os_linux.cpp revision 13134:2befe2aca4b4
1/* 2 * Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25// no precompiled headers 26#include "classfile/classLoader.hpp" 27#include "classfile/systemDictionary.hpp" 28#include "classfile/vmSymbols.hpp" 29#include "code/icBuffer.hpp" 30#include "code/vtableStubs.hpp" 31#include "compiler/compileBroker.hpp" 32#include "compiler/disassembler.hpp" 33#include "interpreter/interpreter.hpp" 34#include "jvm_linux.h" 35#include "logging/log.hpp" 36#include "memory/allocation.inline.hpp" 37#include "memory/filemap.hpp" 38#include "oops/oop.inline.hpp" 39#include "os_linux.inline.hpp" 40#include "os_share_linux.hpp" 41#include "prims/jniFastGetField.hpp" 42#include "prims/jvm.h" 43#include "prims/jvm_misc.hpp" 44#include "runtime/arguments.hpp" 45#include "runtime/atomic.hpp" 46#include "runtime/extendedPC.hpp" 47#include "runtime/globals.hpp" 48#include "runtime/interfaceSupport.hpp" 49#include "runtime/init.hpp" 50#include "runtime/java.hpp" 51#include "runtime/javaCalls.hpp" 52#include "runtime/mutexLocker.hpp" 53#include "runtime/objectMonitor.hpp" 54#include "runtime/orderAccess.inline.hpp" 55#include "runtime/osThread.hpp" 56#include "runtime/perfMemory.hpp" 57#include "runtime/sharedRuntime.hpp" 58#include "runtime/statSampler.hpp" 59#include "runtime/stubRoutines.hpp" 60#include "runtime/thread.inline.hpp" 61#include "runtime/threadCritical.hpp" 62#include "runtime/timer.hpp" 63#include "semaphore_posix.hpp" 64#include "services/attachListener.hpp" 65#include "services/memTracker.hpp" 66#include "services/runtimeService.hpp" 67#include "utilities/decoder.hpp" 68#include "utilities/defaultStream.hpp" 69#include "utilities/events.hpp" 70#include "utilities/elfFile.hpp" 71#include "utilities/growableArray.hpp" 72#include "utilities/macros.hpp" 73#include "utilities/vmError.hpp" 74 75// put OS-includes here 76# include <sys/types.h> 77# include <sys/mman.h> 78# include <sys/stat.h> 79# include <sys/select.h> 80# include <pthread.h> 81# include <signal.h> 82# include <errno.h> 83# include <dlfcn.h> 84# include <stdio.h> 85# include <unistd.h> 86# include <sys/resource.h> 87# include <pthread.h> 88# include <sys/stat.h> 89# include <sys/time.h> 90# include <sys/times.h> 91# include <sys/utsname.h> 92# include <sys/socket.h> 93# include <sys/wait.h> 94# include <pwd.h> 95# include <poll.h> 96# include <semaphore.h> 97# include <fcntl.h> 98# include <string.h> 99# include <syscall.h> 100# include <sys/sysinfo.h> 101# include <gnu/libc-version.h> 102# include <sys/ipc.h> 103# include <sys/shm.h> 104# include <link.h> 105# include <stdint.h> 106# include <inttypes.h> 107# include <sys/ioctl.h> 108 109#ifndef _GNU_SOURCE 110 #define _GNU_SOURCE 111 #include <sched.h> 112 #undef _GNU_SOURCE 113#else 114 #include <sched.h> 115#endif 116 117// if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 118// getrusage() is prepared to handle the associated failure. 119#ifndef RUSAGE_THREAD 120 #define RUSAGE_THREAD (1) /* only the calling thread */ 121#endif 122 123#define MAX_PATH (2 * K) 124 125#define MAX_SECS 100000000 126 127// for timer info max values which include all bits 128#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 129 130#define LARGEPAGES_BIT (1 << 6) 131//////////////////////////////////////////////////////////////////////////////// 132// global variables 133julong os::Linux::_physical_memory = 0; 134 135address os::Linux::_initial_thread_stack_bottom = NULL; 136uintptr_t os::Linux::_initial_thread_stack_size = 0; 137 138int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 139int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 140int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 141Mutex* os::Linux::_createThread_lock = NULL; 142pthread_t os::Linux::_main_thread; 143int os::Linux::_page_size = -1; 144bool os::Linux::_supports_fast_thread_cpu_time = false; 145uint32_t os::Linux::_os_version = 0; 146const char * os::Linux::_glibc_version = NULL; 147const char * os::Linux::_libpthread_version = NULL; 148 149static jlong initial_time_count=0; 150 151static int clock_tics_per_sec = 100; 152 153// For diagnostics to print a message once. see run_periodic_checks 154static sigset_t check_signal_done; 155static bool check_signals = true; 156 157// Signal number used to suspend/resume a thread 158 159// do not use any signal number less than SIGSEGV, see 4355769 160static int SR_signum = SIGUSR2; 161sigset_t SR_sigset; 162 163// utility functions 164 165static int SR_initialize(); 166 167julong os::available_memory() { 168 return Linux::available_memory(); 169} 170 171julong os::Linux::available_memory() { 172 // values in struct sysinfo are "unsigned long" 173 struct sysinfo si; 174 sysinfo(&si); 175 176 return (julong)si.freeram * si.mem_unit; 177} 178 179julong os::physical_memory() { 180 return Linux::physical_memory(); 181} 182 183// Return true if user is running as root. 184 185bool os::have_special_privileges() { 186 static bool init = false; 187 static bool privileges = false; 188 if (!init) { 189 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 190 init = true; 191 } 192 return privileges; 193} 194 195 196#ifndef SYS_gettid 197// i386: 224, ia64: 1105, amd64: 186, sparc 143 198 #ifdef __ia64__ 199 #define SYS_gettid 1105 200 #else 201 #ifdef __i386__ 202 #define SYS_gettid 224 203 #else 204 #ifdef __amd64__ 205 #define SYS_gettid 186 206 #else 207 #ifdef __sparc__ 208 #define SYS_gettid 143 209 #else 210 #error define gettid for the arch 211 #endif 212 #endif 213 #endif 214 #endif 215#endif 216 217 218// pid_t gettid() 219// 220// Returns the kernel thread id of the currently running thread. Kernel 221// thread id is used to access /proc. 222pid_t os::Linux::gettid() { 223 int rslt = syscall(SYS_gettid); 224 assert(rslt != -1, "must be."); // old linuxthreads implementation? 225 return (pid_t)rslt; 226} 227 228// Most versions of linux have a bug where the number of processors are 229// determined by looking at the /proc file system. In a chroot environment, 230// the system call returns 1. This causes the VM to act as if it is 231// a single processor and elide locking (see is_MP() call). 232static bool unsafe_chroot_detected = false; 233static const char *unstable_chroot_error = "/proc file system not found.\n" 234 "Java may be unstable running multithreaded in a chroot " 235 "environment on Linux when /proc filesystem is not mounted."; 236 237void os::Linux::initialize_system_info() { 238 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 239 if (processor_count() == 1) { 240 pid_t pid = os::Linux::gettid(); 241 char fname[32]; 242 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 243 FILE *fp = fopen(fname, "r"); 244 if (fp == NULL) { 245 unsafe_chroot_detected = true; 246 } else { 247 fclose(fp); 248 } 249 } 250 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 251 assert(processor_count() > 0, "linux error"); 252} 253 254void os::init_system_properties_values() { 255 // The next steps are taken in the product version: 256 // 257 // Obtain the JAVA_HOME value from the location of libjvm.so. 258 // This library should be located at: 259 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 260 // 261 // If "/jre/lib/" appears at the right place in the path, then we 262 // assume libjvm.so is installed in a JDK and we use this path. 263 // 264 // Otherwise exit with message: "Could not create the Java virtual machine." 265 // 266 // The following extra steps are taken in the debugging version: 267 // 268 // If "/jre/lib/" does NOT appear at the right place in the path 269 // instead of exit check for $JAVA_HOME environment variable. 270 // 271 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 272 // then we append a fake suffix "hotspot/libjvm.so" to this path so 273 // it looks like libjvm.so is installed there 274 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 275 // 276 // Otherwise exit. 277 // 278 // Important note: if the location of libjvm.so changes this 279 // code needs to be changed accordingly. 280 281 // See ld(1): 282 // The linker uses the following search paths to locate required 283 // shared libraries: 284 // 1: ... 285 // ... 286 // 7: The default directories, normally /lib and /usr/lib. 287#if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 288 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 289#else 290 #define DEFAULT_LIBPATH "/lib:/usr/lib" 291#endif 292 293// Base path of extensions installed on the system. 294#define SYS_EXT_DIR "/usr/java/packages" 295#define EXTENSIONS_DIR "/lib/ext" 296 297 // Buffer that fits several sprintfs. 298 // Note that the space for the colon and the trailing null are provided 299 // by the nulls included by the sizeof operator. 300 const size_t bufsize = 301 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 302 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 303 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 304 305 // sysclasspath, java_home, dll_dir 306 { 307 char *pslash; 308 os::jvm_path(buf, bufsize); 309 310 // Found the full path to libjvm.so. 311 // Now cut the path to <java_home>/jre if we can. 312 pslash = strrchr(buf, '/'); 313 if (pslash != NULL) { 314 *pslash = '\0'; // Get rid of /libjvm.so. 315 } 316 pslash = strrchr(buf, '/'); 317 if (pslash != NULL) { 318 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 319 } 320 Arguments::set_dll_dir(buf); 321 322 if (pslash != NULL) { 323 pslash = strrchr(buf, '/'); 324 if (pslash != NULL) { 325 *pslash = '\0'; // Get rid of /lib. 326 } 327 } 328 Arguments::set_java_home(buf); 329 set_boot_path('/', ':'); 330 } 331 332 // Where to look for native libraries. 333 // 334 // Note: Due to a legacy implementation, most of the library path 335 // is set in the launcher. This was to accomodate linking restrictions 336 // on legacy Linux implementations (which are no longer supported). 337 // Eventually, all the library path setting will be done here. 338 // 339 // However, to prevent the proliferation of improperly built native 340 // libraries, the new path component /usr/java/packages is added here. 341 // Eventually, all the library path setting will be done here. 342 { 343 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 344 // should always exist (until the legacy problem cited above is 345 // addressed). 346 const char *v = ::getenv("LD_LIBRARY_PATH"); 347 const char *v_colon = ":"; 348 if (v == NULL) { v = ""; v_colon = ""; } 349 // That's +1 for the colon and +1 for the trailing '\0'. 350 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 351 strlen(v) + 1 + 352 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 353 mtInternal); 354 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 355 Arguments::set_library_path(ld_library_path); 356 FREE_C_HEAP_ARRAY(char, ld_library_path); 357 } 358 359 // Extensions directories. 360 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 361 Arguments::set_ext_dirs(buf); 362 363 FREE_C_HEAP_ARRAY(char, buf); 364 365#undef DEFAULT_LIBPATH 366#undef SYS_EXT_DIR 367#undef EXTENSIONS_DIR 368} 369 370//////////////////////////////////////////////////////////////////////////////// 371// breakpoint support 372 373void os::breakpoint() { 374 BREAKPOINT; 375} 376 377extern "C" void breakpoint() { 378 // use debugger to set breakpoint here 379} 380 381//////////////////////////////////////////////////////////////////////////////// 382// signal support 383 384debug_only(static bool signal_sets_initialized = false); 385static sigset_t unblocked_sigs, vm_sigs; 386 387bool os::Linux::is_sig_ignored(int sig) { 388 struct sigaction oact; 389 sigaction(sig, (struct sigaction*)NULL, &oact); 390 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 391 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 392 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 393 return true; 394 } else { 395 return false; 396 } 397} 398 399void os::Linux::signal_sets_init() { 400 // Should also have an assertion stating we are still single-threaded. 401 assert(!signal_sets_initialized, "Already initialized"); 402 // Fill in signals that are necessarily unblocked for all threads in 403 // the VM. Currently, we unblock the following signals: 404 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 405 // by -Xrs (=ReduceSignalUsage)); 406 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 407 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 408 // the dispositions or masks wrt these signals. 409 // Programs embedding the VM that want to use the above signals for their 410 // own purposes must, at this time, use the "-Xrs" option to prevent 411 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 412 // (See bug 4345157, and other related bugs). 413 // In reality, though, unblocking these signals is really a nop, since 414 // these signals are not blocked by default. 415 sigemptyset(&unblocked_sigs); 416 sigaddset(&unblocked_sigs, SIGILL); 417 sigaddset(&unblocked_sigs, SIGSEGV); 418 sigaddset(&unblocked_sigs, SIGBUS); 419 sigaddset(&unblocked_sigs, SIGFPE); 420#if defined(PPC64) 421 sigaddset(&unblocked_sigs, SIGTRAP); 422#endif 423 sigaddset(&unblocked_sigs, SR_signum); 424 425 if (!ReduceSignalUsage) { 426 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 427 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 428 } 429 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 430 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 431 } 432 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 433 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 434 } 435 } 436 // Fill in signals that are blocked by all but the VM thread. 437 sigemptyset(&vm_sigs); 438 if (!ReduceSignalUsage) { 439 sigaddset(&vm_sigs, BREAK_SIGNAL); 440 } 441 debug_only(signal_sets_initialized = true); 442 443} 444 445// These are signals that are unblocked while a thread is running Java. 446// (For some reason, they get blocked by default.) 447sigset_t* os::Linux::unblocked_signals() { 448 assert(signal_sets_initialized, "Not initialized"); 449 return &unblocked_sigs; 450} 451 452// These are the signals that are blocked while a (non-VM) thread is 453// running Java. Only the VM thread handles these signals. 454sigset_t* os::Linux::vm_signals() { 455 assert(signal_sets_initialized, "Not initialized"); 456 return &vm_sigs; 457} 458 459void os::Linux::hotspot_sigmask(Thread* thread) { 460 461 //Save caller's signal mask before setting VM signal mask 462 sigset_t caller_sigmask; 463 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 464 465 OSThread* osthread = thread->osthread(); 466 osthread->set_caller_sigmask(caller_sigmask); 467 468 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 469 470 if (!ReduceSignalUsage) { 471 if (thread->is_VM_thread()) { 472 // Only the VM thread handles BREAK_SIGNAL ... 473 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 474 } else { 475 // ... all other threads block BREAK_SIGNAL 476 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 477 } 478 } 479} 480 481////////////////////////////////////////////////////////////////////////////// 482// detecting pthread library 483 484void os::Linux::libpthread_init() { 485 // Save glibc and pthread version strings. 486#if !defined(_CS_GNU_LIBC_VERSION) || \ 487 !defined(_CS_GNU_LIBPTHREAD_VERSION) 488 #error "glibc too old (< 2.3.2)" 489#endif 490 491 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 492 assert(n > 0, "cannot retrieve glibc version"); 493 char *str = (char *)malloc(n, mtInternal); 494 confstr(_CS_GNU_LIBC_VERSION, str, n); 495 os::Linux::set_glibc_version(str); 496 497 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 498 assert(n > 0, "cannot retrieve pthread version"); 499 str = (char *)malloc(n, mtInternal); 500 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 501 os::Linux::set_libpthread_version(str); 502} 503 504///////////////////////////////////////////////////////////////////////////// 505// thread stack expansion 506 507// os::Linux::manually_expand_stack() takes care of expanding the thread 508// stack. Note that this is normally not needed: pthread stacks allocate 509// thread stack using mmap() without MAP_NORESERVE, so the stack is already 510// committed. Therefore it is not necessary to expand the stack manually. 511// 512// Manually expanding the stack was historically needed on LinuxThreads 513// thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 514// it is kept to deal with very rare corner cases: 515// 516// For one, user may run the VM on an own implementation of threads 517// whose stacks are - like the old LinuxThreads - implemented using 518// mmap(MAP_GROWSDOWN). 519// 520// Also, this coding may be needed if the VM is running on the primordial 521// thread. Normally we avoid running on the primordial thread; however, 522// user may still invoke the VM on the primordial thread. 523// 524// The following historical comment describes the details about running 525// on a thread stack allocated with mmap(MAP_GROWSDOWN): 526 527 528// Force Linux kernel to expand current thread stack. If "bottom" is close 529// to the stack guard, caller should block all signals. 530// 531// MAP_GROWSDOWN: 532// A special mmap() flag that is used to implement thread stacks. It tells 533// kernel that the memory region should extend downwards when needed. This 534// allows early versions of LinuxThreads to only mmap the first few pages 535// when creating a new thread. Linux kernel will automatically expand thread 536// stack as needed (on page faults). 537// 538// However, because the memory region of a MAP_GROWSDOWN stack can grow on 539// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 540// region, it's hard to tell if the fault is due to a legitimate stack 541// access or because of reading/writing non-exist memory (e.g. buffer 542// overrun). As a rule, if the fault happens below current stack pointer, 543// Linux kernel does not expand stack, instead a SIGSEGV is sent to the 544// application (see Linux kernel fault.c). 545// 546// This Linux feature can cause SIGSEGV when VM bangs thread stack for 547// stack overflow detection. 548// 549// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 550// not use MAP_GROWSDOWN. 551// 552// To get around the problem and allow stack banging on Linux, we need to 553// manually expand thread stack after receiving the SIGSEGV. 554// 555// There are two ways to expand thread stack to address "bottom", we used 556// both of them in JVM before 1.5: 557// 1. adjust stack pointer first so that it is below "bottom", and then 558// touch "bottom" 559// 2. mmap() the page in question 560// 561// Now alternate signal stack is gone, it's harder to use 2. For instance, 562// if current sp is already near the lower end of page 101, and we need to 563// call mmap() to map page 100, it is possible that part of the mmap() frame 564// will be placed in page 100. When page 100 is mapped, it is zero-filled. 565// That will destroy the mmap() frame and cause VM to crash. 566// 567// The following code works by adjusting sp first, then accessing the "bottom" 568// page to force a page fault. Linux kernel will then automatically expand the 569// stack mapping. 570// 571// _expand_stack_to() assumes its frame size is less than page size, which 572// should always be true if the function is not inlined. 573 574static void NOINLINE _expand_stack_to(address bottom) { 575 address sp; 576 size_t size; 577 volatile char *p; 578 579 // Adjust bottom to point to the largest address within the same page, it 580 // gives us a one-page buffer if alloca() allocates slightly more memory. 581 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 582 bottom += os::Linux::page_size() - 1; 583 584 // sp might be slightly above current stack pointer; if that's the case, we 585 // will alloca() a little more space than necessary, which is OK. Don't use 586 // os::current_stack_pointer(), as its result can be slightly below current 587 // stack pointer, causing us to not alloca enough to reach "bottom". 588 sp = (address)&sp; 589 590 if (sp > bottom) { 591 size = sp - bottom; 592 p = (volatile char *)alloca(size); 593 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 594 p[0] = '\0'; 595 } 596} 597 598bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 599 assert(t!=NULL, "just checking"); 600 assert(t->osthread()->expanding_stack(), "expand should be set"); 601 assert(t->stack_base() != NULL, "stack_base was not initialized"); 602 603 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 604 sigset_t mask_all, old_sigset; 605 sigfillset(&mask_all); 606 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 607 _expand_stack_to(addr); 608 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 609 return true; 610 } 611 return false; 612} 613 614////////////////////////////////////////////////////////////////////////////// 615// create new thread 616 617// Thread start routine for all newly created threads 618static void *thread_native_entry(Thread *thread) { 619 // Try to randomize the cache line index of hot stack frames. 620 // This helps when threads of the same stack traces evict each other's 621 // cache lines. The threads can be either from the same JVM instance, or 622 // from different JVM instances. The benefit is especially true for 623 // processors with hyperthreading technology. 624 static int counter = 0; 625 int pid = os::current_process_id(); 626 alloca(((pid ^ counter++) & 7) * 128); 627 628 thread->initialize_thread_current(); 629 630 OSThread* osthread = thread->osthread(); 631 Monitor* sync = osthread->startThread_lock(); 632 633 osthread->set_thread_id(os::current_thread_id()); 634 635 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 636 os::current_thread_id(), (uintx) pthread_self()); 637 638 if (UseNUMA) { 639 int lgrp_id = os::numa_get_group_id(); 640 if (lgrp_id != -1) { 641 thread->set_lgrp_id(lgrp_id); 642 } 643 } 644 // initialize signal mask for this thread 645 os::Linux::hotspot_sigmask(thread); 646 647 // initialize floating point control register 648 os::Linux::init_thread_fpu_state(); 649 650 // handshaking with parent thread 651 { 652 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 653 654 // notify parent thread 655 osthread->set_state(INITIALIZED); 656 sync->notify_all(); 657 658 // wait until os::start_thread() 659 while (osthread->get_state() == INITIALIZED) { 660 sync->wait(Mutex::_no_safepoint_check_flag); 661 } 662 } 663 664 // call one more level start routine 665 thread->run(); 666 667 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 668 os::current_thread_id(), (uintx) pthread_self()); 669 670 // If a thread has not deleted itself ("delete this") as part of its 671 // termination sequence, we have to ensure thread-local-storage is 672 // cleared before we actually terminate. No threads should ever be 673 // deleted asynchronously with respect to their termination. 674 if (Thread::current_or_null_safe() != NULL) { 675 assert(Thread::current_or_null_safe() == thread, "current thread is wrong"); 676 thread->clear_thread_current(); 677 } 678 679 return 0; 680} 681 682bool os::create_thread(Thread* thread, ThreadType thr_type, 683 size_t req_stack_size) { 684 assert(thread->osthread() == NULL, "caller responsible"); 685 686 // Allocate the OSThread object 687 OSThread* osthread = new OSThread(NULL, NULL); 688 if (osthread == NULL) { 689 return false; 690 } 691 692 // set the correct thread state 693 osthread->set_thread_type(thr_type); 694 695 // Initial state is ALLOCATED but not INITIALIZED 696 osthread->set_state(ALLOCATED); 697 698 thread->set_osthread(osthread); 699 700 // init thread attributes 701 pthread_attr_t attr; 702 pthread_attr_init(&attr); 703 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 704 705 // Calculate stack size if it's not specified by caller. 