 4956 4957//////////////////////////////////////////////////////////////////////////////// 4958// misc 4959 4960// This does not do anything on Linux. This is basically a hook for being 4961// able to use structured exception handling (thread-local exception filters) 4962// on, e.g., Win32. 4963void 4964os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4965 JavaCallArguments* args, Thread* thread) { 4966 f(value, method, args, thread); 4967} 4968 4969void os::print_statistics() { 4970} 4971 4972int os::message_box(const char* title, const char* message) { 4973 int i; 4974 fdStream err(defaultStream::error_fd()); 4975 for (i = 0; i < 78; i++) err.print_raw("="); 4976 err.cr(); 4977 err.print_raw_cr(title); 4978 for (i = 0; i < 78; i++) err.print_raw("-"); 4979 err.cr(); 4980 err.print_raw_cr(message); 4981 for (i = 0; i < 78; i++) err.print_raw("="); 4982 err.cr(); 4983 4984 char buf[16]; 4985 // Prevent process from exiting upon "read error" without consuming all CPU 4986 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4987 4988 return buf[0] == 'y' || buf[0] == 'Y'; 4989} 4990 4991int os::stat(const char *path, struct stat *sbuf) { 4992 char pathbuf[MAX_PATH]; 4993 if (strlen(path) > MAX_PATH - 1) { 4994 errno = ENAMETOOLONG; 4995 return -1; 4996 } 4997 os::native_path(strcpy(pathbuf, path)); 4998 return ::stat(pathbuf, sbuf); 4999} 5000 5001bool os::check_heap(bool force) { 5002 return true; 5003} 5004 5005// Is a (classpath) directory empty? 5006bool os::dir_is_empty(const char* path) { 5007 DIR *dir = NULL; 5008 struct dirent *ptr; 5009 5010 dir = opendir(path); 5011 if (dir == NULL) return true; 5012 5013 // Scan the directory 5014 bool result = true; 5015 char buf[sizeof(struct dirent) + MAX_PATH]; 5016 while (result && (ptr = ::readdir(dir)) != NULL) { 5017 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5018 result = false; 5019 } 5020 } 5021 closedir(dir); 5022 return result; 5023} 5024 5025// This code originates from JDK's sysOpen and open64_w 5026// from src/solaris/hpi/src/system_md.c 5027 5028int os::open(const char *path, int oflag, int mode) { 5029 if (strlen(path) > MAX_PATH - 1) { 5030 errno = ENAMETOOLONG; 5031 return -1; 5032 } 5033 5034 // All file descriptors that are opened in the Java process and not 5035 // specifically destined for a subprocess should have the close-on-exec 5036 // flag set. If we don't set it, then careless 3rd party native code 5037 // might fork and exec without closing all appropriate file descriptors 5038 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5039 // turn might: 5040 // 5041 // - cause end-of-file to fail to be detected on some file 5042 // descriptors, resulting in mysterious hangs, or 5043 // 5044 // - might cause an fopen in the subprocess to fail on a system 5045 // suffering from bug 1085341. 5046 // 5047 // (Yes, the default setting of the close-on-exec flag is a Unix 5048 // design flaw) 5049 // 5050 // See: 5051 // 1085341: 32-bit stdio routines should support file descriptors >255 5052 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5053 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5054 // 5055 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5056 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5057 // because it saves a system call and removes a small window where the flag 5058 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5059 // and we fall back to using FD_CLOEXEC (see below). 5060#ifdef O_CLOEXEC 5061 oflag |= O_CLOEXEC; 5062#endif 5063 5064 int fd = ::open64(path, oflag, mode); 5065 if (fd == -1) return -1; 5066 5067 //If the open succeeded, the file might still be a directory 5068 { 5069 struct stat64 buf64; 5070 int ret = ::fstat64(fd, &buf64); 5071 int st_mode = buf64.st_mode; 5072 5073 if (ret != -1) { 5074 if ((st_mode & S_IFMT) == S_IFDIR) { 5075 errno = EISDIR; 5076 ::close(fd); 5077 return -1; 5078 } 5079 } else { 5080 ::close(fd); 5081 return -1; 5082 } 5083 } 5084 5085#ifdef FD_CLOEXEC 5086 // Validate that the use of the O_CLOEXEC flag on open above worked. 5087 // With recent kernels, we will perform this check exactly once. 5088 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5089 if (!O_CLOEXEC_is_known_to_work) { 5090 int flags = ::fcntl(fd, F_GETFD); 5091 if (flags != -1) { 5092 if ((flags & FD_CLOEXEC) != 0) 5093 O_CLOEXEC_is_known_to_work = 1; 5094 else 5095 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5096 } 5097 } 5098#endif 5099 5100 return fd; 5101} 5102 5103 5104// create binary file, rewriting existing file if required 5105int os::create_binary_file(const char* path, bool rewrite_existing) { 5106 int oflags = O_WRONLY | O_CREAT; 5107 if (!rewrite_existing) { 5108 oflags |= O_EXCL; 5109 } 5110 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5111} 5112 5113// return current position of file pointer 5114jlong os::current_file_offset(int fd) { 5115 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5116} 5117 5118// move file pointer to the specified offset 5119jlong os::seek_to_file_offset(int fd, jlong offset) { 5120 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5121} 5122 5123// This code originates from JDK's sysAvailable 5124// from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5125 