os_linux.cpp revision 7344:1d29b13e8a51
1/* 2 * Copyright (c) 1999, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25// no precompiled headers 26#include "classfile/classLoader.hpp" 27#include "classfile/systemDictionary.hpp" 28#include "classfile/vmSymbols.hpp" 29#include "code/icBuffer.hpp" 30#include "code/vtableStubs.hpp" 31#include "compiler/compileBroker.hpp" 32#include "compiler/disassembler.hpp" 33#include "interpreter/interpreter.hpp" 34#include "jvm_linux.h" 35#include "memory/allocation.inline.hpp" 36#include "memory/filemap.hpp" 37#include "mutex_linux.inline.hpp" 38#include "oops/oop.inline.hpp" 39#include "os_linux.inline.hpp" 40#include "os_share_linux.hpp" 41#include "prims/jniFastGetField.hpp" 42#include "prims/jvm.h" 43#include "prims/jvm_misc.hpp" 44#include "runtime/arguments.hpp" 45#include "runtime/atomic.inline.hpp" 46#include "runtime/extendedPC.hpp" 47#include "runtime/globals.hpp" 48#include "runtime/interfaceSupport.hpp" 49#include "runtime/init.hpp" 50#include "runtime/java.hpp" 51#include "runtime/javaCalls.hpp" 52#include "runtime/mutexLocker.hpp" 53#include "runtime/objectMonitor.hpp" 54#include "runtime/orderAccess.inline.hpp" 55#include "runtime/osThread.hpp" 56#include "runtime/perfMemory.hpp" 57#include "runtime/sharedRuntime.hpp" 58#include "runtime/statSampler.hpp" 59#include "runtime/stubRoutines.hpp" 60#include "runtime/thread.inline.hpp" 61#include "runtime/threadCritical.hpp" 62#include "runtime/timer.hpp" 63#include "services/attachListener.hpp" 64#include "services/memTracker.hpp" 65#include "services/runtimeService.hpp" 66#include "utilities/decoder.hpp" 67#include "utilities/defaultStream.hpp" 68#include "utilities/events.hpp" 69#include "utilities/elfFile.hpp" 70#include "utilities/growableArray.hpp" 71#include "utilities/vmError.hpp" 72 73// put OS-includes here 74# include <sys/types.h> 75# include <sys/mman.h> 76# include <sys/stat.h> 77# include <sys/select.h> 78# include <pthread.h> 79# include <signal.h> 80# include <errno.h> 81# include <dlfcn.h> 82# include <stdio.h> 83# include <unistd.h> 84# include <sys/resource.h> 85# include <pthread.h> 86# include <sys/stat.h> 87# include <sys/time.h> 88# include <sys/times.h> 89# include <sys/utsname.h> 90# include <sys/socket.h> 91# include <sys/wait.h> 92# include <pwd.h> 93# include <poll.h> 94# include <semaphore.h> 95# include <fcntl.h> 96# include <string.h> 97# include <syscall.h> 98# include <sys/sysinfo.h> 99# include <gnu/libc-version.h> 100# include <sys/ipc.h> 101# include <sys/shm.h> 102# include <link.h> 103# include <stdint.h> 104# include <inttypes.h> 105# include <sys/ioctl.h> 106 107PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 108 109// if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 110// getrusage() is prepared to handle the associated failure. 111#ifndef RUSAGE_THREAD 112 #define RUSAGE_THREAD (1) /* only the calling thread */ 113#endif 114 115#define MAX_PATH (2 * K) 116 117#define MAX_SECS 100000000 118 119// for timer info max values which include all bits 120#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 121 122#define LARGEPAGES_BIT (1 << 6) 123//////////////////////////////////////////////////////////////////////////////// 124// global variables 125julong os::Linux::_physical_memory = 0; 126 127address os::Linux::_initial_thread_stack_bottom = NULL; 128uintptr_t os::Linux::_initial_thread_stack_size = 0; 129 130int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 131int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 132int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 133Mutex* os::Linux::_createThread_lock = NULL; 134pthread_t os::Linux::_main_thread; 135int os::Linux::_page_size = -1; 136const int os::Linux::_vm_default_page_size = (8 * K); 137bool os::Linux::_is_floating_stack = false; 138bool os::Linux::_is_NPTL = false; 139bool os::Linux::_supports_fast_thread_cpu_time = false; 140const char * os::Linux::_glibc_version = NULL; 141const char * os::Linux::_libpthread_version = NULL; 142pthread_condattr_t os::Linux::_condattr[1]; 143 144static jlong initial_time_count=0; 145 146static int clock_tics_per_sec = 100; 147 148// For diagnostics to print a message once. see run_periodic_checks 149static sigset_t check_signal_done; 150static bool check_signals = true; 151 152static pid_t _initial_pid = 0; 153 154// Signal number used to suspend/resume a thread 155 156// do not use any signal number less than SIGSEGV, see 4355769 157static int SR_signum = SIGUSR2; 158sigset_t SR_sigset; 159 160// Used to protect dlsym() calls 161static pthread_mutex_t dl_mutex; 162 163// Declarations 164static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 165 166// utility functions 167 168static int SR_initialize(); 169 170julong os::available_memory() { 171 return Linux::available_memory(); 172} 173 174julong os::Linux::available_memory() { 175 // values in struct sysinfo are "unsigned long" 176 struct sysinfo si; 177 sysinfo(&si); 178 179 return (julong)si.freeram * si.mem_unit; 180} 181 182julong os::physical_memory() { 183 return Linux::physical_memory(); 184} 185 186//////////////////////////////////////////////////////////////////////////////// 187// environment support 188 189bool os::getenv(const char* name, char* buf, int len) { 190 const char* val = ::getenv(name); 191 if (val != NULL && strlen(val) < (size_t)len) { 192 strcpy(buf, val); 193 return true; 194 } 195 if (len > 0) buf[0] = 0; // return a null string 196 return false; 197} 198 199 200// Return true if user is running as root. 201 202bool os::have_special_privileges() { 203 static bool init = false; 204 static bool privileges = false; 205 if (!init) { 206 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 207 init = true; 208 } 209 return privileges; 210} 211 212 213#ifndef SYS_gettid 214// i386: 224, ia64: 1105, amd64: 186, sparc 143 215 #ifdef __ia64__ 216 #define SYS_gettid 1105 217 #elif __i386__ 218 #define SYS_gettid 224 219 #elif __amd64__ 220 #define SYS_gettid 186 221 #elif __sparc__ 222 #define SYS_gettid 143 223 #else 224 #error define gettid for the arch 225 #endif 226#endif 227 228// Cpu architecture string 229#if defined(ZERO) 230static char cpu_arch[] = ZERO_LIBARCH; 231#elif defined(IA64) 232static char cpu_arch[] = "ia64"; 233#elif defined(IA32) 234static char cpu_arch[] = "i386"; 235#elif defined(AMD64) 236static char cpu_arch[] = "amd64"; 237#elif defined(ARM) 238static char cpu_arch[] = "arm"; 239#elif defined(PPC32) 240static char cpu_arch[] = "ppc"; 241#elif defined(PPC64) 242static char cpu_arch[] = "ppc64"; 243#elif defined(SPARC) 244 #ifdef _LP64 245static char cpu_arch[] = "sparcv9"; 246 #else 247static char cpu_arch[] = "sparc"; 248 #endif 249#else 250 #error Add appropriate cpu_arch setting 251#endif 252 253 254// pid_t gettid() 255// 256// Returns the kernel thread id of the currently running thread. Kernel 257// thread id is used to access /proc. 258// 259// (Note that getpid() on LinuxThreads returns kernel thread id too; but 260// on NPTL, it returns the same pid for all threads, as required by POSIX.) 261// 262pid_t os::Linux::gettid() { 263 int rslt = syscall(SYS_gettid); 264 if (rslt == -1) { 265 // old kernel, no NPTL support 266 return getpid(); 267 } else { 268 return (pid_t)rslt; 269 } 270} 271 272// Most versions of linux have a bug where the number of processors are 273// determined by looking at the /proc file system. In a chroot environment, 274// the system call returns 1. This causes the VM to act as if it is 275// a single processor and elide locking (see is_MP() call). 276static bool unsafe_chroot_detected = false; 277static const char *unstable_chroot_error = "/proc file system not found.\n" 278 "Java may be unstable running multithreaded in a chroot " 279 "environment on Linux when /proc filesystem is not mounted."; 280 281void os::Linux::initialize_system_info() { 282 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 283 if (processor_count() == 1) { 284 pid_t pid = os::Linux::gettid(); 285 char fname[32]; 286 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 287 FILE *fp = fopen(fname, "r"); 288 if (fp == NULL) { 289 unsafe_chroot_detected = true; 290 } else { 291 fclose(fp); 292 } 293 } 294 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 295 assert(processor_count() > 0, "linux error"); 296} 297 298void os::init_system_properties_values() { 299 // The next steps are taken in the product version: 300 // 301 // Obtain the JAVA_HOME value from the location of libjvm.so. 302 // This library should be located at: 303 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 304 // 305 // If "/jre/lib/" appears at the right place in the path, then we 306 // assume libjvm.so is installed in a JDK and we use this path. 307 // 308 // Otherwise exit with message: "Could not create the Java virtual machine." 309 // 310 // The following extra steps are taken in the debugging version: 311 // 312 // If "/jre/lib/" does NOT appear at the right place in the path 313 // instead of exit check for $JAVA_HOME environment variable. 314 // 315 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 316 // then we append a fake suffix "hotspot/libjvm.so" to this path so 317 // it looks like libjvm.so is installed there 318 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 319 // 320 // Otherwise exit. 321 // 322 // Important note: if the location of libjvm.so changes this 323 // code needs to be changed accordingly. 324 325 // See ld(1): 326 // The linker uses the following search paths to locate required 327 // shared libraries: 328 // 1: ... 329 // ... 330 // 7: The default directories, normally /lib and /usr/lib. 331#if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 332 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 333#else 334 #define DEFAULT_LIBPATH "/lib:/usr/lib" 335#endif 336 337// Base path of extensions installed on the system. 338#define SYS_EXT_DIR "/usr/java/packages" 339#define EXTENSIONS_DIR "/lib/ext" 340 341 // Buffer that fits several sprintfs. 342 // Note that the space for the colon and the trailing null are provided 343 // by the nulls included by the sizeof operator. 344 const size_t bufsize = 345 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 346 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 347 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 348 349 // sysclasspath, java_home, dll_dir 350 { 351 char *pslash; 352 os::jvm_path(buf, bufsize); 353 354 // Found the full path to libjvm.so. 355 // Now cut the path to <java_home>/jre if we can. 356 pslash = strrchr(buf, '/'); 357 if (pslash != NULL) { 358 *pslash = '\0'; // Get rid of /libjvm.so. 359 } 360 pslash = strrchr(buf, '/'); 361 if (pslash != NULL) { 362 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 363 } 364 Arguments::set_dll_dir(buf); 365 366 if (pslash != NULL) { 367 pslash = strrchr(buf, '/'); 368 if (pslash != NULL) { 369 *pslash = '\0'; // Get rid of /<arch>. 370 pslash = strrchr(buf, '/'); 371 if (pslash != NULL) { 372 *pslash = '\0'; // Get rid of /lib. 373 } 374 } 375 } 376 Arguments::set_java_home(buf); 377 set_boot_path('/', ':'); 378 } 379 380 // Where to look for native libraries. 381 // 382 // Note: Due to a legacy implementation, most of the library path 383 // is set in the launcher. This was to accomodate linking restrictions 384 // on legacy Linux implementations (which are no longer supported). 385 // Eventually, all the library path setting will be done here. 386 // 387 // However, to prevent the proliferation of improperly built native 388 // libraries, the new path component /usr/java/packages is added here. 389 // Eventually, all the library path setting will be done here. 390 { 391 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 392 // should always exist (until the legacy problem cited above is 393 // addressed). 394 const char *v = ::getenv("LD_LIBRARY_PATH"); 395 const char *v_colon = ":"; 396 if (v == NULL) { v = ""; v_colon = ""; } 397 // That's +1 for the colon and +1 for the trailing '\0'. 398 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 399 strlen(v) + 1 + 400 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1, 401 mtInternal); 402 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch); 403 Arguments::set_library_path(ld_library_path); 404 FREE_C_HEAP_ARRAY(char, ld_library_path, mtInternal); 405 } 406 407 // Extensions directories. 408 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 409 Arguments::set_ext_dirs(buf); 410 411 FREE_C_HEAP_ARRAY(char, buf, mtInternal); 412 413#undef DEFAULT_LIBPATH 414#undef SYS_EXT_DIR 415#undef EXTENSIONS_DIR 416} 417 418//////////////////////////////////////////////////////////////////////////////// 419// breakpoint support 420 421void os::breakpoint() { 422 BREAKPOINT; 423} 424 425extern "C" void breakpoint() { 426 // use debugger to set breakpoint here 427} 428 429//////////////////////////////////////////////////////////////////////////////// 430// signal support 431 432debug_only(static bool signal_sets_initialized = false); 433static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 434 435bool os::Linux::is_sig_ignored(int sig) { 436 struct sigaction oact; 437 sigaction(sig, (struct sigaction*)NULL, &oact); 438 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 439 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 440 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 441 return true; 442 } else { 443 return false; 444 } 445} 446 447void os::Linux::signal_sets_init() { 448 // Should also have an assertion stating we are still single-threaded. 449 assert(!signal_sets_initialized, "Already initialized"); 450 // Fill in signals that are necessarily unblocked for all threads in 451 // the VM. Currently, we unblock the following signals: 452 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 453 // by -Xrs (=ReduceSignalUsage)); 454 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 455 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 456 // the dispositions or masks wrt these signals. 457 // Programs embedding the VM that want to use the above signals for their 458 // own purposes must, at this time, use the "-Xrs" option to prevent 459 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 460 // (See bug 4345157, and other related bugs). 461 // In reality, though, unblocking these signals is really a nop, since 462 // these signals are not blocked by default. 463 sigemptyset(&unblocked_sigs); 464 sigemptyset(&allowdebug_blocked_sigs); 465 sigaddset(&unblocked_sigs, SIGILL); 466 sigaddset(&unblocked_sigs, SIGSEGV); 467 sigaddset(&unblocked_sigs, SIGBUS); 468 sigaddset(&unblocked_sigs, SIGFPE); 469#if defined(PPC64) 470 sigaddset(&unblocked_sigs, SIGTRAP); 471#endif 472 sigaddset(&unblocked_sigs, SR_signum); 473 474 if (!ReduceSignalUsage) { 475 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 476 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 477 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 478 } 479 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 480 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 481 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 482 } 483 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 484 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 485 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 486 } 487 } 488 // Fill in signals that are blocked by all but the VM thread. 489 sigemptyset(&vm_sigs); 490 if (!ReduceSignalUsage) { 491 sigaddset(&vm_sigs, BREAK_SIGNAL); 492 } 493 debug_only(signal_sets_initialized = true); 494 495} 496 497// These are signals that are unblocked while a thread is running Java. 498// (For some reason, they get blocked by default.) 499sigset_t* os::Linux::unblocked_signals() { 500 assert(signal_sets_initialized, "Not initialized"); 501 return &unblocked_sigs; 502} 503 504// These are the signals that are blocked while a (non-VM) thread is 505// running Java. Only the VM thread handles these signals. 506sigset_t* os::Linux::vm_signals() { 507 assert(signal_sets_initialized, "Not initialized"); 508 return &vm_sigs; 509} 510 511// These are signals that are blocked during cond_wait to allow debugger in 512sigset_t* os::Linux::allowdebug_blocked_signals() { 513 assert(signal_sets_initialized, "Not initialized"); 514 return &allowdebug_blocked_sigs; 515} 516 517void os::Linux::hotspot_sigmask(Thread* thread) { 518 519 //Save caller's signal mask before setting VM signal mask 520 sigset_t caller_sigmask; 521 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 522 523 OSThread* osthread = thread->osthread(); 524 osthread->set_caller_sigmask(caller_sigmask); 525 526 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 527 528 if (!ReduceSignalUsage) { 529 if (thread->is_VM_thread()) { 530 // Only the VM thread handles BREAK_SIGNAL ... 531 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 532 } else { 533 // ... all other threads block BREAK_SIGNAL 534 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 535 } 536 } 537} 538 539////////////////////////////////////////////////////////////////////////////// 540// detecting pthread library 541 542void os::Linux::libpthread_init() { 543 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 544 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 545 // generic name for earlier versions. 546 // Define macros here so we can build HotSpot on old systems. 547#ifndef _CS_GNU_LIBC_VERSION 548 #define _CS_GNU_LIBC_VERSION 2 549#endif 550#ifndef _CS_GNU_LIBPTHREAD_VERSION 551 #define _CS_GNU_LIBPTHREAD_VERSION 3 552#endif 553 554 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 555 if (n > 0) { 556 char *str = (char *)malloc(n, mtInternal); 557 confstr(_CS_GNU_LIBC_VERSION, str, n); 558 os::Linux::set_glibc_version(str); 559 } else { 560 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 561 static char _gnu_libc_version[32]; 562 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 563 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 564 os::Linux::set_glibc_version(_gnu_libc_version); 565 } 566 567 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 568 if (n > 0) { 569 char *str = (char *)malloc(n, mtInternal); 570 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 571 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 572 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 573 // is the case. LinuxThreads has a hard limit on max number of threads. 574 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 575 // On the other hand, NPTL does not have such a limit, sysconf() 576 // will return -1 and errno is not changed. Check if it is really NPTL. 577 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 578 strstr(str, "NPTL") && 579 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 580 free(str); 581 os::Linux::set_libpthread_version("linuxthreads"); 582 } else { 583 os::Linux::set_libpthread_version(str); 584 } 585 } else { 586 // glibc before 2.3.2 only has LinuxThreads. 587 os::Linux::set_libpthread_version("linuxthreads"); 588 } 589 590 if (strstr(libpthread_version(), "NPTL")) { 591 os::Linux::set_is_NPTL(); 592 } else { 593 os::Linux::set_is_LinuxThreads(); 594 } 595 596 // LinuxThreads have two flavors: floating-stack mode, which allows variable 597 // stack size; and fixed-stack mode. NPTL is always floating-stack. 598 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 599 os::Linux::set_is_floating_stack(); 600 } 601} 602 603///////////////////////////////////////////////////////////////////////////// 604// thread stack 605 606// Force Linux kernel to expand current thread stack. If "bottom" is close 607// to the stack guard, caller should block all signals. 608// 609// MAP_GROWSDOWN: 610// A special mmap() flag that is used to implement thread stacks. It tells 611// kernel that the memory region should extend downwards when needed. This 612// allows early versions of LinuxThreads to only mmap the first few pages 613// when creating a new thread. Linux kernel will automatically expand thread 614// stack as needed (on page faults). 615// 616// However, because the memory region of a MAP_GROWSDOWN stack can grow on 617// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 618// region, it's hard to tell if the fault is due to a legitimate stack 619// access or because of reading/writing non-exist memory (e.g. buffer 620// overrun). As a rule, if the fault happens below current stack pointer, 621// Linux kernel does not expand stack, instead a SIGSEGV is sent to the 622// application (see Linux kernel fault.c). 623// 624// This Linux feature can cause SIGSEGV when VM bangs thread stack for 625// stack overflow detection. 626// 627// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 628// not use this flag. However, the stack of initial thread is not created 629// by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 630// unlikely) that user code can create a thread with MAP_GROWSDOWN stack 631// and then attach the thread to JVM. 632// 633// To get around the problem and allow stack banging on Linux, we need to 634// manually expand thread stack after receiving the SIGSEGV. 635// 636// There are two ways to expand thread stack to address "bottom", we used 637// both of them in JVM before 1.5: 638// 1. adjust stack pointer first so that it is below "bottom", and then 639// touch "bottom" 640// 2. mmap() the page in question 641// 642// Now alternate signal stack is gone, it's harder to use 2. For instance, 643// if current sp is already near the lower end of page 101, and we need to 644// call mmap() to map page 100, it is possible that part of the mmap() frame 645// will be placed in page 100. When page 100 is mapped, it is zero-filled. 646// That will destroy the mmap() frame and cause VM to crash. 647// 648// The following code works by adjusting sp first, then accessing the "bottom" 649// page to force a page fault. Linux kernel will then automatically expand the 650// stack mapping. 651// 652// _expand_stack_to() assumes its frame size is less than page size, which 653// should always be true if the function is not inlined. 654 655#if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 656 #define NOINLINE 657#else 658 #define NOINLINE __attribute__ ((noinline)) 659#endif 660 661static void _expand_stack_to(address bottom) NOINLINE; 662 663static void _expand_stack_to(address bottom) { 664 address sp; 665 size_t size; 666 volatile char *p; 667 668 // Adjust bottom to point to the largest address within the same page, it 669 // gives us a one-page buffer if alloca() allocates slightly more memory. 670 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 671 bottom += os::Linux::page_size() - 1; 672 673 // sp might be slightly above current stack pointer; if that's the case, we 674 // will alloca() a little more space than necessary, which is OK. Don't use 675 // os::current_stack_pointer(), as its result can be slightly below current 676 // stack pointer, causing us to not alloca enough to reach "bottom". 677 sp = (address)&sp; 678 679 if (sp > bottom) { 680 size = sp - bottom; 681 p = (volatile char *)alloca(size); 682 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 683 p[0] = '\0'; 684 } 685} 686 687bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 688 assert(t!=NULL, "just checking"); 689 assert(t->osthread()->expanding_stack(), "expand should be set"); 690 assert(t->stack_base() != NULL, "stack_base was not initialized"); 691 692 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 693 sigset_t mask_all, old_sigset; 694 sigfillset(&mask_all); 695 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 696 _expand_stack_to(addr); 697 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 698 return true; 699 } 700 return false; 701} 702 703////////////////////////////////////////////////////////////////////////////// 704// create new thread 705 706static address highest_vm_reserved_address(); 707 708// check if it's safe to start a new thread 709static bool _thread_safety_check(Thread* thread) { 710 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 711 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 712 // Heap is mmap'ed at lower end of memory space. Thread stacks are 713 // allocated (MAP_FIXED) from high address space. Every thread stack 714 // occupies a fixed size slot (usually 2Mbytes, but user can change 715 // it to other values if they rebuild LinuxThreads). 