706 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 707 // In the Linux NPTL pthread implementation the guard size mechanism 708 // is not implemented properly. The posix standard requires adding 709 // the size of the guard pages to the stack size, instead Linux 710 // takes the space out of 'stacksize'. Thus we adapt the requested 711 // stack_size by the size of the guard pages to mimick proper 712 // behaviour. However, be careful not to end up with a size 713 // of zero due to overflow. Don't add the guard page in that case. 714 size_t guard_size = os::Linux::default_guard_size(thr_type); 715 if (stack_size <= SIZE_MAX - guard_size) { 716 stack_size += guard_size; 717 } 718 assert(is_size_aligned(stack_size, os::vm_page_size()), "stack_size not aligned"); 719 720 int status = pthread_attr_setstacksize(&attr, stack_size); 721 assert_status(status == 0, status, "pthread_attr_setstacksize"); 722 723 // Configure glibc guard page. 724 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 725 726 ThreadState state; 727 728 { 729 pthread_t tid; 730 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 731 732 char buf[64]; 733 if (ret == 0) { 734 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 735 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 736 } else { 737 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 738 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 739 } 740 741 pthread_attr_destroy(&attr); 742 743 if (ret != 0) { 744 // Need to clean up stuff we've allocated so far 745 thread->set_osthread(NULL); 746 delete osthread; 747 return false; 748 } 749 750 // Store pthread info into the OSThread 751 osthread->set_pthread_id(tid); 752 753 // Wait until child thread is either initialized or aborted 754 { 755 Monitor* sync_with_child = osthread->startThread_lock(); 756 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 757 while ((state = osthread->get_state()) == ALLOCATED) { 758 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 759 } 760 } 761 } 762 763 // Aborted due to thread limit being reached 764 if (state == ZOMBIE) { 765 thread->set_osthread(NULL); 766 delete osthread; 767 return false; 768 } 769 770 // The thread is returned suspended (in state INITIALIZED), 771 // and is started higher up in the call chain 772 assert(state == INITIALIZED, "race condition"); 773 return true; 774} 775 776///////////////////////////////////////////////////////////////////////////// 777// attach existing thread 778 779// bootstrap the main thread 780bool os::create_main_thread(JavaThread* thread) { 781 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 782 return create_attached_thread(thread); 783} 784 785bool os::create_attached_thread(JavaThread* thread) { 786#ifdef ASSERT 787 thread->verify_not_published(); 788#endif 789 790 // Allocate the OSThread object 791 OSThread* osthread = new OSThread(NULL, NULL); 792 793 if (osthread == NULL) { 794 return false; 795 } 796 797 // Store pthread info into the OSThread 798 osthread->set_thread_id(os::Linux::gettid()); 799 osthread->set_pthread_id(::pthread_self()); 800 801 // initialize floating point control register 802 os::Linux::init_thread_fpu_state(); 803 804 // Initial thread state is RUNNABLE 805 osthread->set_state(RUNNABLE); 806 807 thread->set_osthread(osthread); 808 809 if (UseNUMA) { 810 int lgrp_id = os::numa_get_group_id(); 811 if (lgrp_id != -1) { 812 thread->set_lgrp_id(lgrp_id); 813 } 814 } 815 816 if (os::Linux::is_initial_thread()) { 817 // If current thread is initial thread, its stack is mapped on demand, 818 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 819 // the entire stack region to avoid SEGV in stack banging. 820 // It is also useful to get around the heap-stack-gap problem on SuSE 821 // kernel (see 4821821 for details). We first expand stack to the top 822 // of yellow zone, then enable stack yellow zone (order is significant, 823 // enabling yellow zone first will crash JVM on SuSE Linux), so there 824 // is no gap between the last two virtual memory regions. 825 826 JavaThread *jt = (JavaThread *)thread; 827 address addr = jt->stack_reserved_zone_base(); 828 assert(addr != NULL, "initialization problem?"); 829 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 830 831 osthread->set_expanding_stack(); 832 os::Linux::manually_expand_stack(jt, addr); 833 osthread->clear_expanding_stack(); 834 } 835 836 // initialize signal mask for this thread 837 // and save the caller's signal mask 838 os::Linux::hotspot_sigmask(thread); 839 840 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 841 os::current_thread_id(), (uintx) pthread_self()); 842 843 return true; 844} 845 846void os::pd_start_thread(Thread* thread) { 847 OSThread * osthread = thread->osthread(); 848 assert(osthread->get_state() != INITIALIZED, "just checking"); 849 Monitor* sync_with_child = osthread->startThread_lock(); 850 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 851 sync_with_child->notify(); 852} 853 854// Free Linux resources related to the OSThread 855void os::free_thread(OSThread* osthread) { 856 assert(osthread != NULL, "osthread not set"); 857 858 // We are told to free resources of the argument thread, 859 // but we can only really operate on the current thread. 860 assert(Thread::current()->osthread() == osthread, 861 "os::free_thread but not current thread"); 862 863#ifdef ASSERT 864 sigset_t current; 865 sigemptyset(¤t); 866 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 867 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 868#endif 869 870 // Restore caller's signal mask 871 sigset_t sigmask = osthread->caller_sigmask(); 872 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 873 874 delete osthread; 875} 876 877////////////////////////////////////////////////////////////////////////////// 878// initial thread 879 880// Check if current thread is the initial thread, similar to Solaris thr_main. 881bool os::Linux::is_initial_thread(void) { 882 char dummy; 883 // If called before init complete, thread stack bottom will be null. 884 // Can be called if fatal error occurs before initialization. 885 if (initial_thread_stack_bottom() == NULL) return false; 886 assert(initial_thread_stack_bottom() != NULL && 887 initial_thread_stack_size() != 0, 888 "os::init did not locate initial thread's stack region"); 889 if ((address)&dummy >= initial_thread_stack_bottom() && 890 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 891 return true; 892 } else { 893 return false; 894 } 895} 896 897// Find the virtual memory area that contains addr 898static bool find_vma(address addr, address* vma_low, address* vma_high) { 899 FILE *fp = fopen("/proc/self/maps", "r"); 900 if (fp) { 901 address low, high; 902 while (!feof(fp)) { 903 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 904 if (low <= addr && addr < high) { 905 if (vma_low) *vma_low = low; 906 if (vma_high) *vma_high = high; 907 fclose(fp); 908 return true; 909 } 910 } 911 for (;;) { 912 int ch = fgetc(fp); 913 if (ch == EOF || ch == (int)'\n') break; 914 } 915 } 916 fclose(fp); 917 } 918 return false; 919} 920 921// Locate initial thread stack. This special handling of initial thread stack 922// is needed because pthread_getattr_np() on most (all?) Linux distros returns 923// bogus value for the primordial process thread. While the launcher has created 924// the VM in a new thread since JDK 6, we still have to allow for the use of the 925// JNI invocation API from a primordial thread. 926void os::Linux::capture_initial_stack(size_t max_size) { 927 928 // max_size is either 0 (which means accept OS default for thread stacks) or 929 // a user-specified value known to be at least the minimum needed. If we 930 // are actually on the primordial thread we can make it appear that we have a 931 // smaller max_size stack by inserting the guard pages at that location. But we 932 // cannot do anything to emulate a larger stack than what has been provided by 933 // the OS or threading library. In fact if we try to use a stack greater than 934 // what is set by rlimit then we will crash the hosting process. 935 936 // Maximum stack size is the easy part, get it from RLIMIT_STACK. 937 // If this is "unlimited" then it will be a huge value. 938 struct rlimit rlim; 939 getrlimit(RLIMIT_STACK, &rlim); 940 size_t stack_size = rlim.rlim_cur; 941 942 // 6308388: a bug in ld.so will relocate its own .data section to the 943 // lower end of primordial stack; reduce ulimit -s value a little bit 944 // so we won't install guard page on ld.so's data section. 945 stack_size -= 2 * page_size(); 946 947 // Try to figure out where the stack base (top) is. This is harder. 948 // 949 // When an application is started, glibc saves the initial stack pointer in 950 // a global variable "__libc_stack_end", which is then used by system 951 // libraries. __libc_stack_end should be pretty close to stack top. The 952 // variable is available since the very early days. However, because it is 953 // a private interface, it could disappear in the future. 954 // 955 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 956 // to __libc_stack_end, it is very close to stack top, but isn't the real 957 // stack top. Note that /proc may not exist if VM is running as a chroot 958 // program, so reading /proc/<pid>/stat could fail. Also the contents of 959 // /proc/<pid>/stat could change in the future (though unlikely). 960 // 961 // We try __libc_stack_end first. If that doesn't work, look for 962 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 963 // as a hint, which should work well in most cases. 964 965 uintptr_t stack_start; 966 967 // try __libc_stack_end first 968 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 969 if (p && *p) { 970 stack_start = *p; 971 } else { 972 // see if we can get the start_stack field from /proc/self/stat 973 FILE *fp; 974 int pid; 975 char state; 976 int ppid; 977 int pgrp; 978 int session; 979 int nr; 980 int tpgrp; 981 unsigned long flags; 982 unsigned long minflt; 983 unsigned long cminflt; 984 unsigned long majflt; 985 unsigned long cmajflt; 986 unsigned long utime; 987 unsigned long stime; 988 long cutime; 989 long cstime; 990 long prio; 991 long nice; 992 long junk; 993 long it_real; 994 uintptr_t start; 995 uintptr_t vsize; 996 intptr_t rss; 997 uintptr_t rsslim; 998 uintptr_t scodes; 999 uintptr_t ecode; 1000 int i; 1001 1002 // Figure what the primordial thread stack base is. Code is inspired 1003 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1004 // followed by command name surrounded by parentheses, state, etc. 1005 char stat[2048]; 1006 int statlen; 1007 1008 fp = fopen("/proc/self/stat", "r"); 1009 if (fp) { 1010 statlen = fread(stat, 1, 2047, fp); 1011 stat[statlen] = '\0'; 1012 fclose(fp); 1013 1014 // Skip pid and the command string. Note that we could be dealing with 1015 // weird command names, e.g. user could decide to rename java launcher 1016 // to "java 1.4.2 :)", then the stat file would look like 1017 // 1234 (java 1.4.2 :)) R ... ... 1018 // We don't really need to know the command string, just find the last 1019 // occurrence of ")" and then start parsing from there. See bug 4726580. 1020 char * s = strrchr(stat, ')'); 1021 1022 i = 0; 1023 if (s) { 1024 // Skip blank chars 1025 do { s++; } while (s && isspace(*s)); 1026 1027#define _UFM UINTX_FORMAT 1028#define _DFM INTX_FORMAT 1029 1030 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1031 // 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 1032 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, 1033 &state, // 3 %c 1034 &ppid, // 4 %d 1035 &pgrp, // 5 %d 1036 &session, // 6 %d 1037 &nr, // 7 %d 1038 &tpgrp, // 8 %d 1039 &flags, // 9 %lu 1040 &minflt, // 10 %lu 1041 &cminflt, // 11 %lu 1042 &majflt, // 12 %lu 1043 &cmajflt, // 13 %lu 1044 &utime, // 14 %lu 1045 &stime, // 15 %lu 1046 &cutime, // 16 %ld 1047 &cstime, // 17 %ld 1048 &prio, // 18 %ld 1049 &nice, // 19 %ld 1050 &junk, // 20 %ld 1051 &it_real, // 21 %ld 1052 &start, // 22 UINTX_FORMAT 1053 &vsize, // 23 UINTX_FORMAT 1054 &rss, // 24 INTX_FORMAT 1055 &rsslim, // 25 UINTX_FORMAT 1056 &scodes, // 26 UINTX_FORMAT 1057 &ecode, // 27 UINTX_FORMAT 1058 &stack_start); // 28 UINTX_FORMAT 1059 } 1060 1061#undef _UFM 1062#undef _DFM 1063 1064 if (i != 28 - 2) { 1065 assert(false, "Bad conversion from /proc/self/stat"); 1066 // product mode - assume we are the initial thread, good luck in the 1067 // embedded case. 1068 warning("Can't detect initial thread stack location - bad conversion"); 1069 stack_start = (uintptr_t) &rlim; 1070 } 1071 } else { 1072 // For some reason we can't open /proc/self/stat (for example, running on 1073 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1074 // most cases, so don't abort: 1075 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1076 stack_start = (uintptr_t) &rlim; 1077 } 1078 } 1079 1080 // Now we have a pointer (stack_start) very close to the stack top, the 1081 // next thing to do is to figure out the exact location of stack top. We 1082 // can find out the virtual memory area that contains stack_start by 1083 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1084 // and its upper limit is the real stack top. (again, this would fail if 1085 // running inside chroot, because /proc may not exist.) 1086 1087 uintptr_t stack_top; 1088 address low, high; 1089 if (find_vma((address)stack_start, &low, &high)) { 1090 // success, "high" is the true stack top. (ignore "low", because initial 1091 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1092 stack_top = (uintptr_t)high; 1093 } else { 1094 // failed, likely because /proc/self/maps does not exist 1095 warning("Can't detect initial thread stack location - find_vma failed"); 1096 // best effort: stack_start is normally within a few pages below the real 1097 // stack top, use it as stack top, and reduce stack size so we won't put 1098 // guard page outside stack. 1099 stack_top = stack_start; 1100 stack_size -= 16 * page_size(); 1101 } 1102 1103 // stack_top could be partially down the page so align it 1104 stack_top = align_size_up(stack_top, page_size()); 1105 1106 // Allowed stack value is minimum of max_size and what we derived from rlimit 1107 if (max_size > 0) { 1108 _initial_thread_stack_size = MIN2(max_size, stack_size); 1109 } else { 1110 // Accept the rlimit max, but if stack is unlimited then it will be huge, so 1111 // clamp it at 8MB as we do on Solaris 1112 _initial_thread_stack_size = MIN2(stack_size, 8*M); 1113 } 1114 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1115 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1116 1117 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!"); 1118 1119 if (log_is_enabled(Info, os, thread)) { 1120 // See if we seem to be on primordial process thread 1121 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) && 1122 uintptr_t(&rlim) < stack_top; 1123 1124 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: " 1125 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT, 1126 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K, 1127 stack_top, intptr_t(_initial_thread_stack_bottom)); 1128 } 1129} 1130 1131//////////////////////////////////////////////////////////////////////////////// 1132// time support 1133 1134// Time since start-up in seconds to a fine granularity. 1135// Used by VMSelfDestructTimer and the MemProfiler. 1136double os::elapsedTime() { 1137 1138 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1139} 1140 1141jlong os::elapsed_counter() { 1142 return javaTimeNanos() - initial_time_count; 1143} 1144 1145jlong os::elapsed_frequency() { 1146 return NANOSECS_PER_SEC; // nanosecond resolution 1147} 1148 1149bool os::supports_vtime() { return true; } 1150bool os::enable_vtime() { return false; } 1151bool os::vtime_enabled() { return false; } 1152 1153double os::elapsedVTime() { 1154 struct rusage usage; 1155 int retval = getrusage(RUSAGE_THREAD, &usage); 1156 if (retval == 0) { 1157 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); 1158 } else { 1159 // better than nothing, but not much 1160 return elapsedTime(); 1161 } 1162} 1163 1164jlong os::javaTimeMillis() { 1165 timeval time; 1166 int status = gettimeofday(&time, NULL); 1167 assert(status != -1, "linux error"); 1168 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1169} 1170 1171void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1172 timeval time; 1173 int status = gettimeofday(&time, NULL); 1174 assert(status != -1, "linux error"); 1175 seconds = jlong(time.tv_sec); 1176 nanos = jlong(time.tv_usec) * 1000; 1177} 1178 1179 1180#ifndef CLOCK_MONOTONIC 1181 #define CLOCK_MONOTONIC (1) 1182#endif 1183 1184void os::Linux::clock_init() { 1185 // we do dlopen's in this particular order due to bug in linux 1186 // dynamical loader (see 6348968) leading to crash on exit 1187 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1188 if (handle == NULL) { 1189 handle = dlopen("librt.so", RTLD_LAZY); 1190 } 1191 1192 if (handle) { 1193 int (*clock_getres_func)(clockid_t, struct timespec*) = 1194 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1195 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1196 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1197 if (clock_getres_func && clock_gettime_func) { 1198 // See if monotonic clock is supported by the kernel. Note that some 1199 // early implementations simply return kernel jiffies (updated every 1200 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1201 // for nano time (though the monotonic property is still nice to have). 1202 // It's fixed in newer kernels, however clock_getres() still returns 1203 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1204 // resolution for now. Hopefully as people move to new kernels, this 1205 // won't be a problem. 1206 struct timespec res; 1207 struct timespec tp; 1208 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1209 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1210 // yes, monotonic clock is supported 1211 _clock_gettime = clock_gettime_func; 1212 return; 1213 } else { 1214 // close librt if there is no monotonic clock 1215 dlclose(handle); 1216 } 1217 } 1218 } 1219 warning("No monotonic clock was available - timed services may " \ 1220 "be adversely affected if the time-of-day clock changes"); 1221} 1222 1223#ifndef SYS_clock_getres 1224 #if defined(X86) || defined(PPC64) || defined(S390) 1225 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261) 1226 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1227 #else 1228 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1229 #define sys_clock_getres(x,y) -1 1230 #endif 1231#else 1232 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1233#endif 1234 1235void os::Linux::fast_thread_clock_init() { 1236 if (!UseLinuxPosixThreadCPUClocks) { 1237 return; 1238 } 1239 clockid_t clockid; 1240 struct timespec tp; 1241 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1242 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1243 1244 // Switch to using fast clocks for thread cpu time if 1245 // the sys_clock_getres() returns 0 error code. 1246 // Note, that some kernels may support the current thread 1247 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1248 // returned by the pthread_getcpuclockid(). 1249 // If the fast Posix clocks are supported then the sys_clock_getres() 1250 // must return at least tp.tv_sec == 0 which means a resolution 1251 // better than 1 sec. This is extra check for reliability. 1252 1253 if (pthread_getcpuclockid_func && 1254 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1255 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1256 _supports_fast_thread_cpu_time = true; 1257 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1258 } 1259} 1260 1261jlong os::javaTimeNanos() { 1262 if (os::supports_monotonic_clock()) { 1263 struct timespec tp; 1264 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1265 assert(status == 0, "gettime error"); 1266 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1267 return result; 1268 } else { 1269 timeval time; 1270 int status = gettimeofday(&time, NULL); 1271 assert(status != -1, "linux error"); 1272 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1273 return 1000 * usecs; 1274 } 1275} 1276 1277void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1278 if (os::supports_monotonic_clock()) { 1279 info_ptr->max_value = ALL_64_BITS; 1280 1281 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1282 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1283 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1284 } else { 1285 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1286 info_ptr->max_value = ALL_64_BITS; 1287 1288 // gettimeofday is a real time clock so it skips 1289 info_ptr->may_skip_backward = true; 1290 info_ptr->may_skip_forward = true; 1291 } 1292 1293 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1294} 1295 1296// Return the real, user, and system times in seconds from an 1297// arbitrary fixed point in the past. 1298bool os::getTimesSecs(double* process_real_time, 1299 double* process_user_time, 1300 double* process_system_time) { 1301 struct tms ticks; 1302 clock_t real_ticks = times(&ticks); 1303 1304 if (real_ticks == (clock_t) (-1)) { 1305 return false; 1306 } else { 1307 double ticks_per_second = (double) clock_tics_per_sec; 1308 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1309 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1310 *process_real_time = ((double) real_ticks) / ticks_per_second; 1311 1312 return true; 1313 } 1314} 1315 1316 1317char * os::local_time_string(char *buf, size_t buflen) { 1318 struct tm t; 1319 time_t long_time; 1320 time(&long_time); 1321 localtime_r(&long_time, &t); 1322 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1323 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1324 t.tm_hour, t.tm_min, t.tm_sec); 1325 return buf; 1326} 1327 1328struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1329 return localtime_r(clock, res); 1330} 1331 1332//////////////////////////////////////////////////////////////////////////////// 1333// runtime exit support 1334 1335// Note: os::shutdown() might be called very early during initialization, or 1336// called from signal handler. Before adding something to os::shutdown(), make 1337// sure it is async-safe and can handle partially initialized VM. 1338void os::shutdown() { 1339 1340 // allow PerfMemory to attempt cleanup of any persistent resources 1341 perfMemory_exit(); 1342 1343 // needs to remove object in file system 1344 AttachListener::abort(); 1345 1346 // flush buffered output, finish log files 1347 ostream_abort(); 1348 1349 // Check for abort hook 1350 abort_hook_t abort_hook = Arguments::abort_hook(); 1351 if (abort_hook != NULL) { 1352 abort_hook(); 1353 } 1354 1355} 1356 1357// Note: os::abort() might be called very early during initialization, or 1358// called from signal handler. Before adding something to os::abort(), make 1359// sure it is async-safe and can handle partially initialized VM. 1360void os::abort(bool dump_core, void* siginfo, const void* context) { 1361 os::shutdown(); 1362 if (dump_core) { 1363#ifndef PRODUCT 1364 fdStream out(defaultStream::output_fd()); 1365 out.print_raw("Current thread is "); 1366 char buf[16]; 1367 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1368 out.print_raw_cr(buf); 1369 out.print_raw_cr("Dumping core ..."); 1370#endif 1371 ::abort(); // dump core 1372 } 1373 1374 ::exit(1); 1375} 1376 1377// Die immediately, no exit hook, no abort hook, no cleanup. 1378void os::die() { 1379 ::abort(); 1380} 1381 1382 1383// This method is a copy of JDK's sysGetLastErrorString 1384// from src/solaris/hpi/src/system_md.c 1385 1386size_t os::lasterror(char *buf, size_t len) { 1387 if (errno == 0) return 0; 1388 1389 const char *s = os::strerror(errno); 1390 size_t n = ::strlen(s); 1391 if (n >= len) { 1392 n = len - 1; 1393 } 1394 ::strncpy(buf, s, n); 1395 buf[n] = '\0'; 1396 return n; 1397} 1398 1399// thread_id is kernel thread id (similar to Solaris LWP id) 1400intx os::current_thread_id() { return os::Linux::gettid(); } 1401int os::current_process_id() { 1402 return ::getpid(); 1403} 1404 1405// DLL functions 1406 1407const char* os::dll_file_extension() { return ".so"; } 1408 1409// This must be hard coded because it's the system's temporary 1410// directory not the java application's temp directory, ala java.io.tmpdir. 1411const char* os::get_temp_directory() { return "/tmp"; } 1412 1413static bool file_exists(const char* filename) { 1414 struct stat statbuf; 1415 if (filename == NULL || strlen(filename) == 0) { 1416 return false; 1417 } 1418 return os::stat(filename, &statbuf) == 0; 1419} 1420 1421bool os::dll_build_name(char* buffer, size_t buflen, 1422 const char* pname, const char* fname) { 1423 bool retval = false; 1424 // Copied from libhpi 1425 const size_t pnamelen = pname ? strlen(pname) : 0; 1426 1427 // Return error on buffer overflow. 