5126int os::available(int fd, jlong *bytes) { 5127 jlong cur, end; 5128 int mode; 5129 struct stat64 buf64; 5130 5131 if (::fstat64(fd, &buf64) >= 0) { 5132 mode = buf64.st_mode; 5133 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5134 // XXX: is the following call interruptible? If so, this might 5135 // need to go through the INTERRUPT_IO() wrapper as for other 5136 // blocking, interruptible calls in this file. 5137 int n; 5138 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5139 *bytes = n; 5140 return 1; 5141 } 5142 } 5143 } 5144 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5145 return 0; 5146 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5147 return 0; 5148 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5149 return 0; 5150 } 5151 *bytes = end - cur; 5152 return 1; 5153} 5154 5155// Map a block of memory. 5156char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5157 char *addr, size_t bytes, bool read_only, 5158 bool allow_exec) { 5159 int prot; 5160 int flags = MAP_PRIVATE; 5161 5162 if (read_only) { 5163 prot = PROT_READ; 5164 } else { 5165 prot = PROT_READ | PROT_WRITE; 5166 } 5167 5168 if (allow_exec) { 5169 prot |= PROT_EXEC; 5170 } 5171 5172 if (addr != NULL) { 5173 flags |= MAP_FIXED; 5174 } 5175 5176 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5177 fd, file_offset); 5178 if (mapped_address == MAP_FAILED) { 5179 return NULL; 5180 } 5181 return mapped_address; 5182} 5183 5184 5185// Remap a block of memory. 5186char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5187 char *addr, size_t bytes, bool read_only, 5188 bool allow_exec) { 5189 // same as map_memory() on this OS 5190 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5191 allow_exec); 5192} 5193 5194 5195// Unmap a block of memory. 5196bool os::pd_unmap_memory(char* addr, size_t bytes) { 5197 return munmap(addr, bytes) == 0; 5198} 5199 5200static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5201 5202static clockid_t thread_cpu_clockid(Thread* thread) { 5203 pthread_t tid = thread->osthread()->pthread_id(); 5204 clockid_t clockid; 5205 5206 // Get thread clockid 5207 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5208 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5209 return clockid; 5210} 5211 5212// current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5213// are used by JVM M&M and JVMTI to get user+sys or user CPU time 5214// of a thread. 5215// 5216// current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5217// the fast estimate available on the platform. 5218 5219jlong os::current_thread_cpu_time() { 5220 if (os::Linux::supports_fast_thread_cpu_time()) { 5221 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5222 } else { 5223 // return user + sys since the cost is the same 5224 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5225 } 5226} 5227 5228jlong os::thread_cpu_time(Thread* thread) { 5229 // consistent with what current_thread_cpu_time() returns 5230 if (os::Linux::supports_fast_thread_cpu_time()) { 5231 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5232 } else { 5233 return slow_thread_cpu_time(thread, true /* user + sys */); 5234 } 5235} 5236 5237jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5238 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5239 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5240 } else { 5241 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5242 } 5243} 5244 5245jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5246 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5247 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5248 } else { 5249 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5250 } 5251} 5252 5253// -1 on error. 5254static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5255 pid_t tid = thread->osthread()->thread_id(); 5256 char *s; 5257 char stat[2048]; 5258 int statlen; 5259 char proc_name[64]; 5260 int count; 5261 long sys_time, user_time; 5262 char cdummy; 5263 int idummy; 5264 long ldummy; 5265 FILE *fp; 5266 5267 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5268 fp = fopen(proc_name, "r"); 5269 if (fp == NULL) return -1; 5270 statlen = fread(stat, 1, 2047, fp); 5271 stat[statlen] = '\0'; 5272 fclose(fp); 5273 5274 // Skip pid and the command string. Note that we could be dealing with 5275 // weird command names, e.g. user could decide to rename java launcher 5276 // to "java 1.4.2 :)", then the stat file would look like 5277 // 1234 (java 1.4.2 :)) R ... ... 5278 // We don't really need to know the command string, just find the last 5279 // occurrence of ")" and then start parsing from there. See bug 4726580. 