716 // 717 // Problem with MAP_FIXED is that mmap() can still succeed even part of 718 // the memory region has already been mmap'ed. That means if we have too 719 // many threads and/or very large heap, eventually thread stack will 720 // collide with heap. 721 // 722 // Here we try to prevent heap/stack collision by comparing current 723 // stack bottom with the highest address that has been mmap'ed by JVM 724 // plus a safety margin for memory maps created by native code. 725 // 726 // This feature can be disabled by setting ThreadSafetyMargin to 0 727 // 728 if (ThreadSafetyMargin > 0) { 729 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 730 731 // not safe if our stack extends below the safety margin 732 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 733 } else { 734 return true; 735 } 736 } else { 737 // Floating stack LinuxThreads or NPTL: 738 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 739 // there's not enough space left, pthread_create() will fail. If we come 740 // here, that means enough space has been reserved for stack. 741 return true; 742 } 743} 744 745// Thread start routine for all newly created threads 746static void *java_start(Thread *thread) { 747 // Try to randomize the cache line index of hot stack frames. 748 // This helps when threads of the same stack traces evict each other's 749 // cache lines. The threads can be either from the same JVM instance, or 750 // from different JVM instances. The benefit is especially true for 751 // processors with hyperthreading technology. 752 static int counter = 0; 753 int pid = os::current_process_id(); 754 alloca(((pid ^ counter++) & 7) * 128); 755 756 ThreadLocalStorage::set_thread(thread); 757 758 OSThread* osthread = thread->osthread(); 759 Monitor* sync = osthread->startThread_lock(); 760 761 // non floating stack LinuxThreads needs extra check, see above 762 if (!_thread_safety_check(thread)) { 763 // notify parent thread 764 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 765 osthread->set_state(ZOMBIE); 766 sync->notify_all(); 767 return NULL; 768 } 769 770 // thread_id is kernel thread id (similar to Solaris LWP id) 771 osthread->set_thread_id(os::Linux::gettid()); 772 773 if (UseNUMA) { 774 int lgrp_id = os::numa_get_group_id(); 775 if (lgrp_id != -1) { 776 thread->set_lgrp_id(lgrp_id); 777 } 778 } 779 // initialize signal mask for this thread 780 os::Linux::hotspot_sigmask(thread); 781 782 // initialize floating point control register 783 os::Linux::init_thread_fpu_state(); 784 785 // handshaking with parent thread 786 { 787 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 788 789 // notify parent thread 790 osthread->set_state(INITIALIZED); 791 sync->notify_all(); 792 793 // wait until os::start_thread() 794 while (osthread->get_state() == INITIALIZED) { 795 sync->wait(Mutex::_no_safepoint_check_flag); 796 } 797 } 798 799 // call one more level start routine 800 thread->run(); 801 802 return 0; 803} 804 805bool os::create_thread(Thread* thread, ThreadType thr_type, 806 size_t stack_size) { 807 assert(thread->osthread() == NULL, "caller responsible"); 808 809 // Allocate the OSThread object 810 OSThread* osthread = new OSThread(NULL, NULL); 811 if (osthread == NULL) { 812 return false; 813 } 814 815 // set the correct thread state 816 osthread->set_thread_type(thr_type); 817 818 // Initial state is ALLOCATED but not INITIALIZED 819 osthread->set_state(ALLOCATED); 820 821 thread->set_osthread(osthread); 822 823 // init thread attributes 824 pthread_attr_t attr; 825 pthread_attr_init(&attr); 826 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 827 828 // stack size 829 if (os::Linux::supports_variable_stack_size()) { 830 // calculate stack size if it's not specified by caller 831 if (stack_size == 0) { 832 stack_size = os::Linux::default_stack_size(thr_type); 833 834 switch (thr_type) { 835 case os::java_thread: 836 // Java threads use ThreadStackSize which default value can be 837 // changed with the flag -Xss 838 assert(JavaThread::stack_size_at_create() > 0, "this should be set"); 839 stack_size = JavaThread::stack_size_at_create(); 840 break; 841 case os::compiler_thread: 842 if (CompilerThreadStackSize > 0) { 843 stack_size = (size_t)(CompilerThreadStackSize * K); 844 break; 845 } // else fall through: 846 // use VMThreadStackSize if CompilerThreadStackSize is not defined 847 case os::vm_thread: 848 case os::pgc_thread: 849 case os::cgc_thread: 850 case os::watcher_thread: 851 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 852 break; 853 } 854 } 855 856 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 857 pthread_attr_setstacksize(&attr, stack_size); 858 } else { 859 // let pthread_create() pick the default value. 860 } 861 862 // glibc guard page 863 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 864 865 ThreadState state; 866 867 { 868 // Serialize thread creation if we are running with fixed stack LinuxThreads 869 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 870 if (lock) { 871 os::Linux::createThread_lock()->lock_without_safepoint_check(); 872 } 873 874 pthread_t tid; 875 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 876 877 pthread_attr_destroy(&attr); 878 879 if (ret != 0) { 880 if (PrintMiscellaneous && (Verbose || WizardMode)) { 881 perror("pthread_create()"); 882 } 883 // Need to clean up stuff we've allocated so far 884 thread->set_osthread(NULL); 885 delete osthread; 886 if (lock) os::Linux::createThread_lock()->unlock(); 887 return false; 888 } 889 890 // Store pthread info into the OSThread 891 osthread->set_pthread_id(tid); 892 893 // Wait until child thread is either initialized or aborted 894 { 895 Monitor* sync_with_child = osthread->startThread_lock(); 896 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 897 while ((state = osthread->get_state()) == ALLOCATED) { 898 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 899 } 900 } 901 902 if (lock) { 903 os::Linux::createThread_lock()->unlock(); 904 } 905 } 906 907 // Aborted due to thread limit being reached 908 if (state == ZOMBIE) { 909 thread->set_osthread(NULL); 910 delete osthread; 911 return false; 912 } 913 914 // The thread is returned suspended (in state INITIALIZED), 915 // and is started higher up in the call chain 916 assert(state == INITIALIZED, "race condition"); 917 return true; 918} 919 920///////////////////////////////////////////////////////////////////////////// 921// attach existing thread 922 923// bootstrap the main thread 924bool os::create_main_thread(JavaThread* thread) { 925 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 926 return create_attached_thread(thread); 927} 928 929bool os::create_attached_thread(JavaThread* thread) { 930#ifdef ASSERT 931 thread->verify_not_published(); 932#endif 933 934 // Allocate the OSThread object 935 OSThread* osthread = new OSThread(NULL, NULL); 936 937 if (osthread == NULL) { 938 return false; 939 } 940 941 // Store pthread info into the OSThread 942 osthread->set_thread_id(os::Linux::gettid()); 943 osthread->set_pthread_id(::pthread_self()); 944 945 // initialize floating point control register 946 os::Linux::init_thread_fpu_state(); 947 948 // Initial thread state is RUNNABLE 949 osthread->set_state(RUNNABLE); 950 951 thread->set_osthread(osthread); 952 953 if (UseNUMA) { 954 int lgrp_id = os::numa_get_group_id(); 955 if (lgrp_id != -1) { 956 thread->set_lgrp_id(lgrp_id); 957 } 958 } 959 960 if (os::Linux::is_initial_thread()) { 961 // If current thread is initial thread, its stack is mapped on demand, 962 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 963 // the entire stack region to avoid SEGV in stack banging. 964 // It is also useful to get around the heap-stack-gap problem on SuSE 965 // kernel (see 4821821 for details). We first expand stack to the top 966 // of yellow zone, then enable stack yellow zone (order is significant, 967 // enabling yellow zone first will crash JVM on SuSE Linux), so there 968 // is no gap between the last two virtual memory regions. 969 970 JavaThread *jt = (JavaThread *)thread; 971 address addr = jt->stack_yellow_zone_base(); 972 assert(addr != NULL, "initialization problem?"); 973 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 974 975 osthread->set_expanding_stack(); 976 os::Linux::manually_expand_stack(jt, addr); 977 osthread->clear_expanding_stack(); 978 } 979 980 // initialize signal mask for this thread 981 // and save the caller's signal mask 982 os::Linux::hotspot_sigmask(thread); 983 984 return true; 985} 986 987void os::pd_start_thread(Thread* thread) { 988 OSThread * osthread = thread->osthread(); 989 assert(osthread->get_state() != INITIALIZED, "just checking"); 990 Monitor* sync_with_child = osthread->startThread_lock(); 991 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 992 sync_with_child->notify(); 993} 994 995// Free Linux resources related to the OSThread 996void os::free_thread(OSThread* osthread) { 997 assert(osthread != NULL, "osthread not set"); 998 999 if (Thread::current()->osthread() == osthread) { 1000 // Restore caller's signal mask 1001 sigset_t sigmask = osthread->caller_sigmask(); 1002 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1003 } 1004 1005 delete osthread; 1006} 1007 1008////////////////////////////////////////////////////////////////////////////// 1009// thread local storage 1010 1011// Restore the thread pointer if the destructor is called. This is in case 1012// someone from JNI code sets up a destructor with pthread_key_create to run 1013// detachCurrentThread on thread death. Unless we restore the thread pointer we 1014// will hang or crash. When detachCurrentThread is called the key will be set 1015// to null and we will not be called again. If detachCurrentThread is never 1016// called we could loop forever depending on the pthread implementation. 1017static void restore_thread_pointer(void* p) { 1018 Thread* thread = (Thread*) p; 1019 os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread); 1020} 1021 1022int os::allocate_thread_local_storage() { 1023 pthread_key_t key; 1024 int rslt = pthread_key_create(&key, restore_thread_pointer); 1025 assert(rslt == 0, "cannot allocate thread local storage"); 1026 return (int)key; 1027} 1028 1029// Note: This is currently not used by VM, as we don't destroy TLS key 1030// on VM exit. 1031void os::free_thread_local_storage(int index) { 1032 int rslt = pthread_key_delete((pthread_key_t)index); 1033 assert(rslt == 0, "invalid index"); 1034} 1035 1036void os::thread_local_storage_at_put(int index, void* value) { 1037 int rslt = pthread_setspecific((pthread_key_t)index, value); 1038 assert(rslt == 0, "pthread_setspecific failed"); 1039} 1040 1041extern "C" Thread* get_thread() { 1042 return ThreadLocalStorage::thread(); 1043} 1044 1045////////////////////////////////////////////////////////////////////////////// 1046// initial thread 1047 1048// Check if current thread is the initial thread, similar to Solaris thr_main. 1049bool os::Linux::is_initial_thread(void) { 1050 char dummy; 1051 // If called before init complete, thread stack bottom will be null. 1052 // Can be called if fatal error occurs before initialization. 1053 if (initial_thread_stack_bottom() == NULL) return false; 1054 assert(initial_thread_stack_bottom() != NULL && 1055 initial_thread_stack_size() != 0, 1056 "os::init did not locate initial thread's stack region"); 1057 if ((address)&dummy >= initial_thread_stack_bottom() && 1058 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 1059 return true; 1060 } else { 1061 return false; 1062 } 1063} 1064 1065// Find the virtual memory area that contains addr 1066static bool find_vma(address addr, address* vma_low, address* vma_high) { 1067 FILE *fp = fopen("/proc/self/maps", "r"); 1068 if (fp) { 1069 address low, high; 1070 while (!feof(fp)) { 1071 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1072 if (low <= addr && addr < high) { 1073 if (vma_low) *vma_low = low; 1074 if (vma_high) *vma_high = high; 1075 fclose(fp); 1076 return true; 1077 } 1078 } 1079 for (;;) { 1080 int ch = fgetc(fp); 1081 if (ch == EOF || ch == (int)'\n') break; 1082 } 1083 } 1084 fclose(fp); 1085 } 1086 return false; 1087} 1088 1089// Locate initial thread stack. This special handling of initial thread stack 1090// is needed because pthread_getattr_np() on most (all?) Linux distros returns 1091// bogus value for initial thread. 1092void os::Linux::capture_initial_stack(size_t max_size) { 1093 // stack size is the easy part, get it from RLIMIT_STACK 1094 size_t stack_size; 1095 struct rlimit rlim; 1096 getrlimit(RLIMIT_STACK, &rlim); 1097 stack_size = rlim.rlim_cur; 1098 1099 // 6308388: a bug in ld.so will relocate its own .data section to the 1100 // lower end of primordial stack; reduce ulimit -s value a little bit 1101 // so we won't install guard page on ld.so's data section. 1102 stack_size -= 2 * page_size(); 1103 1104 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1105 // 7.1, in both cases we will get 2G in return value. 1106 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1107 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1108 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1109 // in case other parts in glibc still assumes 2M max stack size. 1110 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1111 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1112 if (stack_size > 2 * K * K IA64_ONLY(*2)) { 1113 stack_size = 2 * K * K IA64_ONLY(*2); 1114 } 1115 // Try to figure out where the stack base (top) is. This is harder. 1116 // 1117 // When an application is started, glibc saves the initial stack pointer in 1118 // a global variable "__libc_stack_end", which is then used by system 1119 // libraries. __libc_stack_end should be pretty close to stack top. The 1120 // variable is available since the very early days. However, because it is 1121 // a private interface, it could disappear in the future. 1122 // 1123 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1124 // to __libc_stack_end, it is very close to stack top, but isn't the real 1125 // stack top. Note that /proc may not exist if VM is running as a chroot 1126 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1127 // /proc/<pid>/stat could change in the future (though unlikely). 1128 // 1129 // We try __libc_stack_end first. If that doesn't work, look for 1130 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1131 // as a hint, which should work well in most cases. 1132 1133 uintptr_t stack_start; 1134 1135 // try __libc_stack_end first 1136 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1137 if (p && *p) { 1138 stack_start = *p; 1139 } else { 1140 // see if we can get the start_stack field from /proc/self/stat 1141 FILE *fp; 1142 int pid; 1143 char state; 1144 int ppid; 1145 int pgrp; 1146 int session; 1147 int nr; 1148 int tpgrp; 1149 unsigned long flags; 1150 unsigned long minflt; 1151 unsigned long cminflt; 1152 unsigned long majflt; 1153 unsigned long cmajflt; 1154 unsigned long utime; 1155 unsigned long stime; 1156 long cutime; 1157 long cstime; 1158 long prio; 1159 long nice; 1160 long junk; 1161 long it_real; 1162 uintptr_t start; 1163 uintptr_t vsize; 1164 intptr_t rss; 1165 uintptr_t rsslim; 1166 uintptr_t scodes; 1167 uintptr_t ecode; 1168 int i; 1169 1170 // Figure what the primordial thread stack base is. Code is inspired 1171 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1172 // followed by command name surrounded by parentheses, state, etc. 1173 char stat[2048]; 1174 int statlen; 1175 1176 fp = fopen("/proc/self/stat", "r"); 1177 if (fp) { 1178 statlen = fread(stat, 1, 2047, fp); 1179 stat[statlen] = '\0'; 1180 fclose(fp); 1181 1182 // Skip pid and the command string. Note that we could be dealing with 1183 // weird command names, e.g. user could decide to rename java launcher 1184 // to "java 1.4.2 :)", then the stat file would look like 1185 // 1234 (java 1.4.2 :)) R ... ... 1186 // We don't really need to know the command string, just find the last 1187 // occurrence of ")" and then start parsing from there. See bug 4726580. 1188 char * s = strrchr(stat, ')'); 1189 1190 i = 0; 1191 if (s) { 1192 // Skip blank chars 1193 do { s++; } while (s && isspace(*s)); 1194 1195#define _UFM UINTX_FORMAT 1196#define _DFM INTX_FORMAT 1197 1198 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1199 // 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 1200 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, 1201 &state, // 3 %c 1202 &ppid, // 4 %d 1203 &pgrp, // 5 %d 1204 &session, // 6 %d 1205 &nr, // 7 %d 1206 &tpgrp, // 8 %d 1207 &flags, // 9 %lu 1208 &minflt, // 10 %lu 1209 &cminflt, // 11 %lu 1210 &majflt, // 12 %lu 1211 &cmajflt, // 13 %lu 1212 &utime, // 14 %lu 1213 &stime, // 15 %lu 1214 &cutime, // 16 %ld 1215 &cstime, // 17 %ld 1216 &prio, // 18 %ld 1217 &nice, // 19 %ld 1218 &junk, // 20 %ld 1219 &it_real, // 21 %ld 1220 &start, // 22 UINTX_FORMAT 1221 &vsize, // 23 UINTX_FORMAT 1222 &rss, // 24 INTX_FORMAT 1223 &rsslim, // 25 UINTX_FORMAT 1224 &scodes, // 26 UINTX_FORMAT 1225 &ecode, // 27 UINTX_FORMAT 1226 &stack_start); // 28 UINTX_FORMAT 1227 } 1228 1229#undef _UFM 1230#undef _DFM 1231 1232 if (i != 28 - 2) { 1233 assert(false, "Bad conversion from /proc/self/stat"); 1234 // product mode - assume we are the initial thread, good luck in the 1235 // embedded case. 1236 warning("Can't detect initial thread stack location - bad conversion"); 1237 stack_start = (uintptr_t) &rlim; 1238 } 1239 } else { 1240 // For some reason we can't open /proc/self/stat (for example, running on 1241 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1242 // most cases, so don't abort: 1243 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1244 stack_start = (uintptr_t) &rlim; 1245 } 1246 } 1247 1248 // Now we have a pointer (stack_start) very close to the stack top, the 1249 // next thing to do is to figure out the exact location of stack top. We 1250 // can find out the virtual memory area that contains stack_start by 1251 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1252 // and its upper limit is the real stack top. (again, this would fail if 1253 // running inside chroot, because /proc may not exist.) 1254 1255 uintptr_t stack_top; 1256 address low, high; 1257 if (find_vma((address)stack_start, &low, &high)) { 1258 // success, "high" is the true stack top. (ignore "low", because initial 1259 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1260 stack_top = (uintptr_t)high; 1261 } else { 1262 // failed, likely because /proc/self/maps does not exist 1263 warning("Can't detect initial thread stack location - find_vma failed"); 1264 // best effort: stack_start is normally within a few pages below the real 1265 // stack top, use it as stack top, and reduce stack size so we won't put 1266 // guard page outside stack. 1267 stack_top = stack_start; 1268 stack_size -= 16 * page_size(); 1269 } 1270 1271 // stack_top could be partially down the page so align it 1272 stack_top = align_size_up(stack_top, page_size()); 1273 1274 if (max_size && stack_size > max_size) { 1275 _initial_thread_stack_size = max_size; 1276 } else { 1277 _initial_thread_stack_size = stack_size; 1278 } 1279 1280 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1281 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1282} 1283 1284//////////////////////////////////////////////////////////////////////////////// 1285// time support 1286 1287// Time since start-up in seconds to a fine granularity. 1288// Used by VMSelfDestructTimer and the MemProfiler. 1289double os::elapsedTime() { 1290 1291 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1292} 1293 1294jlong os::elapsed_counter() { 1295 return javaTimeNanos() - initial_time_count; 1296} 1297 1298jlong os::elapsed_frequency() { 1299 return NANOSECS_PER_SEC; // nanosecond resolution 1300} 1301 1302bool os::supports_vtime() { return true; } 1303bool os::enable_vtime() { return false; } 1304bool os::vtime_enabled() { return false; } 1305 1306double os::elapsedVTime() { 1307 struct rusage usage; 1308 int retval = getrusage(RUSAGE_THREAD, &usage); 1309 if (retval == 0) { 1310 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); 1311 } else { 1312 // better than nothing, but not much 1313 return elapsedTime(); 1314 } 1315} 1316 1317jlong os::javaTimeMillis() { 1318 timeval time; 1319 int status = gettimeofday(&time, NULL); 1320 assert(status != -1, "linux error"); 1321 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1322} 1323 1324#ifndef CLOCK_MONOTONIC 1325 #define CLOCK_MONOTONIC (1) 1326#endif 1327 1328void os::Linux::clock_init() { 1329 // we do dlopen's in this particular order due to bug in linux 1330 // dynamical loader (see 6348968) leading to crash on exit 1331 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1332 if (handle == NULL) { 1333 handle = dlopen("librt.so", RTLD_LAZY); 1334 } 1335 1336 if (handle) { 1337 int (*clock_getres_func)(clockid_t, struct timespec*) = 1338 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1339 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1340 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1341 if (clock_getres_func && clock_gettime_func) { 1342 // See if monotonic clock is supported by the kernel. Note that some 1343 // early implementations simply return kernel jiffies (updated every 1344 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1345 // for nano time (though the monotonic property is still nice to have). 1346 // It's fixed in newer kernels, however clock_getres() still returns 1347 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1348 // resolution for now. Hopefully as people move to new kernels, this 1349 // won't be a problem. 1350 struct timespec res; 1351 struct timespec tp; 1352 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1353 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1354 // yes, monotonic clock is supported 1355 _clock_gettime = clock_gettime_func; 1356 return; 1357 } else { 1358 // close librt if there is no monotonic clock 1359 dlclose(handle); 1360 } 1361 } 1362 } 1363 warning("No monotonic clock was available - timed services may " \ 1364 "be adversely affected if the time-of-day clock changes"); 1365} 1366 1367#ifndef SYS_clock_getres 1368 #if defined(IA32) || defined(AMD64) 1369 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1370 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1371 #else 1372 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1373 #define sys_clock_getres(x,y) -1 1374 #endif 1375#else 1376 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1377#endif 1378 1379void os::Linux::fast_thread_clock_init() { 1380 if (!UseLinuxPosixThreadCPUClocks) { 1381 return; 1382 } 1383 clockid_t clockid; 1384 struct timespec tp; 1385 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1386 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1387 1388 // Switch to using fast clocks for thread cpu time if 1389 // the sys_clock_getres() returns 0 error code. 1390 // Note, that some kernels may support the current thread 1391 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1392 // returned by the pthread_getcpuclockid(). 1393 // If the fast Posix clocks are supported then the sys_clock_getres() 1394 // must return at least tp.tv_sec == 0 which means a resolution 1395 // better than 1 sec. This is extra check for reliability. 