1428 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1429 return retval; 1430 } 1431 1432 if (pnamelen == 0) { 1433 snprintf(buffer, buflen, "lib%s.so", fname); 1434 retval = true; 1435 } else if (strchr(pname, *os::path_separator()) != NULL) { 1436 int n; 1437 char** pelements = split_path(pname, &n); 1438 if (pelements == NULL) { 1439 return false; 1440 } 1441 for (int i = 0; i < n; i++) { 1442 // Really shouldn't be NULL, but check can't hurt 1443 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1444 continue; // skip the empty path values 1445 } 1446 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1447 if (file_exists(buffer)) { 1448 retval = true; 1449 break; 1450 } 1451 } 1452 // release the storage 1453 for (int i = 0; i < n; i++) { 1454 if (pelements[i] != NULL) { 1455 FREE_C_HEAP_ARRAY(char, pelements[i]); 1456 } 1457 } 1458 if (pelements != NULL) { 1459 FREE_C_HEAP_ARRAY(char*, pelements); 1460 } 1461 } else { 1462 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1463 retval = true; 1464 } 1465 return retval; 1466} 1467 1468// check if addr is inside libjvm.so 1469bool os::address_is_in_vm(address addr) { 1470 static address libjvm_base_addr; 1471 Dl_info dlinfo; 1472 1473 if (libjvm_base_addr == NULL) { 1474 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1475 libjvm_base_addr = (address)dlinfo.dli_fbase; 1476 } 1477 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1478 } 1479 1480 if (dladdr((void *)addr, &dlinfo) != 0) { 1481 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1482 } 1483 1484 return false; 1485} 1486 1487bool os::dll_address_to_function_name(address addr, char *buf, 1488 int buflen, int *offset, 1489 bool demangle) { 1490 // buf is not optional, but offset is optional 1491 assert(buf != NULL, "sanity check"); 1492 1493 Dl_info dlinfo; 1494 1495 if (dladdr((void*)addr, &dlinfo) != 0) { 1496 // see if we have a matching symbol 1497 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1498 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1499 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1500 } 1501 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1502 return true; 1503 } 1504 // no matching symbol so try for just file info 1505 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1506 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1507 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1508 return true; 1509 } 1510 } 1511 } 1512 1513 buf[0] = '\0'; 1514 if (offset != NULL) *offset = -1; 1515 return false; 1516} 1517 1518struct _address_to_library_name { 1519 address addr; // input : memory address 1520 size_t buflen; // size of fname 1521 char* fname; // output: library name 1522 address base; // library base addr 1523}; 1524 1525static int address_to_library_name_callback(struct dl_phdr_info *info, 1526 size_t size, void *data) { 1527 int i; 1528 bool found = false; 1529 address libbase = NULL; 1530 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1531 1532 // iterate through all loadable segments 1533 for (i = 0; i < info->dlpi_phnum; i++) { 1534 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1535 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1536 // base address of a library is the lowest address of its loaded 1537 // segments. 1538 if (libbase == NULL || libbase > segbase) { 1539 libbase = segbase; 1540 } 1541 // see if 'addr' is within current segment 1542 if (segbase <= d->addr && 1543 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1544 found = true; 1545 } 1546 } 1547 } 1548 1549 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1550 // so dll_address_to_library_name() can fall through to use dladdr() which 1551 // can figure out executable name from argv[0]. 1552 if (found && info->dlpi_name && info->dlpi_name[0]) { 1553 d->base = libbase; 1554 if (d->fname) { 1555 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1556 } 1557 return 1; 1558 } 1559 return 0; 1560} 1561 1562bool os::dll_address_to_library_name(address addr, char* buf, 1563 int buflen, int* offset) { 1564 // buf is not optional, but offset is optional 1565 assert(buf != NULL, "sanity check"); 1566 1567 Dl_info dlinfo; 1568 struct _address_to_library_name data; 1569 1570 // There is a bug in old glibc dladdr() implementation that it could resolve 1571 // to wrong library name if the .so file has a base address != NULL. Here 1572 // we iterate through the program headers of all loaded libraries to find 1573 // out which library 'addr' really belongs to. This workaround can be 1574 // removed once the minimum requirement for glibc is moved to 2.3.x. 1575 data.addr = addr; 1576 data.fname = buf; 1577 data.buflen = buflen; 1578 data.base = NULL; 1579 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1580 1581 if (rslt) { 1582 // buf already contains library name 1583 if (offset) *offset = addr - data.base; 1584 return true; 1585 } 1586 if (dladdr((void*)addr, &dlinfo) != 0) { 1587 if (dlinfo.dli_fname != NULL) { 1588 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1589 } 1590 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1591 *offset = addr - (address)dlinfo.dli_fbase; 1592 } 1593 return true; 1594 } 1595 1596 buf[0] = '\0'; 1597 if (offset) *offset = -1; 1598 return false; 1599} 1600 1601// Loads .dll/.so and 1602// in case of error it checks if .dll/.so was built for the 1603// same architecture as Hotspot is running on 1604 1605 1606// Remember the stack's state. The Linux dynamic linker will change 1607// the stack to 'executable' at most once, so we must safepoint only once. 1608bool os::Linux::_stack_is_executable = false; 1609 1610// VM operation that loads a library. This is necessary if stack protection 1611// of the Java stacks can be lost during loading the library. If we 1612// do not stop the Java threads, they can stack overflow before the stacks 1613// are protected again. 1614class VM_LinuxDllLoad: public VM_Operation { 1615 private: 1616 const char *_filename; 1617 char *_ebuf; 1618 int _ebuflen; 1619 void *_lib; 1620 public: 1621 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1622 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1623 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1624 void doit() { 1625 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1626 os::Linux::_stack_is_executable = true; 1627 } 1628 void* loaded_library() { return _lib; } 1629}; 1630 1631void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1632 void * result = NULL; 1633 bool load_attempted = false; 1634 1635 // Check whether the library to load might change execution rights 1636 // of the stack. If they are changed, the protection of the stack 1637 // guard pages will be lost. We need a safepoint to fix this. 1638 // 1639 // See Linux man page execstack(8) for more info. 1640 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1641 ElfFile ef(filename); 1642 if (!ef.specifies_noexecstack()) { 1643 if (!is_init_completed()) { 1644 os::Linux::_stack_is_executable = true; 1645 // This is OK - No Java threads have been created yet, and hence no 1646 // stack guard pages to fix. 1647 // 1648 // This should happen only when you are building JDK7 using a very 1649 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1650 // 1651 // Dynamic loader will make all stacks executable after 1652 // this function returns, and will not do that again. 1653 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1654 } else { 1655 warning("You have loaded library %s which might have disabled stack guard. " 1656 "The VM will try to fix the stack guard now.\n" 1657 "It's highly recommended that you fix the library with " 1658 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1659 filename); 1660 1661 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1662 JavaThread *jt = JavaThread::current(); 1663 if (jt->thread_state() != _thread_in_native) { 1664 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1665 // that requires ExecStack. Cannot enter safe point. Let's give up. 1666 warning("Unable to fix stack guard. Giving up."); 1667 } else { 1668 if (!LoadExecStackDllInVMThread) { 1669 // This is for the case where the DLL has an static 1670 // constructor function that executes JNI code. We cannot 1671 // load such DLLs in the VMThread. 1672 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1673 } 1674 1675 ThreadInVMfromNative tiv(jt); 1676 debug_only(VMNativeEntryWrapper vew;) 1677 1678 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1679 VMThread::execute(&op); 1680 if (LoadExecStackDllInVMThread) { 1681 result = op.loaded_library(); 1682 } 1683 load_attempted = true; 1684 } 1685 } 1686 } 1687 } 1688 1689 if (!load_attempted) { 1690 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1691 } 1692 1693 if (result != NULL) { 1694 // Successful loading 1695 return result; 1696 } 1697 1698 Elf32_Ehdr elf_head; 1699 int diag_msg_max_length=ebuflen-strlen(ebuf); 1700 char* diag_msg_buf=ebuf+strlen(ebuf); 1701 1702 if (diag_msg_max_length==0) { 1703 // No more space in ebuf for additional diagnostics message 1704 return NULL; 1705 } 1706 1707 1708 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1709 1710 if (file_descriptor < 0) { 1711 // Can't open library, report dlerror() message 1712 return NULL; 1713 } 1714 1715 bool failed_to_read_elf_head= 1716 (sizeof(elf_head)!= 1717 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1718 1719 ::close(file_descriptor); 1720 if (failed_to_read_elf_head) { 1721 // file i/o error - report dlerror() msg 1722 return NULL; 1723 } 1724 1725 typedef struct { 1726 Elf32_Half code; // Actual value as defined in elf.h 1727 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1728 unsigned char elf_class; // 32 or 64 bit 1729 unsigned char endianess; // MSB or LSB 1730 char* name; // String representation 1731 } arch_t; 1732 1733#ifndef EM_486 1734 #define EM_486 6 /* Intel 80486 */ 1735#endif 1736#ifndef EM_AARCH64 1737 #define EM_AARCH64 183 /* ARM AARCH64 */ 1738#endif 1739 1740 static const arch_t arch_array[]={ 1741 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1742 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1743 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1744 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1745 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1746 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1747 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1748 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1749#if defined(VM_LITTLE_ENDIAN) 1750 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1751#else 1752 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"}, 1753#endif 1754 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1755 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1756 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1757 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1758 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1759 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1760 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1761 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1762 }; 1763 1764#if (defined IA32) 1765 static Elf32_Half running_arch_code=EM_386; 1766#elif (defined AMD64) 1767 static Elf32_Half running_arch_code=EM_X86_64; 1768#elif (defined IA64) 1769 static Elf32_Half running_arch_code=EM_IA_64; 1770#elif (defined __sparc) && (defined _LP64) 1771 static Elf32_Half running_arch_code=EM_SPARCV9; 1772#elif (defined __sparc) && (!defined _LP64) 1773 static Elf32_Half running_arch_code=EM_SPARC; 1774#elif (defined __powerpc64__) 1775 static Elf32_Half running_arch_code=EM_PPC64; 1776#elif (defined __powerpc__) 1777 static Elf32_Half running_arch_code=EM_PPC; 1778#elif (defined AARCH64) 1779 static Elf32_Half running_arch_code=EM_AARCH64; 1780#elif (defined ARM) 1781 static Elf32_Half running_arch_code=EM_ARM; 1782#elif (defined S390) 1783 static Elf32_Half running_arch_code=EM_S390; 1784#elif (defined ALPHA) 1785 static Elf32_Half running_arch_code=EM_ALPHA; 1786#elif (defined MIPSEL) 1787 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1788#elif (defined PARISC) 1789 static Elf32_Half running_arch_code=EM_PARISC; 1790#elif (defined MIPS) 1791 static Elf32_Half running_arch_code=EM_MIPS; 1792#elif (defined M68K) 1793 static Elf32_Half running_arch_code=EM_68K; 1794#else 1795 #error Method os::dll_load requires that one of following is defined:\ 1796 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, __sparc 1797#endif 1798 1799 // Identify compatability class for VM's architecture and library's architecture 1800 // Obtain string descriptions for architectures 1801 1802 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1803 int running_arch_index=-1; 1804 1805 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1806 if (running_arch_code == arch_array[i].code) { 1807 running_arch_index = i; 1808 } 1809 if (lib_arch.code == arch_array[i].code) { 1810 lib_arch.compat_class = arch_array[i].compat_class; 1811 lib_arch.name = arch_array[i].name; 1812 } 1813 } 1814 1815 assert(running_arch_index != -1, 1816 "Didn't find running architecture code (running_arch_code) in arch_array"); 1817 if (running_arch_index == -1) { 1818 // Even though running architecture detection failed 1819 // we may still continue with reporting dlerror() message 1820 return NULL; 1821 } 1822 1823 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1824 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1825 return NULL; 1826 } 1827 1828#ifndef S390 1829 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1830 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1831 return NULL; 1832 } 1833#endif // !S390 1834 1835 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1836 if (lib_arch.name!=NULL) { 1837 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1838 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1839 lib_arch.name, arch_array[running_arch_index].name); 1840 } else { 1841 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1842 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1843 lib_arch.code, 1844 arch_array[running_arch_index].name); 1845 } 1846 } 1847 1848 return NULL; 1849} 1850 1851void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1852 int ebuflen) { 1853 void * result = ::dlopen(filename, RTLD_LAZY); 1854 if (result == NULL) { 1855 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1856 ebuf[ebuflen-1] = '\0'; 1857 } 1858 return result; 1859} 1860 1861void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1862 int ebuflen) { 1863 void * result = NULL; 1864 if (LoadExecStackDllInVMThread) { 1865 result = dlopen_helper(filename, ebuf, ebuflen); 1866 } 1867 1868 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1869 // library that requires an executable stack, or which does not have this 1870 // stack attribute set, dlopen changes the stack attribute to executable. The 1871 // read protection of the guard pages gets lost. 1872 // 1873 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1874 // may have been queued at the same time. 1875 1876 if (!_stack_is_executable) { 1877 JavaThread *jt = Threads::first(); 1878 1879 while (jt) { 1880 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1881 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1882 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1883 warning("Attempt to reguard stack yellow zone failed."); 1884 } 1885 } 1886 jt = jt->next(); 1887 } 1888 } 1889 1890 return result; 1891} 1892 1893void* os::dll_lookup(void* handle, const char* name) { 1894 void* res = dlsym(handle, name); 1895 return res; 1896} 1897 1898void* os::get_default_process_handle() { 1899 return (void*)::dlopen(NULL, RTLD_LAZY); 1900} 1901 1902static bool _print_ascii_file(const char* filename, outputStream* st) { 1903 int fd = ::open(filename, O_RDONLY); 1904 if (fd == -1) { 1905 return false; 1906 } 1907 1908 char buf[33]; 1909 int bytes; 1910 buf[32] = '\0'; 1911 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1912 st->print_raw(buf, bytes); 1913 } 1914 1915 ::close(fd); 1916 1917 return true; 1918} 1919 1920void os::print_dll_info(outputStream *st) { 1921 st->print_cr("Dynamic libraries:"); 1922 1923 char fname[32]; 1924 pid_t pid = os::Linux::gettid(); 1925 1926 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1927 1928 if (!_print_ascii_file(fname, st)) { 1929 st->print("Can not get library information for pid = %d\n", pid); 1930 } 1931} 1932 1933int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1934 FILE *procmapsFile = NULL; 1935 1936 // Open the procfs maps file for the current process 1937 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1938 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1939 char line[PATH_MAX + 100]; 1940 1941 // Read line by line from 'file' 1942 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1943 u8 base, top, offset, inode; 1944 char permissions[5]; 1945 char device[6]; 1946 char name[PATH_MAX + 1]; 1947 1948 // Parse fields from line 1949 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1950 &base, &top, permissions, &offset, device, &inode, name); 1951 1952 // Filter by device id '00:00' so that we only get file system mapped files. 1953 if (strcmp(device, "00:00") != 0) { 1954 1955 // Call callback with the fields of interest 1956 if(callback(name, (address)base, (address)top, param)) { 1957 // Oops abort, callback aborted 1958 fclose(procmapsFile); 1959 return 1; 1960 } 1961 } 1962 } 1963 fclose(procmapsFile); 1964 } 1965 return 0; 1966} 1967 1968void os::print_os_info_brief(outputStream* st) { 1969 os::Linux::print_distro_info(st); 1970 1971 os::Posix::print_uname_info(st); 1972 1973 os::Linux::print_libversion_info(st); 1974 1975} 1976 1977void os::print_os_info(outputStream* st) { 1978 st->print("OS:"); 1979 1980 os::Linux::print_distro_info(st); 1981 1982 os::Posix::print_uname_info(st); 1983 1984 // Print warning if unsafe chroot environment detected 1985 if (unsafe_chroot_detected) { 1986 st->print("WARNING!! "); 1987 st->print_cr("%s", unstable_chroot_error); 1988 } 1989 1990 os::Linux::print_libversion_info(st); 1991 1992 os::Posix::print_rlimit_info(st); 1993 1994 os::Posix::print_load_average(st); 1995 1996 os::Linux::print_full_memory_info(st); 1997} 1998 1999// Try to identify popular distros. 2000// Most Linux distributions have a /etc/XXX-release file, which contains 2001// the OS version string. Newer Linux distributions have a /etc/lsb-release 2002// file that also contains the OS version string. Some have more than one 2003// /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2004// /etc/redhat-release.), so the order is important. 2005// Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2006// their own specific XXX-release file as well as a redhat-release file. 2007// Because of this the XXX-release file needs to be searched for before the 2008// redhat-release file. 2009// Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 2010// search for redhat-release / SuSE-release needs to be before lsb-release. 2011// Since the lsb-release file is the new standard it needs to be searched 2012// before the older style release files. 2013// Searching system-release (Red Hat) and os-release (other Linuxes) are a 2014// next to last resort. The os-release file is a new standard that contains 2015// distribution information and the system-release file seems to be an old 2016// standard that has been replaced by the lsb-release and os-release files. 2017// Searching for the debian_version file is the last resort. It contains 2018// an informative string like "6.0.6" or "wheezy/sid". Because of this 2019// "Debian " is printed before the contents of the debian_version file. 2020 2021const char* distro_files[] = { 2022 "/etc/oracle-release", 2023 "/etc/mandriva-release", 2024 "/etc/mandrake-release", 2025 "/etc/sun-release", 2026 "/etc/redhat-release", 2027 "/etc/SuSE-release", 2028 "/etc/lsb-release", 2029 "/etc/turbolinux-release", 2030 "/etc/gentoo-release", 2031 "/etc/ltib-release", 2032 "/etc/angstrom-version", 2033 "/etc/system-release", 2034 "/etc/os-release", 2035 NULL }; 2036 2037void os::Linux::print_distro_info(outputStream* st) { 2038 for (int i = 0;; i++) { 2039 const char* file = distro_files[i]; 2040 if (file == NULL) { 2041 break; // done 2042 } 2043 // If file prints, we found it. 2044 if (_print_ascii_file(file, st)) { 2045 return; 2046 } 2047 } 2048 2049 if (file_exists("/etc/debian_version")) { 2050 st->print("Debian "); 2051 _print_ascii_file("/etc/debian_version", st); 2052 } else { 2053 st->print("Linux"); 2054 } 2055 st->cr(); 2056} 2057 2058static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2059 char buf[256]; 2060 while (fgets(buf, sizeof(buf), fp)) { 2061 // Edit out extra stuff in expected format 2062 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2063 char* ptr = strstr(buf, "\""); // the name is in quotes 2064 if (ptr != NULL) { 2065 ptr++; // go beyond first quote 2066 char* nl = strchr(ptr, '\"'); 2067 if (nl != NULL) *nl = '\0'; 2068 strncpy(distro, ptr, length); 2069 } else { 2070 ptr = strstr(buf, "="); 2071 ptr++; // go beyond equals then 2072 char* nl = strchr(ptr, '\n'); 2073 if (nl != NULL) *nl = '\0'; 2074 strncpy(distro, ptr, length); 2075 } 2076 return; 2077 } else if (get_first_line) { 2078 char* nl = strchr(buf, '\n'); 2079 if (nl != NULL) *nl = '\0'; 2080 strncpy(distro, buf, length); 2081 return; 2082 } 2083 } 2084 // print last line and close 2085 char* nl = strchr(buf, '\n'); 2086 if (nl != NULL) *nl = '\0'; 2087 strncpy(distro, buf, length); 2088} 2089 2090static void parse_os_info(char* distro, size_t length, const char* file) { 2091 FILE* fp = fopen(file, "r"); 2092 if (fp != NULL) { 2093 // if suse format, print out first line 2094 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2095 parse_os_info_helper(fp, distro, length, get_first_line); 2096 fclose(fp); 2097 } 2098} 2099 2100void os::get_summary_os_info(char* buf, size_t buflen) { 2101 for (int i = 0;; i++) { 2102 const char* file = distro_files[i]; 2103 if (file == NULL) { 2104 break; // ran out of distro_files 2105 } 2106 if (file_exists(file)) { 2107 parse_os_info(buf, buflen, file); 2108 return; 2109 } 2110 } 2111 // special case for debian 2112 if (file_exists("/etc/debian_version")) { 2113 strncpy(buf, "Debian ", buflen); 2114 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2115 } else { 2116 strncpy(buf, "Linux", buflen); 2117 } 2118} 2119 2120void os::Linux::print_libversion_info(outputStream* st) { 2121 // libc, pthread 2122 st->print("libc:"); 2123 st->print("%s ", os::Linux::glibc_version()); 2124 st->print("%s ", os::Linux::libpthread_version()); 2125 st->cr(); 2126} 2127 2128void os::Linux::print_full_memory_info(outputStream* st) { 2129 st->print("\n/proc/meminfo:\n"); 2130 _print_ascii_file("/proc/meminfo", st); 2131 st->cr(); 2132} 2133 2134void os::print_memory_info(outputStream* st) { 2135 2136 st->print("Memory:"); 2137 st->print(" %dk page", os::vm_page_size()>>10); 2138 2139 // values in struct sysinfo are "unsigned long" 2140 struct sysinfo si; 2141 sysinfo(&si); 2142 2143 st->print(", physical " UINT64_FORMAT "k", 2144 os::physical_memory() >> 10); 2145 st->print("(" UINT64_FORMAT "k free)", 2146 os::available_memory() >> 10); 2147 st->print(", swap " UINT64_FORMAT "k", 2148 ((jlong)si.totalswap * si.mem_unit) >> 10); 2149 st->print("(" UINT64_FORMAT "k free)", 2150 ((jlong)si.freeswap * si.mem_unit) >> 10); 2151 st->cr(); 2152} 2153 2154// Print the first "model name" line and the first "flags" line 2155// that we find and nothing more. We assume "model name" comes 2156// before "flags" so if we find a second "model name", then the 2157// "flags" field is considered missing. 2158static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2159#if defined(IA32) || defined(AMD64) 2160 // Other platforms have less repetitive cpuinfo files 2161 FILE *fp = fopen("/proc/cpuinfo", "r"); 2162 if (fp) { 2163 while (!feof(fp)) { 2164 if (fgets(buf, buflen, fp)) { 2165 // Assume model name comes before flags 2166 bool model_name_printed = false; 2167 if (strstr(buf, "model name") != NULL) { 2168 if (!model_name_printed) { 2169 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2170 st->print_raw(buf); 2171 model_name_printed = true; 2172 } else { 2173 // model name printed but not flags? Odd, just return 2174 fclose(fp); 2175 return true; 2176 } 2177 } 2178 // print the flags line too 2179 if (strstr(buf, "flags") != NULL) { 2180 st->print_raw(buf); 2181 fclose(fp); 2182 return true; 2183 } 2184 } 2185 } 2186 fclose(fp); 2187 } 2188#endif // x86 platforms 2189 return false; 2190} 2191 2192void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2193 // Only print the model name if the platform provides this as a summary 2194 if (!print_model_name_and_flags(st, buf, buflen)) { 2195 st->print("\n/proc/cpuinfo:\n"); 2196 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2197 st->print_cr(" <Not Available>"); 2198 } 2199 } 2200} 2201 2202#if defined(AMD64) || defined(IA32) || defined(X32) 2203const char* search_string = "model name"; 2204#elif defined(PPC64) 2205const char* search_string = "cpu"; 2206#elif defined(S390) 2207const char* search_string = "processor"; 2208#elif defined(SPARC) 2209const char* search_string = "cpu"; 2210#else 2211const char* search_string = "Processor"; 2212#endif 2213 2214// Parses the cpuinfo file for string representing the model name. 2215void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2216 FILE* fp = fopen("/proc/cpuinfo", "r"); 2217 if (fp != NULL) { 2218 while (!feof(fp)) { 2219 char buf[256]; 2220 if (fgets(buf, sizeof(buf), fp)) { 2221 char* start = strstr(buf, search_string); 2222 if (start != NULL) { 2223 char *ptr = start + strlen(search_string); 2224 char *end = buf + strlen(buf); 2225 while (ptr != end) { 2226 // skip whitespace and colon for the rest of the name. 2227 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2228 break; 2229 } 2230 ptr++; 2231 } 2232 if (ptr != end) { 2233 // reasonable string, get rid of newline and keep the rest 2234 char* nl = strchr(buf, '\n'); 2235 if (nl != NULL) *nl = '\0'; 2236 strncpy(cpuinfo, ptr, length); 2237 fclose(fp); 2238 return; 2239 } 2240 } 2241 } 2242 } 2243 fclose(fp); 2244 } 2245 // cpuinfo not found or parsing failed, just print generic string. The entire 2246 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2247#if defined(AARCH64) 2248 strncpy(cpuinfo, "AArch64", length); 2249#elif defined(AMD64) 2250 strncpy(cpuinfo, "x86_64", length); 2251#elif defined(ARM) // Order wrt. AARCH64 is relevant! 