5280 s = strrchr(stat, ')'); 5281 if (s == NULL) return -1; 5282 5283 // Skip blank chars 5284 do { s++; } while (s && isspace(*s)); 5285 5286 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5287 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5288 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5289 &user_time, &sys_time); 5290 if (count != 13) return -1; 5291 if (user_sys_cpu_time) { 5292 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5293 } else { 5294 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5295 } 5296} 5297 5298void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5299 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5300 info_ptr->may_skip_backward = false; // elapsed time not wall time 5301 info_ptr->may_skip_forward = false; // elapsed time not wall time 5302 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5303} 5304 5305void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5306 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5307 info_ptr->may_skip_backward = false; // elapsed time not wall time 5308 info_ptr->may_skip_forward = false; // elapsed time not wall time 5309 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5310} 5311 5312bool os::is_thread_cpu_time_supported() { 5313 return true; 5314} 5315 5316// System loadavg support. Returns -1 if load average cannot be obtained. 5317// Linux doesn't yet have a (official) notion of processor sets, 5318// so just return the system wide load average. 5319int os::loadavg(double loadavg[], int nelem) { 5320 return ::getloadavg(loadavg, nelem); 5321} 5322 5323void os::pause() { 5324 char filename[MAX_PATH]; 5325 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5326 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 5327 } else { 5328 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5329 } 5330 5331 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5332 if (fd != -1) { 5333 struct stat buf; 5334 ::close(fd); 5335 while (::stat(filename, &buf) == 0) { 5336 (void)::poll(NULL, 0, 100); 5337 } 5338 } else { 5339 jio_fprintf(stderr, 5340 "Could not open pause file '%s', continuing immediately.\n", filename); 5341 } 5342} 5343 5344 5345// Refer to the comments in os_solaris.cpp park-unpark. The next two 5346// comment paragraphs are worth repeating here: 5347// 5348// Assumption: 5349// Only one parker can exist on an event, which is why we allocate 5350// them per-thread. Multiple unparkers can coexist. 5351// 5352// _Event serves as a restricted-range semaphore. 5353// -1 : thread is blocked, i.e. there is a waiter 5354// 0 : neutral: thread is running or ready, 5355// could have been signaled after a wait started 5356// 1 : signaled - thread is running or ready 5357// 5358// Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 5359// hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 5360// For specifics regarding the bug see GLIBC BUGID 261237 : 5361// http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 5362// Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 5363// will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 5364// is used. (The simple C test-case provided in the GLIBC bug report manifests the 5365// hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 5366// and monitorenter when we're using 1-0 locking. All those operations may result in 5367// calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 5368// of libpthread avoids the problem, but isn't practical. 5369// 5370// Possible remedies: 5371// 5372// 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 5373// This is palliative and probabilistic, however. If the thread is preempted 5374// between the call to compute_abstime() and pthread_cond_timedwait(), more 5375// than the minimum period may have passed, and the abstime may be stale (in the 5376// past) resultin in a hang. Using this technique reduces the odds of a hang 5377// but the JVM is still vulnerable, particularly on heavily loaded systems. 5378// 5379// 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 5380// of the usual flag-condvar-mutex idiom. The write side of the pipe is set 5381// NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 5382// reduces to poll()+read(). This works well, but consumes 2 FDs per extant 5383// thread. 5384// 5385// 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 5386// that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 5387// a timeout request to the chron thread and then blocking via pthread_cond_wait(). 5388// This also works well. In fact it avoids kernel-level scalability impediments 5389// on certain platforms that don't handle lots of active pthread_cond_timedwait() 5390// timers in a graceful fashion. 5391// 5392// 4. When the abstime value is in the past it appears that control returns 5393// correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 5394// Subsequent timedwait/wait calls may hang indefinitely. Given that, we 5395// can avoid the problem by reinitializing the condvar -- by cond_destroy() 5396// followed by cond_init() -- after all calls to pthread_cond_timedwait(). 5397// It may be possible to avoid reinitialization by checking the return 5398// value from pthread_cond_timedwait(). In addition to reinitializing the 5399// condvar we must establish the invariant that cond_signal() is only called 5400// within critical sections protected by the adjunct mutex. This prevents 5401// cond_signal() from "seeing" a condvar that's in the midst of being 5402// reinitialized or that is corrupt. Sadly, this invariant obviates the 5403// desirable signal-after-unlock optimization that avoids futile context switching. 