1396 1397 if (pthread_getcpuclockid_func && 1398 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1399 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1400 _supports_fast_thread_cpu_time = true; 1401 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1402 } 1403} 1404 1405jlong os::javaTimeNanos() { 1406 if (os::supports_monotonic_clock()) { 1407 struct timespec tp; 1408 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1409 assert(status == 0, "gettime error"); 1410 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1411 return result; 1412 } else { 1413 timeval time; 1414 int status = gettimeofday(&time, NULL); 1415 assert(status != -1, "linux error"); 1416 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1417 return 1000 * usecs; 1418 } 1419} 1420 1421void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1422 if (os::supports_monotonic_clock()) { 1423 info_ptr->max_value = ALL_64_BITS; 1424 1425 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1426 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1427 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1428 } else { 1429 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1430 info_ptr->max_value = ALL_64_BITS; 1431 1432 // gettimeofday is a real time clock so it skips 1433 info_ptr->may_skip_backward = true; 1434 info_ptr->may_skip_forward = true; 1435 } 1436 1437 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1438} 1439 1440// Return the real, user, and system times in seconds from an 1441// arbitrary fixed point in the past. 1442bool os::getTimesSecs(double* process_real_time, 1443 double* process_user_time, 1444 double* process_system_time) { 1445 struct tms ticks; 1446 clock_t real_ticks = times(&ticks); 1447 1448 if (real_ticks == (clock_t) (-1)) { 1449 return false; 1450 } else { 1451 double ticks_per_second = (double) clock_tics_per_sec; 1452 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1453 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1454 *process_real_time = ((double) real_ticks) / ticks_per_second; 1455 1456 return true; 1457 } 1458} 1459 1460 1461char * os::local_time_string(char *buf, size_t buflen) { 1462 struct tm t; 1463 time_t long_time; 1464 time(&long_time); 1465 localtime_r(&long_time, &t); 1466 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1467 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1468 t.tm_hour, t.tm_min, t.tm_sec); 1469 return buf; 1470} 1471 1472struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1473 return localtime_r(clock, res); 1474} 1475 1476//////////////////////////////////////////////////////////////////////////////// 1477// runtime exit support 1478 1479// Note: os::shutdown() might be called very early during initialization, or 1480// called from signal handler. Before adding something to os::shutdown(), make 1481// sure it is async-safe and can handle partially initialized VM. 1482void os::shutdown() { 1483 1484 // allow PerfMemory to attempt cleanup of any persistent resources 1485 perfMemory_exit(); 1486 1487 // needs to remove object in file system 1488 AttachListener::abort(); 1489 1490 // flush buffered output, finish log files 1491 ostream_abort(); 1492 1493 // Check for abort hook 1494 abort_hook_t abort_hook = Arguments::abort_hook(); 1495 if (abort_hook != NULL) { 1496 abort_hook(); 1497 } 1498 1499} 1500 1501// Note: os::abort() might be called very early during initialization, or 1502// called from signal handler. Before adding something to os::abort(), make 1503// sure it is async-safe and can handle partially initialized VM. 1504void os::abort(bool dump_core) { 1505 os::shutdown(); 1506 if (dump_core) { 1507#ifndef PRODUCT 1508 fdStream out(defaultStream::output_fd()); 1509 out.print_raw("Current thread is "); 1510 char buf[16]; 1511 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1512 out.print_raw_cr(buf); 1513 out.print_raw_cr("Dumping core ..."); 1514#endif 1515 ::abort(); // dump core 1516 } 1517 1518 ::exit(1); 1519} 1520 1521// Die immediately, no exit hook, no abort hook, no cleanup. 1522void os::die() { 1523 // _exit() on LinuxThreads only kills current thread 1524 ::abort(); 1525} 1526 1527 1528// This method is a copy of JDK's sysGetLastErrorString 1529// from src/solaris/hpi/src/system_md.c 1530 1531size_t os::lasterror(char *buf, size_t len) { 1532 if (errno == 0) return 0; 1533 1534 const char *s = ::strerror(errno); 1535 size_t n = ::strlen(s); 1536 if (n >= len) { 1537 n = len - 1; 1538 } 1539 ::strncpy(buf, s, n); 1540 buf[n] = '\0'; 1541 return n; 1542} 1543 1544intx os::current_thread_id() { return (intx)pthread_self(); } 1545int os::current_process_id() { 1546 1547 // Under the old linux thread library, linux gives each thread 1548 // its own process id. Because of this each thread will return 1549 // a different pid if this method were to return the result 1550 // of getpid(2). Linux provides no api that returns the pid 1551 // of the launcher thread for the vm. This implementation 1552 // returns a unique pid, the pid of the launcher thread 1553 // that starts the vm 'process'. 1554 1555 // Under the NPTL, getpid() returns the same pid as the 1556 // launcher thread rather than a unique pid per thread. 1557 // Use gettid() if you want the old pre NPTL behaviour. 1558 1559 // if you are looking for the result of a call to getpid() that 1560 // returns a unique pid for the calling thread, then look at the 1561 // OSThread::thread_id() method in osThread_linux.hpp file 1562 1563 return (int)(_initial_pid ? _initial_pid : getpid()); 1564} 1565 1566// DLL functions 1567 1568const char* os::dll_file_extension() { return ".so"; } 1569 1570// This must be hard coded because it's the system's temporary 1571// directory not the java application's temp directory, ala java.io.tmpdir. 1572const char* os::get_temp_directory() { return "/tmp"; } 1573 1574static bool file_exists(const char* filename) { 1575 struct stat statbuf; 1576 if (filename == NULL || strlen(filename) == 0) { 1577 return false; 1578 } 1579 return os::stat(filename, &statbuf) == 0; 1580} 1581 1582bool os::dll_build_name(char* buffer, size_t buflen, 1583 const char* pname, const char* fname) { 1584 bool retval = false; 1585 // Copied from libhpi 1586 const size_t pnamelen = pname ? strlen(pname) : 0; 1587 1588 // Return error on buffer overflow. 1589 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1590 return retval; 1591 } 1592 1593 if (pnamelen == 0) { 1594 snprintf(buffer, buflen, "lib%s.so", fname); 1595 retval = true; 1596 } else if (strchr(pname, *os::path_separator()) != NULL) { 1597 int n; 1598 char** pelements = split_path(pname, &n); 1599 if (pelements == NULL) { 1600 return false; 1601 } 1602 for (int i = 0; i < n; i++) { 1603 // Really shouldn't be NULL, but check can't hurt 1604 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1605 continue; // skip the empty path values 1606 } 1607 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1608 if (file_exists(buffer)) { 1609 retval = true; 1610 break; 1611 } 1612 } 1613 // release the storage 1614 for (int i = 0; i < n; i++) { 1615 if (pelements[i] != NULL) { 1616 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal); 1617 } 1618 } 1619 if (pelements != NULL) { 1620 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal); 1621 } 1622 } else { 1623 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1624 retval = true; 1625 } 1626 return retval; 1627} 1628 1629// check if addr is inside libjvm.so 1630bool os::address_is_in_vm(address addr) { 1631 static address libjvm_base_addr; 1632 Dl_info dlinfo; 1633 1634 if (libjvm_base_addr == NULL) { 1635 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1636 libjvm_base_addr = (address)dlinfo.dli_fbase; 1637 } 1638 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1639 } 1640 1641 if (dladdr((void *)addr, &dlinfo) != 0) { 1642 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1643 } 1644 1645 return false; 1646} 1647 1648bool os::dll_address_to_function_name(address addr, char *buf, 1649 int buflen, int *offset) { 1650 // buf is not optional, but offset is optional 1651 assert(buf != NULL, "sanity check"); 1652 1653 Dl_info dlinfo; 1654 1655 if (dladdr((void*)addr, &dlinfo) != 0) { 1656 // see if we have a matching symbol 1657 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1658 if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1659 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1660 } 1661 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1662 return true; 1663 } 1664 // no matching symbol so try for just file info 1665 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1666 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1667 buf, buflen, offset, dlinfo.dli_fname)) { 1668 return true; 1669 } 1670 } 1671 } 1672 1673 buf[0] = '\0'; 1674 if (offset != NULL) *offset = -1; 1675 return false; 1676} 1677 1678struct _address_to_library_name { 1679 address addr; // input : memory address 1680 size_t buflen; // size of fname 1681 char* fname; // output: library name 1682 address base; // library base addr 1683}; 1684 1685static int address_to_library_name_callback(struct dl_phdr_info *info, 1686 size_t size, void *data) { 1687 int i; 1688 bool found = false; 1689 address libbase = NULL; 1690 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1691 1692 // iterate through all loadable segments 1693 for (i = 0; i < info->dlpi_phnum; i++) { 1694 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1695 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1696 // base address of a library is the lowest address of its loaded 1697 // segments. 1698 if (libbase == NULL || libbase > segbase) { 1699 libbase = segbase; 1700 } 1701 // see if 'addr' is within current segment 1702 if (segbase <= d->addr && 1703 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1704 found = true; 1705 } 1706 } 1707 } 1708 1709 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1710 // so dll_address_to_library_name() can fall through to use dladdr() which 1711 // can figure out executable name from argv[0]. 1712 if (found && info->dlpi_name && info->dlpi_name[0]) { 1713 d->base = libbase; 1714 if (d->fname) { 1715 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1716 } 1717 return 1; 1718 } 1719 return 0; 1720} 1721 1722bool os::dll_address_to_library_name(address addr, char* buf, 1723 int buflen, int* offset) { 1724 // buf is not optional, but offset is optional 1725 assert(buf != NULL, "sanity check"); 1726 1727 Dl_info dlinfo; 1728 struct _address_to_library_name data; 1729 1730 // There is a bug in old glibc dladdr() implementation that it could resolve 1731 // to wrong library name if the .so file has a base address != NULL. Here 1732 // we iterate through the program headers of all loaded libraries to find 1733 // out which library 'addr' really belongs to. This workaround can be 1734 // removed once the minimum requirement for glibc is moved to 2.3.x. 1735 data.addr = addr; 1736 data.fname = buf; 1737 data.buflen = buflen; 1738 data.base = NULL; 1739 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1740 1741 if (rslt) { 1742 // buf already contains library name 1743 if (offset) *offset = addr - data.base; 1744 return true; 1745 } 1746 if (dladdr((void*)addr, &dlinfo) != 0) { 1747 if (dlinfo.dli_fname != NULL) { 1748 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1749 } 1750 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1751 *offset = addr - (address)dlinfo.dli_fbase; 1752 } 1753 return true; 1754 } 1755 1756 buf[0] = '\0'; 1757 if (offset) *offset = -1; 1758 return false; 1759} 1760 1761// Loads .dll/.so and 1762// in case of error it checks if .dll/.so was built for the 1763// same architecture as Hotspot is running on 1764 1765 1766// Remember the stack's state. The Linux dynamic linker will change 1767// the stack to 'executable' at most once, so we must safepoint only once. 1768bool os::Linux::_stack_is_executable = false; 1769 1770// VM operation that loads a library. This is necessary if stack protection 1771// of the Java stacks can be lost during loading the library. If we 1772// do not stop the Java threads, they can stack overflow before the stacks 1773// are protected again. 1774class VM_LinuxDllLoad: public VM_Operation { 1775 private: 1776 const char *_filename; 1777 char *_ebuf; 1778 int _ebuflen; 1779 void *_lib; 1780 public: 1781 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1782 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1783 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1784 void doit() { 1785 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1786 os::Linux::_stack_is_executable = true; 1787 } 1788 void* loaded_library() { return _lib; } 1789}; 1790 1791void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1792 void * result = NULL; 1793 bool load_attempted = false; 1794 1795 // Check whether the library to load might change execution rights 1796 // of the stack. If they are changed, the protection of the stack 1797 // guard pages will be lost. We need a safepoint to fix this. 1798 // 1799 // See Linux man page execstack(8) for more info. 1800 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1801 ElfFile ef(filename); 1802 if (!ef.specifies_noexecstack()) { 1803 if (!is_init_completed()) { 1804 os::Linux::_stack_is_executable = true; 1805 // This is OK - No Java threads have been created yet, and hence no 1806 // stack guard pages to fix. 1807 // 1808 // This should happen only when you are building JDK7 using a very 1809 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1810 // 1811 // Dynamic loader will make all stacks executable after 1812 // this function returns, and will not do that again. 1813 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1814 } else { 1815 warning("You have loaded library %s which might have disabled stack guard. " 1816 "The VM will try to fix the stack guard now.\n" 1817 "It's highly recommended that you fix the library with " 1818 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1819 filename); 1820 1821 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1822 JavaThread *jt = JavaThread::current(); 1823 if (jt->thread_state() != _thread_in_native) { 1824 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1825 // that requires ExecStack. Cannot enter safe point. Let's give up. 1826 warning("Unable to fix stack guard. Giving up."); 1827 } else { 1828 if (!LoadExecStackDllInVMThread) { 1829 // This is for the case where the DLL has an static 1830 // constructor function that executes JNI code. We cannot 1831 // load such DLLs in the VMThread. 1832 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1833 } 1834 1835 ThreadInVMfromNative tiv(jt); 1836 debug_only(VMNativeEntryWrapper vew;) 1837 1838 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1839 VMThread::execute(&op); 1840 if (LoadExecStackDllInVMThread) { 1841 result = op.loaded_library(); 1842 } 1843 load_attempted = true; 1844 } 1845 } 1846 } 1847 } 1848 1849 if (!load_attempted) { 1850 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1851 } 1852 1853 if (result != NULL) { 1854 // Successful loading 1855 return result; 1856 } 1857 1858 Elf32_Ehdr elf_head; 1859 int diag_msg_max_length=ebuflen-strlen(ebuf); 1860 char* diag_msg_buf=ebuf+strlen(ebuf); 1861 1862 if (diag_msg_max_length==0) { 1863 // No more space in ebuf for additional diagnostics message 1864 return NULL; 1865 } 1866 1867 1868 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1869 1870 if (file_descriptor < 0) { 1871 // Can't open library, report dlerror() message 1872 return NULL; 1873 } 1874 1875 bool failed_to_read_elf_head= 1876 (sizeof(elf_head)!= 1877 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1878 1879 ::close(file_descriptor); 1880 if (failed_to_read_elf_head) { 1881 // file i/o error - report dlerror() msg 1882 return NULL; 1883 } 1884 1885 typedef struct { 1886 Elf32_Half code; // Actual value as defined in elf.h 1887 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1888 char elf_class; // 32 or 64 bit 1889 char endianess; // MSB or LSB 1890 char* name; // String representation 1891 } arch_t; 1892 1893#ifndef EM_486 1894 #define EM_486 6 /* Intel 80486 */ 1895#endif 1896 1897 static const arch_t arch_array[]={ 1898 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1899 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1900 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1901 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1902 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1903 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1904 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1905 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1906#if defined(VM_LITTLE_ENDIAN) 1907 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1908#else 1909 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1910#endif 1911 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1912 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1913 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1914 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1915 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1916 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1917 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1918 }; 1919 1920#if (defined IA32) 1921 static Elf32_Half running_arch_code=EM_386; 1922#elif (defined AMD64) 1923 static Elf32_Half running_arch_code=EM_X86_64; 1924#elif (defined IA64) 1925 static Elf32_Half running_arch_code=EM_IA_64; 1926#elif (defined __sparc) && (defined _LP64) 1927 static Elf32_Half running_arch_code=EM_SPARCV9; 1928#elif (defined __sparc) && (!defined _LP64) 1929 static Elf32_Half running_arch_code=EM_SPARC; 1930#elif (defined __powerpc64__) 1931 static Elf32_Half running_arch_code=EM_PPC64; 1932#elif (defined __powerpc__) 1933 static Elf32_Half running_arch_code=EM_PPC; 1934#elif (defined ARM) 1935 static Elf32_Half running_arch_code=EM_ARM; 1936#elif (defined S390) 1937 static Elf32_Half running_arch_code=EM_S390; 1938#elif (defined ALPHA) 1939 static Elf32_Half running_arch_code=EM_ALPHA; 1940#elif (defined MIPSEL) 1941 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1942#elif (defined PARISC) 1943 static Elf32_Half running_arch_code=EM_PARISC; 1944#elif (defined MIPS) 1945 static Elf32_Half running_arch_code=EM_MIPS; 1946#elif (defined M68K) 1947 static Elf32_Half running_arch_code=EM_68K; 1948#else 1949 #error Method os::dll_load requires that one of following is defined:\ 1950 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1951#endif 1952 1953 // Identify compatability class for VM's architecture and library's architecture 1954 // Obtain string descriptions for architectures 1955 1956 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1957 int running_arch_index=-1; 1958 1959 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1960 if (running_arch_code == arch_array[i].code) { 1961 running_arch_index = i; 1962 } 1963 if (lib_arch.code == arch_array[i].code) { 1964 lib_arch.compat_class = arch_array[i].compat_class; 1965 lib_arch.name = arch_array[i].name; 1966 } 1967 } 1968 1969 assert(running_arch_index != -1, 1970 "Didn't find running architecture code (running_arch_code) in arch_array"); 1971 if (running_arch_index == -1) { 1972 // Even though running architecture detection failed 1973 // we may still continue with reporting dlerror() message 1974 return NULL; 1975 } 1976 1977 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1978 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1979 return NULL; 1980 } 1981 1982#ifndef S390 1983 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1984 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1985 return NULL; 1986 } 1987#endif // !S390 1988 1989 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1990 if (lib_arch.name!=NULL) { 1991 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1992 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1993 lib_arch.name, arch_array[running_arch_index].name); 1994 } else { 1995 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1996 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1997 lib_arch.code, 1998 arch_array[running_arch_index].name); 1999 } 2000 } 2001 2002 return NULL; 2003} 2004 2005void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 2006 int ebuflen) { 2007 void * result = ::dlopen(filename, RTLD_LAZY); 2008 if (result == NULL) { 2009 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 2010 ebuf[ebuflen-1] = '\0'; 2011 } 2012 return result; 2013} 2014 2015void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 2016 int ebuflen) { 2017 void * result = NULL; 2018 if (LoadExecStackDllInVMThread) { 2019 result = dlopen_helper(filename, ebuf, ebuflen); 2020 } 2021 2022 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 2023 // library that requires an executable stack, or which does not have this 2024 // stack attribute set, dlopen changes the stack attribute to executable. The 2025 // read protection of the guard pages gets lost. 2026 // 2027 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 2028 // may have been queued at the same time. 2029 2030 if (!_stack_is_executable) { 2031 JavaThread *jt = Threads::first(); 2032 2033 while (jt) { 2034 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 2035 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions 2036 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(), 2037 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) { 2038 warning("Attempt to reguard stack yellow zone failed."); 2039 } 2040 } 2041 jt = jt->next(); 2042 } 2043 } 2044 2045 return result; 2046} 2047 2048// glibc-2.0 libdl is not MT safe. If you are building with any glibc, 2049// chances are you might want to run the generated bits against glibc-2.0 2050// libdl.so, so always use locking for any version of glibc. 2051// 2052void* os::dll_lookup(void* handle, const char* name) { 2053 pthread_mutex_lock(&dl_mutex); 2054 void* res = dlsym(handle, name); 2055 pthread_mutex_unlock(&dl_mutex); 2056 return res; 2057} 2058 2059void* os::get_default_process_handle() { 2060 return (void*)::dlopen(NULL, RTLD_LAZY); 2061} 2062 2063static bool _print_ascii_file(const char* filename, outputStream* st) { 2064 int fd = ::open(filename, O_RDONLY); 2065 if (fd == -1) { 2066 return false; 2067 } 2068 2069 char buf[32]; 2070 int bytes; 2071 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 2072 st->print_raw(buf, bytes); 2073 } 2074 2075 ::close(fd); 2076 2077 return true; 2078} 2079 2080void os::print_dll_info(outputStream *st) { 2081 st->print_cr("Dynamic libraries:"); 2082 2083 char fname[32]; 2084 pid_t pid = os::Linux::gettid(); 2085 2086 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2087 2088 if (!_print_ascii_file(fname, st)) { 2089 st->print("Can not get library information for pid = %d\n", pid); 2090 } 2091} 2092 2093int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 2094 FILE *procmapsFile = NULL; 2095 2096 // Open the procfs maps file for the current process 2097 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 2098 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 2099 char line[PATH_MAX + 100]; 2100 2101 // Read line by line from 'file' 2102 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 2103 u8 base, top, offset, inode; 2104 char permissions[5]; 2105 char device[6]; 2106 char name[PATH_MAX + 1]; 2107 2108 // Parse fields from line 2109 sscanf(line, "%lx-%lx %4s %lx %5s %ld %s", &base, &top, permissions, &offset, device, &inode, name); 2110 2111 // Filter by device id '00:00' so that we only get file system mapped files. 2112 if (strcmp(device, "00:00") != 0) { 2113 2114 // Call callback with the fields of interest 2115 if(callback(name, (address)base, (address)top, param)) { 2116 // Oops abort, callback aborted 2117 fclose(procmapsFile); 2118 return 1; 2119 } 2120 } 2121 } 2122 fclose(procmapsFile); 2123 } 2124 return 0; 2125} 2126 2127void os::print_os_info_brief(outputStream* st) { 2128 os::Linux::print_distro_info(st); 2129 2130 os::Posix::print_uname_info(st); 2131 2132 os::Linux::print_libversion_info(st); 2133 2134} 2135 2136void os::print_os_info(outputStream* st) { 2137 st->print("OS:"); 2138 2139 os::Linux::print_distro_info(st); 2140 2141 os::Posix::print_uname_info(st); 2142 2143 // Print warning if unsafe chroot environment detected 2144 if (unsafe_chroot_detected) { 2145 st->print("WARNING!! "); 2146 st->print_cr("%s", unstable_chroot_error); 2147 } 2148 2149 os::Linux::print_libversion_info(st); 2150 2151 os::Posix::print_rlimit_info(st); 2152 2153 os::Posix::print_load_average(st); 2154 2155 os::Linux::print_full_memory_info(st); 2156} 2157 2158// Try to identify popular distros. 2159// Most Linux distributions have a /etc/XXX-release file, which contains 2160// the OS version string. Newer Linux distributions have a /etc/lsb-release 2161// file that also contains the OS version string. Some have more than one 2162// /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2163// /etc/redhat-release.), so the order is important. 2164// Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2165// their own specific XXX-release file as well as a redhat-release file. 2166// Because of this the XXX-release file needs to be searched for before the 2167// redhat-release file. 2168// Since Red Hat has a lsb-release file that is not very descriptive the 2169// search for redhat-release needs to be before lsb-release. 