2252 strncpy(cpuinfo, "ARM", length); 2253#elif defined(IA32) 2254 strncpy(cpuinfo, "x86_32", length); 2255#elif defined(IA64) 2256 strncpy(cpuinfo, "IA64", length); 2257#elif defined(PPC) 2258 strncpy(cpuinfo, "PPC64", length); 2259#elif defined(S390) 2260 strncpy(cpuinfo, "S390", length); 2261#elif defined(SPARC) 2262 strncpy(cpuinfo, "sparcv9", length); 2263#elif defined(ZERO_LIBARCH) 2264 strncpy(cpuinfo, ZERO_LIBARCH, length); 2265#else 2266 strncpy(cpuinfo, "unknown", length); 2267#endif 2268} 2269 2270static void print_signal_handler(outputStream* st, int sig, 2271 char* buf, size_t buflen); 2272 2273void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2274 st->print_cr("Signal Handlers:"); 2275 print_signal_handler(st, SIGSEGV, buf, buflen); 2276 print_signal_handler(st, SIGBUS , buf, buflen); 2277 print_signal_handler(st, SIGFPE , buf, buflen); 2278 print_signal_handler(st, SIGPIPE, buf, buflen); 2279 print_signal_handler(st, SIGXFSZ, buf, buflen); 2280 print_signal_handler(st, SIGILL , buf, buflen); 2281 print_signal_handler(st, SR_signum, buf, buflen); 2282 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2283 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2284 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2285 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2286#if defined(PPC64) 2287 print_signal_handler(st, SIGTRAP, buf, buflen); 2288#endif 2289} 2290 2291static char saved_jvm_path[MAXPATHLEN] = {0}; 2292 2293// Find the full path to the current module, libjvm.so 2294void os::jvm_path(char *buf, jint buflen) { 2295 // Error checking. 2296 if (buflen < MAXPATHLEN) { 2297 assert(false, "must use a large-enough buffer"); 2298 buf[0] = '\0'; 2299 return; 2300 } 2301 // Lazy resolve the path to current module. 2302 if (saved_jvm_path[0] != 0) { 2303 strcpy(buf, saved_jvm_path); 2304 return; 2305 } 2306 2307 char dli_fname[MAXPATHLEN]; 2308 bool ret = dll_address_to_library_name( 2309 CAST_FROM_FN_PTR(address, os::jvm_path), 2310 dli_fname, sizeof(dli_fname), NULL); 2311 assert(ret, "cannot locate libjvm"); 2312 char *rp = NULL; 2313 if (ret && dli_fname[0] != '\0') { 2314 rp = os::Posix::realpath(dli_fname, buf, buflen); 2315 } 2316 if (rp == NULL) { 2317 return; 2318 } 2319 2320 if (Arguments::sun_java_launcher_is_altjvm()) { 2321 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2322 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2323 // If "/jre/lib/" appears at the right place in the string, then 2324 // assume we are installed in a JDK and we're done. Otherwise, check 2325 // for a JAVA_HOME environment variable and fix up the path so it 2326 // looks like libjvm.so is installed there (append a fake suffix 2327 // hotspot/libjvm.so). 2328 const char *p = buf + strlen(buf) - 1; 2329 for (int count = 0; p > buf && count < 5; ++count) { 2330 for (--p; p > buf && *p != '/'; --p) 2331 /* empty */ ; 2332 } 2333 2334 if (strncmp(p, "/jre/lib/", 9) != 0) { 2335 // Look for JAVA_HOME in the environment. 2336 char* java_home_var = ::getenv("JAVA_HOME"); 2337 if (java_home_var != NULL && java_home_var[0] != 0) { 2338 char* jrelib_p; 2339 int len; 2340 2341 // Check the current module name "libjvm.so". 2342 p = strrchr(buf, '/'); 2343 if (p == NULL) { 2344 return; 2345 } 2346 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2347 2348 rp = os::Posix::realpath(java_home_var, buf, buflen); 2349 if (rp == NULL) { 2350 return; 2351 } 2352 2353 // determine if this is a legacy image or modules image 2354 // modules image doesn't have "jre" subdirectory 2355 len = strlen(buf); 2356 assert(len < buflen, "Ran out of buffer room"); 2357 jrelib_p = buf + len; 2358 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2359 if (0 != access(buf, F_OK)) { 2360 snprintf(jrelib_p, buflen-len, "/lib"); 2361 } 2362 2363 if (0 == access(buf, F_OK)) { 2364 // Use current module name "libjvm.so" 2365 len = strlen(buf); 2366 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2367 } else { 2368 // Go back to path of .so 2369 rp = os::Posix::realpath(dli_fname, buf, buflen); 2370 if (rp == NULL) { 2371 return; 2372 } 2373 } 2374 } 2375 } 2376 } 2377 2378 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2379 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2380} 2381 2382void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2383 // no prefix required, not even "_" 2384} 2385 2386void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2387 // no suffix required 2388} 2389 2390//////////////////////////////////////////////////////////////////////////////// 2391// sun.misc.Signal support 2392 2393static volatile jint sigint_count = 0; 2394 2395static void UserHandler(int sig, void *siginfo, void *context) { 2396 // 4511530 - sem_post is serialized and handled by the manager thread. When 2397 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2398 // don't want to flood the manager thread with sem_post requests. 2399 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2400 return; 2401 } 2402 2403 // Ctrl-C is pressed during error reporting, likely because the error 2404 // handler fails to abort. Let VM die immediately. 2405 if (sig == SIGINT && is_error_reported()) { 2406 os::die(); 2407 } 2408 2409 os::signal_notify(sig); 2410} 2411 2412void* os::user_handler() { 2413 return CAST_FROM_FN_PTR(void*, UserHandler); 2414} 2415 2416struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2417 struct timespec ts; 2418 // Semaphore's are always associated with CLOCK_REALTIME 2419 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2420 // see unpackTime for discussion on overflow checking 2421 if (sec >= MAX_SECS) { 2422 ts.tv_sec += MAX_SECS; 2423 ts.tv_nsec = 0; 2424 } else { 2425 ts.tv_sec += sec; 2426 ts.tv_nsec += nsec; 2427 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2428 ts.tv_nsec -= NANOSECS_PER_SEC; 2429 ++ts.tv_sec; // note: this must be <= max_secs 2430 } 2431 } 2432 2433 return ts; 2434} 2435 2436extern "C" { 2437 typedef void (*sa_handler_t)(int); 2438 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2439} 2440 2441void* os::signal(int signal_number, void* handler) { 2442 struct sigaction sigAct, oldSigAct; 2443 2444 sigfillset(&(sigAct.sa_mask)); 2445 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2446 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2447 2448 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2449 // -1 means registration failed 2450 return (void *)-1; 2451 } 2452 2453 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2454} 2455 2456void os::signal_raise(int signal_number) { 2457 ::raise(signal_number); 2458} 2459 2460// The following code is moved from os.cpp for making this 2461// code platform specific, which it is by its very nature. 2462 2463// Will be modified when max signal is changed to be dynamic 2464int os::sigexitnum_pd() { 2465 return NSIG; 2466} 2467 2468// a counter for each possible signal value 2469static volatile jint pending_signals[NSIG+1] = { 0 }; 2470 2471// Linux(POSIX) specific hand shaking semaphore. 2472static sem_t sig_sem; 2473static PosixSemaphore sr_semaphore; 2474 2475void os::signal_init_pd() { 2476 // Initialize signal structures 2477 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2478 2479 // Initialize signal semaphore 2480 ::sem_init(&sig_sem, 0, 0); 2481} 2482 2483void os::signal_notify(int sig) { 2484 Atomic::inc(&pending_signals[sig]); 2485 ::sem_post(&sig_sem); 2486} 2487 2488static int check_pending_signals(bool wait) { 2489 Atomic::store(0, &sigint_count); 2490 for (;;) { 2491 for (int i = 0; i < NSIG + 1; i++) { 2492 jint n = pending_signals[i]; 2493 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2494 return i; 2495 } 2496 } 2497 if (!wait) { 2498 return -1; 2499 } 2500 JavaThread *thread = JavaThread::current(); 2501 ThreadBlockInVM tbivm(thread); 2502 2503 bool threadIsSuspended; 2504 do { 2505 thread->set_suspend_equivalent(); 2506 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2507 ::sem_wait(&sig_sem); 2508 2509 // were we externally suspended while we were waiting? 2510 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2511 if (threadIsSuspended) { 2512 // The semaphore has been incremented, but while we were waiting 2513 // another thread suspended us. We don't want to continue running 2514 // while suspended because that would surprise the thread that 2515 // suspended us. 2516 ::sem_post(&sig_sem); 2517 2518 thread->java_suspend_self(); 2519 } 2520 } while (threadIsSuspended); 2521 } 2522} 2523 2524int os::signal_lookup() { 2525 return check_pending_signals(false); 2526} 2527 2528int os::signal_wait() { 2529 return check_pending_signals(true); 2530} 2531 2532//////////////////////////////////////////////////////////////////////////////// 2533// Virtual Memory 2534 2535int os::vm_page_size() { 2536 // Seems redundant as all get out 2537 assert(os::Linux::page_size() != -1, "must call os::init"); 2538 return os::Linux::page_size(); 2539} 2540 2541// Solaris allocates memory by pages. 2542int os::vm_allocation_granularity() { 2543 assert(os::Linux::page_size() != -1, "must call os::init"); 2544 return os::Linux::page_size(); 2545} 2546 2547// Rationale behind this function: 2548// current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2549// mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2550// samples for JITted code. Here we create private executable mapping over the code cache 2551// and then we can use standard (well, almost, as mapping can change) way to provide 2552// info for the reporting script by storing timestamp and location of symbol 2553void linux_wrap_code(char* base, size_t size) { 2554 static volatile jint cnt = 0; 2555 2556 if (!UseOprofile) { 2557 return; 2558 } 2559 2560 char buf[PATH_MAX+1]; 2561 int num = Atomic::add(1, &cnt); 2562 2563 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2564 os::get_temp_directory(), os::current_process_id(), num); 2565 unlink(buf); 2566 2567 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2568 2569 if (fd != -1) { 2570 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2571 if (rv != (off_t)-1) { 2572 if (::write(fd, "", 1) == 1) { 2573 mmap(base, size, 2574 PROT_READ|PROT_WRITE|PROT_EXEC, 2575 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2576 } 2577 } 2578 ::close(fd); 2579 unlink(buf); 2580 } 2581} 2582 2583static bool recoverable_mmap_error(int err) { 2584 // See if the error is one we can let the caller handle. This 2585 // list of errno values comes from JBS-6843484. I can't find a 2586 // Linux man page that documents this specific set of errno 2587 // values so while this list currently matches Solaris, it may 2588 // change as we gain experience with this failure mode. 2589 switch (err) { 2590 case EBADF: 2591 case EINVAL: 2592 case ENOTSUP: 2593 // let the caller deal with these errors 2594 return true; 2595 2596 default: 2597 // Any remaining errors on this OS can cause our reserved mapping 2598 // to be lost. That can cause confusion where different data 2599 // structures think they have the same memory mapped. The worst 2600 // scenario is if both the VM and a library think they have the 2601 // same memory mapped. 2602 return false; 2603 } 2604} 2605 2606static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2607 int err) { 2608 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2609 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2610 os::strerror(err), err); 2611} 2612 2613static void warn_fail_commit_memory(char* addr, size_t size, 2614 size_t alignment_hint, bool exec, 2615 int err) { 2616 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2617 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2618 alignment_hint, exec, os::strerror(err), err); 2619} 2620 2621// NOTE: Linux kernel does not really reserve the pages for us. 2622// All it does is to check if there are enough free pages 2623// left at the time of mmap(). This could be a potential 2624// problem. 2625int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2626 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2627 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2628 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2629 if (res != (uintptr_t) MAP_FAILED) { 2630 if (UseNUMAInterleaving) { 2631 numa_make_global(addr, size); 2632 } 2633 return 0; 2634 } 2635 2636 int err = errno; // save errno from mmap() call above 2637 2638 if (!recoverable_mmap_error(err)) { 2639 warn_fail_commit_memory(addr, size, exec, err); 2640 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2641 } 2642 2643 return err; 2644} 2645 2646bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2647 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2648} 2649 2650void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2651 const char* mesg) { 2652 assert(mesg != NULL, "mesg must be specified"); 2653 int err = os::Linux::commit_memory_impl(addr, size, exec); 2654 if (err != 0) { 2655 // the caller wants all commit errors to exit with the specified mesg: 2656 warn_fail_commit_memory(addr, size, exec, err); 2657 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2658 } 2659} 2660 2661// Define MAP_HUGETLB here so we can build HotSpot on old systems. 2662#ifndef MAP_HUGETLB 2663 #define MAP_HUGETLB 0x40000 2664#endif 2665 2666// Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2667#ifndef MADV_HUGEPAGE 2668 #define MADV_HUGEPAGE 14 2669#endif 2670 2671int os::Linux::commit_memory_impl(char* addr, size_t size, 2672 size_t alignment_hint, bool exec) { 2673 int err = os::Linux::commit_memory_impl(addr, size, exec); 2674 if (err == 0) { 2675 realign_memory(addr, size, alignment_hint); 2676 } 2677 return err; 2678} 2679 2680bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2681 bool exec) { 2682 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2683} 2684 2685void os::pd_commit_memory_or_exit(char* addr, size_t size, 2686 size_t alignment_hint, bool exec, 2687 const char* mesg) { 2688 assert(mesg != NULL, "mesg must be specified"); 2689 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2690 if (err != 0) { 2691 // the caller wants all commit errors to exit with the specified mesg: 2692 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2693 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2694 } 2695} 2696 2697void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2698 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2699 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2700 // be supported or the memory may already be backed by huge pages. 2701 ::madvise(addr, bytes, MADV_HUGEPAGE); 2702 } 2703} 2704 2705void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2706 // This method works by doing an mmap over an existing mmaping and effectively discarding 2707 // the existing pages. However it won't work for SHM-based large pages that cannot be 2708 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2709 // small pages on top of the SHM segment. This method always works for small pages, so we 2710 // allow that in any case. 2711 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2712 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2713 } 2714} 2715 2716void os::numa_make_global(char *addr, size_t bytes) { 2717 Linux::numa_interleave_memory(addr, bytes); 2718} 2719 2720// Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2721// bind policy to MPOL_PREFERRED for the current thread. 2722#define USE_MPOL_PREFERRED 0 2723 2724void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2725 // To make NUMA and large pages more robust when both enabled, we need to ease 2726 // the requirements on where the memory should be allocated. MPOL_BIND is the 2727 // default policy and it will force memory to be allocated on the specified 2728 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2729 // the specified node, but will not force it. Using this policy will prevent 2730 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2731 // free large pages. 2732 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2733 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2734} 2735 2736bool os::numa_topology_changed() { return false; } 2737 2738size_t os::numa_get_groups_num() { 2739 // Return just the number of nodes in which it's possible to allocate memory 2740 // (in numa terminology, configured nodes). 2741 return Linux::numa_num_configured_nodes(); 2742} 2743 2744int os::numa_get_group_id() { 2745 int cpu_id = Linux::sched_getcpu(); 2746 if (cpu_id != -1) { 2747 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2748 if (lgrp_id != -1) { 2749 return lgrp_id; 2750 } 2751 } 2752 return 0; 2753} 2754 2755int os::Linux::get_existing_num_nodes() { 2756 size_t node; 2757 size_t highest_node_number = Linux::numa_max_node(); 2758 int num_nodes = 0; 2759 2760 // Get the total number of nodes in the system including nodes without memory. 2761 for (node = 0; node <= highest_node_number; node++) { 2762 if (isnode_in_existing_nodes(node)) { 2763 num_nodes++; 2764 } 2765 } 2766 return num_nodes; 2767} 2768 2769size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2770 size_t highest_node_number = Linux::numa_max_node(); 2771 size_t i = 0; 2772 2773 // Map all node ids in which is possible to allocate memory. Also nodes are 2774 // not always consecutively available, i.e. available from 0 to the highest 2775 // node number. 2776 for (size_t node = 0; node <= highest_node_number; node++) { 2777 if (Linux::isnode_in_configured_nodes(node)) { 2778 ids[i++] = node; 2779 } 2780 } 2781 return i; 2782} 2783 2784bool os::get_page_info(char *start, page_info* info) { 2785 return false; 2786} 2787 2788char *os::scan_pages(char *start, char* end, page_info* page_expected, 2789 page_info* page_found) { 2790 return end; 2791} 2792 2793 2794int os::Linux::sched_getcpu_syscall(void) { 2795 unsigned int cpu = 0; 2796 int retval = -1; 2797 2798#if defined(IA32) 2799 #ifndef SYS_getcpu 2800 #define SYS_getcpu 318 2801 #endif 2802 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2803#elif defined(AMD64) 2804// Unfortunately we have to bring all these macros here from vsyscall.h 2805// to be able to compile on old linuxes. 2806 #define __NR_vgetcpu 2 2807 #define VSYSCALL_START (-10UL << 20) 2808 #define VSYSCALL_SIZE 1024 2809 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2810 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2811 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2812 retval = vgetcpu(&cpu, NULL, NULL); 2813#endif 2814 2815 return (retval == -1) ? retval : cpu; 2816} 2817 2818// Something to do with the numa-aware allocator needs these symbols 2819extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2820extern "C" JNIEXPORT void numa_error(char *where) { } 2821 2822// Handle request to load libnuma symbol version 1.1 (API v1). If it fails 2823// load symbol from base version instead. 2824void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2825 void *f = dlvsym(handle, name, "libnuma_1.1"); 2826 if (f == NULL) { 2827 f = dlsym(handle, name); 2828 } 2829 return f; 2830} 2831 2832// Handle request to load libnuma symbol version 1.2 (API v2) only. 2833// Return NULL if the symbol is not defined in this particular version. 2834void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) { 2835 return dlvsym(handle, name, "libnuma_1.2"); 2836} 2837 2838bool os::Linux::libnuma_init() { 2839 // sched_getcpu() should be in libc. 2840 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2841 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2842 2843 // If it's not, try a direct syscall. 2844 if (sched_getcpu() == -1) { 2845 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2846 (void*)&sched_getcpu_syscall)); 2847 } 2848 2849 if (sched_getcpu() != -1) { // Does it work? 2850 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2851 if (handle != NULL) { 2852 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2853 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2854 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2855 libnuma_dlsym(handle, "numa_max_node"))); 2856 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t, 2857 libnuma_dlsym(handle, "numa_num_configured_nodes"))); 2858 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2859 libnuma_dlsym(handle, "numa_available"))); 2860 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2861 libnuma_dlsym(handle, "numa_tonode_memory"))); 2862 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2863 libnuma_dlsym(handle, "numa_interleave_memory"))); 2864 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t, 2865 libnuma_v2_dlsym(handle, "numa_interleave_memory"))); 2866 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2867 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2868 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t, 2869 libnuma_dlsym(handle, "numa_bitmask_isbitset"))); 2870 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t, 2871 libnuma_dlsym(handle, "numa_distance"))); 2872 2873 if (numa_available() != -1) { 2874 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2875 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr")); 2876 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr")); 2877 // Create an index -> node mapping, since nodes are not always consecutive 2878 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2879 rebuild_nindex_to_node_map(); 2880 // Create a cpu -> node mapping 2881 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2882 rebuild_cpu_to_node_map(); 2883 return true; 2884 } 2885 } 2886 } 2887 return false; 2888} 2889 2890size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 2891 // Creating guard page is very expensive. Java thread has HotSpot 2892 // guard pages, only enable glibc guard page for non-Java threads. 2893 // (Remember: compiler thread is a Java thread, too!) 2894 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 2895} 2896 2897void os::Linux::rebuild_nindex_to_node_map() { 2898 int highest_node_number = Linux::numa_max_node(); 2899 2900 nindex_to_node()->clear(); 2901 for (int node = 0; node <= highest_node_number; node++) { 2902 if (Linux::isnode_in_existing_nodes(node)) { 2903 nindex_to_node()->append(node); 2904 } 2905 } 2906} 2907 2908// rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2909// The table is later used in get_node_by_cpu(). 2910void os::Linux::rebuild_cpu_to_node_map() { 2911 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2912 // in libnuma (possible values are starting from 16, 2913 // and continuing up with every other power of 2, but less 2914 // than the maximum number of CPUs supported by kernel), and 2915 // is a subject to change (in libnuma version 2 the requirements 2916 // are more reasonable) we'll just hardcode the number they use 2917 // in the library. 2918 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2919 2920 size_t cpu_num = processor_count(); 2921 size_t cpu_map_size = NCPUS / BitsPerCLong; 2922 size_t cpu_map_valid_size = 2923 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2924 2925 cpu_to_node()->clear(); 2926 cpu_to_node()->at_grow(cpu_num - 1); 2927 2928 size_t node_num = get_existing_num_nodes(); 2929 2930 int distance = 0; 2931 int closest_distance = INT_MAX; 2932 int closest_node = 0; 2933 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2934 for (size_t i = 0; i < node_num; i++) { 2935 // Check if node is configured (not a memory-less node). If it is not, find 2936 // the closest configured node. 2937 if (!isnode_in_configured_nodes(nindex_to_node()->at(i))) { 2938 closest_distance = INT_MAX; 2939 // Check distance from all remaining nodes in the system. Ignore distance 2940 // from itself and from another non-configured node. 2941 for (size_t m = 0; m < node_num; m++) { 2942 if (m != i && isnode_in_configured_nodes(nindex_to_node()->at(m))) { 2943 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m)); 2944 // If a closest node is found, update. There is always at least one 2945 // configured node in the system so there is always at least one node 2946 // close. 