5404// 5405// I'm also concerned that some versions of NTPL might allocate an auxilliary 5406// structure when a condvar is used or initialized. cond_destroy() would 5407// release the helper structure. Our reinitialize-after-timedwait fix 5408// put excessive stress on malloc/free and locks protecting the c-heap. 5409// 5410// We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 5411// It may be possible to refine (4) by checking the kernel and NTPL verisons 5412// and only enabling the work-around for vulnerable environments. 5413 5414// utility to compute the abstime argument to timedwait: 5415// millis is the relative timeout time 5416// abstime will be the absolute timeout time 5417// TODO: replace compute_abstime() with unpackTime() 5418 5419static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5420 if (millis < 0) millis = 0; 5421 5422 jlong seconds = millis / 1000; 5423 millis %= 1000; 5424 if (seconds > 50000000) { // see man cond_timedwait(3T) 5425 seconds = 50000000; 5426 } 5427 5428 if (os::supports_monotonic_clock()) { 5429 struct timespec now; 5430 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5431 assert_status(status == 0, status, "clock_gettime"); 5432 abstime->tv_sec = now.tv_sec + seconds; 5433 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5434 if (nanos >= NANOSECS_PER_SEC) { 5435 abstime->tv_sec += 1; 5436 nanos -= NANOSECS_PER_SEC; 5437 } 5438 abstime->tv_nsec = nanos; 5439 } else { 5440 struct timeval now; 5441 int status = gettimeofday(&now, NULL); 5442 assert(status == 0, "gettimeofday"); 5443 abstime->tv_sec = now.tv_sec + seconds; 5444 long usec = now.tv_usec + millis * 1000; 5445 if (usec >= 1000000) { 5446 abstime->tv_sec += 1; 5447 usec -= 1000000; 5448 } 5449 abstime->tv_nsec = usec * 1000; 5450 } 5451 return abstime; 5452} 5453 5454void os::PlatformEvent::park() { // AKA "down()" 5455 // Transitions for _Event: 5456 // -1 => -1 : illegal 5457 // 1 => 0 : pass - return immediately 5458 // 0 => -1 : block; then set _Event to 0 before returning 5459 5460 // Invariant: Only the thread associated with the Event/PlatformEvent 5461 // may call park(). 5462 // TODO: assert that _Assoc != NULL or _Assoc == Self 5463 assert(_nParked == 0, "invariant"); 5464 5465 int v; 5466 for (;;) { 5467 v = _Event; 5468 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5469 } 5470 guarantee(v >= 0, "invariant"); 5471 if (v == 0) { 5472 // Do this the hard way by blocking ... 5473 int status = pthread_mutex_lock(_mutex); 5474 assert_status(status == 0, status, "mutex_lock"); 5475 guarantee(_nParked == 0, "invariant"); 5476 ++_nParked; 5477 while (_Event < 0) { 5478 status = pthread_cond_wait(_cond, _mutex); 5479 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5480 // Treat this the same as if the wait was interrupted 5481 if (status == ETIME) { status = EINTR; } 5482 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5483 } 5484 --_nParked; 5485 5486 _Event = 0; 5487 status = pthread_mutex_unlock(_mutex); 5488 assert_status(status == 0, status, "mutex_unlock"); 5489 // Paranoia to ensure our locked and lock-free paths interact 5490 // correctly with each other. 5491 OrderAccess::fence(); 5492 } 5493 guarantee(_Event >= 0, "invariant"); 5494} 5495 5496int os::PlatformEvent::park(jlong millis) { 5497 // Transitions for _Event: 5498 // -1 => -1 : illegal 5499 // 1 => 0 : pass - return immediately 5500 // 0 => -1 : block; then set _Event to 0 before returning 5501 5502 guarantee(_nParked == 0, "invariant"); 5503 5504 int v; 5505 for (;;) { 5506 v = _Event; 5507 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5508 } 5509 guarantee(v >= 0, "invariant"); 5510 if (v != 0) return OS_OK; 5511 5512 // We do this the hard way, by blocking the thread. 5513 // Consider enforcing a minimum timeout value. 5514 struct timespec abst; 5515 compute_abstime(&abst, millis); 5516 5517 int ret = OS_TIMEOUT; 5518 int status = pthread_mutex_lock(_mutex); 5519 assert_status(status == 0, status, "mutex_lock"); 5520 guarantee(_nParked == 0, "invariant"); 5521 ++_nParked; 5522 5523 // Object.wait(timo) will return because of 5524 // (a) notification 5525 // (b) timeout 5526 // (c) thread.interrupt 5527 // 5528 // Thread.interrupt and object.notify{All} both call Event::set. 5529 // That is, we treat thread.interrupt as a special case of notification. 5530 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5531 // We assume all ETIME returns are valid. 5532 // 5533 // TODO: properly differentiate simultaneous notify+interrupt. 5534 // In that case, we should propagate the notify to another waiter. 5535 5536 while (_Event < 0) { 5537 status = pthread_cond_timedwait(_cond, _mutex, &abst); 5538 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5539 pthread_cond_destroy(_cond); 5540 pthread_cond_init(_cond, os::Linux::condAttr()); 5541 } 5542 assert_status(status == 0 || status == EINTR || 5543 status == ETIME || status == ETIMEDOUT, 5544 status, "cond_timedwait"); 5545 if (!FilterSpuriousWakeups) break; // previous semantics 5546 if (status == ETIME || status == ETIMEDOUT) break; 5547 // We consume and ignore EINTR and spurious wakeups. 5548 } 5549 --_nParked; 5550 if (_Event >= 0) { 5551 ret = OS_OK; 5552 } 5553 _Event = 0; 5554 status = pthread_mutex_unlock(_mutex); 5555 assert_status(status == 0, status, "mutex_unlock"); 5556 assert(_nParked == 0, "invariant"); 5557 // Paranoia to ensure our locked and lock-free paths interact 5558 // correctly with each other. 