2170// Since the lsb-release file is the new standard it needs to be searched 2171// before the older style release files. 2172// Searching system-release (Red Hat) and os-release (other Linuxes) are a 2173// next to last resort. The os-release file is a new standard that contains 2174// distribution information and the system-release file seems to be an old 2175// standard that has been replaced by the lsb-release and os-release files. 2176// Searching for the debian_version file is the last resort. It contains 2177// an informative string like "6.0.6" or "wheezy/sid". Because of this 2178// "Debian " is printed before the contents of the debian_version file. 2179void os::Linux::print_distro_info(outputStream* st) { 2180 if (!_print_ascii_file("/etc/oracle-release", st) && 2181 !_print_ascii_file("/etc/mandriva-release", st) && 2182 !_print_ascii_file("/etc/mandrake-release", st) && 2183 !_print_ascii_file("/etc/sun-release", st) && 2184 !_print_ascii_file("/etc/redhat-release", st) && 2185 !_print_ascii_file("/etc/lsb-release", st) && 2186 !_print_ascii_file("/etc/SuSE-release", st) && 2187 !_print_ascii_file("/etc/turbolinux-release", st) && 2188 !_print_ascii_file("/etc/gentoo-release", st) && 2189 !_print_ascii_file("/etc/ltib-release", st) && 2190 !_print_ascii_file("/etc/angstrom-version", st) && 2191 !_print_ascii_file("/etc/system-release", st) && 2192 !_print_ascii_file("/etc/os-release", st)) { 2193 2194 if (file_exists("/etc/debian_version")) { 2195 st->print("Debian "); 2196 _print_ascii_file("/etc/debian_version", st); 2197 } else { 2198 st->print("Linux"); 2199 } 2200 } 2201 st->cr(); 2202} 2203 2204void os::Linux::print_libversion_info(outputStream* st) { 2205 // libc, pthread 2206 st->print("libc:"); 2207 st->print("%s ", os::Linux::glibc_version()); 2208 st->print("%s ", os::Linux::libpthread_version()); 2209 if (os::Linux::is_LinuxThreads()) { 2210 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2211 } 2212 st->cr(); 2213} 2214 2215void os::Linux::print_full_memory_info(outputStream* st) { 2216 st->print("\n/proc/meminfo:\n"); 2217 _print_ascii_file("/proc/meminfo", st); 2218 st->cr(); 2219} 2220 2221void os::print_memory_info(outputStream* st) { 2222 2223 st->print("Memory:"); 2224 st->print(" %dk page", os::vm_page_size()>>10); 2225 2226 // values in struct sysinfo are "unsigned long" 2227 struct sysinfo si; 2228 sysinfo(&si); 2229 2230 st->print(", physical " UINT64_FORMAT "k", 2231 os::physical_memory() >> 10); 2232 st->print("(" UINT64_FORMAT "k free)", 2233 os::available_memory() >> 10); 2234 st->print(", swap " UINT64_FORMAT "k", 2235 ((jlong)si.totalswap * si.mem_unit) >> 10); 2236 st->print("(" UINT64_FORMAT "k free)", 2237 ((jlong)si.freeswap * si.mem_unit) >> 10); 2238 st->cr(); 2239} 2240 2241void os::pd_print_cpu_info(outputStream* st) { 2242 st->print("\n/proc/cpuinfo:\n"); 2243 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2244 st->print(" <Not Available>"); 2245 } 2246 st->cr(); 2247} 2248 2249void os::print_siginfo(outputStream* st, void* siginfo) { 2250 const siginfo_t* si = (const siginfo_t*)siginfo; 2251 2252 os::Posix::print_siginfo_brief(st, si); 2253#if INCLUDE_CDS 2254 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2255 UseSharedSpaces) { 2256 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2257 if (mapinfo->is_in_shared_space(si->si_addr)) { 2258 st->print("\n\nError accessing class data sharing archive." \ 2259 " Mapped file inaccessible during execution, " \ 2260 " possible disk/network problem."); 2261 } 2262 } 2263#endif 2264 st->cr(); 2265} 2266 2267 2268static void print_signal_handler(outputStream* st, int sig, 2269 char* buf, size_t buflen); 2270 2271void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2272 st->print_cr("Signal Handlers:"); 2273 print_signal_handler(st, SIGSEGV, buf, buflen); 2274 print_signal_handler(st, SIGBUS , buf, buflen); 2275 print_signal_handler(st, SIGFPE , buf, buflen); 2276 print_signal_handler(st, SIGPIPE, buf, buflen); 2277 print_signal_handler(st, SIGXFSZ, buf, buflen); 2278 print_signal_handler(st, SIGILL , buf, buflen); 2279 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2280 print_signal_handler(st, SR_signum, buf, buflen); 2281 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2282 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2283 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2284 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2285#if defined(PPC64) 2286 print_signal_handler(st, SIGTRAP, buf, buflen); 2287#endif 2288} 2289 2290static char saved_jvm_path[MAXPATHLEN] = {0}; 2291 2292// Find the full path to the current module, libjvm.so 2293void os::jvm_path(char *buf, jint buflen) { 2294 // Error checking. 2295 if (buflen < MAXPATHLEN) { 2296 assert(false, "must use a large-enough buffer"); 2297 buf[0] = '\0'; 2298 return; 2299 } 2300 // Lazy resolve the path to current module. 2301 if (saved_jvm_path[0] != 0) { 2302 strcpy(buf, saved_jvm_path); 2303 return; 2304 } 2305 2306 char dli_fname[MAXPATHLEN]; 2307 bool ret = dll_address_to_library_name( 2308 CAST_FROM_FN_PTR(address, os::jvm_path), 2309 dli_fname, sizeof(dli_fname), NULL); 2310 assert(ret, "cannot locate libjvm"); 2311 char *rp = NULL; 2312 if (ret && dli_fname[0] != '\0') { 2313 rp = realpath(dli_fname, buf); 2314 } 2315 if (rp == NULL) { 2316 return; 2317 } 2318 2319 if (Arguments::sun_java_launcher_is_altjvm()) { 2320 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2321 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". 2322 // If "/jre/lib/" appears at the right place in the string, then 2323 // assume we are installed in a JDK and we're done. Otherwise, check 2324 // for a JAVA_HOME environment variable and fix up the path so it 2325 // looks like libjvm.so is installed there (append a fake suffix 2326 // hotspot/libjvm.so). 2327 const char *p = buf + strlen(buf) - 1; 2328 for (int count = 0; p > buf && count < 5; ++count) { 2329 for (--p; p > buf && *p != '/'; --p) 2330 /* empty */ ; 2331 } 2332 2333 if (strncmp(p, "/jre/lib/", 9) != 0) { 2334 // Look for JAVA_HOME in the environment. 2335 char* java_home_var = ::getenv("JAVA_HOME"); 2336 if (java_home_var != NULL && java_home_var[0] != 0) { 2337 char* jrelib_p; 2338 int len; 2339 2340 // Check the current module name "libjvm.so". 2341 p = strrchr(buf, '/'); 2342 if (p == NULL) { 2343 return; 2344 } 2345 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2346 2347 rp = realpath(java_home_var, buf); 2348 if (rp == NULL) { 2349 return; 2350 } 2351 2352 // determine if this is a legacy image or modules image 2353 // modules image doesn't have "jre" subdirectory 2354 len = strlen(buf); 2355 assert(len < buflen, "Ran out of buffer room"); 2356 jrelib_p = buf + len; 2357 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2358 if (0 != access(buf, F_OK)) { 2359 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2360 } 2361 2362 if (0 == access(buf, F_OK)) { 2363 // Use current module name "libjvm.so" 2364 len = strlen(buf); 2365 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2366 } else { 2367 // Go back to path of .so 2368 rp = realpath(dli_fname, buf); 2369 if (rp == NULL) { 2370 return; 2371 } 2372 } 2373 } 2374 } 2375 } 2376 2377 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2378 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2379} 2380 2381void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2382 // no prefix required, not even "_" 2383} 2384 2385void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2386 // no suffix required 2387} 2388 2389//////////////////////////////////////////////////////////////////////////////// 2390// sun.misc.Signal support 2391 2392static volatile jint sigint_count = 0; 2393 2394static void UserHandler(int sig, void *siginfo, void *context) { 2395 // 4511530 - sem_post is serialized and handled by the manager thread. When 2396 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2397 // don't want to flood the manager thread with sem_post requests. 2398 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2399 return; 2400 } 2401 2402 // Ctrl-C is pressed during error reporting, likely because the error 2403 // handler fails to abort. Let VM die immediately. 2404 if (sig == SIGINT && is_error_reported()) { 2405 os::die(); 2406 } 2407 2408 os::signal_notify(sig); 2409} 2410 2411void* os::user_handler() { 2412 return CAST_FROM_FN_PTR(void*, UserHandler); 2413} 2414 2415class Semaphore : public StackObj { 2416 public: 2417 Semaphore(); 2418 ~Semaphore(); 2419 void signal(); 2420 void wait(); 2421 bool trywait(); 2422 bool timedwait(unsigned int sec, int nsec); 2423 private: 2424 sem_t _semaphore; 2425}; 2426 2427Semaphore::Semaphore() { 2428 sem_init(&_semaphore, 0, 0); 2429} 2430 2431Semaphore::~Semaphore() { 2432 sem_destroy(&_semaphore); 2433} 2434 2435void Semaphore::signal() { 2436 sem_post(&_semaphore); 2437} 2438 2439void Semaphore::wait() { 2440 sem_wait(&_semaphore); 2441} 2442 2443bool Semaphore::trywait() { 2444 return sem_trywait(&_semaphore) == 0; 2445} 2446 2447bool Semaphore::timedwait(unsigned int sec, int nsec) { 2448 2449 struct timespec ts; 2450 // Semaphore's are always associated with CLOCK_REALTIME 2451 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2452 // see unpackTime for discussion on overflow checking 2453 if (sec >= MAX_SECS) { 2454 ts.tv_sec += MAX_SECS; 2455 ts.tv_nsec = 0; 2456 } else { 2457 ts.tv_sec += sec; 2458 ts.tv_nsec += nsec; 2459 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2460 ts.tv_nsec -= NANOSECS_PER_SEC; 2461 ++ts.tv_sec; // note: this must be <= max_secs 2462 } 2463 } 2464 2465 while (1) { 2466 int result = sem_timedwait(&_semaphore, &ts); 2467 if (result == 0) { 2468 return true; 2469 } else if (errno == EINTR) { 2470 continue; 2471 } else if (errno == ETIMEDOUT) { 2472 return false; 2473 } else { 2474 return false; 2475 } 2476 } 2477} 2478 2479extern "C" { 2480 typedef void (*sa_handler_t)(int); 2481 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2482} 2483 2484void* os::signal(int signal_number, void* handler) { 2485 struct sigaction sigAct, oldSigAct; 2486 2487 sigfillset(&(sigAct.sa_mask)); 2488 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2489 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2490 2491 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2492 // -1 means registration failed 2493 return (void *)-1; 2494 } 2495 2496 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2497} 2498 2499void os::signal_raise(int signal_number) { 2500 ::raise(signal_number); 2501} 2502 2503// The following code is moved from os.cpp for making this 2504// code platform specific, which it is by its very nature. 2505 2506// Will be modified when max signal is changed to be dynamic 2507int os::sigexitnum_pd() { 2508 return NSIG; 2509} 2510 2511// a counter for each possible signal value 2512static volatile jint pending_signals[NSIG+1] = { 0 }; 2513 2514// Linux(POSIX) specific hand shaking semaphore. 2515static sem_t sig_sem; 2516static Semaphore sr_semaphore; 2517 2518void os::signal_init_pd() { 2519 // Initialize signal structures 2520 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2521 2522 // Initialize signal semaphore 2523 ::sem_init(&sig_sem, 0, 0); 2524} 2525 2526void os::signal_notify(int sig) { 2527 Atomic::inc(&pending_signals[sig]); 2528 ::sem_post(&sig_sem); 2529} 2530 2531static int check_pending_signals(bool wait) { 2532 Atomic::store(0, &sigint_count); 2533 for (;;) { 2534 for (int i = 0; i < NSIG + 1; i++) { 2535 jint n = pending_signals[i]; 2536 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2537 return i; 2538 } 2539 } 2540 if (!wait) { 2541 return -1; 2542 } 2543 JavaThread *thread = JavaThread::current(); 2544 ThreadBlockInVM tbivm(thread); 2545 2546 bool threadIsSuspended; 2547 do { 2548 thread->set_suspend_equivalent(); 2549 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2550 ::sem_wait(&sig_sem); 2551 2552 // were we externally suspended while we were waiting? 2553 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2554 if (threadIsSuspended) { 2555 // The semaphore has been incremented, but while we were waiting 2556 // another thread suspended us. We don't want to continue running 2557 // while suspended because that would surprise the thread that 2558 // suspended us. 2559 ::sem_post(&sig_sem); 2560 2561 thread->java_suspend_self(); 2562 } 2563 } while (threadIsSuspended); 2564 } 2565} 2566 2567int os::signal_lookup() { 2568 return check_pending_signals(false); 2569} 2570 2571int os::signal_wait() { 2572 return check_pending_signals(true); 2573} 2574 2575//////////////////////////////////////////////////////////////////////////////// 2576// Virtual Memory 2577 2578int os::vm_page_size() { 2579 // Seems redundant as all get out 2580 assert(os::Linux::page_size() != -1, "must call os::init"); 2581 return os::Linux::page_size(); 2582} 2583 2584// Solaris allocates memory by pages. 2585int os::vm_allocation_granularity() { 2586 assert(os::Linux::page_size() != -1, "must call os::init"); 2587 return os::Linux::page_size(); 2588} 2589 2590// Rationale behind this function: 2591// current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2592// mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2593// samples for JITted code. Here we create private executable mapping over the code cache 2594// and then we can use standard (well, almost, as mapping can change) way to provide 2595// info for the reporting script by storing timestamp and location of symbol 2596void linux_wrap_code(char* base, size_t size) { 2597 static volatile jint cnt = 0; 2598 2599 if (!UseOprofile) { 2600 return; 2601 } 2602 2603 char buf[PATH_MAX+1]; 2604 int num = Atomic::add(1, &cnt); 2605 2606 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2607 os::get_temp_directory(), os::current_process_id(), num); 2608 unlink(buf); 2609 2610 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2611 2612 if (fd != -1) { 2613 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2614 if (rv != (off_t)-1) { 2615 if (::write(fd, "", 1) == 1) { 2616 mmap(base, size, 2617 PROT_READ|PROT_WRITE|PROT_EXEC, 2618 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2619 } 2620 } 2621 ::close(fd); 2622 unlink(buf); 2623 } 2624} 2625 2626static bool recoverable_mmap_error(int err) { 2627 // See if the error is one we can let the caller handle. This 2628 // list of errno values comes from JBS-6843484. I can't find a 2629 // Linux man page that documents this specific set of errno 2630 // values so while this list currently matches Solaris, it may 2631 // change as we gain experience with this failure mode. 2632 switch (err) { 2633 case EBADF: 2634 case EINVAL: 2635 case ENOTSUP: 2636 // let the caller deal with these errors 2637 return true; 2638 2639 default: 2640 // Any remaining errors on this OS can cause our reserved mapping 2641 // to be lost. That can cause confusion where different data 2642 // structures think they have the same memory mapped. The worst 2643 // scenario is if both the VM and a library think they have the 2644 // same memory mapped. 2645 return false; 2646 } 2647} 2648 2649static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2650 int err) { 2651 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2652 ", %d) failed; error='%s' (errno=%d)", addr, size, exec, 2653 strerror(err), err); 2654} 2655 2656static void warn_fail_commit_memory(char* addr, size_t size, 2657 size_t alignment_hint, bool exec, 2658 int err) { 2659 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2660 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size, 2661 alignment_hint, exec, strerror(err), err); 2662} 2663 2664// NOTE: Linux kernel does not really reserve the pages for us. 2665// All it does is to check if there are enough free pages 2666// left at the time of mmap(). This could be a potential 2667// problem. 2668int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2669 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2670 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2671 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2672 if (res != (uintptr_t) MAP_FAILED) { 2673 if (UseNUMAInterleaving) { 2674 numa_make_global(addr, size); 2675 } 2676 return 0; 2677 } 2678 2679 int err = errno; // save errno from mmap() call above 2680 2681 if (!recoverable_mmap_error(err)) { 2682 warn_fail_commit_memory(addr, size, exec, err); 2683 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2684 } 2685 2686 return err; 2687} 2688 2689bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2690 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2691} 2692 2693void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2694 const char* mesg) { 2695 assert(mesg != NULL, "mesg must be specified"); 2696 int err = os::Linux::commit_memory_impl(addr, size, exec); 2697 if (err != 0) { 2698 // the caller wants all commit errors to exit with the specified mesg: 2699 warn_fail_commit_memory(addr, size, exec, err); 2700 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg); 2701 } 2702} 2703 2704// Define MAP_HUGETLB here so we can build HotSpot on old systems. 2705#ifndef MAP_HUGETLB 2706 #define MAP_HUGETLB 0x40000 2707#endif 2708 2709// Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2710#ifndef MADV_HUGEPAGE 2711 #define MADV_HUGEPAGE 14 2712#endif 2713 2714int os::Linux::commit_memory_impl(char* addr, size_t size, 2715 size_t alignment_hint, bool exec) { 2716 int err = os::Linux::commit_memory_impl(addr, size, exec); 2717 if (err == 0) { 2718 realign_memory(addr, size, alignment_hint); 2719 } 2720 return err; 2721} 2722 2723bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2724 bool exec) { 2725 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2726} 2727 2728void os::pd_commit_memory_or_exit(char* addr, size_t size, 2729 size_t alignment_hint, bool exec, 2730 const char* mesg) { 2731 assert(mesg != NULL, "mesg must be specified"); 2732 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2733 if (err != 0) { 2734 // the caller wants all commit errors to exit with the specified mesg: 2735 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2736 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg); 2737 } 2738} 2739 2740void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2741 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2742 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2743 // be supported or the memory may already be backed by huge pages. 2744 ::madvise(addr, bytes, MADV_HUGEPAGE); 2745 } 2746} 2747 2748void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2749 // This method works by doing an mmap over an existing mmaping and effectively discarding 2750 // the existing pages. However it won't work for SHM-based large pages that cannot be 2751 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2752 // small pages on top of the SHM segment. This method always works for small pages, so we 2753 // allow that in any case. 2754 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2755 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2756 } 2757} 2758 2759void os::numa_make_global(char *addr, size_t bytes) { 2760 Linux::numa_interleave_memory(addr, bytes); 2761} 2762 2763// Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2764// bind policy to MPOL_PREFERRED for the current thread. 2765#define USE_MPOL_PREFERRED 0 2766 2767void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2768 // To make NUMA and large pages more robust when both enabled, we need to ease 2769 // the requirements on where the memory should be allocated. MPOL_BIND is the 2770 // default policy and it will force memory to be allocated on the specified 2771 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2772 // the specified node, but will not force it. Using this policy will prevent 2773 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2774 // free large pages. 2775 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2776 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2777} 2778 2779bool os::numa_topology_changed() { return false; } 2780 2781size_t os::numa_get_groups_num() { 2782 int max_node = Linux::numa_max_node(); 2783 return max_node > 0 ? max_node + 1 : 1; 2784} 2785 2786int os::numa_get_group_id() { 2787 int cpu_id = Linux::sched_getcpu(); 2788 if (cpu_id != -1) { 2789 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2790 if (lgrp_id != -1) { 2791 return lgrp_id; 2792 } 2793 } 2794 return 0; 2795} 2796 2797size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2798 for (size_t i = 0; i < size; i++) { 2799 ids[i] = i; 2800 } 2801 return size; 2802} 2803 2804bool os::get_page_info(char *start, page_info* info) { 2805 return false; 2806} 2807 2808char *os::scan_pages(char *start, char* end, page_info* page_expected, 2809 page_info* page_found) { 2810 return end; 2811} 2812 2813 2814int os::Linux::sched_getcpu_syscall(void) { 2815 unsigned int cpu; 2816 int retval = -1; 2817 2818#if defined(IA32) 2819 #ifndef SYS_getcpu 2820 #define SYS_getcpu 318 2821 #endif 2822 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2823#elif defined(AMD64) 2824// Unfortunately we have to bring all these macros here from vsyscall.h 2825// to be able to compile on old linuxes. 2826 #define __NR_vgetcpu 2 2827 #define VSYSCALL_START (-10UL << 20) 2828 #define VSYSCALL_SIZE 1024 2829 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2830 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2831 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2832 retval = vgetcpu(&cpu, NULL, NULL); 2833#endif 2834 2835 return (retval == -1) ? retval : cpu; 2836} 2837 2838// Something to do with the numa-aware allocator needs these symbols 2839extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2840extern "C" JNIEXPORT void numa_error(char *where) { } 2841extern "C" JNIEXPORT int fork1() { return fork(); } 2842 2843 2844// If we are running with libnuma version > 2, then we should 2845// be trying to use symbols with versions 1.1 2846// If we are running with earlier version, which did not have symbol versions, 2847// we should use the base version. 2848void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2849 void *f = dlvsym(handle, name, "libnuma_1.1"); 2850 if (f == NULL) { 2851 f = dlsym(handle, name); 2852 } 2853 return f; 2854} 2855 2856bool os::Linux::libnuma_init() { 2857 // sched_getcpu() should be in libc. 2858 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2859 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2860 2861 // If it's not, try a direct syscall. 2862 if (sched_getcpu() == -1) { 2863 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2864 (void*)&sched_getcpu_syscall)); 2865 } 2866 2867 if (sched_getcpu() != -1) { // Does it work? 2868 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2869 if (handle != NULL) { 2870 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2871 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2872 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2873 libnuma_dlsym(handle, "numa_max_node"))); 2874 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2875 libnuma_dlsym(handle, "numa_available"))); 2876 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2877 libnuma_dlsym(handle, "numa_tonode_memory"))); 2878 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2879 libnuma_dlsym(handle, "numa_interleave_memory"))); 2880 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2881 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2882 2883 2884 if (numa_available() != -1) { 2885 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2886 // Create a cpu -> node mapping 2887 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2888 rebuild_cpu_to_node_map(); 2889 return true; 2890 } 2891 } 2892 } 2893 return false; 2894} 2895 2896// rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2897// The table is later used in get_node_by_cpu(). 2898void os::Linux::rebuild_cpu_to_node_map() { 2899 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2900 // in libnuma (possible values are starting from 16, 2901 // and continuing up with every other power of 2, but less 2902 // than the maximum number of CPUs supported by kernel), and 2903 // is a subject to change (in libnuma version 2 the requirements 2904 // are more reasonable) we'll just hardcode the number they use 2905 // in the library. 