2947 if (distance != 0 && distance < closest_distance) { 2948 closest_distance = distance; 2949 closest_node = nindex_to_node()->at(m); 2950 } 2951 } 2952 } 2953 } else { 2954 // Current node is already a configured node. 2955 closest_node = nindex_to_node()->at(i); 2956 } 2957 2958 // Get cpus from the original node and map them to the closest node. If node 2959 // is a configured node (not a memory-less node), then original node and 2960 // closest node are the same. 2961 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2962 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2963 if (cpu_map[j] != 0) { 2964 for (size_t k = 0; k < BitsPerCLong; k++) { 2965 if (cpu_map[j] & (1UL << k)) { 2966 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node); 2967 } 2968 } 2969 } 2970 } 2971 } 2972 } 2973 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2974} 2975 2976int os::Linux::get_node_by_cpu(int cpu_id) { 2977 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2978 return cpu_to_node()->at(cpu_id); 2979 } 2980 return -1; 2981} 2982 2983GrowableArray<int>* os::Linux::_cpu_to_node; 2984GrowableArray<int>* os::Linux::_nindex_to_node; 2985os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2986os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2987os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2988os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes; 2989os::Linux::numa_available_func_t os::Linux::_numa_available; 2990os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2991os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2992os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2; 2993os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2994os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset; 2995os::Linux::numa_distance_func_t os::Linux::_numa_distance; 2996unsigned long* os::Linux::_numa_all_nodes; 2997struct bitmask* os::Linux::_numa_all_nodes_ptr; 2998struct bitmask* os::Linux::_numa_nodes_ptr; 2999 3000bool os::pd_uncommit_memory(char* addr, size_t size) { 3001 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 3002 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 3003 return res != (uintptr_t) MAP_FAILED; 3004} 3005 3006static address get_stack_commited_bottom(address bottom, size_t size) { 3007 address nbot = bottom; 3008 address ntop = bottom + size; 3009 3010 size_t page_sz = os::vm_page_size(); 3011 unsigned pages = size / page_sz; 3012 3013 unsigned char vec[1]; 3014 unsigned imin = 1, imax = pages + 1, imid; 3015 int mincore_return_value = 0; 3016 3017 assert(imin <= imax, "Unexpected page size"); 3018 3019 while (imin < imax) { 3020 imid = (imax + imin) / 2; 3021 nbot = ntop - (imid * page_sz); 3022 3023 // Use a trick with mincore to check whether the page is mapped or not. 3024 // mincore sets vec to 1 if page resides in memory and to 0 if page 3025 // is swapped output but if page we are asking for is unmapped 3026 // it returns -1,ENOMEM 3027 mincore_return_value = mincore(nbot, page_sz, vec); 3028 3029 if (mincore_return_value == -1) { 3030 // Page is not mapped go up 3031 // to find first mapped page 3032 if (errno != EAGAIN) { 3033 assert(errno == ENOMEM, "Unexpected mincore errno"); 3034 imax = imid; 3035 } 3036 } else { 3037 // Page is mapped go down 3038 // to find first not mapped page 3039 imin = imid + 1; 3040 } 3041 } 3042 3043 nbot = nbot + page_sz; 3044 3045 // Adjust stack bottom one page up if last checked page is not mapped 3046 if (mincore_return_value == -1) { 3047 nbot = nbot + page_sz; 3048 } 3049 3050 return nbot; 3051} 3052 3053 3054// Linux uses a growable mapping for the stack, and if the mapping for 3055// the stack guard pages is not removed when we detach a thread the 3056// stack cannot grow beyond the pages where the stack guard was 3057// mapped. If at some point later in the process the stack expands to 3058// that point, the Linux kernel cannot expand the stack any further 3059// because the guard pages are in the way, and a segfault occurs. 3060// 3061// However, it's essential not to split the stack region by unmapping 3062// a region (leaving a hole) that's already part of the stack mapping, 3063// so if the stack mapping has already grown beyond the guard pages at 3064// the time we create them, we have to truncate the stack mapping. 3065// So, we need to know the extent of the stack mapping when 3066// create_stack_guard_pages() is called. 3067 3068// We only need this for stacks that are growable: at the time of 3069// writing thread stacks don't use growable mappings (i.e. those 3070// creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3071// only applies to the main thread. 3072 3073// If the (growable) stack mapping already extends beyond the point 3074// where we're going to put our guard pages, truncate the mapping at 3075// that point by munmap()ping it. This ensures that when we later 3076// munmap() the guard pages we don't leave a hole in the stack 3077// mapping. This only affects the main/initial thread 3078 3079bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3080 if (os::Linux::is_initial_thread()) { 3081 // As we manually grow stack up to bottom inside create_attached_thread(), 3082 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3083 // we don't need to do anything special. 3084 // Check it first, before calling heavy function. 3085 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3086 unsigned char vec[1]; 3087 3088 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3089 // Fallback to slow path on all errors, including EAGAIN 3090 stack_extent = (uintptr_t) get_stack_commited_bottom( 3091 os::Linux::initial_thread_stack_bottom(), 3092 (size_t)addr - stack_extent); 3093 } 3094 3095 if (stack_extent < (uintptr_t)addr) { 3096 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3097 } 3098 } 3099 3100 return os::commit_memory(addr, size, !ExecMem); 3101} 3102 3103// If this is a growable mapping, remove the guard pages entirely by 3104// munmap()ping them. If not, just call uncommit_memory(). This only 3105// affects the main/initial thread, but guard against future OS changes 3106// It's safe to always unmap guard pages for initial thread because we 3107// always place it right after end of the mapped region 3108 3109bool os::remove_stack_guard_pages(char* addr, size_t size) { 3110 uintptr_t stack_extent, stack_base; 3111 3112 if (os::Linux::is_initial_thread()) { 3113 return ::munmap(addr, size) == 0; 3114 } 3115 3116 return os::uncommit_memory(addr, size); 3117} 3118 3119// If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3120// at 'requested_addr'. If there are existing memory mappings at the same 3121// location, however, they will be overwritten. If 'fixed' is false, 3122// 'requested_addr' is only treated as a hint, the return value may or 3123// may not start from the requested address. Unlike Linux mmap(), this 3124// function returns NULL to indicate failure. 3125static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3126 char * addr; 3127 int flags; 3128 3129 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3130 if (fixed) { 3131 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3132 flags |= MAP_FIXED; 3133 } 3134 3135 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3136 // touch an uncommitted page. Otherwise, the read/write might 3137 // succeed if we have enough swap space to back the physical page. 3138 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3139 flags, -1, 0); 3140 3141 return addr == MAP_FAILED ? NULL : addr; 3142} 3143 3144// Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3145// (req_addr != NULL) or with a given alignment. 3146// - bytes shall be a multiple of alignment. 3147// - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3148// - alignment sets the alignment at which memory shall be allocated. 3149// It must be a multiple of allocation granularity. 3150// Returns address of memory or NULL. If req_addr was not NULL, will only return 3151// req_addr or NULL. 3152static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3153 3154 size_t extra_size = bytes; 3155 if (req_addr == NULL && alignment > 0) { 3156 extra_size += alignment; 3157 } 3158 3159 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3160 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3161 -1, 0); 3162 if (start == MAP_FAILED) { 3163 start = NULL; 3164 } else { 3165 if (req_addr != NULL) { 3166 if (start != req_addr) { 3167 ::munmap(start, extra_size); 3168 start = NULL; 3169 } 3170 } else { 3171 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3172 char* const end_aligned = start_aligned + bytes; 3173 char* const end = start + extra_size; 3174 if (start_aligned > start) { 3175 ::munmap(start, start_aligned - start); 3176 } 3177 if (end_aligned < end) { 3178 ::munmap(end_aligned, end - end_aligned); 3179 } 3180 start = start_aligned; 3181 } 3182 } 3183 return start; 3184} 3185 3186static int anon_munmap(char * addr, size_t size) { 3187 return ::munmap(addr, size) == 0; 3188} 3189 3190char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3191 size_t alignment_hint) { 3192 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3193} 3194 3195bool os::pd_release_memory(char* addr, size_t size) { 3196 return anon_munmap(addr, size); 3197} 3198 3199static bool linux_mprotect(char* addr, size_t size, int prot) { 3200 // Linux wants the mprotect address argument to be page aligned. 3201 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3202 3203 // According to SUSv3, mprotect() should only be used with mappings 3204 // established by mmap(), and mmap() always maps whole pages. Unaligned 3205 // 'addr' likely indicates problem in the VM (e.g. trying to change 3206 // protection of malloc'ed or statically allocated memory). Check the 3207 // caller if you hit this assert. 3208 assert(addr == bottom, "sanity check"); 3209 3210 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3211 return ::mprotect(bottom, size, prot) == 0; 3212} 3213 3214// Set protections specified 3215bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3216 bool is_committed) { 3217 unsigned int p = 0; 3218 switch (prot) { 3219 case MEM_PROT_NONE: p = PROT_NONE; break; 3220 case MEM_PROT_READ: p = PROT_READ; break; 3221 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3222 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3223 default: 3224 ShouldNotReachHere(); 3225 } 3226 // is_committed is unused. 3227 return linux_mprotect(addr, bytes, p); 3228} 3229 3230bool os::guard_memory(char* addr, size_t size) { 3231 return linux_mprotect(addr, size, PROT_NONE); 3232} 3233 3234bool os::unguard_memory(char* addr, size_t size) { 3235 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3236} 3237 3238bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3239 size_t page_size) { 3240 bool result = false; 3241 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3242 MAP_ANONYMOUS|MAP_PRIVATE, 3243 -1, 0); 3244 if (p != MAP_FAILED) { 3245 void *aligned_p = align_ptr_up(p, page_size); 3246 3247 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3248 3249 munmap(p, page_size * 2); 3250 } 3251 3252 if (warn && !result) { 3253 warning("TransparentHugePages is not supported by the operating system."); 3254 } 3255 3256 return result; 3257} 3258 3259bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3260 bool result = false; 3261 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3262 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3263 -1, 0); 3264 3265 if (p != MAP_FAILED) { 3266 // We don't know if this really is a huge page or not. 3267 FILE *fp = fopen("/proc/self/maps", "r"); 3268 if (fp) { 3269 while (!feof(fp)) { 3270 char chars[257]; 3271 long x = 0; 3272 if (fgets(chars, sizeof(chars), fp)) { 3273 if (sscanf(chars, "%lx-%*x", &x) == 1 3274 && x == (long)p) { 3275 if (strstr (chars, "hugepage")) { 3276 result = true; 3277 break; 3278 } 3279 } 3280 } 3281 } 3282 fclose(fp); 3283 } 3284 munmap(p, page_size); 3285 } 3286 3287 if (warn && !result) { 3288 warning("HugeTLBFS is not supported by the operating system."); 3289 } 3290 3291 return result; 3292} 3293 3294// Set the coredump_filter bits to include largepages in core dump (bit 6) 3295// 3296// From the coredump_filter documentation: 3297// 3298// - (bit 0) anonymous private memory 3299// - (bit 1) anonymous shared memory 3300// - (bit 2) file-backed private memory 3301// - (bit 3) file-backed shared memory 3302// - (bit 4) ELF header pages in file-backed private memory areas (it is 3303// effective only if the bit 2 is cleared) 3304// - (bit 5) hugetlb private memory 3305// - (bit 6) hugetlb shared memory 3306// 3307static void set_coredump_filter(void) { 3308 FILE *f; 3309 long cdm; 3310 3311 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3312 return; 3313 } 3314 3315 if (fscanf(f, "%lx", &cdm) != 1) { 3316 fclose(f); 3317 return; 3318 } 3319 3320 rewind(f); 3321 3322 if ((cdm & LARGEPAGES_BIT) == 0) { 3323 cdm |= LARGEPAGES_BIT; 3324 fprintf(f, "%#lx", cdm); 3325 } 3326 3327 fclose(f); 3328} 3329 3330// Large page support 3331 3332static size_t _large_page_size = 0; 3333 3334size_t os::Linux::find_large_page_size() { 3335 size_t large_page_size = 0; 3336 3337 // large_page_size on Linux is used to round up heap size. x86 uses either 3338 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3339 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3340 // page as large as 256M. 3341 // 3342 // Here we try to figure out page size by parsing /proc/meminfo and looking 3343 // for a line with the following format: 3344 // Hugepagesize: 2048 kB 3345 // 3346 // If we can't determine the value (e.g. /proc is not mounted, or the text 3347 // format has been changed), we'll use the largest page size supported by 3348 // the processor. 3349 3350#ifndef ZERO 3351 large_page_size = 3352 AARCH64_ONLY(2 * M) 3353 AMD64_ONLY(2 * M) 3354 ARM32_ONLY(2 * M) 3355 IA32_ONLY(4 * M) 3356 IA64_ONLY(256 * M) 3357 PPC_ONLY(4 * M) 3358 S390_ONLY(1 * M) 3359 SPARC_ONLY(4 * M); 3360#endif // ZERO 3361 3362 FILE *fp = fopen("/proc/meminfo", "r"); 3363 if (fp) { 3364 while (!feof(fp)) { 3365 int x = 0; 3366 char buf[16]; 3367 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3368 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3369 large_page_size = x * K; 3370 break; 3371 } 3372 } else { 3373 // skip to next line 3374 for (;;) { 3375 int ch = fgetc(fp); 3376 if (ch == EOF || ch == (int)'\n') break; 3377 } 3378 } 3379 } 3380 fclose(fp); 3381 } 3382 3383 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3384 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3385 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3386 proper_unit_for_byte_size(large_page_size)); 3387 } 3388 3389 return large_page_size; 3390} 3391 3392size_t os::Linux::setup_large_page_size() { 3393 _large_page_size = Linux::find_large_page_size(); 3394 const size_t default_page_size = (size_t)Linux::page_size(); 3395 if (_large_page_size > default_page_size) { 3396 _page_sizes[0] = _large_page_size; 3397 _page_sizes[1] = default_page_size; 3398 _page_sizes[2] = 0; 3399 } 3400 3401 return _large_page_size; 3402} 3403 3404bool os::Linux::setup_large_page_type(size_t page_size) { 3405 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3406 FLAG_IS_DEFAULT(UseSHM) && 3407 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3408 3409 // The type of large pages has not been specified by the user. 3410 3411 // Try UseHugeTLBFS and then UseSHM. 3412 UseHugeTLBFS = UseSHM = true; 3413 3414 // Don't try UseTransparentHugePages since there are known 3415 // performance issues with it turned on. This might change in the future. 3416 UseTransparentHugePages = false; 3417 } 3418 3419 if (UseTransparentHugePages) { 3420 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3421 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3422 UseHugeTLBFS = false; 3423 UseSHM = false; 3424 return true; 3425 } 3426 UseTransparentHugePages = false; 3427 } 3428 3429 if (UseHugeTLBFS) { 3430 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3431 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3432 UseSHM = false; 3433 return true; 3434 } 3435 UseHugeTLBFS = false; 3436 } 3437 3438 return UseSHM; 3439} 3440 3441void os::large_page_init() { 3442 if (!UseLargePages && 3443 !UseTransparentHugePages && 3444 !UseHugeTLBFS && 3445 !UseSHM) { 3446 // Not using large pages. 3447 return; 3448 } 3449 3450 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3451 // The user explicitly turned off large pages. 3452 // Ignore the rest of the large pages flags. 3453 UseTransparentHugePages = false; 3454 UseHugeTLBFS = false; 3455 UseSHM = false; 3456 return; 3457 } 3458 3459 size_t large_page_size = Linux::setup_large_page_size(); 3460 UseLargePages = Linux::setup_large_page_type(large_page_size); 3461 3462 set_coredump_filter(); 3463} 3464 3465#ifndef SHM_HUGETLB 3466 #define SHM_HUGETLB 04000 3467#endif 3468 3469#define shm_warning_format(format, ...) \ 3470 do { \ 3471 if (UseLargePages && \ 3472 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3473 !FLAG_IS_DEFAULT(UseSHM) || \ 3474 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3475 warning(format, __VA_ARGS__); \ 3476 } \ 3477 } while (0) 3478 3479#define shm_warning(str) shm_warning_format("%s", str) 3480 3481#define shm_warning_with_errno(str) \ 3482 do { \ 3483 int err = errno; \ 3484 shm_warning_format(str " (error = %d)", err); \ 3485 } while (0) 3486 3487static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3488 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment"); 3489 3490 if (!is_size_aligned(alignment, SHMLBA)) { 3491 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3492 return NULL; 3493 } 3494 3495 // To ensure that we get 'alignment' aligned memory from shmat, 3496 // we pre-reserve aligned virtual memory and then attach to that. 3497 3498 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3499 if (pre_reserved_addr == NULL) { 3500 // Couldn't pre-reserve aligned memory. 3501 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3502 return NULL; 3503 } 3504 3505 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3506 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3507 3508 if ((intptr_t)addr == -1) { 3509 int err = errno; 3510 shm_warning_with_errno("Failed to attach shared memory."); 3511 3512 assert(err != EACCES, "Unexpected error"); 3513 assert(err != EIDRM, "Unexpected error"); 3514 assert(err != EINVAL, "Unexpected error"); 3515 3516 // Since we don't know if the kernel unmapped the pre-reserved memory area 3517 // we can't unmap it, since that would potentially unmap memory that was 3518 // mapped from other threads. 3519 return NULL; 3520 } 3521 3522 return addr; 3523} 3524 3525static char* shmat_at_address(int shmid, char* req_addr) { 3526 if (!is_ptr_aligned(req_addr, SHMLBA)) { 3527 assert(false, "Requested address needs to be SHMLBA aligned"); 3528 return NULL; 3529 } 3530 3531 char* addr = (char*)shmat(shmid, req_addr, 0); 3532 3533 if ((intptr_t)addr == -1) { 3534 shm_warning_with_errno("Failed to attach shared memory."); 3535 return NULL; 3536 } 3537 3538 return addr; 3539} 3540 3541static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3542 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3543 if (req_addr != NULL) { 3544 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3545 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3546 return shmat_at_address(shmid, req_addr); 3547 } 3548 3549 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3550 // return large page size aligned memory addresses when req_addr == NULL. 3551 // However, if the alignment is larger than the large page size, we have 3552 // to manually ensure that the memory returned is 'alignment' aligned. 3553 if (alignment > os::large_page_size()) { 3554 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3555 return shmat_with_alignment(shmid, bytes, alignment); 3556 } else { 3557 return shmat_at_address(shmid, NULL); 3558 } 3559} 3560 3561char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3562 char* req_addr, bool exec) { 3563 // "exec" is passed in but not used. Creating the shared image for 3564 // the code cache doesn't have an SHM_X executable permission to check. 3565 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3566 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3567 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address"); 3568 3569 if (!is_size_aligned(bytes, os::large_page_size())) { 3570 return NULL; // Fallback to small pages. 3571 } 3572 3573 // Create a large shared memory region to attach to based on size. 3574 // Currently, size is the total size of the heap. 3575 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3576 if (shmid == -1) { 3577 // Possible reasons for shmget failure: 3578 // 1. shmmax is too small for Java heap. 3579 // > check shmmax value: cat /proc/sys/kernel/shmmax 3580 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3581 // 2. not enough large page memory. 3582 // > check available large pages: cat /proc/meminfo 3583 // > increase amount of large pages: 3584 // echo new_value > /proc/sys/vm/nr_hugepages 3585 // Note 1: different Linux may use different name for this property, 3586 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3587 // Note 2: it's possible there's enough physical memory available but 3588 // they are so fragmented after a long run that they can't 3589 // coalesce into large pages. Try to reserve large pages when 3590 // the system is still "fresh". 3591 shm_warning_with_errno("Failed to reserve shared memory."); 3592 return NULL; 3593 } 3594 3595 // Attach to the region. 3596 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3597 3598 // Remove shmid. If shmat() is successful, the actual shared memory segment 3599 // will be deleted when it's detached by shmdt() or when the process 3600 // terminates. If shmat() is not successful this will remove the shared 3601 // segment immediately. 3602 shmctl(shmid, IPC_RMID, NULL); 3603 3604 return addr; 3605} 3606 3607static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3608 int error) { 3609 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3610 3611 bool warn_on_failure = UseLargePages && 3612 (!FLAG_IS_DEFAULT(UseLargePages) || 3613 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3614 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3615 3616 if (warn_on_failure) { 3617 char msg[128]; 3618 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3619 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3620 warning("%s", msg); 3621 } 3622} 3623 3624char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3625 char* req_addr, 3626 bool exec) { 3627 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3628 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3629 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3630 3631 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3632 char* addr = (char*)::mmap(req_addr, bytes, prot, 3633 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3634 -1, 0); 3635 3636 if (addr == MAP_FAILED) { 3637 warn_on_large_pages_failure(req_addr, bytes, errno); 3638 return NULL; 3639 } 3640 3641 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3642 3643 return addr; 3644} 3645 3646// Reserve memory using mmap(MAP_HUGETLB). 3647// - bytes shall be a multiple of alignment. 3648// - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3649// - alignment sets the alignment at which memory shall be allocated. 3650// It must be a multiple of allocation granularity. 3651// Returns address of memory or NULL. If req_addr was not NULL, will only return 3652// req_addr or NULL. 3653char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3654 size_t alignment, 3655 char* req_addr, 3656 bool exec) { 3657 size_t large_page_size = os::large_page_size(); 3658 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3659 3660 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3661 assert(is_size_aligned(bytes, alignment), "Must be"); 3662 3663 // First reserve - but not commit - the address range in small pages. 3664 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3665 3666 if (start == NULL) { 3667 return NULL; 3668 } 3669 3670 assert(is_ptr_aligned(start, alignment), "Must be"); 3671 3672 char* end = start + bytes; 3673 3674 // Find the regions of the allocated chunk that can be promoted to large pages. 3675 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3676 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3677 3678 size_t lp_bytes = lp_end - lp_start; 3679 3680 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3681 3682 if (lp_bytes == 0) { 3683 // The mapped region doesn't even span the start and the end of a large page. 3684 // Fall back to allocate a non-special area. 3685 ::munmap(start, end - start); 3686 return NULL; 3687 } 3688 3689 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3690 3691 void* result; 3692 3693 // Commit small-paged leading area. 3694 if (start != lp_start) { 3695 result = ::mmap(start, lp_start - start, prot, 3696 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3697 -1, 0); 3698 if (result == MAP_FAILED) { 3699 ::munmap(lp_start, end - lp_start); 3700 return NULL; 3701 } 3702 } 3703 3704 // Commit large-paged area. 3705 result = ::mmap(lp_start, lp_bytes, prot, 3706 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3707 -1, 0); 3708 if (result == MAP_FAILED) { 3709 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3710 // If the mmap above fails, the large pages region will be unmapped and we 3711 // have regions before and after with small pages. Release these regions. 