5559 OrderAccess::fence(); 5560 return ret; 5561} 5562 5563void os::PlatformEvent::unpark() { 5564 // Transitions for _Event: 5565 // 0 => 1 : just return 5566 // 1 => 1 : just return 5567 // -1 => either 0 or 1; must signal target thread 5568 // That is, we can safely transition _Event from -1 to either 5569 // 0 or 1. 5570 // See also: "Semaphores in Plan 9" by Mullender & Cox 5571 // 5572 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5573 // that it will take two back-to-back park() calls for the owning 5574 // thread to block. This has the benefit of forcing a spurious return 5575 // from the first park() call after an unpark() call which will help 5576 // shake out uses of park() and unpark() without condition variables. 5577 5578 if (Atomic::xchg(1, &_Event) >= 0) return; 5579 5580 // Wait for the thread associated with the event to vacate 5581 int status = pthread_mutex_lock(_mutex); 5582 assert_status(status == 0, status, "mutex_lock"); 5583 int AnyWaiters = _nParked; 5584 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5585 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5586 AnyWaiters = 0; 5587 pthread_cond_signal(_cond); 5588 } 5589 status = pthread_mutex_unlock(_mutex); 5590 assert_status(status == 0, status, "mutex_unlock"); 5591 if (AnyWaiters != 0) { 5592 // Note that we signal() *after* dropping the lock for "immortal" Events. 5593 // This is safe and avoids a common class of futile wakeups. In rare 5594 // circumstances this can cause a thread to return prematurely from 5595 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5596 // will simply re-test the condition and re-park itself. 5597 // This provides particular benefit if the underlying platform does not 5598 // provide wait morphing. 5599 status = pthread_cond_signal(_cond); 5600 assert_status(status == 0, status, "cond_signal"); 5601 } 5602} 5603 5604 5605// JSR166 5606// ------------------------------------------------------- 5607 5608// The solaris and linux implementations of park/unpark are fairly 5609// conservative for now, but can be improved. They currently use a 5610// mutex/condvar pair, plus a a count. 5611// Park decrements count if > 0, else does a condvar wait. Unpark 5612// sets count to 1 and signals condvar. Only one thread ever waits 5613// on the condvar. Contention seen when trying to park implies that someone 5614// is unparking you, so don't wait. And spurious returns are fine, so there 5615// is no need to track notifications. 5616 5617// This code is common to linux and solaris and will be moved to a 5618// common place in dolphin. 5619// 5620// The passed in time value is either a relative time in nanoseconds 5621// or an absolute time in milliseconds. Either way it has to be unpacked 5622// into suitable seconds and nanoseconds components and stored in the 5623// given timespec structure. 5624// Given time is a 64-bit value and the time_t used in the timespec is only 5625// a signed-32-bit value (except on 64-bit Linux) we have to watch for 5626// overflow if times way in the future are given. Further on Solaris versions 5627// prior to 10 there is a restriction (see cond_timedwait) that the specified 5628// number of seconds, in abstime, is less than current_time + 100,000,000. 5629// As it will be 28 years before "now + 100000000" will overflow we can 5630// ignore overflow and just impose a hard-limit on seconds using the value 5631// of "now + 100,000,000". This places a limit on the timeout of about 3.17 5632// years from "now". 5633 5634static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5635 assert(time > 0, "convertTime"); 5636 time_t max_secs = 0; 5637 5638 if (!os::supports_monotonic_clock() || isAbsolute) { 5639 struct timeval now; 5640 int status = gettimeofday(&now, NULL); 5641 assert(status == 0, "gettimeofday"); 5642 5643 max_secs = now.tv_sec + MAX_SECS; 5644 5645 if (isAbsolute) { 5646 jlong secs = time / 1000; 5647 if (secs > max_secs) { 5648 absTime->tv_sec = max_secs; 5649 } else { 5650 absTime->tv_sec = secs; 5651 } 5652 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5653 } else { 5654 jlong secs = time / NANOSECS_PER_SEC; 5655 if (secs >= MAX_SECS) { 5656 absTime->tv_sec = max_secs; 5657 absTime->tv_nsec = 0; 5658 } else { 5659 absTime->tv_sec = now.tv_sec + secs; 5660 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5661 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5662 absTime->tv_nsec -= NANOSECS_PER_SEC; 5663 ++absTime->tv_sec; // note: this must be <= max_secs 5664 } 5665 } 5666 } 5667 } else { 5668 // must be relative using monotonic clock 5669 struct timespec now; 5670 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5671 assert_status(status == 0, status, "clock_gettime"); 5672 max_secs = now.tv_sec + MAX_SECS; 5673 jlong secs = time / NANOSECS_PER_SEC; 5674 if (secs >= MAX_SECS) { 5675 absTime->tv_sec = max_secs; 5676 absTime->tv_nsec = 0; 5677 } else { 5678 absTime->tv_sec = now.tv_sec + secs; 5679 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5680 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5681 absTime->tv_nsec -= NANOSECS_PER_SEC; 5682 ++absTime->tv_sec; // note: this must be <= max_secs 5683 } 5684 } 5685 } 5686 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5687 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5688 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5689 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5690} 5691 5692void Parker::park(bool isAbsolute, jlong time) { 5693 // Ideally we'd do something useful while spinning, such 5694 // as calling unpackTime(). 