2906 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2907 2908 size_t cpu_num = os::active_processor_count(); 2909 size_t cpu_map_size = NCPUS / BitsPerCLong; 2910 size_t cpu_map_valid_size = 2911 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2912 2913 cpu_to_node()->clear(); 2914 cpu_to_node()->at_grow(cpu_num - 1); 2915 size_t node_num = numa_get_groups_num(); 2916 2917 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2918 for (size_t i = 0; i < node_num; i++) { 2919 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2920 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2921 if (cpu_map[j] != 0) { 2922 for (size_t k = 0; k < BitsPerCLong; k++) { 2923 if (cpu_map[j] & (1UL << k)) { 2924 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2925 } 2926 } 2927 } 2928 } 2929 } 2930 } 2931 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal); 2932} 2933 2934int os::Linux::get_node_by_cpu(int cpu_id) { 2935 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2936 return cpu_to_node()->at(cpu_id); 2937 } 2938 return -1; 2939} 2940 2941GrowableArray<int>* os::Linux::_cpu_to_node; 2942os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2943os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2944os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2945os::Linux::numa_available_func_t os::Linux::_numa_available; 2946os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2947os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2948os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2949unsigned long* os::Linux::_numa_all_nodes; 2950 2951bool os::pd_uncommit_memory(char* addr, size_t size) { 2952 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2953 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2954 return res != (uintptr_t) MAP_FAILED; 2955} 2956 2957static address get_stack_commited_bottom(address bottom, size_t size) { 2958 address nbot = bottom; 2959 address ntop = bottom + size; 2960 2961 size_t page_sz = os::vm_page_size(); 2962 unsigned pages = size / page_sz; 2963 2964 unsigned char vec[1]; 2965 unsigned imin = 1, imax = pages + 1, imid; 2966 int mincore_return_value = 0; 2967 2968 assert(imin <= imax, "Unexpected page size"); 2969 2970 while (imin < imax) { 2971 imid = (imax + imin) / 2; 2972 nbot = ntop - (imid * page_sz); 2973 2974 // Use a trick with mincore to check whether the page is mapped or not. 2975 // mincore sets vec to 1 if page resides in memory and to 0 if page 2976 // is swapped output but if page we are asking for is unmapped 2977 // it returns -1,ENOMEM 2978 mincore_return_value = mincore(nbot, page_sz, vec); 2979 2980 if (mincore_return_value == -1) { 2981 // Page is not mapped go up 2982 // to find first mapped page 2983 if (errno != EAGAIN) { 2984 assert(errno == ENOMEM, "Unexpected mincore errno"); 2985 imax = imid; 2986 } 2987 } else { 2988 // Page is mapped go down 2989 // to find first not mapped page 2990 imin = imid + 1; 2991 } 2992 } 2993 2994 nbot = nbot + page_sz; 2995 2996 // Adjust stack bottom one page up if last checked page is not mapped 2997 if (mincore_return_value == -1) { 2998 nbot = nbot + page_sz; 2999 } 3000 3001 return nbot; 3002} 3003 3004 3005// Linux uses a growable mapping for the stack, and if the mapping for 3006// the stack guard pages is not removed when we detach a thread the 3007// stack cannot grow beyond the pages where the stack guard was 3008// mapped. If at some point later in the process the stack expands to 3009// that point, the Linux kernel cannot expand the stack any further 3010// because the guard pages are in the way, and a segfault occurs. 3011// 3012// However, it's essential not to split the stack region by unmapping 3013// a region (leaving a hole) that's already part of the stack mapping, 3014// so if the stack mapping has already grown beyond the guard pages at 3015// the time we create them, we have to truncate the stack mapping. 3016// So, we need to know the extent of the stack mapping when 3017// create_stack_guard_pages() is called. 3018 3019// We only need this for stacks that are growable: at the time of 3020// writing thread stacks don't use growable mappings (i.e. those 3021// creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3022// only applies to the main thread. 3023 3024// If the (growable) stack mapping already extends beyond the point 3025// where we're going to put our guard pages, truncate the mapping at 3026// that point by munmap()ping it. This ensures that when we later 3027// munmap() the guard pages we don't leave a hole in the stack 3028// mapping. This only affects the main/initial thread 3029 3030bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3031 if (os::Linux::is_initial_thread()) { 3032 // As we manually grow stack up to bottom inside create_attached_thread(), 3033 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3034 // we don't need to do anything special. 3035 // Check it first, before calling heavy function. 3036 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3037 unsigned char vec[1]; 3038 3039 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3040 // Fallback to slow path on all errors, including EAGAIN 3041 stack_extent = (uintptr_t) get_stack_commited_bottom( 3042 os::Linux::initial_thread_stack_bottom(), 3043 (size_t)addr - stack_extent); 3044 } 3045 3046 if (stack_extent < (uintptr_t)addr) { 3047 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3048 } 3049 } 3050 3051 return os::commit_memory(addr, size, !ExecMem); 3052} 3053 3054// If this is a growable mapping, remove the guard pages entirely by 3055// munmap()ping them. If not, just call uncommit_memory(). This only 3056// affects the main/initial thread, but guard against future OS changes 3057// It's safe to always unmap guard pages for initial thread because we 3058// always place it right after end of the mapped region 3059 3060bool os::remove_stack_guard_pages(char* addr, size_t size) { 3061 uintptr_t stack_extent, stack_base; 3062 3063 if (os::Linux::is_initial_thread()) { 3064 return ::munmap(addr, size) == 0; 3065 } 3066 3067 return os::uncommit_memory(addr, size); 3068} 3069 3070static address _highest_vm_reserved_address = NULL; 3071 3072// If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3073// at 'requested_addr'. If there are existing memory mappings at the same 3074// location, however, they will be overwritten. If 'fixed' is false, 3075// 'requested_addr' is only treated as a hint, the return value may or 3076// may not start from the requested address. Unlike Linux mmap(), this 3077// function returns NULL to indicate failure. 3078static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3079 char * addr; 3080 int flags; 3081 3082 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3083 if (fixed) { 3084 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3085 flags |= MAP_FIXED; 3086 } 3087 3088 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3089 // touch an uncommitted page. Otherwise, the read/write might 3090 // succeed if we have enough swap space to back the physical page. 3091 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3092 flags, -1, 0); 3093 3094 if (addr != MAP_FAILED) { 3095 // anon_mmap() should only get called during VM initialization, 3096 // don't need lock (actually we can skip locking even it can be called 3097 // from multiple threads, because _highest_vm_reserved_address is just a 3098 // hint about the upper limit of non-stack memory regions.) 3099 if ((address)addr + bytes > _highest_vm_reserved_address) { 3100 _highest_vm_reserved_address = (address)addr + bytes; 3101 } 3102 } 3103 3104 return addr == MAP_FAILED ? NULL : addr; 3105} 3106 3107// Don't update _highest_vm_reserved_address, because there might be memory 3108// regions above addr + size. If so, releasing a memory region only creates 3109// a hole in the address space, it doesn't help prevent heap-stack collision. 3110// 3111static int anon_munmap(char * addr, size_t size) { 3112 return ::munmap(addr, size) == 0; 3113} 3114 3115char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3116 size_t alignment_hint) { 3117 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3118} 3119 3120bool os::pd_release_memory(char* addr, size_t size) { 3121 return anon_munmap(addr, size); 3122} 3123 3124static address highest_vm_reserved_address() { 3125 return _highest_vm_reserved_address; 3126} 3127 3128static bool linux_mprotect(char* addr, size_t size, int prot) { 3129 // Linux wants the mprotect address argument to be page aligned. 3130 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3131 3132 // According to SUSv3, mprotect() should only be used with mappings 3133 // established by mmap(), and mmap() always maps whole pages. Unaligned 3134 // 'addr' likely indicates problem in the VM (e.g. trying to change 3135 // protection of malloc'ed or statically allocated memory). Check the 3136 // caller if you hit this assert. 3137 assert(addr == bottom, "sanity check"); 3138 3139 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3140 return ::mprotect(bottom, size, prot) == 0; 3141} 3142 3143// Set protections specified 3144bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3145 bool is_committed) { 3146 unsigned int p = 0; 3147 switch (prot) { 3148 case MEM_PROT_NONE: p = PROT_NONE; break; 3149 case MEM_PROT_READ: p = PROT_READ; break; 3150 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3151 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3152 default: 3153 ShouldNotReachHere(); 3154 } 3155 // is_committed is unused. 3156 return linux_mprotect(addr, bytes, p); 3157} 3158 3159bool os::guard_memory(char* addr, size_t size) { 3160 return linux_mprotect(addr, size, PROT_NONE); 3161} 3162 3163bool os::unguard_memory(char* addr, size_t size) { 3164 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3165} 3166 3167bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3168 size_t page_size) { 3169 bool result = false; 3170 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3171 MAP_ANONYMOUS|MAP_PRIVATE, 3172 -1, 0); 3173 if (p != MAP_FAILED) { 3174 void *aligned_p = align_ptr_up(p, page_size); 3175 3176 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3177 3178 munmap(p, page_size * 2); 3179 } 3180 3181 if (warn && !result) { 3182 warning("TransparentHugePages is not supported by the operating system."); 3183 } 3184 3185 return result; 3186} 3187 3188bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3189 bool result = false; 3190 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3191 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3192 -1, 0); 3193 3194 if (p != MAP_FAILED) { 3195 // We don't know if this really is a huge page or not. 3196 FILE *fp = fopen("/proc/self/maps", "r"); 3197 if (fp) { 3198 while (!feof(fp)) { 3199 char chars[257]; 3200 long x = 0; 3201 if (fgets(chars, sizeof(chars), fp)) { 3202 if (sscanf(chars, "%lx-%*x", &x) == 1 3203 && x == (long)p) { 3204 if (strstr (chars, "hugepage")) { 3205 result = true; 3206 break; 3207 } 3208 } 3209 } 3210 } 3211 fclose(fp); 3212 } 3213 munmap(p, page_size); 3214 } 3215 3216 if (warn && !result) { 3217 warning("HugeTLBFS is not supported by the operating system."); 3218 } 3219 3220 return result; 3221} 3222 3223// Set the coredump_filter bits to include largepages in core dump (bit 6) 3224// 3225// From the coredump_filter documentation: 3226// 3227// - (bit 0) anonymous private memory 3228// - (bit 1) anonymous shared memory 3229// - (bit 2) file-backed private memory 3230// - (bit 3) file-backed shared memory 3231// - (bit 4) ELF header pages in file-backed private memory areas (it is 3232// effective only if the bit 2 is cleared) 3233// - (bit 5) hugetlb private memory 3234// - (bit 6) hugetlb shared memory 3235// 3236static void set_coredump_filter(void) { 3237 FILE *f; 3238 long cdm; 3239 3240 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3241 return; 3242 } 3243 3244 if (fscanf(f, "%lx", &cdm) != 1) { 3245 fclose(f); 3246 return; 3247 } 3248 3249 rewind(f); 3250 3251 if ((cdm & LARGEPAGES_BIT) == 0) { 3252 cdm |= LARGEPAGES_BIT; 3253 fprintf(f, "%#lx", cdm); 3254 } 3255 3256 fclose(f); 3257} 3258 3259// Large page support 3260 3261static size_t _large_page_size = 0; 3262 3263size_t os::Linux::find_large_page_size() { 3264 size_t large_page_size = 0; 3265 3266 // large_page_size on Linux is used to round up heap size. x86 uses either 3267 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3268 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3269 // page as large as 256M. 3270 // 3271 // Here we try to figure out page size by parsing /proc/meminfo and looking 3272 // for a line with the following format: 3273 // Hugepagesize: 2048 kB 3274 // 3275 // If we can't determine the value (e.g. /proc is not mounted, or the text 3276 // format has been changed), we'll use the largest page size supported by 3277 // the processor. 3278 3279#ifndef ZERO 3280 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3281 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 3282#endif // ZERO 3283 3284 FILE *fp = fopen("/proc/meminfo", "r"); 3285 if (fp) { 3286 while (!feof(fp)) { 3287 int x = 0; 3288 char buf[16]; 3289 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3290 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3291 large_page_size = x * K; 3292 break; 3293 } 3294 } else { 3295 // skip to next line 3296 for (;;) { 3297 int ch = fgetc(fp); 3298 if (ch == EOF || ch == (int)'\n') break; 3299 } 3300 } 3301 } 3302 fclose(fp); 3303 } 3304 3305 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3306 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3307 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3308 proper_unit_for_byte_size(large_page_size)); 3309 } 3310 3311 return large_page_size; 3312} 3313 3314size_t os::Linux::setup_large_page_size() { 3315 _large_page_size = Linux::find_large_page_size(); 3316 const size_t default_page_size = (size_t)Linux::page_size(); 3317 if (_large_page_size > default_page_size) { 3318 _page_sizes[0] = _large_page_size; 3319 _page_sizes[1] = default_page_size; 3320 _page_sizes[2] = 0; 3321 } 3322 3323 return _large_page_size; 3324} 3325 3326bool os::Linux::setup_large_page_type(size_t page_size) { 3327 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3328 FLAG_IS_DEFAULT(UseSHM) && 3329 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3330 3331 // The type of large pages has not been specified by the user. 3332 3333 // Try UseHugeTLBFS and then UseSHM. 3334 UseHugeTLBFS = UseSHM = true; 3335 3336 // Don't try UseTransparentHugePages since there are known 3337 // performance issues with it turned on. This might change in the future. 3338 UseTransparentHugePages = false; 3339 } 3340 3341 if (UseTransparentHugePages) { 3342 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3343 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3344 UseHugeTLBFS = false; 3345 UseSHM = false; 3346 return true; 3347 } 3348 UseTransparentHugePages = false; 3349 } 3350 3351 if (UseHugeTLBFS) { 3352 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3353 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3354 UseSHM = false; 3355 return true; 3356 } 3357 UseHugeTLBFS = false; 3358 } 3359 3360 return UseSHM; 3361} 3362 3363void os::large_page_init() { 3364 if (!UseLargePages && 3365 !UseTransparentHugePages && 3366 !UseHugeTLBFS && 3367 !UseSHM) { 3368 // Not using large pages. 3369 return; 3370 } 3371 3372 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3373 // The user explicitly turned off large pages. 3374 // Ignore the rest of the large pages flags. 3375 UseTransparentHugePages = false; 3376 UseHugeTLBFS = false; 3377 UseSHM = false; 3378 return; 3379 } 3380 3381 size_t large_page_size = Linux::setup_large_page_size(); 3382 UseLargePages = Linux::setup_large_page_type(large_page_size); 3383 3384 set_coredump_filter(); 3385} 3386 3387#ifndef SHM_HUGETLB 3388 #define SHM_HUGETLB 04000 3389#endif 3390 3391char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3392 char* req_addr, bool exec) { 3393 // "exec" is passed in but not used. Creating the shared image for 3394 // the code cache doesn't have an SHM_X executable permission to check. 3395 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3396 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3397 3398 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) { 3399 return NULL; // Fallback to small pages. 3400 } 3401 3402 key_t key = IPC_PRIVATE; 3403 char *addr; 3404 3405 bool warn_on_failure = UseLargePages && 3406 (!FLAG_IS_DEFAULT(UseLargePages) || 3407 !FLAG_IS_DEFAULT(UseSHM) || 3408 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3409 char msg[128]; 3410 3411 // Create a large shared memory region to attach to based on size. 3412 // Currently, size is the total size of the heap 3413 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3414 if (shmid == -1) { 3415 // Possible reasons for shmget failure: 3416 // 1. shmmax is too small for Java heap. 3417 // > check shmmax value: cat /proc/sys/kernel/shmmax 3418 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3419 // 2. not enough large page memory. 3420 // > check available large pages: cat /proc/meminfo 3421 // > increase amount of large pages: 3422 // echo new_value > /proc/sys/vm/nr_hugepages 3423 // Note 1: different Linux may use different name for this property, 3424 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3425 // Note 2: it's possible there's enough physical memory available but 3426 // they are so fragmented after a long run that they can't 3427 // coalesce into large pages. Try to reserve large pages when 3428 // the system is still "fresh". 3429 if (warn_on_failure) { 3430 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3431 warning("%s", msg); 3432 } 3433 return NULL; 3434 } 3435 3436 // attach to the region 3437 addr = (char*)shmat(shmid, req_addr, 0); 3438 int err = errno; 3439 3440 // Remove shmid. If shmat() is successful, the actual shared memory segment 3441 // will be deleted when it's detached by shmdt() or when the process 3442 // terminates. If shmat() is not successful this will remove the shared 3443 // segment immediately. 3444 shmctl(shmid, IPC_RMID, NULL); 3445 3446 if ((intptr_t)addr == -1) { 3447 if (warn_on_failure) { 3448 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3449 warning("%s", msg); 3450 } 3451 return NULL; 3452 } 3453 3454 return addr; 3455} 3456 3457static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3458 int error) { 3459 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3460 3461 bool warn_on_failure = UseLargePages && 3462 (!FLAG_IS_DEFAULT(UseLargePages) || 3463 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3464 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3465 3466 if (warn_on_failure) { 3467 char msg[128]; 3468 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3469 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3470 warning("%s", msg); 3471 } 3472} 3473 3474char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3475 char* req_addr, 3476 bool exec) { 3477 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3478 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3479 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3480 3481 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3482 char* addr = (char*)::mmap(req_addr, bytes, prot, 3483 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3484 -1, 0); 3485 3486 if (addr == MAP_FAILED) { 3487 warn_on_large_pages_failure(req_addr, bytes, errno); 3488 return NULL; 3489 } 3490 3491 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3492 3493 return addr; 3494} 3495 3496char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3497 size_t alignment, 3498 char* req_addr, 3499 bool exec) { 3500 size_t large_page_size = os::large_page_size(); 3501 3502 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3503 3504 // Allocate small pages. 3505 3506 char* start; 3507 if (req_addr != NULL) { 3508 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3509 assert(is_size_aligned(bytes, alignment), "Must be"); 3510 start = os::reserve_memory(bytes, req_addr); 3511 assert(start == NULL || start == req_addr, "Must be"); 3512 } else { 3513 start = os::reserve_memory_aligned(bytes, alignment); 3514 } 3515 3516 if (start == NULL) { 3517 return NULL; 3518 } 3519 3520 assert(is_ptr_aligned(start, alignment), "Must be"); 3521 3522 if (MemTracker::tracking_level() > NMT_minimal) { 3523 // os::reserve_memory_special will record this memory area. 3524 // Need to release it here to prevent overlapping reservations. 3525 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3526 tkr.record((address)start, bytes); 3527 } 3528 3529 char* end = start + bytes; 3530 3531 // Find the regions of the allocated chunk that can be promoted to large pages. 3532 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3533 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3534 3535 size_t lp_bytes = lp_end - lp_start; 3536 3537 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3538 3539 if (lp_bytes == 0) { 3540 // The mapped region doesn't even span the start and the end of a large page. 3541 // Fall back to allocate a non-special area. 3542 ::munmap(start, end - start); 3543 return NULL; 3544 } 3545 3546 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3547 3548 3549 void* result; 3550 3551 if (start != lp_start) { 3552 result = ::mmap(start, lp_start - start, prot, 3553 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3554 -1, 0); 3555 if (result == MAP_FAILED) { 3556 ::munmap(lp_start, end - lp_start); 3557 return NULL; 3558 } 3559 } 3560 3561 result = ::mmap(lp_start, lp_bytes, prot, 3562 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3563 -1, 0); 3564 if (result == MAP_FAILED) { 3565 warn_on_large_pages_failure(req_addr, bytes, errno); 3566 // If the mmap above fails, the large pages region will be unmapped and we 3567 // have regions before and after with small pages. Release these regions. 3568 // 3569 // | mapped | unmapped | mapped | 3570 // ^ ^ ^ ^ 3571 // start lp_start lp_end end 3572 // 3573 ::munmap(start, lp_start - start); 3574 ::munmap(lp_end, end - lp_end); 3575 return NULL; 3576 } 3577 3578 if (lp_end != end) { 3579 result = ::mmap(lp_end, end - lp_end, prot, 3580 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3581 -1, 0); 3582 if (result == MAP_FAILED) { 3583 ::munmap(start, lp_end - start); 3584 return NULL; 3585 } 3586 } 3587 3588 return start; 3589} 3590 3591char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3592 size_t alignment, 3593 char* req_addr, 3594 bool exec) { 3595 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3596 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3597 assert(is_power_of_2(alignment), "Must be"); 3598 assert(is_power_of_2(os::large_page_size()), "Must be"); 3599 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3600 3601 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3602 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3603 } else { 3604 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3605 } 3606} 3607 3608char* os::reserve_memory_special(size_t bytes, size_t alignment, 3609 char* req_addr, bool exec) { 3610 assert(UseLargePages, "only for large pages"); 3611 3612 char* addr; 3613 if (UseSHM) { 3614 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3615 } else { 3616 assert(UseHugeTLBFS, "must be"); 3617 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3618 } 3619 3620 if (addr != NULL) { 3621 if (UseNUMAInterleaving) { 3622 numa_make_global(addr, bytes); 3623 } 3624 3625 // The memory is committed 3626 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3627 } 3628 3629 return addr; 3630} 3631 3632bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3633 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3634 return shmdt(base) == 0; 3635} 3636 3637bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3638 return pd_release_memory(base, bytes); 3639} 3640 3641bool os::release_memory_special(char* base, size_t bytes) { 3642 bool res; 3643 if (MemTracker::tracking_level() > NMT_minimal) { 3644 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3645 res = os::Linux::release_memory_special_impl(base, bytes); 3646 if (res) { 3647 tkr.record((address)base, bytes); 3648 } 3649 3650 } else { 3651 res = os::Linux::release_memory_special_impl(base, bytes); 3652 } 3653 return res; 3654} 3655 3656bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3657 assert(UseLargePages, "only for large pages"); 3658 bool res; 3659 3660 if (UseSHM) { 3661 res = os::Linux::release_memory_special_shm(base, bytes); 3662 } else { 3663 assert(UseHugeTLBFS, "must be"); 3664 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3665 } 3666 return res; 3667} 3668 3669size_t os::large_page_size() { 3670 return _large_page_size; 3671} 3672 3673// With SysV SHM the entire memory region must be allocated as shared 3674// memory. 