3712 // 3713 // | mapped | unmapped | mapped | 3714 // ^ ^ ^ ^ 3715 // start lp_start lp_end end 3716 // 3717 ::munmap(start, lp_start - start); 3718 ::munmap(lp_end, end - lp_end); 3719 return NULL; 3720 } 3721 3722 // Commit small-paged trailing area. 3723 if (lp_end != end) { 3724 result = ::mmap(lp_end, end - lp_end, prot, 3725 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3726 -1, 0); 3727 if (result == MAP_FAILED) { 3728 ::munmap(start, lp_end - start); 3729 return NULL; 3730 } 3731 } 3732 3733 return start; 3734} 3735 3736char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3737 size_t alignment, 3738 char* req_addr, 3739 bool exec) { 3740 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3741 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3742 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3743 assert(is_power_of_2(os::large_page_size()), "Must be"); 3744 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3745 3746 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3747 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3748 } else { 3749 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3750 } 3751} 3752 3753char* os::reserve_memory_special(size_t bytes, size_t alignment, 3754 char* req_addr, bool exec) { 3755 assert(UseLargePages, "only for large pages"); 3756 3757 char* addr; 3758 if (UseSHM) { 3759 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3760 } else { 3761 assert(UseHugeTLBFS, "must be"); 3762 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3763 } 3764 3765 if (addr != NULL) { 3766 if (UseNUMAInterleaving) { 3767 numa_make_global(addr, bytes); 3768 } 3769 3770 // The memory is committed 3771 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3772 } 3773 3774 return addr; 3775} 3776 3777bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3778 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3779 return shmdt(base) == 0; 3780} 3781 3782bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3783 return pd_release_memory(base, bytes); 3784} 3785 3786bool os::release_memory_special(char* base, size_t bytes) { 3787 bool res; 3788 if (MemTracker::tracking_level() > NMT_minimal) { 3789 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3790 res = os::Linux::release_memory_special_impl(base, bytes); 3791 if (res) { 3792 tkr.record((address)base, bytes); 3793 } 3794 3795 } else { 3796 res = os::Linux::release_memory_special_impl(base, bytes); 3797 } 3798 return res; 3799} 3800 3801bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3802 assert(UseLargePages, "only for large pages"); 3803 bool res; 3804 3805 if (UseSHM) { 3806 res = os::Linux::release_memory_special_shm(base, bytes); 3807 } else { 3808 assert(UseHugeTLBFS, "must be"); 3809 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3810 } 3811 return res; 3812} 3813 3814size_t os::large_page_size() { 3815 return _large_page_size; 3816} 3817 3818// With SysV SHM the entire memory region must be allocated as shared 3819// memory. 3820// HugeTLBFS allows application to commit large page memory on demand. 3821// However, when committing memory with HugeTLBFS fails, the region 3822// that was supposed to be committed will lose the old reservation 3823// and allow other threads to steal that memory region. Because of this 3824// behavior we can't commit HugeTLBFS memory. 3825bool os::can_commit_large_page_memory() { 3826 return UseTransparentHugePages; 3827} 3828 3829bool os::can_execute_large_page_memory() { 3830 return UseTransparentHugePages || UseHugeTLBFS; 3831} 3832 3833// Reserve memory at an arbitrary address, only if that area is 3834// available (and not reserved for something else). 3835 3836char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3837 const int max_tries = 10; 3838 char* base[max_tries]; 3839 size_t size[max_tries]; 3840 const size_t gap = 0x000000; 3841 3842 // Assert only that the size is a multiple of the page size, since 3843 // that's all that mmap requires, and since that's all we really know 3844 // about at this low abstraction level. If we need higher alignment, 3845 // we can either pass an alignment to this method or verify alignment 3846 // in one of the methods further up the call chain. See bug 5044738. 3847 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3848 3849 // Repeatedly allocate blocks until the block is allocated at the 3850 // right spot. 3851 3852 // Linux mmap allows caller to pass an address as hint; give it a try first, 3853 // if kernel honors the hint then we can return immediately. 3854 char * addr = anon_mmap(requested_addr, bytes, false); 3855 if (addr == requested_addr) { 3856 return requested_addr; 3857 } 3858 3859 if (addr != NULL) { 3860 // mmap() is successful but it fails to reserve at the requested address 3861 anon_munmap(addr, bytes); 3862 } 3863 3864 int i; 3865 for (i = 0; i < max_tries; ++i) { 3866 base[i] = reserve_memory(bytes); 3867 3868 if (base[i] != NULL) { 3869 // Is this the block we wanted? 3870 if (base[i] == requested_addr) { 3871 size[i] = bytes; 3872 break; 3873 } 3874 3875 // Does this overlap the block we wanted? Give back the overlapped 3876 // parts and try again. 3877 3878 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3879 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3880 unmap_memory(base[i], top_overlap); 3881 base[i] += top_overlap; 3882 size[i] = bytes - top_overlap; 3883 } else { 3884 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3885 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3886 unmap_memory(requested_addr, bottom_overlap); 3887 size[i] = bytes - bottom_overlap; 3888 } else { 3889 size[i] = bytes; 3890 } 3891 } 3892 } 3893 } 3894 3895 // Give back the unused reserved pieces. 3896 3897 for (int j = 0; j < i; ++j) { 3898 if (base[j] != NULL) { 3899 unmap_memory(base[j], size[j]); 3900 } 3901 } 3902 3903 if (i < max_tries) { 3904 return requested_addr; 3905 } else { 3906 return NULL; 3907 } 3908} 3909 3910size_t os::read(int fd, void *buf, unsigned int nBytes) { 3911 return ::read(fd, buf, nBytes); 3912} 3913 3914size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3915 return ::pread(fd, buf, nBytes, offset); 3916} 3917 3918// Short sleep, direct OS call. 3919// 3920// Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3921// sched_yield(2) will actually give up the CPU: 3922// 3923// * Alone on this pariticular CPU, keeps running. 3924// * Before the introduction of "skip_buddy" with "compat_yield" disabled 3925// (pre 2.6.39). 3926// 3927// So calling this with 0 is an alternative. 3928// 3929void os::naked_short_sleep(jlong ms) { 3930 struct timespec req; 3931 3932 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3933 req.tv_sec = 0; 3934 if (ms > 0) { 3935 req.tv_nsec = (ms % 1000) * 1000000; 3936 } else { 3937 req.tv_nsec = 1; 3938 } 3939 3940 nanosleep(&req, NULL); 3941 3942 return; 3943} 3944 3945// Sleep forever; naked call to OS-specific sleep; use with CAUTION 3946void os::infinite_sleep() { 3947 while (true) { // sleep forever ... 3948 ::sleep(100); // ... 100 seconds at a time 3949 } 3950} 3951 3952// Used to convert frequent JVM_Yield() to nops 3953bool os::dont_yield() { 3954 return DontYieldALot; 3955} 3956 3957void os::naked_yield() { 3958 sched_yield(); 3959} 3960 3961//////////////////////////////////////////////////////////////////////////////// 3962// thread priority support 3963 3964// Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3965// only supports dynamic priority, static priority must be zero. For real-time 3966// applications, Linux supports SCHED_RR which allows static priority (1-99). 3967// However, for large multi-threaded applications, SCHED_RR is not only slower 3968// than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3969// of 5 runs - Sep 2005). 3970// 3971// The following code actually changes the niceness of kernel-thread/LWP. It 3972// has an assumption that setpriority() only modifies one kernel-thread/LWP, 3973// not the entire user process, and user level threads are 1:1 mapped to kernel 3974// threads. It has always been the case, but could change in the future. For 3975// this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3976// It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3977 3978int os::java_to_os_priority[CriticalPriority + 1] = { 3979 19, // 0 Entry should never be used 3980 3981 4, // 1 MinPriority 3982 3, // 2 3983 2, // 3 3984 3985 1, // 4 3986 0, // 5 NormPriority 3987 -1, // 6 3988 3989 -2, // 7 3990 -3, // 8 3991 -4, // 9 NearMaxPriority 3992 3993 -5, // 10 MaxPriority 3994 3995 -5 // 11 CriticalPriority 3996}; 3997 3998static int prio_init() { 3999 if (ThreadPriorityPolicy == 1) { 4000 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 4001 // if effective uid is not root. Perhaps, a more elegant way of doing 4002 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 4003 if (geteuid() != 0) { 4004 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 4005 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 4006 } 4007 ThreadPriorityPolicy = 0; 4008 } 4009 } 4010 if (UseCriticalJavaThreadPriority) { 4011 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 4012 } 4013 return 0; 4014} 4015 4016OSReturn os::set_native_priority(Thread* thread, int newpri) { 4017 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 4018 4019 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 4020 return (ret == 0) ? OS_OK : OS_ERR; 4021} 4022 4023OSReturn os::get_native_priority(const Thread* const thread, 4024 int *priority_ptr) { 4025 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 4026 *priority_ptr = java_to_os_priority[NormPriority]; 4027 return OS_OK; 4028 } 4029 4030 errno = 0; 4031 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 4032 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 4033} 4034 4035// Hint to the underlying OS that a task switch would not be good. 4036// Void return because it's a hint and can fail. 4037void os::hint_no_preempt() {} 4038 4039//////////////////////////////////////////////////////////////////////////////// 4040// suspend/resume support 4041 4042// the low-level signal-based suspend/resume support is a remnant from the 4043// old VM-suspension that used to be for java-suspension, safepoints etc, 4044// within hotspot. Now there is a single use-case for this: 4045// - calling get_thread_pc() on the VMThread by the flat-profiler task 4046// that runs in the watcher thread. 4047// The remaining code is greatly simplified from the more general suspension 4048// code that used to be used. 4049// 4050// The protocol is quite simple: 4051// - suspend: 4052// - sends a signal to the target thread 4053// - polls the suspend state of the osthread using a yield loop 4054// - target thread signal handler (SR_handler) sets suspend state 4055// and blocks in sigsuspend until continued 4056// - resume: 4057// - sets target osthread state to continue 4058// - sends signal to end the sigsuspend loop in the SR_handler 4059// 4060// Note that the SR_lock plays no role in this suspend/resume protocol, 4061// but is checked for NULL in SR_handler as a thread termination indicator. 4062 4063static void resume_clear_context(OSThread *osthread) { 4064 osthread->set_ucontext(NULL); 4065 osthread->set_siginfo(NULL); 4066} 4067 4068static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 4069 ucontext_t* context) { 4070 osthread->set_ucontext(context); 4071 osthread->set_siginfo(siginfo); 4072} 4073 4074// Handler function invoked when a thread's execution is suspended or 4075// resumed. We have to be careful that only async-safe functions are 4076// called here (Note: most pthread functions are not async safe and 4077// should be avoided.) 4078// 4079// Note: sigwait() is a more natural fit than sigsuspend() from an 4080// interface point of view, but sigwait() prevents the signal hander 4081// from being run. libpthread would get very confused by not having 4082// its signal handlers run and prevents sigwait()'s use with the 4083// mutex granting granting signal. 4084// 4085// Currently only ever called on the VMThread and JavaThreads (PC sampling) 4086// 4087static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4088 // Save and restore errno to avoid confusing native code with EINTR 4089 // after sigsuspend. 4090 int old_errno = errno; 4091 4092 Thread* thread = Thread::current_or_null_safe(); 4093 assert(thread != NULL, "Missing current thread in SR_handler"); 4094 4095 // On some systems we have seen signal delivery get "stuck" until the signal 4096 // mask is changed as part of thread termination. Check that the current thread 4097 // has not already terminated (via SR_lock()) - else the following assertion 4098 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4099 // destructor has completed. 4100 4101 if (thread->SR_lock() == NULL) { 4102 return; 4103 } 4104 4105 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4106 4107 OSThread* osthread = thread->osthread(); 4108 4109 os::SuspendResume::State current = osthread->sr.state(); 4110 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4111 suspend_save_context(osthread, siginfo, context); 4112 4113 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4114 os::SuspendResume::State state = osthread->sr.suspended(); 4115 if (state == os::SuspendResume::SR_SUSPENDED) { 4116 sigset_t suspend_set; // signals for sigsuspend() 4117 sigemptyset(&suspend_set); 4118 // get current set of blocked signals and unblock resume signal 4119 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4120 sigdelset(&suspend_set, SR_signum); 4121 4122 sr_semaphore.signal(); 4123 // wait here until we are resumed 4124 while (1) { 4125 sigsuspend(&suspend_set); 4126 4127 os::SuspendResume::State result = osthread->sr.running(); 4128 if (result == os::SuspendResume::SR_RUNNING) { 4129 sr_semaphore.signal(); 4130 break; 4131 } 4132 } 4133 4134 } else if (state == os::SuspendResume::SR_RUNNING) { 4135 // request was cancelled, continue 4136 } else { 4137 ShouldNotReachHere(); 4138 } 4139 4140 resume_clear_context(osthread); 4141 } else if (current == os::SuspendResume::SR_RUNNING) { 4142 // request was cancelled, continue 4143 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4144 // ignore 4145 } else { 4146 // ignore 4147 } 4148 4149 errno = old_errno; 4150} 4151 4152static int SR_initialize() { 4153 struct sigaction act; 4154 char *s; 4155 4156 // Get signal number to use for suspend/resume 4157 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4158 int sig = ::strtol(s, 0, 10); 4159 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4160 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4161 SR_signum = sig; 4162 } else { 4163 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4164 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4165 } 4166 } 4167 4168 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4169 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4170 4171 sigemptyset(&SR_sigset); 4172 sigaddset(&SR_sigset, SR_signum); 4173 4174 // Set up signal handler for suspend/resume 4175 act.sa_flags = SA_RESTART|SA_SIGINFO; 4176 act.sa_handler = (void (*)(int)) SR_handler; 4177 4178 // SR_signum is blocked by default. 4179 // 4528190 - We also need to block pthread restart signal (32 on all 4180 // supported Linux platforms). Note that LinuxThreads need to block 4181 // this signal for all threads to work properly. So we don't have 4182 // to use hard-coded signal number when setting up the mask. 4183 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4184 4185 if (sigaction(SR_signum, &act, 0) == -1) { 4186 return -1; 4187 } 4188 4189 // Save signal flag 4190 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4191 return 0; 4192} 4193 4194static int sr_notify(OSThread* osthread) { 4195 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4196 assert_status(status == 0, status, "pthread_kill"); 4197 return status; 4198} 4199 4200// "Randomly" selected value for how long we want to spin 4201// before bailing out on suspending a thread, also how often 4202// we send a signal to a thread we want to resume 4203static const int RANDOMLY_LARGE_INTEGER = 1000000; 4204static const int RANDOMLY_LARGE_INTEGER2 = 100; 4205 4206// returns true on success and false on error - really an error is fatal 4207// but this seems the normal response to library errors 4208static bool do_suspend(OSThread* osthread) { 4209 assert(osthread->sr.is_running(), "thread should be running"); 4210 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4211 4212 // mark as suspended and send signal 4213 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4214 // failed to switch, state wasn't running? 4215 ShouldNotReachHere(); 4216 return false; 4217 } 4218 4219 if (sr_notify(osthread) != 0) { 4220 ShouldNotReachHere(); 4221 } 4222 4223 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4224 while (true) { 4225 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4226 break; 4227 } else { 4228 // timeout 4229 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4230 if (cancelled == os::SuspendResume::SR_RUNNING) { 4231 return false; 4232 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4233 // make sure that we consume the signal on the semaphore as well 4234 sr_semaphore.wait(); 4235 break; 4236 } else { 4237 ShouldNotReachHere(); 4238 return false; 4239 } 4240 } 4241 } 4242 4243 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4244 return true; 4245} 4246 4247static void do_resume(OSThread* osthread) { 4248 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4249 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4250 4251 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4252 // failed to switch to WAKEUP_REQUEST 4253 ShouldNotReachHere(); 4254 return; 4255 } 4256 4257 while (true) { 4258 if (sr_notify(osthread) == 0) { 4259 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4260 if (osthread->sr.is_running()) { 4261 return; 4262 } 4263 } 4264 } else { 4265 ShouldNotReachHere(); 4266 } 4267 } 4268 4269 guarantee(osthread->sr.is_running(), "Must be running!"); 4270} 4271 4272/////////////////////////////////////////////////////////////////////////////////// 4273// signal handling (except suspend/resume) 4274 4275// This routine may be used by user applications as a "hook" to catch signals. 4276// The user-defined signal handler must pass unrecognized signals to this 4277// routine, and if it returns true (non-zero), then the signal handler must 4278// return immediately. If the flag "abort_if_unrecognized" is true, then this 4279// routine will never retun false (zero), but instead will execute a VM panic 4280// routine kill the process. 4281// 4282// If this routine returns false, it is OK to call it again. This allows 4283// the user-defined signal handler to perform checks either before or after 4284// the VM performs its own checks. Naturally, the user code would be making 4285// a serious error if it tried to handle an exception (such as a null check 4286// or breakpoint) that the VM was generating for its own correct operation. 4287// 4288// This routine may recognize any of the following kinds of signals: 4289// SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4290// It should be consulted by handlers for any of those signals. 4291// 4292// The caller of this routine must pass in the three arguments supplied 4293// to the function referred to in the "sa_sigaction" (not the "sa_handler") 4294// field of the structure passed to sigaction(). This routine assumes that 4295// the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4296// 4297// Note that the VM will print warnings if it detects conflicting signal 4298// handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4299// 4300extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4301 siginfo_t* siginfo, 4302 void* ucontext, 4303 int abort_if_unrecognized); 4304 4305void signalHandler(int sig, siginfo_t* info, void* uc) { 4306 assert(info != NULL && uc != NULL, "it must be old kernel"); 4307 int orig_errno = errno; // Preserve errno value over signal handler. 4308 JVM_handle_linux_signal(sig, info, uc, true); 4309 errno = orig_errno; 4310} 4311 4312 4313// This boolean allows users to forward their own non-matching signals 4314// to JVM_handle_linux_signal, harmlessly. 4315bool os::Linux::signal_handlers_are_installed = false; 4316 4317// For signal-chaining 4318struct sigaction sigact[NSIG]; 4319uint64_t sigs = 0; 4320#if (64 < NSIG-1) 4321#error "Not all signals can be encoded in sigs. Adapt its type!" 4322#endif 4323bool os::Linux::libjsig_is_loaded = false; 4324typedef struct sigaction *(*get_signal_t)(int); 4325get_signal_t os::Linux::get_signal_action = NULL; 4326 4327struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4328 struct sigaction *actp = NULL; 4329 4330 if (libjsig_is_loaded) { 4331 // Retrieve the old signal handler from libjsig 4332 actp = (*get_signal_action)(sig); 4333 } 4334 if (actp == NULL) { 4335 // Retrieve the preinstalled signal handler from jvm 4336 actp = get_preinstalled_handler(sig); 4337 } 4338 4339 return actp; 4340} 4341 4342static bool call_chained_handler(struct sigaction *actp, int sig, 4343 siginfo_t *siginfo, void *context) { 4344 // Call the old signal handler 4345 if (actp->sa_handler == SIG_DFL) { 4346 // It's more reasonable to let jvm treat it as an unexpected exception 4347 // instead of taking the default action. 4348 return false; 4349 } else if (actp->sa_handler != SIG_IGN) { 4350 if ((actp->sa_flags & SA_NODEFER) == 0) { 4351 // automaticlly block the signal 4352 sigaddset(&(actp->sa_mask), sig); 4353 } 4354 4355 sa_handler_t hand = NULL; 4356 sa_sigaction_t sa = NULL; 4357 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4358 // retrieve the chained handler 4359 if (siginfo_flag_set) { 4360 sa = actp->sa_sigaction; 4361 } else { 4362 hand = actp->sa_handler; 4363 } 4364 4365 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4366 actp->sa_handler = SIG_DFL; 4367 } 4368 4369 // try to honor the signal mask 4370 sigset_t oset; 4371 sigemptyset(&oset); 4372 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4373 4374 // call into the chained handler 4375 if (siginfo_flag_set) { 4376 (*sa)(sig, siginfo, context); 4377 } else { 4378 (*hand)(sig); 4379 } 4380 4381 // restore the signal mask 4382 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4383 } 4384 // Tell jvm's signal handler the signal is taken care of. 4385 return true; 4386} 4387 4388bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4389 bool chained = false; 4390 // signal-chaining 4391 if (UseSignalChaining) { 4392 struct sigaction *actp = get_chained_signal_action(sig); 4393 if (actp != NULL) { 4394 chained = call_chained_handler(actp, sig, siginfo, context); 4395 } 4396 } 4397 return chained; 4398} 4399 4400struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4401 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4402 return &sigact[sig]; 4403 } 4404 return NULL; 4405} 4406 4407void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4408 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4409 sigact[sig] = oldAct; 4410 sigs |= (uint64_t)1 << (sig-1); 4411} 4412 4413// for diagnostic 4414int sigflags[NSIG]; 4415 4416int os::Linux::get_our_sigflags(int sig) { 4417 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4418 return sigflags[sig]; 4419} 4420 4421void os::Linux::set_our_sigflags(int sig, int flags) { 4422 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4423 if (sig > 0 && sig < NSIG) { 4424 sigflags[sig] = flags; 4425 } 4426} 4427 4428void os::Linux::set_signal_handler(int sig, bool set_installed) { 4429 // Check for overwrite. 4430 struct sigaction oldAct; 4431 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4432 4433 void* oldhand = oldAct.sa_sigaction 4434 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4435 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4436 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4437 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4438 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4439 if (AllowUserSignalHandlers || !set_installed) { 4440 // Do not overwrite; user takes responsibility to forward to us. 4441 return; 4442 } else if (UseSignalChaining) { 4443 // save the old handler in jvm 4444 save_preinstalled_handler(sig, oldAct); 4445 // libjsig also interposes the sigaction() call below and saves the 4446 // old sigaction on it own. 4447 } else { 4448 fatal("Encountered unexpected pre-existing sigaction handler " 4449 "%#lx for signal %d.", (long)oldhand, sig); 4450 } 4451 } 4452 4453 struct sigaction sigAct; 4454 sigfillset(&(sigAct.sa_mask)); 4455 sigAct.sa_handler = SIG_DFL; 4456 if (!set_installed) { 4457 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4458 } else { 4459 sigAct.sa_sigaction = signalHandler; 4460 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4461 } 4462 // Save flags, which are set by ours 4463 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4464 sigflags[sig] = sigAct.sa_flags; 4465 4466 int ret = sigaction(sig, &sigAct, &oldAct); 4467 assert(ret == 0, "check"); 4468 4469 void* oldhand2 = oldAct.sa_sigaction 4470 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4471 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4472 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4473} 4474 4475// install signal handlers for signals that HotSpot needs to 4476// handle in order to support Java-level exception handling. 