5695 5696 // Optional fast-path check: 5697 // Return immediately if a permit is available. 5698 // We depend on Atomic::xchg() having full barrier semantics 5699 // since we are doing a lock-free update to _counter. 5700 if (Atomic::xchg(0, &_counter) > 0) return; 5701 5702 Thread* thread = Thread::current(); 5703 assert(thread->is_Java_thread(), "Must be JavaThread"); 5704 JavaThread *jt = (JavaThread *)thread; 5705 5706 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5707 // Check interrupt before trying to wait 5708 if (Thread::is_interrupted(thread, false)) { 5709 return; 5710 } 5711 5712 // Next, demultiplex/decode time arguments 5713 timespec absTime; 5714 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5715 return; 5716 } 5717 if (time > 0) { 5718 unpackTime(&absTime, isAbsolute, time); 5719 } 5720 5721 5722 // Enter safepoint region 5723 // Beware of deadlocks such as 6317397. 5724 // The per-thread Parker:: mutex is a classic leaf-lock. 5725 // In particular a thread must never block on the Threads_lock while 5726 // holding the Parker:: mutex. If safepoints are pending both the 5727 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5728 ThreadBlockInVM tbivm(jt); 5729 5730 // Don't wait if cannot get lock since interference arises from 5731 // unblocking. Also. check interrupt before trying wait 5732 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5733 return; 5734 } 5735 5736 int status; 5737 if (_counter > 0) { // no wait needed 5738 _counter = 0; 5739 status = pthread_mutex_unlock(_mutex); 5740 assert(status == 0, "invariant"); 5741 // Paranoia to ensure our locked and lock-free paths interact 5742 // correctly with each other and Java-level accesses. 5743 OrderAccess::fence(); 5744 return; 5745 } 5746 5747#ifdef ASSERT 5748 // Don't catch signals while blocked; let the running threads have the signals. 5749 // (This allows a debugger to break into the running thread.) 5750 sigset_t oldsigs; 5751 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5752 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5753#endif 5754 5755 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5756 jt->set_suspend_equivalent(); 5757 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5758 5759 assert(_cur_index == -1, "invariant"); 5760 if (time == 0) { 5761 _cur_index = REL_INDEX; // arbitrary choice when not timed 5762 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5763 } else { 5764 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5765 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5766 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5767 pthread_cond_destroy(&_cond[_cur_index]); 5768 pthread_cond_init(&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr()); 5769 } 5770 } 5771 _cur_index = -1; 5772 assert_status(status == 0 || status == EINTR || 5773 status == ETIME || status == ETIMEDOUT, 5774 status, "cond_timedwait"); 5775 5776#ifdef ASSERT 5777 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5778#endif 5779 5780 _counter = 0; 5781 status = pthread_mutex_unlock(_mutex); 5782 assert_status(status == 0, status, "invariant"); 5783 // Paranoia to ensure our locked and lock-free paths interact 5784 // correctly with each other and Java-level accesses. 5785 OrderAccess::fence(); 5786 5787 // If externally suspended while waiting, re-suspend 5788 if (jt->handle_special_suspend_equivalent_condition()) { 5789 jt->java_suspend_self(); 5790 } 5791} 5792 5793void Parker::unpark() { 5794 int status = pthread_mutex_lock(_mutex); 5795 assert(status == 0, "invariant"); 5796 const int s = _counter; 5797 _counter = 1; 5798 if (s < 1) { 5799 // thread might be parked 5800 if (_cur_index != -1) { 5801 // thread is definitely parked 5802 if (WorkAroundNPTLTimedWaitHang) { 5803 status = pthread_cond_signal(&_cond[_cur_index]); 5804 assert(status == 0, "invariant"); 5805 status = pthread_mutex_unlock(_mutex); 5806 assert(status == 0, "invariant"); 5807 } else { 5808 // must capture correct index before unlocking 5809 int index = _cur_index; 5810 status = pthread_mutex_unlock(_mutex); 5811 assert(status == 0, "invariant"); 5812 status = pthread_cond_signal(&_cond[index]); 5813 assert(status == 0, "invariant"); 5814 } 5815 } else { 5816 pthread_mutex_unlock(_mutex); 5817 assert(status == 0, "invariant"); 5818 } 5819 } else { 5820 pthread_mutex_unlock(_mutex); 5821 assert(status == 0, "invariant"); 5822 } 5823} 5824 5825 5826extern char** environ; 5827 5828// Run the specified command in a separate process. Return its exit value, 5829// or -1 on failure (e.g. can't fork a new process). 