3675// HugeTLBFS allows application to commit large page memory on demand. 3676// However, when committing memory with HugeTLBFS fails, the region 3677// that was supposed to be committed will lose the old reservation 3678// and allow other threads to steal that memory region. Because of this 3679// behavior we can't commit HugeTLBFS memory. 3680bool os::can_commit_large_page_memory() { 3681 return UseTransparentHugePages; 3682} 3683 3684bool os::can_execute_large_page_memory() { 3685 return UseTransparentHugePages || UseHugeTLBFS; 3686} 3687 3688// Reserve memory at an arbitrary address, only if that area is 3689// available (and not reserved for something else). 3690 3691char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3692 const int max_tries = 10; 3693 char* base[max_tries]; 3694 size_t size[max_tries]; 3695 const size_t gap = 0x000000; 3696 3697 // Assert only that the size is a multiple of the page size, since 3698 // that's all that mmap requires, and since that's all we really know 3699 // about at this low abstraction level. If we need higher alignment, 3700 // we can either pass an alignment to this method or verify alignment 3701 // in one of the methods further up the call chain. See bug 5044738. 3702 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3703 3704 // Repeatedly allocate blocks until the block is allocated at the 3705 // right spot. Give up after max_tries. Note that reserve_memory() will 3706 // automatically update _highest_vm_reserved_address if the call is 3707 // successful. The variable tracks the highest memory address every reserved 3708 // by JVM. It is used to detect heap-stack collision if running with 3709 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 3710 // space than needed, it could confuse the collision detecting code. To 3711 // solve the problem, save current _highest_vm_reserved_address and 3712 // calculate the correct value before return. 3713 address old_highest = _highest_vm_reserved_address; 3714 3715 // Linux mmap allows caller to pass an address as hint; give it a try first, 3716 // if kernel honors the hint then we can return immediately. 3717 char * addr = anon_mmap(requested_addr, bytes, false); 3718 if (addr == requested_addr) { 3719 return requested_addr; 3720 } 3721 3722 if (addr != NULL) { 3723 // mmap() is successful but it fails to reserve at the requested address 3724 anon_munmap(addr, bytes); 3725 } 3726 3727 int i; 3728 for (i = 0; i < max_tries; ++i) { 3729 base[i] = reserve_memory(bytes); 3730 3731 if (base[i] != NULL) { 3732 // Is this the block we wanted? 3733 if (base[i] == requested_addr) { 3734 size[i] = bytes; 3735 break; 3736 } 3737 3738 // Does this overlap the block we wanted? Give back the overlapped 3739 // parts and try again. 3740 3741 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3742 if (top_overlap >= 0 && top_overlap < bytes) { 3743 unmap_memory(base[i], top_overlap); 3744 base[i] += top_overlap; 3745 size[i] = bytes - top_overlap; 3746 } else { 3747 size_t bottom_overlap = base[i] + bytes - requested_addr; 3748 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3749 unmap_memory(requested_addr, bottom_overlap); 3750 size[i] = bytes - bottom_overlap; 3751 } else { 3752 size[i] = bytes; 3753 } 3754 } 3755 } 3756 } 3757 3758 // Give back the unused reserved pieces. 3759 3760 for (int j = 0; j < i; ++j) { 3761 if (base[j] != NULL) { 3762 unmap_memory(base[j], size[j]); 3763 } 3764 } 3765 3766 if (i < max_tries) { 3767 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3768 return requested_addr; 3769 } else { 3770 _highest_vm_reserved_address = old_highest; 3771 return NULL; 3772 } 3773} 3774 3775size_t os::read(int fd, void *buf, unsigned int nBytes) { 3776 return ::read(fd, buf, nBytes); 3777} 3778 3779size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3780 return ::pread(fd, buf, nBytes, offset); 3781} 3782 3783// Short sleep, direct OS call. 3784// 3785// Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3786// sched_yield(2) will actually give up the CPU: 3787// 3788// * Alone on this pariticular CPU, keeps running. 3789// * Before the introduction of "skip_buddy" with "compat_yield" disabled 3790// (pre 2.6.39). 3791// 3792// So calling this with 0 is an alternative. 3793// 3794void os::naked_short_sleep(jlong ms) { 3795 struct timespec req; 3796 3797 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3798 req.tv_sec = 0; 3799 if (ms > 0) { 3800 req.tv_nsec = (ms % 1000) * 1000000; 3801 } else { 3802 req.tv_nsec = 1; 3803 } 3804 3805 nanosleep(&req, NULL); 3806 3807 return; 3808} 3809 3810// Sleep forever; naked call to OS-specific sleep; use with CAUTION 3811void os::infinite_sleep() { 3812 while (true) { // sleep forever ... 3813 ::sleep(100); // ... 100 seconds at a time 3814 } 3815} 3816 3817// Used to convert frequent JVM_Yield() to nops 3818bool os::dont_yield() { 3819 return DontYieldALot; 3820} 3821 3822void os::naked_yield() { 3823 sched_yield(); 3824} 3825 3826//////////////////////////////////////////////////////////////////////////////// 3827// thread priority support 3828 3829// Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3830// only supports dynamic priority, static priority must be zero. For real-time 3831// applications, Linux supports SCHED_RR which allows static priority (1-99). 3832// However, for large multi-threaded applications, SCHED_RR is not only slower 3833// than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3834// of 5 runs - Sep 2005). 3835// 3836// The following code actually changes the niceness of kernel-thread/LWP. It 3837// has an assumption that setpriority() only modifies one kernel-thread/LWP, 3838// not the entire user process, and user level threads are 1:1 mapped to kernel 3839// threads. It has always been the case, but could change in the future. For 3840// this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3841// It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3842 3843int os::java_to_os_priority[CriticalPriority + 1] = { 3844 19, // 0 Entry should never be used 3845 3846 4, // 1 MinPriority 3847 3, // 2 3848 2, // 3 3849 3850 1, // 4 3851 0, // 5 NormPriority 3852 -1, // 6 3853 3854 -2, // 7 3855 -3, // 8 3856 -4, // 9 NearMaxPriority 3857 3858 -5, // 10 MaxPriority 3859 3860 -5 // 11 CriticalPriority 3861}; 3862 3863static int prio_init() { 3864 if (ThreadPriorityPolicy == 1) { 3865 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3866 // if effective uid is not root. Perhaps, a more elegant way of doing 3867 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3868 if (geteuid() != 0) { 3869 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3870 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3871 } 3872 ThreadPriorityPolicy = 0; 3873 } 3874 } 3875 if (UseCriticalJavaThreadPriority) { 3876 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3877 } 3878 return 0; 3879} 3880 3881OSReturn os::set_native_priority(Thread* thread, int newpri) { 3882 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3883 3884 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3885 return (ret == 0) ? OS_OK : OS_ERR; 3886} 3887 3888OSReturn os::get_native_priority(const Thread* const thread, 3889 int *priority_ptr) { 3890 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3891 *priority_ptr = java_to_os_priority[NormPriority]; 3892 return OS_OK; 3893 } 3894 3895 errno = 0; 3896 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3897 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3898} 3899 3900// Hint to the underlying OS that a task switch would not be good. 3901// Void return because it's a hint and can fail. 3902void os::hint_no_preempt() {} 3903 3904//////////////////////////////////////////////////////////////////////////////// 3905// suspend/resume support 3906 3907// the low-level signal-based suspend/resume support is a remnant from the 3908// old VM-suspension that used to be for java-suspension, safepoints etc, 3909// within hotspot. Now there is a single use-case for this: 3910// - calling get_thread_pc() on the VMThread by the flat-profiler task 3911// that runs in the watcher thread. 3912// The remaining code is greatly simplified from the more general suspension 3913// code that used to be used. 3914// 3915// The protocol is quite simple: 3916// - suspend: 3917// - sends a signal to the target thread 3918// - polls the suspend state of the osthread using a yield loop 3919// - target thread signal handler (SR_handler) sets suspend state 3920// and blocks in sigsuspend until continued 3921// - resume: 3922// - sets target osthread state to continue 3923// - sends signal to end the sigsuspend loop in the SR_handler 3924// 3925// Note that the SR_lock plays no role in this suspend/resume protocol. 3926 3927static void resume_clear_context(OSThread *osthread) { 3928 osthread->set_ucontext(NULL); 3929 osthread->set_siginfo(NULL); 3930} 3931 3932static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 3933 ucontext_t* context) { 3934 osthread->set_ucontext(context); 3935 osthread->set_siginfo(siginfo); 3936} 3937 3938// Handler function invoked when a thread's execution is suspended or 3939// resumed. We have to be careful that only async-safe functions are 3940// called here (Note: most pthread functions are not async safe and 3941// should be avoided.) 3942// 3943// Note: sigwait() is a more natural fit than sigsuspend() from an 3944// interface point of view, but sigwait() prevents the signal hander 3945// from being run. libpthread would get very confused by not having 3946// its signal handlers run and prevents sigwait()'s use with the 3947// mutex granting granting signal. 3948// 3949// Currently only ever called on the VMThread and JavaThreads (PC sampling) 3950// 3951static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3952 // Save and restore errno to avoid confusing native code with EINTR 3953 // after sigsuspend. 3954 int old_errno = errno; 3955 3956 Thread* thread = Thread::current(); 3957 OSThread* osthread = thread->osthread(); 3958 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 3959 3960 os::SuspendResume::State current = osthread->sr.state(); 3961 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 3962 suspend_save_context(osthread, siginfo, context); 3963 3964 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 3965 os::SuspendResume::State state = osthread->sr.suspended(); 3966 if (state == os::SuspendResume::SR_SUSPENDED) { 3967 sigset_t suspend_set; // signals for sigsuspend() 3968 3969 // get current set of blocked signals and unblock resume signal 3970 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3971 sigdelset(&suspend_set, SR_signum); 3972 3973 sr_semaphore.signal(); 3974 // wait here until we are resumed 3975 while (1) { 3976 sigsuspend(&suspend_set); 3977 3978 os::SuspendResume::State result = osthread->sr.running(); 3979 if (result == os::SuspendResume::SR_RUNNING) { 3980 sr_semaphore.signal(); 3981 break; 3982 } 3983 } 3984 3985 } else if (state == os::SuspendResume::SR_RUNNING) { 3986 // request was cancelled, continue 3987 } else { 3988 ShouldNotReachHere(); 3989 } 3990 3991 resume_clear_context(osthread); 3992 } else if (current == os::SuspendResume::SR_RUNNING) { 3993 // request was cancelled, continue 3994 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 3995 // ignore 3996 } else { 3997 // ignore 3998 } 3999 4000 errno = old_errno; 4001} 4002 4003 4004static int SR_initialize() { 4005 struct sigaction act; 4006 char *s; 4007 // Get signal number to use for suspend/resume 4008 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4009 int sig = ::strtol(s, 0, 10); 4010 if (sig > 0 || sig < _NSIG) { 4011 SR_signum = sig; 4012 } 4013 } 4014 4015 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4016 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4017 4018 sigemptyset(&SR_sigset); 4019 sigaddset(&SR_sigset, SR_signum); 4020 4021 // Set up signal handler for suspend/resume 4022 act.sa_flags = SA_RESTART|SA_SIGINFO; 4023 act.sa_handler = (void (*)(int)) SR_handler; 4024 4025 // SR_signum is blocked by default. 4026 // 4528190 - We also need to block pthread restart signal (32 on all 4027 // supported Linux platforms). Note that LinuxThreads need to block 4028 // this signal for all threads to work properly. So we don't have 4029 // to use hard-coded signal number when setting up the mask. 4030 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4031 4032 if (sigaction(SR_signum, &act, 0) == -1) { 4033 return -1; 4034 } 4035 4036 // Save signal flag 4037 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4038 return 0; 4039} 4040 4041static int sr_notify(OSThread* osthread) { 4042 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4043 assert_status(status == 0, status, "pthread_kill"); 4044 return status; 4045} 4046 4047// "Randomly" selected value for how long we want to spin 4048// before bailing out on suspending a thread, also how often 4049// we send a signal to a thread we want to resume 4050static const int RANDOMLY_LARGE_INTEGER = 1000000; 4051static const int RANDOMLY_LARGE_INTEGER2 = 100; 4052 4053// returns true on success and false on error - really an error is fatal 4054// but this seems the normal response to library errors 4055static bool do_suspend(OSThread* osthread) { 4056 assert(osthread->sr.is_running(), "thread should be running"); 4057 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4058 4059 // mark as suspended and send signal 4060 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4061 // failed to switch, state wasn't running? 4062 ShouldNotReachHere(); 4063 return false; 4064 } 4065 4066 if (sr_notify(osthread) != 0) { 4067 ShouldNotReachHere(); 4068 } 4069 4070 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4071 while (true) { 4072 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4073 break; 4074 } else { 4075 // timeout 4076 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4077 if (cancelled == os::SuspendResume::SR_RUNNING) { 4078 return false; 4079 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4080 // make sure that we consume the signal on the semaphore as well 4081 sr_semaphore.wait(); 4082 break; 4083 } else { 4084 ShouldNotReachHere(); 4085 return false; 4086 } 4087 } 4088 } 4089 4090 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4091 return true; 4092} 4093 4094static void do_resume(OSThread* osthread) { 4095 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4096 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4097 4098 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4099 // failed to switch to WAKEUP_REQUEST 4100 ShouldNotReachHere(); 4101 return; 4102 } 4103 4104 while (true) { 4105 if (sr_notify(osthread) == 0) { 4106 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4107 if (osthread->sr.is_running()) { 4108 return; 4109 } 4110 } 4111 } else { 4112 ShouldNotReachHere(); 4113 } 4114 } 4115 4116 guarantee(osthread->sr.is_running(), "Must be running!"); 4117} 4118 4119/////////////////////////////////////////////////////////////////////////////////// 4120// signal handling (except suspend/resume) 4121 4122// This routine may be used by user applications as a "hook" to catch signals. 4123// The user-defined signal handler must pass unrecognized signals to this 4124// routine, and if it returns true (non-zero), then the signal handler must 4125// return immediately. If the flag "abort_if_unrecognized" is true, then this 4126// routine will never retun false (zero), but instead will execute a VM panic 4127// routine kill the process. 4128// 4129// If this routine returns false, it is OK to call it again. This allows 4130// the user-defined signal handler to perform checks either before or after 4131// the VM performs its own checks. Naturally, the user code would be making 4132// a serious error if it tried to handle an exception (such as a null check 4133// or breakpoint) that the VM was generating for its own correct operation. 4134// 4135// This routine may recognize any of the following kinds of signals: 4136// SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4137// It should be consulted by handlers for any of those signals. 4138// 4139// The caller of this routine must pass in the three arguments supplied 4140// to the function referred to in the "sa_sigaction" (not the "sa_handler") 4141// field of the structure passed to sigaction(). This routine assumes that 4142// the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4143// 4144// Note that the VM will print warnings if it detects conflicting signal 4145// handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4146// 4147extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4148 siginfo_t* siginfo, 4149 void* ucontext, 4150 int abort_if_unrecognized); 4151 4152void signalHandler(int sig, siginfo_t* info, void* uc) { 4153 assert(info != NULL && uc != NULL, "it must be old kernel"); 4154 int orig_errno = errno; // Preserve errno value over signal handler. 4155 JVM_handle_linux_signal(sig, info, uc, true); 4156 errno = orig_errno; 4157} 4158 4159 4160// This boolean allows users to forward their own non-matching signals 4161// to JVM_handle_linux_signal, harmlessly. 4162bool os::Linux::signal_handlers_are_installed = false; 4163 4164// For signal-chaining 4165struct sigaction os::Linux::sigact[MAXSIGNUM]; 4166unsigned int os::Linux::sigs = 0; 4167bool os::Linux::libjsig_is_loaded = false; 4168typedef struct sigaction *(*get_signal_t)(int); 4169get_signal_t os::Linux::get_signal_action = NULL; 4170 4171struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4172 struct sigaction *actp = NULL; 4173 4174 if (libjsig_is_loaded) { 4175 // Retrieve the old signal handler from libjsig 4176 actp = (*get_signal_action)(sig); 4177 } 4178 if (actp == NULL) { 4179 // Retrieve the preinstalled signal handler from jvm 4180 actp = get_preinstalled_handler(sig); 4181 } 4182 4183 return actp; 4184} 4185 4186static bool call_chained_handler(struct sigaction *actp, int sig, 4187 siginfo_t *siginfo, void *context) { 4188 // Call the old signal handler 4189 if (actp->sa_handler == SIG_DFL) { 4190 // It's more reasonable to let jvm treat it as an unexpected exception 4191 // instead of taking the default action. 4192 return false; 4193 } else if (actp->sa_handler != SIG_IGN) { 4194 if ((actp->sa_flags & SA_NODEFER) == 0) { 4195 // automaticlly block the signal 4196 sigaddset(&(actp->sa_mask), sig); 4197 } 4198 4199 sa_handler_t hand; 4200 sa_sigaction_t sa; 4201 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4202 // retrieve the chained handler 4203 if (siginfo_flag_set) { 4204 sa = actp->sa_sigaction; 4205 } else { 4206 hand = actp->sa_handler; 4207 } 4208 4209 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4210 actp->sa_handler = SIG_DFL; 4211 } 4212 4213 // try to honor the signal mask 4214 sigset_t oset; 4215 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4216 4217 // call into the chained handler 4218 if (siginfo_flag_set) { 4219 (*sa)(sig, siginfo, context); 4220 } else { 4221 (*hand)(sig); 4222 } 4223 4224 // restore the signal mask 4225 pthread_sigmask(SIG_SETMASK, &oset, 0); 4226 } 4227 // Tell jvm's signal handler the signal is taken care of. 4228 return true; 4229} 4230 4231bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4232 bool chained = false; 4233 // signal-chaining 4234 if (UseSignalChaining) { 4235 struct sigaction *actp = get_chained_signal_action(sig); 4236 if (actp != NULL) { 4237 chained = call_chained_handler(actp, sig, siginfo, context); 4238 } 4239 } 4240 return chained; 4241} 4242 4243struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4244 if ((((unsigned int)1 << sig) & sigs) != 0) { 4245 return &sigact[sig]; 4246 } 4247 return NULL; 4248} 4249 4250void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4251 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4252 sigact[sig] = oldAct; 4253 sigs |= (unsigned int)1 << sig; 4254} 4255 4256// for diagnostic 4257int os::Linux::sigflags[MAXSIGNUM]; 4258 4259int os::Linux::get_our_sigflags(int sig) { 4260 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4261 return sigflags[sig]; 4262} 4263 4264void os::Linux::set_our_sigflags(int sig, int flags) { 4265 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4266 sigflags[sig] = flags; 4267} 4268 4269void os::Linux::set_signal_handler(int sig, bool set_installed) { 4270 // Check for overwrite. 4271 struct sigaction oldAct; 4272 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4273 4274 void* oldhand = oldAct.sa_sigaction 4275 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4276 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4277 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4278 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4279 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4280 if (AllowUserSignalHandlers || !set_installed) { 4281 // Do not overwrite; user takes responsibility to forward to us. 4282 return; 4283 } else if (UseSignalChaining) { 4284 // save the old handler in jvm 4285 save_preinstalled_handler(sig, oldAct); 4286 // libjsig also interposes the sigaction() call below and saves the 4287 // old sigaction on it own. 4288 } else { 4289 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 4290 "%#lx for signal %d.", (long)oldhand, sig)); 4291 } 4292 } 4293 4294 struct sigaction sigAct; 4295 sigfillset(&(sigAct.sa_mask)); 4296 sigAct.sa_handler = SIG_DFL; 4297 if (!set_installed) { 4298 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4299 } else { 4300 sigAct.sa_sigaction = signalHandler; 4301 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4302 } 4303 // Save flags, which are set by ours 4304 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 4305 sigflags[sig] = sigAct.sa_flags; 4306 4307 int ret = sigaction(sig, &sigAct, &oldAct); 4308 assert(ret == 0, "check"); 4309 4310 void* oldhand2 = oldAct.sa_sigaction 4311 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4312 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4313 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4314} 4315 4316// install signal handlers for signals that HotSpot needs to 4317// handle in order to support Java-level exception handling. 4318 4319void os::Linux::install_signal_handlers() { 4320 if (!signal_handlers_are_installed) { 4321 signal_handlers_are_installed = true; 4322 4323 // signal-chaining 4324 typedef void (*signal_setting_t)(); 4325 signal_setting_t begin_signal_setting = NULL; 4326 signal_setting_t end_signal_setting = NULL; 4327 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4328 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4329 if (begin_signal_setting != NULL) { 4330 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4331 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4332 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4333 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4334 libjsig_is_loaded = true; 4335 assert(UseSignalChaining, "should enable signal-chaining"); 4336 } 4337 if (libjsig_is_loaded) { 4338 // Tell libjsig jvm is setting signal handlers 4339 (*begin_signal_setting)(); 4340 } 4341 4342 set_signal_handler(SIGSEGV, true); 4343 set_signal_handler(SIGPIPE, true); 4344 set_signal_handler(SIGBUS, true); 4345 set_signal_handler(SIGILL, true); 4346 set_signal_handler(SIGFPE, true); 4347#if defined(PPC64) 4348 set_signal_handler(SIGTRAP, true); 4349#endif 4350 set_signal_handler(SIGXFSZ, true); 4351 4352 if (libjsig_is_loaded) { 4353 // Tell libjsig jvm finishes setting signal handlers 4354 (*end_signal_setting)(); 4355 } 4356 4357 // We don't activate signal checker if libjsig is in place, we trust ourselves 4358 // and if UserSignalHandler is installed all bets are off. 4359 // Log that signal checking is off only if -verbose:jni is specified. 