4477 4478void os::Linux::install_signal_handlers() { 4479 if (!signal_handlers_are_installed) { 4480 signal_handlers_are_installed = true; 4481 4482 // signal-chaining 4483 typedef void (*signal_setting_t)(); 4484 signal_setting_t begin_signal_setting = NULL; 4485 signal_setting_t end_signal_setting = NULL; 4486 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4487 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4488 if (begin_signal_setting != NULL) { 4489 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4490 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4491 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4492 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4493 libjsig_is_loaded = true; 4494 assert(UseSignalChaining, "should enable signal-chaining"); 4495 } 4496 if (libjsig_is_loaded) { 4497 // Tell libjsig jvm is setting signal handlers 4498 (*begin_signal_setting)(); 4499 } 4500 4501 set_signal_handler(SIGSEGV, true); 4502 set_signal_handler(SIGPIPE, true); 4503 set_signal_handler(SIGBUS, true); 4504 set_signal_handler(SIGILL, true); 4505 set_signal_handler(SIGFPE, true); 4506#if defined(PPC64) 4507 set_signal_handler(SIGTRAP, true); 4508#endif 4509 set_signal_handler(SIGXFSZ, true); 4510 4511 if (libjsig_is_loaded) { 4512 // Tell libjsig jvm finishes setting signal handlers 4513 (*end_signal_setting)(); 4514 } 4515 4516 // We don't activate signal checker if libjsig is in place, we trust ourselves 4517 // and if UserSignalHandler is installed all bets are off. 4518 // Log that signal checking is off only if -verbose:jni is specified. 4519 if (CheckJNICalls) { 4520 if (libjsig_is_loaded) { 4521 if (PrintJNIResolving) { 4522 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4523 } 4524 check_signals = false; 4525 } 4526 if (AllowUserSignalHandlers) { 4527 if (PrintJNIResolving) { 4528 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4529 } 4530 check_signals = false; 4531 } 4532 } 4533 } 4534} 4535 4536// This is the fastest way to get thread cpu time on Linux. 4537// Returns cpu time (user+sys) for any thread, not only for current. 4538// POSIX compliant clocks are implemented in the kernels 2.6.16+. 4539// It might work on 2.6.10+ with a special kernel/glibc patch. 4540// For reference, please, see IEEE Std 1003.1-2004: 4541// http://www.unix.org/single_unix_specification 4542 4543jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4544 struct timespec tp; 4545 int rc = os::Linux::clock_gettime(clockid, &tp); 4546 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4547 4548 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4549} 4550 4551void os::Linux::initialize_os_info() { 4552 assert(_os_version == 0, "OS info already initialized"); 4553 4554 struct utsname _uname; 4555 4556 uint32_t major; 4557 uint32_t minor; 4558 uint32_t fix; 4559 4560 int rc; 4561 4562 // Kernel version is unknown if 4563 // verification below fails. 4564 _os_version = 0x01000000; 4565 4566 rc = uname(&_uname); 4567 if (rc != -1) { 4568 4569 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4570 if (rc == 3) { 4571 4572 if (major < 256 && minor < 256 && fix < 256) { 4573 // Kernel version format is as expected, 4574 // set it overriding unknown state. 4575 _os_version = (major << 16) | 4576 (minor << 8 ) | 4577 (fix << 0 ) ; 4578 } 4579 } 4580 } 4581} 4582 4583uint32_t os::Linux::os_version() { 4584 assert(_os_version != 0, "not initialized"); 4585 return _os_version & 0x00FFFFFF; 4586} 4587 4588bool os::Linux::os_version_is_known() { 4589 assert(_os_version != 0, "not initialized"); 4590 return _os_version & 0x01000000 ? false : true; 4591} 4592 4593///// 4594// glibc on Linux platform uses non-documented flag 4595// to indicate, that some special sort of signal 4596// trampoline is used. 4597// We will never set this flag, and we should 4598// ignore this flag in our diagnostic 4599#ifdef SIGNIFICANT_SIGNAL_MASK 4600 #undef SIGNIFICANT_SIGNAL_MASK 4601#endif 4602#define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4603 4604static const char* get_signal_handler_name(address handler, 4605 char* buf, int buflen) { 4606 int offset = 0; 4607 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4608 if (found) { 4609 // skip directory names 4610 const char *p1, *p2; 4611 p1 = buf; 4612 size_t len = strlen(os::file_separator()); 4613 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4614 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4615 } else { 4616 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4617 } 4618 return buf; 4619} 4620 4621static void print_signal_handler(outputStream* st, int sig, 4622 char* buf, size_t buflen) { 4623 struct sigaction sa; 4624 4625 sigaction(sig, NULL, &sa); 4626 4627 // See comment for SIGNIFICANT_SIGNAL_MASK define 4628 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4629 4630 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4631 4632 address handler = (sa.sa_flags & SA_SIGINFO) 4633 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4634 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4635 4636 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4637 st->print("SIG_DFL"); 4638 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4639 st->print("SIG_IGN"); 4640 } else { 4641 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4642 } 4643 4644 st->print(", sa_mask[0]="); 4645 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4646 4647 address rh = VMError::get_resetted_sighandler(sig); 4648 // May be, handler was resetted by VMError? 4649 if (rh != NULL) { 4650 handler = rh; 4651 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4652 } 4653 4654 st->print(", sa_flags="); 4655 os::Posix::print_sa_flags(st, sa.sa_flags); 4656 4657 // Check: is it our handler? 4658 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4659 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4660 // It is our signal handler 4661 // check for flags, reset system-used one! 4662 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4663 st->print( 4664 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4665 os::Linux::get_our_sigflags(sig)); 4666 } 4667 } 4668 st->cr(); 4669} 4670 4671 4672#define DO_SIGNAL_CHECK(sig) \ 4673 do { \ 4674 if (!sigismember(&check_signal_done, sig)) { \ 4675 os::Linux::check_signal_handler(sig); \ 4676 } \ 4677 } while (0) 4678 4679// This method is a periodic task to check for misbehaving JNI applications 4680// under CheckJNI, we can add any periodic checks here 4681 4682void os::run_periodic_checks() { 4683 if (check_signals == false) return; 4684 4685 // SEGV and BUS if overridden could potentially prevent 4686 // generation of hs*.log in the event of a crash, debugging 4687 // such a case can be very challenging, so we absolutely 4688 // check the following for a good measure: 4689 DO_SIGNAL_CHECK(SIGSEGV); 4690 DO_SIGNAL_CHECK(SIGILL); 4691 DO_SIGNAL_CHECK(SIGFPE); 4692 DO_SIGNAL_CHECK(SIGBUS); 4693 DO_SIGNAL_CHECK(SIGPIPE); 4694 DO_SIGNAL_CHECK(SIGXFSZ); 4695#if defined(PPC64) 4696 DO_SIGNAL_CHECK(SIGTRAP); 4697#endif 4698 4699 // ReduceSignalUsage allows the user to override these handlers 4700 // see comments at the very top and jvm_solaris.h 4701 if (!ReduceSignalUsage) { 4702 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4703 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4704 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4705 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4706 } 4707 4708 DO_SIGNAL_CHECK(SR_signum); 4709} 4710 4711typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4712 4713static os_sigaction_t os_sigaction = NULL; 4714 4715void os::Linux::check_signal_handler(int sig) { 4716 char buf[O_BUFLEN]; 4717 address jvmHandler = NULL; 4718 4719 4720 struct sigaction act; 4721 if (os_sigaction == NULL) { 4722 // only trust the default sigaction, in case it has been interposed 4723 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4724 if (os_sigaction == NULL) return; 4725 } 4726 4727 os_sigaction(sig, (struct sigaction*)NULL, &act); 4728 4729 4730 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4731 4732 address thisHandler = (act.sa_flags & SA_SIGINFO) 4733 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4734 : CAST_FROM_FN_PTR(address, act.sa_handler); 4735 4736 4737 switch (sig) { 4738 case SIGSEGV: 4739 case SIGBUS: 4740 case SIGFPE: 4741 case SIGPIPE: 4742 case SIGILL: 4743 case SIGXFSZ: 4744 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4745 break; 4746 4747 case SHUTDOWN1_SIGNAL: 4748 case SHUTDOWN2_SIGNAL: 4749 case SHUTDOWN3_SIGNAL: 4750 case BREAK_SIGNAL: 4751 jvmHandler = (address)user_handler(); 4752 break; 4753 4754 default: 4755 if (sig == SR_signum) { 4756 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4757 } else { 4758 return; 4759 } 4760 break; 4761 } 4762 4763 if (thisHandler != jvmHandler) { 4764 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4765 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4766 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4767 // No need to check this sig any longer 4768 sigaddset(&check_signal_done, sig); 4769 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4770 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4771 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4772 exception_name(sig, buf, O_BUFLEN)); 4773 } 4774 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4775 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4776 tty->print("expected:"); 4777 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4778 tty->cr(); 4779 tty->print(" found:"); 4780 os::Posix::print_sa_flags(tty, act.sa_flags); 4781 tty->cr(); 4782 // No need to check this sig any longer 4783 sigaddset(&check_signal_done, sig); 4784 } 4785 4786 // Dump all the signal 4787 if (sigismember(&check_signal_done, sig)) { 4788 print_signal_handlers(tty, buf, O_BUFLEN); 4789 } 4790} 4791 4792extern void report_error(char* file_name, int line_no, char* title, 4793 char* format, ...); 4794 4795// this is called _before_ the most of global arguments have been parsed 4796void os::init(void) { 4797 char dummy; // used to get a guess on initial stack address 4798// first_hrtime = gethrtime(); 4799 4800 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4801 4802 init_random(1234567); 4803 4804 ThreadCritical::initialize(); 4805 4806 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4807 if (Linux::page_size() == -1) { 4808 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4809 os::strerror(errno)); 4810 } 4811 init_page_sizes((size_t) Linux::page_size()); 4812 4813 Linux::initialize_system_info(); 4814 4815 Linux::initialize_os_info(); 4816 4817 // main_thread points to the aboriginal thread 4818 Linux::_main_thread = pthread_self(); 4819 4820 Linux::clock_init(); 4821 initial_time_count = javaTimeNanos(); 4822 4823 // retrieve entry point for pthread_setname_np 4824 Linux::_pthread_setname_np = 4825 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4826 4827 os::Posix::init(); 4828} 4829 4830// To install functions for atexit system call 4831extern "C" { 4832 static void perfMemory_exit_helper() { 4833 perfMemory_exit(); 4834 } 4835} 4836 4837// this is called _after_ the global arguments have been parsed 4838jint os::init_2(void) { 4839 4840 os::Posix::init_2(); 4841 4842 Linux::fast_thread_clock_init(); 4843 4844 // Allocate a single page and mark it as readable for safepoint polling 4845 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4846 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4847 4848 os::set_polling_page(polling_page); 4849 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page)); 4850 4851 if (!UseMembar) { 4852 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4853 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4854 os::set_memory_serialize_page(mem_serialize_page); 4855 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page)); 4856 } 4857 4858 // initialize suspend/resume support - must do this before signal_sets_init() 4859 if (SR_initialize() != 0) { 4860 perror("SR_initialize failed"); 4861 return JNI_ERR; 4862 } 4863 4864 Linux::signal_sets_init(); 4865 Linux::install_signal_handlers(); 4866 4867 // Check and sets minimum stack sizes against command line options 4868 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 4869 return JNI_ERR; 4870 } 4871 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4872 4873#if defined(IA32) 4874 workaround_expand_exec_shield_cs_limit(); 4875#endif 4876 4877 Linux::libpthread_init(); 4878 log_info(os)("HotSpot is running with %s, %s", 4879 Linux::glibc_version(), Linux::libpthread_version()); 4880 4881 if (UseNUMA) { 4882 if (!Linux::libnuma_init()) { 4883 UseNUMA = false; 4884 } else { 4885 if ((Linux::numa_max_node() < 1)) { 4886 // There's only one node(they start from 0), disable NUMA. 4887 UseNUMA = false; 4888 } 4889 } 4890 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4891 // we can make the adaptive lgrp chunk resizing work. If the user specified 4892 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4893 // disable adaptive resizing. 4894 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4895 if (FLAG_IS_DEFAULT(UseNUMA)) { 4896 UseNUMA = false; 4897 } else { 4898 if (FLAG_IS_DEFAULT(UseLargePages) && 4899 FLAG_IS_DEFAULT(UseSHM) && 4900 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4901 UseLargePages = false; 4902 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4903 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4904 UseAdaptiveSizePolicy = false; 4905 UseAdaptiveNUMAChunkSizing = false; 4906 } 4907 } 4908 } 4909 if (!UseNUMA && ForceNUMA) { 4910 UseNUMA = true; 4911 } 4912 } 4913 4914 if (MaxFDLimit) { 4915 // set the number of file descriptors to max. print out error 4916 // if getrlimit/setrlimit fails but continue regardless. 4917 struct rlimit nbr_files; 4918 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4919 if (status != 0) { 4920 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 4921 } else { 4922 nbr_files.rlim_cur = nbr_files.rlim_max; 4923 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4924 if (status != 0) { 4925 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 4926 } 4927 } 4928 } 4929 4930 // Initialize lock used to serialize thread creation (see os::create_thread) 4931 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4932 4933 // at-exit methods are called in the reverse order of their registration. 4934 // atexit functions are called on return from main or as a result of a 4935 // call to exit(3C). There can be only 32 of these functions registered 4936 // and atexit() does not set errno. 4937 4938 if (PerfAllowAtExitRegistration) { 4939 // only register atexit functions if PerfAllowAtExitRegistration is set. 4940 // atexit functions can be delayed until process exit time, which 4941 // can be problematic for embedded VM situations. Embedded VMs should 4942 // call DestroyJavaVM() to assure that VM resources are released. 4943 4944 // note: perfMemory_exit_helper atexit function may be removed in 4945 // the future if the appropriate cleanup code can be added to the 4946 // VM_Exit VMOperation's doit method. 4947 if (atexit(perfMemory_exit_helper) != 0) { 4948 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4949 } 4950 } 4951 4952 // initialize thread priority policy 4953 prio_init(); 4954 4955 return JNI_OK; 4956} 4957 4958// Mark the polling page as unreadable 4959void os::make_polling_page_unreadable(void) { 4960 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4961 fatal("Could not disable polling page"); 4962 } 4963} 4964 4965// Mark the polling page as readable 4966void os::make_polling_page_readable(void) { 4967 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4968 fatal("Could not enable polling page"); 4969 } 4970} 4971 4972// older glibc versions don't have this macro (which expands to 4973// an optimized bit-counting function) so we have to roll our own 4974#ifndef CPU_COUNT 4975 4976static int _cpu_count(const cpu_set_t* cpus) { 4977 int count = 0; 4978 // only look up to the number of configured processors 4979 for (int i = 0; i < os::processor_count(); i++) { 4980 if (CPU_ISSET(i, cpus)) { 4981 count++; 4982 } 4983 } 4984 return count; 4985} 4986 4987#define CPU_COUNT(cpus) _cpu_count(cpus) 4988 4989#endif // CPU_COUNT 4990 4991// Get the current number of available processors for this process. 4992// This value can change at any time during a process's lifetime. 4993// sched_getaffinity gives an accurate answer as it accounts for cpusets. 4994// If it appears there may be more than 1024 processors then we do a 4995// dynamic check - see 6515172 for details. 4996// If anything goes wrong we fallback to returning the number of online 4997// processors - which can be greater than the number available to the process. 4998int os::active_processor_count() { 4999 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 5000 cpu_set_t* cpus_p = &cpus; 5001 int cpus_size = sizeof(cpu_set_t); 5002 5003 int configured_cpus = processor_count(); // upper bound on available cpus 5004 int cpu_count = 0; 5005 5006// old build platforms may not support dynamic cpu sets 5007#ifdef CPU_ALLOC 5008 5009 // To enable easy testing of the dynamic path on different platforms we 5010 // introduce a diagnostic flag: UseCpuAllocPath 5011 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 5012 // kernel may use a mask bigger than cpu_set_t 5013 log_trace(os)("active_processor_count: using dynamic path %s" 5014 "- configured processors: %d", 5015 UseCpuAllocPath ? "(forced) " : "", 5016 configured_cpus); 5017 cpus_p = CPU_ALLOC(configured_cpus); 5018 if (cpus_p != NULL) { 5019 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 5020 // zero it just to be safe 5021 CPU_ZERO_S(cpus_size, cpus_p); 5022 } 5023 else { 5024 // failed to allocate so fallback to online cpus 5025 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 5026 log_trace(os)("active_processor_count: " 5027 "CPU_ALLOC failed (%s) - using " 5028 "online processor count: %d", 5029 os::strerror(errno), online_cpus); 5030 return online_cpus; 5031 } 5032 } 5033 else { 5034 log_trace(os)("active_processor_count: using static path - configured processors: %d", 5035 configured_cpus); 5036 } 5037#else // CPU_ALLOC 5038// these stubs won't be executed 5039#define CPU_COUNT_S(size, cpus) -1 5040#define CPU_FREE(cpus) 5041 5042 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 5043 configured_cpus); 5044#endif // CPU_ALLOC 5045 5046 // pid 0 means the current thread - which we have to assume represents the process 5047 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 5048 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5049 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 5050 } 5051 else { 5052 cpu_count = CPU_COUNT(cpus_p); 5053 } 5054 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 5055 } 5056 else { 5057 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 5058 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 5059 "which may exceed available processors", os::strerror(errno), cpu_count); 5060 } 5061 5062 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5063 CPU_FREE(cpus_p); 5064 } 5065 5066 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check"); 5067 return cpu_count; 5068} 5069 5070void os::set_native_thread_name(const char *name) { 5071 if (Linux::_pthread_setname_np) { 5072 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5073 snprintf(buf, sizeof(buf), "%s", name); 5074 buf[sizeof(buf) - 1] = '\0'; 5075 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5076 // ERANGE should not happen; all other errors should just be ignored. 5077 assert(rc != ERANGE, "pthread_setname_np failed"); 5078 } 5079} 5080 5081bool os::distribute_processes(uint length, uint* distribution) { 5082 // Not yet implemented. 5083 return false; 5084} 5085 5086bool os::bind_to_processor(uint processor_id) { 5087 // Not yet implemented. 5088 return false; 5089} 5090 5091/// 5092 5093void os::SuspendedThreadTask::internal_do_task() { 5094 if (do_suspend(_thread->osthread())) { 5095 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5096 do_task(context); 5097 do_resume(_thread->osthread()); 5098 } 5099} 5100 5101class PcFetcher : public os::SuspendedThreadTask { 5102 public: 5103 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 5104 ExtendedPC result(); 5105 protected: 5106 void do_task(const os::SuspendedThreadTaskContext& context); 5107 private: 5108 ExtendedPC _epc; 5109}; 5110 5111ExtendedPC PcFetcher::result() { 5112 guarantee(is_done(), "task is not done yet."); 5113 return _epc; 5114} 5115 5116void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 5117 Thread* thread = context.thread(); 5118 OSThread* osthread = thread->osthread(); 5119 if (osthread->ucontext() != NULL) { 5120 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext()); 5121 } else { 5122 // NULL context is unexpected, double-check this is the VMThread 5123 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 5124 } 5125} 5126 5127// Suspends the target using the signal mechanism and then grabs the PC before 5128// resuming the target. Used by the flat-profiler only 5129ExtendedPC os::get_thread_pc(Thread* thread) { 5130 // Make sure that it is called by the watcher for the VMThread 5131 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 5132 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 5133 5134 PcFetcher fetcher(thread); 5135 fetcher.run(); 5136 return fetcher.result(); 5137} 5138 5139//////////////////////////////////////////////////////////////////////////////// 5140// debug support 5141 5142bool os::find(address addr, outputStream* st) { 5143 Dl_info dlinfo; 5144 memset(&dlinfo, 0, sizeof(dlinfo)); 5145 if (dladdr(addr, &dlinfo) != 0) { 5146 st->print(PTR_FORMAT ": ", p2i(addr)); 5147 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5148 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5149 p2i(addr) - p2i(dlinfo.dli_saddr)); 5150 } else if (dlinfo.dli_fbase != NULL) { 5151 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5152 } else { 5153 st->print("<absolute address>"); 5154 } 5155 if (dlinfo.dli_fname != NULL) { 5156 st->print(" in %s", dlinfo.dli_fname); 5157 } 5158 if (dlinfo.dli_fbase != NULL) { 5159 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5160 } 5161 st->cr(); 5162 5163 if (Verbose) { 5164 // decode some bytes around the PC 5165 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5166 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5167 address lowest = (address) dlinfo.dli_sname; 5168 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5169 if (begin < lowest) begin = lowest; 5170 Dl_info dlinfo2; 5171 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5172 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5173 end = (address) dlinfo2.dli_saddr; 5174 } 5175 Disassembler::decode(begin, end, st); 5176 } 5177 return true; 5178 } 5179 return false; 5180} 5181 5182//////////////////////////////////////////////////////////////////////////////// 5183// misc 5184 5185// This does not do anything on Linux. This is basically a hook for being 5186// able to use structured exception handling (thread-local exception filters) 5187// on, e.g., Win32. 5188void 5189os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5190 JavaCallArguments* args, Thread* thread) { 5191 f(value, method, args, thread); 5192} 5193 5194void os::print_statistics() { 5195} 5196 5197bool os::message_box(const char* title, const char* message) { 5198 int i; 5199 fdStream err(defaultStream::error_fd()); 5200 for (i = 0; i < 78; i++) err.print_raw("="); 5201 err.cr(); 5202 err.print_raw_cr(title); 5203 for (i = 0; i < 78; i++) err.print_raw("-"); 5204 err.cr(); 5205 err.print_raw_cr(message); 5206 for (i = 0; i < 78; i++) err.print_raw("="); 5207 err.cr(); 5208 5209 char buf[16]; 5210 // Prevent process from exiting upon "read error" without consuming all CPU 5211 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5212 5213 return buf[0] == 'y' || buf[0] == 'Y'; 5214} 5215 5216int os::stat(const char *path, struct stat *sbuf) { 5217 char pathbuf[MAX_PATH]; 5218 if (strlen(path) > MAX_PATH - 1) { 5219 errno = ENAMETOOLONG; 5220 return -1; 5221 } 5222 os::native_path(strcpy(pathbuf, path)); 5223 return ::stat(pathbuf, sbuf); 5224} 5225 5226// Is a (classpath) directory empty? 5227bool os::dir_is_empty(const char* path) { 5228 DIR *dir = NULL; 5229 struct dirent *ptr; 5230 5231 dir = opendir(path); 5232 if (dir == NULL) return true; 5233 5234 // Scan the directory 5235 bool result = true; 5236 char buf[sizeof(struct dirent) + MAX_PATH]; 5237 while (result && (ptr = ::readdir(dir)) != NULL) { 5238 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5239 result = false; 5240 } 5241 } 5242 closedir(dir); 5243 return result; 5244} 5245 5246// This code originates from JDK's sysOpen and open64_w 5247// from src/solaris/hpi/src/system_md.c 5248 5249int os::open(const char *path, int oflag, int mode) { 5250 if (strlen(path) > MAX_PATH - 1) { 5251 errno = ENAMETOOLONG; 5252 return -1; 5253 } 5254 5255 // All file descriptors that are opened in the Java process and not 5256 // specifically destined for a subprocess should have the close-on-exec 5257 // flag set. If we don't set it, then careless 3rd party native code 5258 // might fork and exec without closing all appropriate file descriptors 5259 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5260 // turn might: 5261 // 5262 // - cause end-of-file to fail to be detected on some file 5263 // descriptors, resulting in mysterious hangs, or 5264 // 5265 // - might cause an fopen in the subprocess to fail on a system 5266 // suffering from bug 1085341. 