5830// Unlike system(), this function can be called from signal handler. It 5831// doesn't block SIGINT et al. 5832int os::fork_and_exec(char* cmd) { 5833 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5834 5835 pid_t pid = fork(); 5836 5837 if (pid < 0) { 5838 // fork failed 5839 return -1; 5840 5841 } else if (pid == 0) { 5842 // child process 5843 5844 execve("/bin/sh", (char* const*)argv, environ); 5845 5846 // execve failed 5847 _exit(-1); 5848 5849 } else { 5850 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5851 // care about the actual exit code, for now. 5852 5853 int status; 5854 5855 // Wait for the child process to exit. This returns immediately if 5856 // the child has already exited. */ 5857 while (waitpid(pid, &status, 0) < 0) { 5858 switch (errno) { 5859 case ECHILD: return 0; 5860 case EINTR: break; 5861 default: return -1; 5862 } 5863 } 5864 5865 if (WIFEXITED(status)) { 5866 // The child exited normally; get its exit code. 5867 return WEXITSTATUS(status); 5868 } else if (WIFSIGNALED(status)) { 5869 // The child exited because of a signal 5870 // The best value to return is 0x80 + signal number, 5871 // because that is what all Unix shells do, and because 5872 // it allows callers to distinguish between process exit and 5873 // process death by signal. 5874 return 0x80 + WTERMSIG(status); 5875 } else { 5876 // Unknown exit code; pass it through 5877 return status; 5878 } 5879 } 5880} 5881 5882// is_headless_jre() 5883// 5884// Test for the existence of xawt/libmawt.so or libawt_xawt.so 5885// in order to report if we are running in a headless jre 5886// 5887// Since JDK8 xawt/libmawt.so was moved into the same directory 5888// as libawt.so, and renamed libawt_xawt.so 5889// 5890bool os::is_headless_jre() { 5891 struct stat statbuf; 5892 char buf[MAXPATHLEN]; 5893 char libmawtpath[MAXPATHLEN]; 5894 const char *xawtstr = "/xawt/libmawt.so"; 5895 const char *new_xawtstr = "/libawt_xawt.so"; 5896 char *p; 5897 5898 // Get path to libjvm.so 5899 os::jvm_path(buf, sizeof(buf)); 5900 5901 // Get rid of libjvm.so 5902 p = strrchr(buf, '/'); 5903 if (p == NULL) { 5904 return false; 5905 } else { 5906 *p = '\0'; 5907 } 5908 5909 // Get rid of client or server 5910 p = strrchr(buf, '/'); 5911 if (p == NULL) { 5912 return false; 5913 } else { 5914 *p = '\0'; 5915 } 5916 5917 // check xawt/libmawt.so 5918 strcpy(libmawtpath, buf); 5919 strcat(libmawtpath, xawtstr); 5920 if (::stat(libmawtpath, &statbuf) == 0) return false; 5921 5922 // check libawt_xawt.so 5923 strcpy(libmawtpath, buf); 5924 strcat(libmawtpath, new_xawtstr); 5925 if (::stat(libmawtpath, &statbuf) == 0) return false; 5926 5927 return true; 5928} 5929 5930// Get the default path to the core file 5931// Returns the length of the string 5932int os::get_core_path(char* buffer, size_t bufferSize) { 5933 /* 5934 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5935 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5936 */ 5937 const int core_pattern_len = 129; 5938 char core_pattern[core_pattern_len] = {0}; 5939 5940 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5941 if (core_pattern_file != -1) { 5942 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5943 ::close(core_pattern_file); 5944 5945 if (ret > 0) { 5946 char *last_char = core_pattern + strlen(core_pattern) - 1; 5947 5948 if (*last_char == '\n') { 5949 *last_char = '\0'; 5950 } 5951 } 5952 } 5953 5954 if (strlen(core_pattern) == 0) { 5955 return -1; 5956 } 5957 5958 char *pid_pos = strstr(core_pattern, "%p"); 5959 int written; 5960 5961 if (core_pattern[0] == '/') { 5962 written = jio_snprintf(buffer, bufferSize, core_pattern); 5963 } else { 5964 char cwd[PATH_MAX]; 5965 5966 const char* p = get_current_directory(cwd, PATH_MAX); 5967 if (p == NULL) { 5968 return -1; 5969 } 5970 5971 if (core_pattern[0] == '|') { 5972 written = jio_snprintf(buffer, bufferSize, 5973 "\"%s\" (or dumping to %s/core.%d)", 5974 &core_pattern[1], p, current_process_id()); 5975 } else { 5976 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5977 } 5978 } 5979 5980 if (written < 0) { 5981 return -1; 5982 } 5983 5984 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5985 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5986 5987 if (core_uses_pid_file != -1) { 5988 char core_uses_pid = 0; 5989 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5990 ::close(core_uses_pid_file); 5991 5992 if (core_uses_pid == '1') { 5993 jio_snprintf(buffer + written, bufferSize - written, 5994 ".%d", current_process_id()); 5995 } 5996 } 5997 } 5998 5999 return strlen(buffer); 6000} 6001 6002/////////////// Unit tests /////////////// 6003 6004#ifndef PRODUCT 6005 6006#define test_log(...) \ 6007 do { \ 6008 if (VerboseInternalVMTests) { \ 6009 tty->print_cr(__VA_ARGS__); \ 6010 tty->flush(); \ 6011 } \ 6012 } while (false) 6013 6014class TestReserveMemorySpecial : AllStatic { 6015 public: 6016 static void small_page_write(void* addr, size_t size) { 6017 size_t page_size = os::vm_page_size(); 6018 6019 char* end = (char*)addr + size; 6020 for (char* p = (char*)addr; p < end; p += page_size) { 6021 *p = 1; 6022 } 6023 } 6024 6025 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6026 if (!UseHugeTLBFS) { 6027 return; 6028 } 6029 6030 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6031 6032 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6033 6034 if (addr != NULL) { 6035 small_page_write(addr, size); 6036 6037 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6038 } 6039 } 6040 