4360 if (CheckJNICalls) { 4361 if (libjsig_is_loaded) { 4362 if (PrintJNIResolving) { 4363 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4364 } 4365 check_signals = false; 4366 } 4367 if (AllowUserSignalHandlers) { 4368 if (PrintJNIResolving) { 4369 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4370 } 4371 check_signals = false; 4372 } 4373 } 4374 } 4375} 4376 4377// This is the fastest way to get thread cpu time on Linux. 4378// Returns cpu time (user+sys) for any thread, not only for current. 4379// POSIX compliant clocks are implemented in the kernels 2.6.16+. 4380// It might work on 2.6.10+ with a special kernel/glibc patch. 4381// For reference, please, see IEEE Std 1003.1-2004: 4382// http://www.unix.org/single_unix_specification 4383 4384jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4385 struct timespec tp; 4386 int rc = os::Linux::clock_gettime(clockid, &tp); 4387 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4388 4389 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4390} 4391 4392///// 4393// glibc on Linux platform uses non-documented flag 4394// to indicate, that some special sort of signal 4395// trampoline is used. 4396// We will never set this flag, and we should 4397// ignore this flag in our diagnostic 4398#ifdef SIGNIFICANT_SIGNAL_MASK 4399 #undef SIGNIFICANT_SIGNAL_MASK 4400#endif 4401#define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4402 4403static const char* get_signal_handler_name(address handler, 4404 char* buf, int buflen) { 4405 int offset; 4406 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4407 if (found) { 4408 // skip directory names 4409 const char *p1, *p2; 4410 p1 = buf; 4411 size_t len = strlen(os::file_separator()); 4412 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4413 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4414 } else { 4415 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4416 } 4417 return buf; 4418} 4419 4420static void print_signal_handler(outputStream* st, int sig, 4421 char* buf, size_t buflen) { 4422 struct sigaction sa; 4423 4424 sigaction(sig, NULL, &sa); 4425 4426 // See comment for SIGNIFICANT_SIGNAL_MASK define 4427 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4428 4429 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4430 4431 address handler = (sa.sa_flags & SA_SIGINFO) 4432 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4433 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4434 4435 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4436 st->print("SIG_DFL"); 4437 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4438 st->print("SIG_IGN"); 4439 } else { 4440 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4441 } 4442 4443 st->print(", sa_mask[0]="); 4444 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4445 4446 address rh = VMError::get_resetted_sighandler(sig); 4447 // May be, handler was resetted by VMError? 4448 if (rh != NULL) { 4449 handler = rh; 4450 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4451 } 4452 4453 st->print(", sa_flags="); 4454 os::Posix::print_sa_flags(st, sa.sa_flags); 4455 4456 // Check: is it our handler? 4457 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4458 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4459 // It is our signal handler 4460 // check for flags, reset system-used one! 4461 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4462 st->print( 4463 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4464 os::Linux::get_our_sigflags(sig)); 4465 } 4466 } 4467 st->cr(); 4468} 4469 4470 4471#define DO_SIGNAL_CHECK(sig) \ 4472 do { \ 4473 if (!sigismember(&check_signal_done, sig)) { \ 4474 os::Linux::check_signal_handler(sig); \ 4475 } \ 4476 } while (0) 4477 4478// This method is a periodic task to check for misbehaving JNI applications 4479// under CheckJNI, we can add any periodic checks here 4480 4481void os::run_periodic_checks() { 4482 if (check_signals == false) return; 4483 4484 // SEGV and BUS if overridden could potentially prevent 4485 // generation of hs*.log in the event of a crash, debugging 4486 // such a case can be very challenging, so we absolutely 4487 // check the following for a good measure: 4488 DO_SIGNAL_CHECK(SIGSEGV); 4489 DO_SIGNAL_CHECK(SIGILL); 4490 DO_SIGNAL_CHECK(SIGFPE); 4491 DO_SIGNAL_CHECK(SIGBUS); 4492 DO_SIGNAL_CHECK(SIGPIPE); 4493 DO_SIGNAL_CHECK(SIGXFSZ); 4494#if defined(PPC64) 4495 DO_SIGNAL_CHECK(SIGTRAP); 4496#endif 4497 4498 // ReduceSignalUsage allows the user to override these handlers 4499 // see comments at the very top and jvm_solaris.h 4500 if (!ReduceSignalUsage) { 4501 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4502 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4503 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4504 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4505 } 4506 4507 DO_SIGNAL_CHECK(SR_signum); 4508 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 4509} 4510 4511typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4512 4513static os_sigaction_t os_sigaction = NULL; 4514 4515void os::Linux::check_signal_handler(int sig) { 4516 char buf[O_BUFLEN]; 4517 address jvmHandler = NULL; 4518 4519 4520 struct sigaction act; 4521 if (os_sigaction == NULL) { 4522 // only trust the default sigaction, in case it has been interposed 4523 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4524 if (os_sigaction == NULL) return; 4525 } 4526 4527 os_sigaction(sig, (struct sigaction*)NULL, &act); 4528 4529 4530 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4531 4532 address thisHandler = (act.sa_flags & SA_SIGINFO) 4533 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4534 : CAST_FROM_FN_PTR(address, act.sa_handler); 4535 4536 4537 switch (sig) { 4538 case SIGSEGV: 4539 case SIGBUS: 4540 case SIGFPE: 4541 case SIGPIPE: 4542 case SIGILL: 4543 case SIGXFSZ: 4544 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4545 break; 4546 4547 case SHUTDOWN1_SIGNAL: 4548 case SHUTDOWN2_SIGNAL: 4549 case SHUTDOWN3_SIGNAL: 4550 case BREAK_SIGNAL: 4551 jvmHandler = (address)user_handler(); 4552 break; 4553 4554 case INTERRUPT_SIGNAL: 4555 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4556 break; 4557 4558 default: 4559 if (sig == SR_signum) { 4560 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4561 } else { 4562 return; 4563 } 4564 break; 4565 } 4566 4567 if (thisHandler != jvmHandler) { 4568 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4569 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4570 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4571 // No need to check this sig any longer 4572 sigaddset(&check_signal_done, sig); 4573 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4574 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4575 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4576 exception_name(sig, buf, O_BUFLEN)); 4577 } 4578 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4579 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4580 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4581 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4582 // No need to check this sig any longer 4583 sigaddset(&check_signal_done, sig); 4584 } 4585 4586 // Dump all the signal 4587 if (sigismember(&check_signal_done, sig)) { 4588 print_signal_handlers(tty, buf, O_BUFLEN); 4589 } 4590} 4591 4592extern void report_error(char* file_name, int line_no, char* title, 4593 char* format, ...); 4594 4595extern bool signal_name(int signo, char* buf, size_t len); 4596 4597const char* os::exception_name(int exception_code, char* buf, size_t size) { 4598 if (0 < exception_code && exception_code <= SIGRTMAX) { 4599 // signal 4600 if (!signal_name(exception_code, buf, size)) { 4601 jio_snprintf(buf, size, "SIG%d", exception_code); 4602 } 4603 return buf; 4604 } else { 4605 return NULL; 4606 } 4607} 4608 4609// this is called _before_ the most of global arguments have been parsed 4610void os::init(void) { 4611 char dummy; // used to get a guess on initial stack address 4612// first_hrtime = gethrtime(); 4613 4614 // With LinuxThreads the JavaMain thread pid (primordial thread) 4615 // is different than the pid of the java launcher thread. 4616 // So, on Linux, the launcher thread pid is passed to the VM 4617 // via the sun.java.launcher.pid property. 4618 // Use this property instead of getpid() if it was correctly passed. 4619 // See bug 6351349. 4620 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 4621 4622 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 4623 4624 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4625 4626 init_random(1234567); 4627 4628 ThreadCritical::initialize(); 4629 4630 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4631 if (Linux::page_size() == -1) { 4632 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 4633 strerror(errno))); 4634 } 4635 init_page_sizes((size_t) Linux::page_size()); 4636 4637 Linux::initialize_system_info(); 4638 4639 // main_thread points to the aboriginal thread 4640 Linux::_main_thread = pthread_self(); 4641 4642 Linux::clock_init(); 4643 initial_time_count = javaTimeNanos(); 4644 4645 // pthread_condattr initialization for monotonic clock 4646 int status; 4647 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4648 if ((status = pthread_condattr_init(_condattr)) != 0) { 4649 fatal(err_msg("pthread_condattr_init: %s", strerror(status))); 4650 } 4651 // Only set the clock if CLOCK_MONOTONIC is available 4652 if (os::supports_monotonic_clock()) { 4653 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4654 if (status == EINVAL) { 4655 warning("Unable to use monotonic clock with relative timed-waits" \ 4656 " - changes to the time-of-day clock may have adverse affects"); 4657 } else { 4658 fatal(err_msg("pthread_condattr_setclock: %s", strerror(status))); 4659 } 4660 } 4661 } 4662 // else it defaults to CLOCK_REALTIME 4663 4664 pthread_mutex_init(&dl_mutex, NULL); 4665 4666 // If the pagesize of the VM is greater than 8K determine the appropriate 4667 // number of initial guard pages. The user can change this with the 4668 // command line arguments, if needed. 4669 if (vm_page_size() > (int)Linux::vm_default_page_size()) { 4670 StackYellowPages = 1; 4671 StackRedPages = 1; 4672 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size(); 4673 } 4674 4675 // retrieve entry point for pthread_setname_np 4676 Linux::_pthread_setname_np = 4677 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4678 4679} 4680 4681// To install functions for atexit system call 4682extern "C" { 4683 static void perfMemory_exit_helper() { 4684 perfMemory_exit(); 4685 } 4686} 4687 4688// this is called _after_ the global arguments have been parsed 4689jint os::init_2(void) { 4690 Linux::fast_thread_clock_init(); 4691 4692 // Allocate a single page and mark it as readable for safepoint polling 4693 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4694 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4695 4696 os::set_polling_page(polling_page); 4697 4698#ifndef PRODUCT 4699 if (Verbose && PrintMiscellaneous) { 4700 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", 4701 (intptr_t)polling_page); 4702 } 4703#endif 4704 4705 if (!UseMembar) { 4706 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4707 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4708 os::set_memory_serialize_page(mem_serialize_page); 4709 4710#ifndef PRODUCT 4711 if (Verbose && PrintMiscellaneous) { 4712 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", 4713 (intptr_t)mem_serialize_page); 4714 } 4715#endif 4716 } 4717 4718 // initialize suspend/resume support - must do this before signal_sets_init() 4719 if (SR_initialize() != 0) { 4720 perror("SR_initialize failed"); 4721 return JNI_ERR; 4722 } 4723 4724 Linux::signal_sets_init(); 4725 Linux::install_signal_handlers(); 4726 4727 // Check minimum allowable stack size for thread creation and to initialize 4728 // the java system classes, including StackOverflowError - depends on page 4729 // size. Add a page for compiler2 recursion in main thread. 4730 // Add in 2*BytesPerWord times page size to account for VM stack during 4731 // class initialization depending on 32 or 64 bit VM. 4732 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4733 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() + 4734 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size()); 4735 4736 size_t threadStackSizeInBytes = ThreadStackSize * K; 4737 if (threadStackSizeInBytes != 0 && 4738 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4739 tty->print_cr("\nThe stack size specified is too small, " 4740 "Specify at least %dk", 4741 os::Linux::min_stack_allowed/ K); 4742 return JNI_ERR; 4743 } 4744 4745 // Make the stack size a multiple of the page size so that 4746 // the yellow/red zones can be guarded. 4747 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4748 vm_page_size())); 4749 4750 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4751 4752#if defined(IA32) 4753 workaround_expand_exec_shield_cs_limit(); 4754#endif 4755 4756 Linux::libpthread_init(); 4757 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4758 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4759 Linux::glibc_version(), Linux::libpthread_version(), 4760 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4761 } 4762 4763 if (UseNUMA) { 4764 if (!Linux::libnuma_init()) { 4765 UseNUMA = false; 4766 } else { 4767 if ((Linux::numa_max_node() < 1)) { 4768 // There's only one node(they start from 0), disable NUMA. 4769 UseNUMA = false; 4770 } 4771 } 4772 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4773 // we can make the adaptive lgrp chunk resizing work. If the user specified 4774 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4775 // disable adaptive resizing. 4776 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4777 if (FLAG_IS_DEFAULT(UseNUMA)) { 4778 UseNUMA = false; 4779 } else { 4780 if (FLAG_IS_DEFAULT(UseLargePages) && 4781 FLAG_IS_DEFAULT(UseSHM) && 4782 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4783 UseLargePages = false; 4784 } else { 4785 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing"); 4786 UseAdaptiveSizePolicy = false; 4787 UseAdaptiveNUMAChunkSizing = false; 4788 } 4789 } 4790 } 4791 if (!UseNUMA && ForceNUMA) { 4792 UseNUMA = true; 4793 } 4794 } 4795 4796 if (MaxFDLimit) { 4797 // set the number of file descriptors to max. print out error 4798 // if getrlimit/setrlimit fails but continue regardless. 4799 struct rlimit nbr_files; 4800 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4801 if (status != 0) { 4802 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4803 perror("os::init_2 getrlimit failed"); 4804 } 4805 } else { 4806 nbr_files.rlim_cur = nbr_files.rlim_max; 4807 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4808 if (status != 0) { 4809 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4810 perror("os::init_2 setrlimit failed"); 4811 } 4812 } 4813 } 4814 } 4815 4816 // Initialize lock used to serialize thread creation (see os::create_thread) 4817 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4818 4819 // at-exit methods are called in the reverse order of their registration. 4820 // atexit functions are called on return from main or as a result of a 4821 // call to exit(3C). There can be only 32 of these functions registered 4822 // and atexit() does not set errno. 4823 4824 if (PerfAllowAtExitRegistration) { 4825 // only register atexit functions if PerfAllowAtExitRegistration is set. 4826 // atexit functions can be delayed until process exit time, which 4827 // can be problematic for embedded VM situations. Embedded VMs should 4828 // call DestroyJavaVM() to assure that VM resources are released. 4829 4830 // note: perfMemory_exit_helper atexit function may be removed in 4831 // the future if the appropriate cleanup code can be added to the 4832 // VM_Exit VMOperation's doit method. 4833 if (atexit(perfMemory_exit_helper) != 0) { 4834 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4835 } 4836 } 4837 4838 // initialize thread priority policy 4839 prio_init(); 4840 4841 return JNI_OK; 4842} 4843 4844// Mark the polling page as unreadable 4845void os::make_polling_page_unreadable(void) { 4846 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4847 fatal("Could not disable polling page"); 4848 } 4849} 4850 4851// Mark the polling page as readable 4852void os::make_polling_page_readable(void) { 4853 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4854 fatal("Could not enable polling page"); 4855 } 4856} 4857 4858int os::active_processor_count() { 4859 // Linux doesn't yet have a (official) notion of processor sets, 4860 // so just return the number of online processors. 4861 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4862 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4863 return online_cpus; 4864} 4865 4866void os::set_native_thread_name(const char *name) { 4867 if (Linux::_pthread_setname_np) { 4868 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 4869 snprintf(buf, sizeof(buf), "%s", name); 4870 buf[sizeof(buf) - 1] = '\0'; 4871 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 4872 // ERANGE should not happen; all other errors should just be ignored. 4873 assert(rc != ERANGE, "pthread_setname_np failed"); 4874 } 4875} 4876 4877bool os::distribute_processes(uint length, uint* distribution) { 4878 // Not yet implemented. 4879 return false; 4880} 4881 4882bool os::bind_to_processor(uint processor_id) { 4883 // Not yet implemented. 4884 return false; 4885} 4886 4887/// 4888 4889void os::SuspendedThreadTask::internal_do_task() { 4890 if (do_suspend(_thread->osthread())) { 4891 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 4892 do_task(context); 4893 do_resume(_thread->osthread()); 4894 } 4895} 4896 4897class PcFetcher : public os::SuspendedThreadTask { 4898 public: 4899 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 4900 ExtendedPC result(); 4901 protected: 4902 void do_task(const os::SuspendedThreadTaskContext& context); 4903 private: 4904 ExtendedPC _epc; 4905}; 4906 4907ExtendedPC PcFetcher::result() { 4908 guarantee(is_done(), "task is not done yet."); 4909 return _epc; 4910} 4911 4912void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 4913 Thread* thread = context.thread(); 4914 OSThread* osthread = thread->osthread(); 4915 if (osthread->ucontext() != NULL) { 4916 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext()); 4917 } else { 4918 // NULL context is unexpected, double-check this is the VMThread 4919 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4920 } 4921} 4922 4923// Suspends the target using the signal mechanism and then grabs the PC before 4924// resuming the target. Used by the flat-profiler only 4925ExtendedPC os::get_thread_pc(Thread* thread) { 4926 // Make sure that it is called by the watcher for the VMThread 4927 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4928 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4929 4930 PcFetcher fetcher(thread); 4931 fetcher.run(); 4932 return fetcher.result(); 4933} 4934 4935int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, 4936 pthread_mutex_t *_mutex, 4937 const struct timespec *_abstime) { 4938 if (is_NPTL()) { 4939 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4940 } else { 4941 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4942 // word back to default 64bit precision if condvar is signaled. Java 4943 // wants 53bit precision. Save and restore current value. 4944 int fpu = get_fpu_control_word(); 4945 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4946 set_fpu_control_word(fpu); 4947 return status; 4948 } 4949} 4950 4951//////////////////////////////////////////////////////////////////////////////// 4952// debug support 4953 4954bool os::find(address addr, outputStream* st) { 4955 Dl_info dlinfo; 4956 memset(&dlinfo, 0, sizeof(dlinfo)); 4957 if (dladdr(addr, &dlinfo) != 0) { 4958 st->print(PTR_FORMAT ": ", addr); 4959 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 4960 st->print("%s+%#x", dlinfo.dli_sname, 4961 addr - (intptr_t)dlinfo.dli_saddr); 4962 } else if (dlinfo.dli_fbase != NULL) { 4963 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4964 } else { 4965 st->print("<absolute address>"); 4966 } 4967 if (dlinfo.dli_fname != NULL) { 4968 st->print(" in %s", dlinfo.dli_fname); 4969 } 4970 if (dlinfo.dli_fbase != NULL) { 4971 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4972 } 4973 st->cr(); 4974 4975 if (Verbose) { 4976 // decode some bytes around the PC 4977 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 4978 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 4979 address lowest = (address) dlinfo.dli_sname; 4980 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4981 if (begin < lowest) begin = lowest; 4982 Dl_info dlinfo2; 4983 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 4984 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 4985 end = (address) dlinfo2.dli_saddr; 4986 } 4987 Disassembler::decode(begin, end, st); 4988 } 4989 return true; 4990 } 4991 return false; 4992} 4993 4994//////////////////////////////////////////////////////////////////////////////// 4995// misc 4996 4997// This does not do anything on Linux. This is basically a hook for being 4998// able to use structured exception handling (thread-local exception filters) 4999// on, e.g., Win32. 5000void 5001os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 5002 JavaCallArguments* args, Thread* thread) { 5003 f(value, method, args, thread); 5004} 5005 5006void os::print_statistics() { 5007} 5008 5009int os::message_box(const char* title, const char* message) { 5010 int i; 5011 fdStream err(defaultStream::error_fd()); 5012 for (i = 0; i < 78; i++) err.print_raw("="); 5013 err.cr(); 5014 err.print_raw_cr(title); 5015 for (i = 0; i < 78; i++) err.print_raw("-"); 5016 err.cr(); 5017 err.print_raw_cr(message); 5018 for (i = 0; i < 78; i++) err.print_raw("="); 5019 err.cr(); 5020 5021 char buf[16]; 5022 // Prevent process from exiting upon "read error" without consuming all CPU 5023 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5024 5025 return buf[0] == 'y' || buf[0] == 'Y'; 5026} 5027 5028int os::stat(const char *path, struct stat *sbuf) { 5029 char pathbuf[MAX_PATH]; 5030 if (strlen(path) > MAX_PATH - 1) { 5031 errno = ENAMETOOLONG; 5032 return -1; 5033 } 5034 os::native_path(strcpy(pathbuf, path)); 5035 return ::stat(pathbuf, sbuf); 5036} 5037 5038bool os::check_heap(bool force) { 5039 return true; 5040} 5041 5042// Is a (classpath) directory empty? 5043bool os::dir_is_empty(const char* path) { 5044 DIR *dir = NULL; 5045 struct dirent *ptr; 5046 5047 dir = opendir(path); 5048 if (dir == NULL) return true; 5049 5050 // Scan the directory 5051 bool result = true; 5052 char buf[sizeof(struct dirent) + MAX_PATH]; 5053 while (result && (ptr = ::readdir(dir)) != NULL) { 5054 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5055 result = false; 5056 } 5057 } 5058 closedir(dir); 5059 return result; 5060} 5061 5062// This code originates from JDK's sysOpen and open64_w 5063// from src/solaris/hpi/src/system_md.c 5064 5065int os::open(const char *path, int oflag, int mode) { 5066 if (strlen(path) > MAX_PATH - 1) { 5067 errno = ENAMETOOLONG; 5068 return -1; 5069 } 5070 5071 // All file descriptors that are opened in the Java process and not 5072 // specifically destined for a subprocess should have the close-on-exec 5073 // flag set. If we don't set it, then careless 3rd party native code 5074 // might fork and exec without closing all appropriate file descriptors 5075 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5076 // turn might: 5077 // 5078 // - cause end-of-file to fail to be detected on some file 5079 // descriptors, resulting in mysterious hangs, or 5080 // 5081 // - might cause an fopen in the subprocess to fail on a system 5082 // suffering from bug 1085341. 