5267 // 5268 // (Yes, the default setting of the close-on-exec flag is a Unix 5269 // design flaw) 5270 // 5271 // See: 5272 // 1085341: 32-bit stdio routines should support file descriptors >255 5273 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5274 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5275 // 5276 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5277 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5278 // because it saves a system call and removes a small window where the flag 5279 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5280 // and we fall back to using FD_CLOEXEC (see below). 5281#ifdef O_CLOEXEC 5282 oflag |= O_CLOEXEC; 5283#endif 5284 5285 int fd = ::open64(path, oflag, mode); 5286 if (fd == -1) return -1; 5287 5288 //If the open succeeded, the file might still be a directory 5289 { 5290 struct stat64 buf64; 5291 int ret = ::fstat64(fd, &buf64); 5292 int st_mode = buf64.st_mode; 5293 5294 if (ret != -1) { 5295 if ((st_mode & S_IFMT) == S_IFDIR) { 5296 errno = EISDIR; 5297 ::close(fd); 5298 return -1; 5299 } 5300 } else { 5301 ::close(fd); 5302 return -1; 5303 } 5304 } 5305 5306#ifdef FD_CLOEXEC 5307 // Validate that the use of the O_CLOEXEC flag on open above worked. 5308 // With recent kernels, we will perform this check exactly once. 5309 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5310 if (!O_CLOEXEC_is_known_to_work) { 5311 int flags = ::fcntl(fd, F_GETFD); 5312 if (flags != -1) { 5313 if ((flags & FD_CLOEXEC) != 0) 5314 O_CLOEXEC_is_known_to_work = 1; 5315 else 5316 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5317 } 5318 } 5319#endif 5320 5321 return fd; 5322} 5323 5324 5325// create binary file, rewriting existing file if required 5326int os::create_binary_file(const char* path, bool rewrite_existing) { 5327 int oflags = O_WRONLY | O_CREAT; 5328 if (!rewrite_existing) { 5329 oflags |= O_EXCL; 5330 } 5331 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5332} 5333 5334// return current position of file pointer 5335jlong os::current_file_offset(int fd) { 5336 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5337} 5338 5339// move file pointer to the specified offset 5340jlong os::seek_to_file_offset(int fd, jlong offset) { 5341 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5342} 5343 5344// This code originates from JDK's sysAvailable 5345// from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5346 5347int os::available(int fd, jlong *bytes) { 5348 jlong cur, end; 5349 int mode; 5350 struct stat64 buf64; 5351 5352 if (::fstat64(fd, &buf64) >= 0) { 5353 mode = buf64.st_mode; 5354 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5355 int n; 5356 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5357 *bytes = n; 5358 return 1; 5359 } 5360 } 5361 } 5362 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5363 return 0; 5364 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5365 return 0; 5366 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5367 return 0; 5368 } 5369 *bytes = end - cur; 5370 return 1; 5371} 5372 5373// Map a block of memory. 5374char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5375 char *addr, size_t bytes, bool read_only, 5376 bool allow_exec) { 5377 int prot; 5378 int flags = MAP_PRIVATE; 5379 5380 if (read_only) { 5381 prot = PROT_READ; 5382 } else { 5383 prot = PROT_READ | PROT_WRITE; 5384 } 5385 5386 if (allow_exec) { 5387 prot |= PROT_EXEC; 5388 } 5389 5390 if (addr != NULL) { 5391 flags |= MAP_FIXED; 5392 } 5393 5394 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5395 fd, file_offset); 5396 if (mapped_address == MAP_FAILED) { 5397 return NULL; 5398 } 5399 return mapped_address; 5400} 5401 5402 5403// Remap a block of memory. 5404char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5405 char *addr, size_t bytes, bool read_only, 5406 bool allow_exec) { 5407 // same as map_memory() on this OS 5408 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5409 allow_exec); 5410} 5411 5412 5413// Unmap a block of memory. 5414bool os::pd_unmap_memory(char* addr, size_t bytes) { 5415 return munmap(addr, bytes) == 0; 5416} 5417 5418static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5419 5420static clockid_t thread_cpu_clockid(Thread* thread) { 5421 pthread_t tid = thread->osthread()->pthread_id(); 5422 clockid_t clockid; 5423 5424 // Get thread clockid 5425 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5426 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5427 return clockid; 5428} 5429 5430// current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5431// are used by JVM M&M and JVMTI to get user+sys or user CPU time 5432// of a thread. 5433// 5434// current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5435// the fast estimate available on the platform. 5436 5437jlong os::current_thread_cpu_time() { 5438 if (os::Linux::supports_fast_thread_cpu_time()) { 5439 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5440 } else { 5441 // return user + sys since the cost is the same 5442 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5443 } 5444} 5445 5446jlong os::thread_cpu_time(Thread* thread) { 5447 // consistent with what current_thread_cpu_time() returns 5448 if (os::Linux::supports_fast_thread_cpu_time()) { 5449 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5450 } else { 5451 return slow_thread_cpu_time(thread, true /* user + sys */); 5452 } 5453} 5454 5455jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5456 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5457 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5458 } else { 5459 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5460 } 5461} 5462 5463jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5464 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5465 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5466 } else { 5467 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5468 } 5469} 5470 5471// -1 on error. 5472static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5473 pid_t tid = thread->osthread()->thread_id(); 5474 char *s; 5475 char stat[2048]; 5476 int statlen; 5477 char proc_name[64]; 5478 int count; 5479 long sys_time, user_time; 5480 char cdummy; 5481 int idummy; 5482 long ldummy; 5483 FILE *fp; 5484 5485 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5486 fp = fopen(proc_name, "r"); 5487 if (fp == NULL) return -1; 5488 statlen = fread(stat, 1, 2047, fp); 5489 stat[statlen] = '\0'; 5490 fclose(fp); 5491 5492 // Skip pid and the command string. Note that we could be dealing with 5493 // weird command names, e.g. user could decide to rename java launcher 5494 // to "java 1.4.2 :)", then the stat file would look like 5495 // 1234 (java 1.4.2 :)) R ... ... 5496 // We don't really need to know the command string, just find the last 5497 // occurrence of ")" and then start parsing from there. See bug 4726580. 5498 s = strrchr(stat, ')'); 5499 if (s == NULL) return -1; 5500 5501 // Skip blank chars 5502 do { s++; } while (s && isspace(*s)); 5503 5504 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5505 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5506 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5507 &user_time, &sys_time); 5508 if (count != 13) return -1; 5509 if (user_sys_cpu_time) { 5510 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5511 } else { 5512 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5513 } 5514} 5515 5516void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5517 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5518 info_ptr->may_skip_backward = false; // elapsed time not wall time 5519 info_ptr->may_skip_forward = false; // elapsed time not wall time 5520 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5521} 5522 5523void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5524 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5525 info_ptr->may_skip_backward = false; // elapsed time not wall time 5526 info_ptr->may_skip_forward = false; // elapsed time not wall time 5527 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5528} 5529 5530bool os::is_thread_cpu_time_supported() { 5531 return true; 5532} 5533 5534// System loadavg support. Returns -1 if load average cannot be obtained. 5535// Linux doesn't yet have a (official) notion of processor sets, 5536// so just return the system wide load average. 5537int os::loadavg(double loadavg[], int nelem) { 5538 return ::getloadavg(loadavg, nelem); 5539} 5540 5541void os::pause() { 5542 char filename[MAX_PATH]; 5543 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5544 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5545 } else { 5546 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5547 } 5548 5549 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5550 if (fd != -1) { 5551 struct stat buf; 5552 ::close(fd); 5553 while (::stat(filename, &buf) == 0) { 5554 (void)::poll(NULL, 0, 100); 5555 } 5556 } else { 5557 jio_fprintf(stderr, 5558 "Could not open pause file '%s', continuing immediately.\n", filename); 5559 } 5560} 5561 5562extern char** environ; 5563 5564// Run the specified command in a separate process. Return its exit value, 5565// or -1 on failure (e.g. can't fork a new process). 5566// Unlike system(), this function can be called from signal handler. It 5567// doesn't block SIGINT et al. 5568int os::fork_and_exec(char* cmd) { 5569 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5570 5571 pid_t pid = fork(); 5572 5573 if (pid < 0) { 5574 // fork failed 5575 return -1; 5576 5577 } else if (pid == 0) { 5578 // child process 5579 5580 execve("/bin/sh", (char* const*)argv, environ); 5581 5582 // execve failed 5583 _exit(-1); 5584 5585 } else { 5586 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5587 // care about the actual exit code, for now. 5588 5589 int status; 5590 5591 // Wait for the child process to exit. This returns immediately if 5592 // the child has already exited. */ 5593 while (waitpid(pid, &status, 0) < 0) { 5594 switch (errno) { 5595 case ECHILD: return 0; 5596 case EINTR: break; 5597 default: return -1; 5598 } 5599 } 5600 5601 if (WIFEXITED(status)) { 5602 // The child exited normally; get its exit code. 5603 return WEXITSTATUS(status); 5604 } else if (WIFSIGNALED(status)) { 5605 // The child exited because of a signal 5606 // The best value to return is 0x80 + signal number, 5607 // because that is what all Unix shells do, and because 5608 // it allows callers to distinguish between process exit and 5609 // process death by signal. 5610 return 0x80 + WTERMSIG(status); 5611 } else { 5612 // Unknown exit code; pass it through 5613 return status; 5614 } 5615 } 5616} 5617 5618// is_headless_jre() 5619// 5620// Test for the existence of xawt/libmawt.so or libawt_xawt.so 5621// in order to report if we are running in a headless jre 5622// 5623// Since JDK8 xawt/libmawt.so was moved into the same directory 5624// as libawt.so, and renamed libawt_xawt.so 5625// 5626bool os::is_headless_jre() { 5627 struct stat statbuf; 5628 char buf[MAXPATHLEN]; 5629 char libmawtpath[MAXPATHLEN]; 5630 const char *xawtstr = "/xawt/libmawt.so"; 5631 const char *new_xawtstr = "/libawt_xawt.so"; 5632 char *p; 5633 5634 // Get path to libjvm.so 5635 os::jvm_path(buf, sizeof(buf)); 5636 5637 // Get rid of libjvm.so 5638 p = strrchr(buf, '/'); 5639 if (p == NULL) { 5640 return false; 5641 } else { 5642 *p = '\0'; 5643 } 5644 5645 // Get rid of client or server 5646 p = strrchr(buf, '/'); 5647 if (p == NULL) { 5648 return false; 5649 } else { 5650 *p = '\0'; 5651 } 5652 5653 // check xawt/libmawt.so 5654 strcpy(libmawtpath, buf); 5655 strcat(libmawtpath, xawtstr); 5656 if (::stat(libmawtpath, &statbuf) == 0) return false; 5657 5658 // check libawt_xawt.so 5659 strcpy(libmawtpath, buf); 5660 strcat(libmawtpath, new_xawtstr); 5661 if (::stat(libmawtpath, &statbuf) == 0) return false; 5662 5663 return true; 5664} 5665 5666// Get the default path to the core file 5667// Returns the length of the string 5668int os::get_core_path(char* buffer, size_t bufferSize) { 5669 /* 5670 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5671 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5672 */ 5673 const int core_pattern_len = 129; 5674 char core_pattern[core_pattern_len] = {0}; 5675 5676 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5677 if (core_pattern_file == -1) { 5678 return -1; 5679 } 5680 5681 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5682 ::close(core_pattern_file); 5683 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5684 return -1; 5685 } 5686 if (core_pattern[ret-1] == '\n') { 5687 core_pattern[ret-1] = '\0'; 5688 } else { 5689 core_pattern[ret] = '\0'; 5690 } 5691 5692 char *pid_pos = strstr(core_pattern, "%p"); 5693 int written; 5694 5695 if (core_pattern[0] == '/') { 5696 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5697 } else { 5698 char cwd[PATH_MAX]; 5699 5700 const char* p = get_current_directory(cwd, PATH_MAX); 5701 if (p == NULL) { 5702 return -1; 5703 } 5704 5705 if (core_pattern[0] == '|') { 5706 written = jio_snprintf(buffer, bufferSize, 5707 "\"%s\" (or dumping to %s/core.%d)", 5708 &core_pattern[1], p, current_process_id()); 5709 } else { 5710 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5711 } 5712 } 5713 5714 if (written < 0) { 5715 return -1; 5716 } 5717 5718 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5719 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5720 5721 if (core_uses_pid_file != -1) { 5722 char core_uses_pid = 0; 5723 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5724 ::close(core_uses_pid_file); 5725 5726 if (core_uses_pid == '1') { 5727 jio_snprintf(buffer + written, bufferSize - written, 5728 ".%d", current_process_id()); 5729 } 5730 } 5731 } 5732 5733 return strlen(buffer); 5734} 5735 5736bool os::start_debugging(char *buf, int buflen) { 5737 int len = (int)strlen(buf); 5738 char *p = &buf[len]; 5739 5740 jio_snprintf(p, buflen-len, 5741 "\n\n" 5742 "Do you want to debug the problem?\n\n" 5743 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 5744 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 5745 "Otherwise, press RETURN to abort...", 5746 os::current_process_id(), os::current_process_id(), 5747 os::current_thread_id(), os::current_thread_id()); 5748 5749 bool yes = os::message_box("Unexpected Error", buf); 5750 5751 if (yes) { 5752 // yes, user asked VM to launch debugger 5753 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 5754 os::current_process_id(), os::current_process_id()); 5755 5756 os::fork_and_exec(buf); 5757 yes = false; 5758 } 5759 return yes; 5760} 5761 5762 5763// Java/Compiler thread: 5764// 5765// Low memory addresses 5766// P0 +------------------------+ 5767// | |\ Java thread created by VM does not have glibc 5768// | glibc guard page | - guard page, attached Java thread usually has 5769// | |/ 1 glibc guard page. 5770// P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 5771// | |\ 5772// | HotSpot Guard Pages | - red, yellow and reserved pages 5773// | |/ 5774// +------------------------+ JavaThread::stack_reserved_zone_base() 5775// | |\ 5776// | Normal Stack | - 5777// | |/ 5778// P2 +------------------------+ Thread::stack_base() 5779// 5780// Non-Java thread: 5781// 5782// Low memory addresses 5783// P0 +------------------------+ 5784// | |\ 5785// | glibc guard page | - usually 1 page 5786// | |/ 5787// P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 5788// | |\ 5789// | Normal Stack | - 5790// | |/ 5791// P2 +------------------------+ Thread::stack_base() 5792// 5793// ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 5794// returned from pthread_attr_getstack(). 5795// ** Due to NPTL implementation error, linux takes the glibc guard page out 5796// of the stack size given in pthread_attr. We work around this for 5797// threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 5798// 5799#ifndef ZERO 5800static void current_stack_region(address * bottom, size_t * size) { 5801 if (os::Linux::is_initial_thread()) { 5802 // initial thread needs special handling because pthread_getattr_np() 5803 // may return bogus value. 5804 *bottom = os::Linux::initial_thread_stack_bottom(); 5805 *size = os::Linux::initial_thread_stack_size(); 5806 } else { 5807 pthread_attr_t attr; 5808 5809 int rslt = pthread_getattr_np(pthread_self(), &attr); 5810 5811 // JVM needs to know exact stack location, abort if it fails 5812 if (rslt != 0) { 5813 if (rslt == ENOMEM) { 5814 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 5815 } else { 5816 fatal("pthread_getattr_np failed with error = %d", rslt); 5817 } 5818 } 5819 5820 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 5821 fatal("Cannot locate current stack attributes!"); 5822 } 5823 5824 // Work around NPTL stack guard error. 5825 size_t guard_size = 0; 5826 rslt = pthread_attr_getguardsize(&attr, &guard_size); 5827 if (rslt != 0) { 5828 fatal("pthread_attr_getguardsize failed with error = %d", rslt); 5829 } 5830 *bottom += guard_size; 5831 *size -= guard_size; 5832 5833 pthread_attr_destroy(&attr); 5834 5835 } 5836 assert(os::current_stack_pointer() >= *bottom && 5837 os::current_stack_pointer() < *bottom + *size, "just checking"); 5838} 5839 5840address os::current_stack_base() { 5841 address bottom; 5842 size_t size; 5843 current_stack_region(&bottom, &size); 5844 return (bottom + size); 5845} 5846 5847size_t os::current_stack_size() { 5848 // This stack size includes the usable stack and HotSpot guard pages 5849 // (for the threads that have Hotspot guard pages). 5850 address bottom; 5851 size_t size; 5852 current_stack_region(&bottom, &size); 5853 return size; 5854} 5855#endif 5856 5857static inline struct timespec get_mtime(const char* filename) { 5858 struct stat st; 5859 int ret = os::stat(filename, &st); 5860 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno)); 5861 return st.st_mtim; 5862} 5863 5864int os::compare_file_modified_times(const char* file1, const char* file2) { 5865 struct timespec filetime1 = get_mtime(file1); 5866 struct timespec filetime2 = get_mtime(file2); 5867 int diff = filetime1.tv_sec - filetime2.tv_sec; 5868 if (diff == 0) { 5869 return filetime1.tv_nsec - filetime2.tv_nsec; 5870 } 5871 return diff; 5872} 5873 5874/////////////// Unit tests /////////////// 5875 5876#ifndef PRODUCT 5877 5878#define test_log(...) \ 5879 do { \ 5880 if (VerboseInternalVMTests) { \ 5881 tty->print_cr(__VA_ARGS__); \ 5882 tty->flush(); \ 5883 } \ 5884 } while (false) 5885 5886class TestReserveMemorySpecial : AllStatic { 5887 public: 5888 static void small_page_write(void* addr, size_t size) { 5889 size_t page_size = os::vm_page_size(); 5890 5891 char* end = (char*)addr + size; 5892 for (char* p = (char*)addr; p < end; p += page_size) { 5893 *p = 1; 5894 } 5895 } 5896 5897 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 5898 if (!UseHugeTLBFS) { 5899 return; 5900 } 5901 5902 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 5903 5904 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 5905 5906 if (addr != NULL) { 5907 small_page_write(addr, size); 5908 5909 os::Linux::release_memory_special_huge_tlbfs(addr, size); 5910 } 5911 } 5912 5913 static void test_reserve_memory_special_huge_tlbfs_only() { 5914 if (!UseHugeTLBFS) { 5915 return; 5916 } 5917 5918 size_t lp = os::large_page_size(); 5919 5920 for (size_t size = lp; size <= lp * 10; size += lp) { 5921 test_reserve_memory_special_huge_tlbfs_only(size); 5922 } 5923 } 5924 5925 static void test_reserve_memory_special_huge_tlbfs_mixed() { 5926 size_t lp = os::large_page_size(); 5927 size_t ag = os::vm_allocation_granularity(); 5928 5929 // sizes to test 5930 const size_t sizes[] = { 5931 lp, lp + ag, lp + lp / 2, lp * 2, 5932 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 5933 lp * 10, lp * 10 + lp / 2 5934 }; 5935 const int num_sizes = sizeof(sizes) / sizeof(size_t); 5936 5937 // For each size/alignment combination, we test three scenarios: 5938 // 1) with req_addr == NULL 5939 // 2) with a non-null req_addr at which we expect to successfully allocate 5940 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 5941 // expect the allocation to either fail or to ignore req_addr 5942 5943 // Pre-allocate two areas; they shall be as large as the largest allocation 5944 // and aligned to the largest alignment we will be testing. 5945 const size_t mapping_size = sizes[num_sizes - 1] * 2; 5946 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 5947 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 5948 -1, 0); 5949 assert(mapping1 != MAP_FAILED, "should work"); 5950 5951 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 5952 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 5953 -1, 0); 5954 assert(mapping2 != MAP_FAILED, "should work"); 5955 5956 // Unmap the first mapping, but leave the second mapping intact: the first 5957 // mapping will serve as a value for a "good" req_addr (case 2). The second 5958 // mapping, still intact, as "bad" req_addr (case 3). 5959 ::munmap(mapping1, mapping_size); 5960 5961 // Case 1 5962 test_log("%s, req_addr NULL:", __FUNCTION__); 5963 test_log("size align result"); 5964 5965 for (int i = 0; i < num_sizes; i++) { 5966 const size_t size = sizes[i]; 5967 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 5968 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 5969 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 5970 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 5971 if (p != NULL) { 5972 assert(is_ptr_aligned(p, alignment), "must be"); 5973 small_page_write(p, size); 5974 os::Linux::release_memory_special_huge_tlbfs(p, size); 5975 } 5976 } 5977 } 5978 5979 // Case 2 5980 test_log("%s, req_addr non-NULL:", __FUNCTION__); 5981 test_log("size align req_addr result"); 5982 5983 for (int i = 0; i < num_sizes; i++) { 5984 const size_t size = sizes[i]; 5985 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 5986 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 5987 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 5988 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 5989 size, alignment, p2i(req_addr), p2i(p), 5990 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 5991 if (p != NULL) { 5992 assert(p == req_addr, "must be"); 5993 small_page_write(p, size); 5994 os::Linux::release_memory_special_huge_tlbfs(p, size); 5995 } 5996 } 5997 } 5998 5999 // Case 3 6000 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6001 test_log("size align req_addr result"); 6002 6003 for (int i = 0; i < num_sizes; i++) { 6004 const size_t size = sizes[i]; 6005 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6006 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6007 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6008 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6009 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6010 // as the area around req_addr contains already existing mappings, the API should always 6011 // return NULL (as per contract, it cannot return another address) 6012 assert(p == NULL, "must be"); 6013 } 6014 } 6015 6016 ::munmap(mapping2, mapping_size); 6017 6018 } 6019 6020 static void test_reserve_memory_special_huge_tlbfs() { 6021 if (!UseHugeTLBFS) { 6022 return; 6023 } 6024 6025 test_reserve_memory_special_huge_tlbfs_only(); 6026 test_reserve_memory_special_huge_tlbfs_mixed(); 6027 } 6028 6029 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6030 if (!UseSHM) { 6031 return; 6032 } 6033 6034 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6035 6036 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6037 6038 if (addr != NULL) { 6039 assert(is_ptr_aligned(addr, alignment), "Check"); 6040 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6041 6042 small_page_write(addr, size); 6043 6044 os::Linux::release_memory_special_shm(addr, size); 6045 } 6046 } 6047 6048 static void test_reserve_memory_special_shm() { 6049 size_t lp = os::large_page_size(); 6050 size_t ag = os::vm_allocation_granularity(); 6051 6052 for (size_t size = ag; size < lp * 3; size += ag) { 6053 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6054 test_reserve_memory_special_shm(size, alignment); 6055 } 6056 } 6057 } 6058 6059 static void test() { 6060 test_reserve_memory_special_huge_tlbfs(); 6061 test_reserve_memory_special_shm(); 6062 } 6063}; 6064 6065void TestReserveMemorySpecial_test() { 6066 TestReserveMemorySpecial::test(); 6067} 6068 6069#endif 6070