6041 static void test_reserve_memory_special_huge_tlbfs_only() { 6042 if (!UseHugeTLBFS) { 6043 return; 6044 } 6045 6046 size_t lp = os::large_page_size(); 6047 6048 for (size_t size = lp; size <= lp * 10; size += lp) { 6049 test_reserve_memory_special_huge_tlbfs_only(size); 6050 } 6051 } 6052 6053 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6054 size_t lp = os::large_page_size(); 6055 size_t ag = os::vm_allocation_granularity(); 6056 6057 // sizes to test 6058 const size_t sizes[] = { 6059 lp, lp + ag, lp + lp / 2, lp * 2, 6060 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6061 lp * 10, lp * 10 + lp / 2 6062 }; 6063 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6064 6065 // For each size/alignment combination, we test three scenarios: 6066 // 1) with req_addr == NULL 6067 // 2) with a non-null req_addr at which we expect to successfully allocate 6068 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6069 // expect the allocation to either fail or to ignore req_addr 6070 6071 // Pre-allocate two areas; they shall be as large as the largest allocation 6072 // and aligned to the largest alignment we will be testing. 6073 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6074 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6075 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6076 -1, 0); 6077 assert(mapping1 != MAP_FAILED, "should work"); 6078 6079 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6080 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6081 -1, 0); 6082 assert(mapping2 != MAP_FAILED, "should work"); 6083 6084 // Unmap the first mapping, but leave the second mapping intact: the first 6085 // mapping will serve as a value for a "good" req_addr (case 2). The second 6086 // mapping, still intact, as "bad" req_addr (case 3). 6087 ::munmap(mapping1, mapping_size); 6088 6089 // Case 1 6090 test_log("%s, req_addr NULL:", __FUNCTION__); 6091 test_log("size align result"); 6092 6093 for (int i = 0; i < num_sizes; i++) { 6094 const size_t size = sizes[i]; 6095 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6096 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6097 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6098 size, alignment, p, (p != NULL ? "" : "(failed)")); 6099 if (p != NULL) { 6100 assert(is_ptr_aligned(p, alignment), "must be"); 6101 small_page_write(p, size); 6102 os::Linux::release_memory_special_huge_tlbfs(p, size); 6103 } 6104 } 6105 } 6106 6107 // Case 2 6108 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6109 test_log("size align req_addr result"); 6110 6111 for (int i = 0; i < num_sizes; i++) { 6112 const size_t size = sizes[i]; 6113 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6114 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 6115 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6116 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6117 size, alignment, req_addr, p, 6118 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6119 if (p != NULL) { 6120 assert(p == req_addr, "must be"); 6121 small_page_write(p, size); 6122 os::Linux::release_memory_special_huge_tlbfs(p, size); 6123 } 6124 } 6125 } 6126 6127 // Case 3 6128 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6129 test_log("size align req_addr result"); 6130 6131 for (int i = 0; i < num_sizes; i++) { 6132 const size_t size = sizes[i]; 6133 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6134 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6135 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6136 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6137 size, alignment, req_addr, p, 6138 ((p != NULL ? "" : "(failed)"))); 6139 // as the area around req_addr contains already existing mappings, the API should always 6140 // return NULL (as per contract, it cannot return another address) 6141 assert(p == NULL, "must be"); 6142 } 6143 } 6144 6145 ::munmap(mapping2, mapping_size); 6146 6147 } 6148 6149 static void test_reserve_memory_special_huge_tlbfs() { 6150 if (!UseHugeTLBFS) { 6151 return; 6152 } 6153 6154 test_reserve_memory_special_huge_tlbfs_only(); 6155 test_reserve_memory_special_huge_tlbfs_mixed(); 6156 } 6157 6158 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6159 if (!UseSHM) { 6160 return; 6161 } 6162 6163 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6164 6165 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6166 6167 if (addr != NULL) { 6168 assert(is_ptr_aligned(addr, alignment), "Check"); 6169 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6170 6171 small_page_write(addr, size); 6172 6173 os::Linux::release_memory_special_shm(addr, size); 6174 } 6175 } 6176 6177 static void test_reserve_memory_special_shm() { 6178 size_t lp = os::large_page_size(); 6179 size_t ag = os::vm_allocation_granularity(); 6180 6181 for (size_t size = ag; size < lp * 3; size += ag) { 6182 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6183 test_reserve_memory_special_shm(size, alignment); 6184 } 6185 } 6186 } 6187 6188 static void test() { 6189 test_reserve_memory_special_huge_tlbfs(); 6190 test_reserve_memory_special_shm(); 6191 } 6192}; 6193 6194void TestReserveMemorySpecial_test() { 6195 TestReserveMemorySpecial::test(); 6196} 6197 6198#endif 6199