5083 // 5084 // (Yes, the default setting of the close-on-exec flag is a Unix 5085 // design flaw) 5086 // 5087 // See: 5088 // 1085341: 32-bit stdio routines should support file descriptors >255 5089 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5090 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5091 // 5092 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5093 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5094 // because it saves a system call and removes a small window where the flag 5095 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5096 // and we fall back to using FD_CLOEXEC (see below). 5097#ifdef O_CLOEXEC 5098 oflag |= O_CLOEXEC; 5099#endif 5100 5101 int fd = ::open64(path, oflag, mode); 5102 if (fd == -1) return -1; 5103 5104 //If the open succeeded, the file might still be a directory 5105 { 5106 struct stat64 buf64; 5107 int ret = ::fstat64(fd, &buf64); 5108 int st_mode = buf64.st_mode; 5109 5110 if (ret != -1) { 5111 if ((st_mode & S_IFMT) == S_IFDIR) { 5112 errno = EISDIR; 5113 ::close(fd); 5114 return -1; 5115 } 5116 } else { 5117 ::close(fd); 5118 return -1; 5119 } 5120 } 5121 5122#ifdef FD_CLOEXEC 5123 // Validate that the use of the O_CLOEXEC flag on open above worked. 5124 // With recent kernels, we will perform this check exactly once. 5125 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5126 if (!O_CLOEXEC_is_known_to_work) { 5127 int flags = ::fcntl(fd, F_GETFD); 5128 if (flags != -1) { 5129 if ((flags & FD_CLOEXEC) != 0) 5130 O_CLOEXEC_is_known_to_work = 1; 5131 else 5132 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5133 } 5134 } 5135#endif 5136 5137 return fd; 5138} 5139 5140 5141// create binary file, rewriting existing file if required 5142int os::create_binary_file(const char* path, bool rewrite_existing) { 5143 int oflags = O_WRONLY | O_CREAT; 5144 if (!rewrite_existing) { 5145 oflags |= O_EXCL; 5146 } 5147 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5148} 5149 5150// return current position of file pointer 5151jlong os::current_file_offset(int fd) { 5152 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5153} 5154 5155// move file pointer to the specified offset 5156jlong os::seek_to_file_offset(int fd, jlong offset) { 5157 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5158} 5159 5160// This code originates from JDK's sysAvailable 5161// from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5162 5163int os::available(int fd, jlong *bytes) { 5164 jlong cur, end; 5165 int mode; 5166 struct stat64 buf64; 5167 5168 if (::fstat64(fd, &buf64) >= 0) { 5169 mode = buf64.st_mode; 5170 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5171 // XXX: is the following call interruptible? If so, this might 5172 // need to go through the INTERRUPT_IO() wrapper as for other 5173 // blocking, interruptible calls in this file. 5174 int n; 5175 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5176 *bytes = n; 5177 return 1; 5178 } 5179 } 5180 } 5181 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5182 return 0; 5183 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5184 return 0; 5185 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5186 return 0; 5187 } 5188 *bytes = end - cur; 5189 return 1; 5190} 5191 5192// Map a block of memory. 5193char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5194 char *addr, size_t bytes, bool read_only, 5195 bool allow_exec) { 5196 int prot; 5197 int flags = MAP_PRIVATE; 5198 5199 if (read_only) { 5200 prot = PROT_READ; 5201 } else { 5202 prot = PROT_READ | PROT_WRITE; 5203 } 5204 5205 if (allow_exec) { 5206 prot |= PROT_EXEC; 5207 } 5208 5209 if (addr != NULL) { 5210 flags |= MAP_FIXED; 5211 } 5212 5213 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5214 fd, file_offset); 5215 if (mapped_address == MAP_FAILED) { 5216 return NULL; 5217 } 5218 return mapped_address; 5219} 5220 5221 5222// Remap a block of memory. 5223char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5224 char *addr, size_t bytes, bool read_only, 5225 bool allow_exec) { 5226 // same as map_memory() on this OS 5227 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5228 allow_exec); 5229} 5230 5231 5232// Unmap a block of memory. 5233bool os::pd_unmap_memory(char* addr, size_t bytes) { 5234 return munmap(addr, bytes) == 0; 5235} 5236 5237static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5238 5239static clockid_t thread_cpu_clockid(Thread* thread) { 5240 pthread_t tid = thread->osthread()->pthread_id(); 5241 clockid_t clockid; 5242 5243 // Get thread clockid 5244 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5245 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5246 return clockid; 5247} 5248 5249// current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5250// are used by JVM M&M and JVMTI to get user+sys or user CPU time 5251// of a thread. 5252// 5253// current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5254// the fast estimate available on the platform. 5255 5256jlong os::current_thread_cpu_time() { 5257 if (os::Linux::supports_fast_thread_cpu_time()) { 5258 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5259 } else { 5260 // return user + sys since the cost is the same 5261 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5262 } 5263} 5264 5265jlong os::thread_cpu_time(Thread* thread) { 5266 // consistent with what current_thread_cpu_time() returns 5267 if (os::Linux::supports_fast_thread_cpu_time()) { 5268 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5269 } else { 5270 return slow_thread_cpu_time(thread, true /* user + sys */); 5271 } 5272} 5273 5274jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5275 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5276 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5277 } else { 5278 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5279 } 5280} 5281 5282jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5283 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5284 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5285 } else { 5286 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5287 } 5288} 5289 5290// -1 on error. 5291static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5292 pid_t tid = thread->osthread()->thread_id(); 5293 char *s; 5294 char stat[2048]; 5295 int statlen; 5296 char proc_name[64]; 5297 int count; 5298 long sys_time, user_time; 5299 char cdummy; 5300 int idummy; 5301 long ldummy; 5302 FILE *fp; 5303 5304 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5305 fp = fopen(proc_name, "r"); 5306 if (fp == NULL) return -1; 5307 statlen = fread(stat, 1, 2047, fp); 5308 stat[statlen] = '\0'; 5309 fclose(fp); 5310 5311 // Skip pid and the command string. Note that we could be dealing with 5312 // weird command names, e.g. user could decide to rename java launcher 5313 // to "java 1.4.2 :)", then the stat file would look like 5314 // 1234 (java 1.4.2 :)) R ... ... 5315 // We don't really need to know the command string, just find the last 5316 // occurrence of ")" and then start parsing from there. See bug 4726580. 5317 s = strrchr(stat, ')'); 5318 if (s == NULL) return -1; 5319 5320 // Skip blank chars 5321 do { s++; } while (s && isspace(*s)); 5322 5323 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5324 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5325 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5326 &user_time, &sys_time); 5327 if (count != 13) return -1; 5328 if (user_sys_cpu_time) { 5329 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5330 } else { 5331 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5332 } 5333} 5334 5335void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5336 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5337 info_ptr->may_skip_backward = false; // elapsed time not wall time 5338 info_ptr->may_skip_forward = false; // elapsed time not wall time 5339 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5340} 5341 5342void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5343 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5344 info_ptr->may_skip_backward = false; // elapsed time not wall time 5345 info_ptr->may_skip_forward = false; // elapsed time not wall time 5346 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5347} 5348 5349bool os::is_thread_cpu_time_supported() { 5350 return true; 5351} 5352 5353// System loadavg support. Returns -1 if load average cannot be obtained. 5354// Linux doesn't yet have a (official) notion of processor sets, 5355// so just return the system wide load average. 5356int os::loadavg(double loadavg[], int nelem) { 5357 return ::getloadavg(loadavg, nelem); 5358} 5359 5360void os::pause() { 5361 char filename[MAX_PATH]; 5362 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5363 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 5364 } else { 5365 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5366 } 5367 5368 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5369 if (fd != -1) { 5370 struct stat buf; 5371 ::close(fd); 5372 while (::stat(filename, &buf) == 0) { 5373 (void)::poll(NULL, 0, 100); 5374 } 5375 } else { 5376 jio_fprintf(stderr, 5377 "Could not open pause file '%s', continuing immediately.\n", filename); 5378 } 5379} 5380 5381 5382// Refer to the comments in os_solaris.cpp park-unpark. The next two 5383// comment paragraphs are worth repeating here: 5384// 5385// Assumption: 5386// Only one parker can exist on an event, which is why we allocate 5387// them per-thread. Multiple unparkers can coexist. 5388// 5389// _Event serves as a restricted-range semaphore. 5390// -1 : thread is blocked, i.e. there is a waiter 5391// 0 : neutral: thread is running or ready, 5392// could have been signaled after a wait started 5393// 1 : signaled - thread is running or ready 5394// 5395// Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 5396// hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 5397// For specifics regarding the bug see GLIBC BUGID 261237 : 5398// http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 5399// Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 5400// will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 5401// is used. (The simple C test-case provided in the GLIBC bug report manifests the 5402// hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 5403// and monitorenter when we're using 1-0 locking. All those operations may result in 5404// calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 5405// of libpthread avoids the problem, but isn't practical. 5406// 5407// Possible remedies: 5408// 5409// 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 5410// This is palliative and probabilistic, however. If the thread is preempted 5411// between the call to compute_abstime() and pthread_cond_timedwait(), more 5412// than the minimum period may have passed, and the abstime may be stale (in the 5413// past) resultin in a hang. Using this technique reduces the odds of a hang 5414// but the JVM is still vulnerable, particularly on heavily loaded systems. 5415// 5416// 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 5417// of the usual flag-condvar-mutex idiom. The write side of the pipe is set 5418// NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 5419// reduces to poll()+read(). This works well, but consumes 2 FDs per extant 5420// thread. 5421// 5422// 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 5423// that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 5424// a timeout request to the chron thread and then blocking via pthread_cond_wait(). 5425// This also works well. In fact it avoids kernel-level scalability impediments 5426// on certain platforms that don't handle lots of active pthread_cond_timedwait() 5427// timers in a graceful fashion. 5428// 5429// 4. When the abstime value is in the past it appears that control returns 5430// correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 5431// Subsequent timedwait/wait calls may hang indefinitely. Given that, we 5432// can avoid the problem by reinitializing the condvar -- by cond_destroy() 5433// followed by cond_init() -- after all calls to pthread_cond_timedwait(). 5434// It may be possible to avoid reinitialization by checking the return 5435// value from pthread_cond_timedwait(). In addition to reinitializing the 5436// condvar we must establish the invariant that cond_signal() is only called 5437// within critical sections protected by the adjunct mutex. This prevents 5438// cond_signal() from "seeing" a condvar that's in the midst of being 5439// reinitialized or that is corrupt. Sadly, this invariant obviates the 5440// desirable signal-after-unlock optimization that avoids futile context switching. 5441// 5442// I'm also concerned that some versions of NTPL might allocate an auxilliary 5443// structure when a condvar is used or initialized. cond_destroy() would 5444// release the helper structure. Our reinitialize-after-timedwait fix 5445// put excessive stress on malloc/free and locks protecting the c-heap. 5446// 5447// We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 5448// It may be possible to refine (4) by checking the kernel and NTPL verisons 5449// and only enabling the work-around for vulnerable environments. 5450 5451// utility to compute the abstime argument to timedwait: 5452// millis is the relative timeout time 5453// abstime will be the absolute timeout time 5454// TODO: replace compute_abstime() with unpackTime() 5455 5456static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5457 if (millis < 0) millis = 0; 5458 5459 jlong seconds = millis / 1000; 5460 millis %= 1000; 5461 if (seconds > 50000000) { // see man cond_timedwait(3T) 5462 seconds = 50000000; 5463 } 5464 5465 if (os::supports_monotonic_clock()) { 5466 struct timespec now; 5467 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5468 assert_status(status == 0, status, "clock_gettime"); 5469 abstime->tv_sec = now.tv_sec + seconds; 5470 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5471 if (nanos >= NANOSECS_PER_SEC) { 5472 abstime->tv_sec += 1; 5473 nanos -= NANOSECS_PER_SEC; 5474 } 5475 abstime->tv_nsec = nanos; 5476 } else { 5477 struct timeval now; 5478 int status = gettimeofday(&now, NULL); 5479 assert(status == 0, "gettimeofday"); 5480 abstime->tv_sec = now.tv_sec + seconds; 5481 long usec = now.tv_usec + millis * 1000; 5482 if (usec >= 1000000) { 5483 abstime->tv_sec += 1; 5484 usec -= 1000000; 5485 } 5486 abstime->tv_nsec = usec * 1000; 5487 } 5488 return abstime; 5489} 5490 5491void os::PlatformEvent::park() { // AKA "down()" 5492 // Transitions for _Event: 5493 // -1 => -1 : illegal 5494 // 1 => 0 : pass - return immediately 5495 // 0 => -1 : block; then set _Event to 0 before returning 5496 5497 // Invariant: Only the thread associated with the Event/PlatformEvent 5498 // may call park(). 5499 // TODO: assert that _Assoc != NULL or _Assoc == Self 5500 assert(_nParked == 0, "invariant"); 5501 5502 int v; 5503 for (;;) { 5504 v = _Event; 5505 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5506 } 5507 guarantee(v >= 0, "invariant"); 5508 if (v == 0) { 5509 // Do this the hard way by blocking ... 5510 int status = pthread_mutex_lock(_mutex); 5511 assert_status(status == 0, status, "mutex_lock"); 5512 guarantee(_nParked == 0, "invariant"); 5513 ++_nParked; 5514 while (_Event < 0) { 5515 status = pthread_cond_wait(_cond, _mutex); 5516 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5517 // Treat this the same as if the wait was interrupted 5518 if (status == ETIME) { status = EINTR; } 5519 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5520 } 5521 --_nParked; 5522 5523 _Event = 0; 5524 status = pthread_mutex_unlock(_mutex); 5525 assert_status(status == 0, status, "mutex_unlock"); 5526 // Paranoia to ensure our locked and lock-free paths interact 5527 // correctly with each other. 5528 OrderAccess::fence(); 5529 } 5530 guarantee(_Event >= 0, "invariant"); 5531} 5532 5533int os::PlatformEvent::park(jlong millis) { 5534 // Transitions for _Event: 5535 // -1 => -1 : illegal 5536 // 1 => 0 : pass - return immediately 5537 // 0 => -1 : block; then set _Event to 0 before returning 5538 5539 guarantee(_nParked == 0, "invariant"); 5540 5541 int v; 5542 for (;;) { 5543 v = _Event; 5544 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5545 } 5546 guarantee(v >= 0, "invariant"); 5547 if (v != 0) return OS_OK; 5548 5549 // We do this the hard way, by blocking the thread. 5550 // Consider enforcing a minimum timeout value. 5551 struct timespec abst; 5552 compute_abstime(&abst, millis); 5553 5554 int ret = OS_TIMEOUT; 5555 int status = pthread_mutex_lock(_mutex); 5556 assert_status(status == 0, status, "mutex_lock"); 5557 guarantee(_nParked == 0, "invariant"); 5558 ++_nParked; 5559 5560 // Object.wait(timo) will return because of 5561 // (a) notification 5562 // (b) timeout 5563 // (c) thread.interrupt 5564 // 5565 // Thread.interrupt and object.notify{All} both call Event::set. 5566 // That is, we treat thread.interrupt as a special case of notification. 5567 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5568 // We assume all ETIME returns are valid. 5569 // 5570 // TODO: properly differentiate simultaneous notify+interrupt. 5571 // In that case, we should propagate the notify to another waiter. 5572 5573 while (_Event < 0) { 5574 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 5575 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5576 pthread_cond_destroy(_cond); 5577 pthread_cond_init(_cond, os::Linux::condAttr()); 5578 } 5579 assert_status(status == 0 || status == EINTR || 5580 status == ETIME || status == ETIMEDOUT, 5581 status, "cond_timedwait"); 5582 if (!FilterSpuriousWakeups) break; // previous semantics 5583 if (status == ETIME || status == ETIMEDOUT) break; 5584 // We consume and ignore EINTR and spurious wakeups. 5585 } 5586 --_nParked; 5587 if (_Event >= 0) { 5588 ret = OS_OK; 5589 } 5590 _Event = 0; 5591 status = pthread_mutex_unlock(_mutex); 5592 assert_status(status == 0, status, "mutex_unlock"); 5593 assert(_nParked == 0, "invariant"); 5594 // Paranoia to ensure our locked and lock-free paths interact 5595 // correctly with each other. 5596 OrderAccess::fence(); 5597 return ret; 5598} 5599 5600void os::PlatformEvent::unpark() { 5601 // Transitions for _Event: 5602 // 0 => 1 : just return 5603 // 1 => 1 : just return 5604 // -1 => either 0 or 1; must signal target thread 5605 // That is, we can safely transition _Event from -1 to either 5606 // 0 or 1. 5607 // See also: "Semaphores in Plan 9" by Mullender & Cox 5608 // 5609 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5610 // that it will take two back-to-back park() calls for the owning 5611 // thread to block. This has the benefit of forcing a spurious return 5612 // from the first park() call after an unpark() call which will help 5613 // shake out uses of park() and unpark() without condition variables. 5614 5615 if (Atomic::xchg(1, &_Event) >= 0) return; 5616 5617 // Wait for the thread associated with the event to vacate 5618 int status = pthread_mutex_lock(_mutex); 5619 assert_status(status == 0, status, "mutex_lock"); 5620 int AnyWaiters = _nParked; 5621 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5622 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5623 AnyWaiters = 0; 5624 pthread_cond_signal(_cond); 5625 } 5626 status = pthread_mutex_unlock(_mutex); 5627 assert_status(status == 0, status, "mutex_unlock"); 5628 if (AnyWaiters != 0) { 5629 // Note that we signal() *after* dropping the lock for "immortal" Events. 5630 // This is safe and avoids a common class of futile wakeups. In rare 5631 // circumstances this can cause a thread to return prematurely from 5632 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5633 // will simply re-test the condition and re-park itself. 5634 // This provides particular benefit if the underlying platform does not 5635 // provide wait morphing. 5636 status = pthread_cond_signal(_cond); 5637 assert_status(status == 0, status, "cond_signal"); 5638 } 5639} 5640 5641 5642// JSR166 5643// ------------------------------------------------------- 5644 5645// The solaris and linux implementations of park/unpark are fairly 5646// conservative for now, but can be improved. They currently use a 5647// mutex/condvar pair, plus a a count. 5648// Park decrements count if > 0, else does a condvar wait. Unpark 5649// sets count to 1 and signals condvar. Only one thread ever waits 5650// on the condvar. Contention seen when trying to park implies that someone 5651// is unparking you, so don't wait. And spurious returns are fine, so there 5652// is no need to track notifications. 5653 5654// This code is common to linux and solaris and will be moved to a 5655// common place in dolphin. 5656// 5657// The passed in time value is either a relative time in nanoseconds 5658// or an absolute time in milliseconds. Either way it has to be unpacked 5659// into suitable seconds and nanoseconds components and stored in the 5660// given timespec structure. 5661// Given time is a 64-bit value and the time_t used in the timespec is only 5662// a signed-32-bit value (except on 64-bit Linux) we have to watch for 5663// overflow if times way in the future are given. Further on Solaris versions 5664// prior to 10 there is a restriction (see cond_timedwait) that the specified 5665// number of seconds, in abstime, is less than current_time + 100,000,000. 5666// As it will be 28 years before "now + 100000000" will overflow we can 5667// ignore overflow and just impose a hard-limit on seconds using the value 5668// of "now + 100,000,000". This places a limit on the timeout of about 3.17 5669// years from "now". 5670 5671static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5672 assert(time > 0, "convertTime"); 5673 time_t max_secs = 0; 5674 5675 if (!os::supports_monotonic_clock() || isAbsolute) { 5676 struct timeval now; 5677 int status = gettimeofday(&now, NULL); 5678 assert(status == 0, "gettimeofday"); 5679 5680 max_secs = now.tv_sec + MAX_SECS; 5681 5682 if (isAbsolute) { 5683 jlong secs = time / 1000; 5684 if (secs > max_secs) { 5685 absTime->tv_sec = max_secs; 5686 } else { 5687 absTime->tv_sec = secs; 5688 } 5689 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5690 } else { 5691 jlong secs = time / NANOSECS_PER_SEC; 5692 if (secs >= MAX_SECS) { 5693 absTime->tv_sec = max_secs; 5694 absTime->tv_nsec = 0; 5695 } else { 5696 absTime->tv_sec = now.tv_sec + secs; 5697 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5698 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5699 absTime->tv_nsec -= NANOSECS_PER_SEC; 5700 ++absTime->tv_sec; // note: this must be <= max_secs 5701 } 5702 } 5703 } 5704 } else { 5705 // must be relative using monotonic clock 5706 struct timespec now; 5707 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5708 assert_status(status == 0, status, "clock_gettime"); 5709 max_secs = now.tv_sec + MAX_SECS; 5710 jlong secs = time / NANOSECS_PER_SEC; 5711 if (secs >= MAX_SECS) { 5712 absTime->tv_sec = max_secs; 5713 absTime->tv_nsec = 0; 5714 } else { 5715 absTime->tv_sec = now.tv_sec + secs; 5716 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5717 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5718 absTime->tv_nsec -= NANOSECS_PER_SEC; 5719 ++absTime->tv_sec; // note: this must be <= max_secs 5720 } 5721 } 5722 } 5723 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5724 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5725 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5726 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5727} 5728 5729void Parker::park(bool isAbsolute, jlong time) { 5730 // Ideally we'd do something useful while spinning, such 5731 // as calling unpackTime(). 5732 5733 // Optional fast-path check: 5734 // Return immediately if a permit is available. 5735 // We depend on Atomic::xchg() having full barrier semantics 5736 // since we are doing a lock-free update to _counter. 5737 if (Atomic::xchg(0, &_counter) > 0) return; 5738 5739 Thread* thread = Thread::current(); 5740 assert(thread->is_Java_thread(), "Must be JavaThread"); 5741 JavaThread *jt = (JavaThread *)thread; 5742 5743 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5744 // Check interrupt before trying to wait 5745 if (Thread::is_interrupted(thread, false)) { 5746 return; 5747 } 5748 5749 // Next, demultiplex/decode time arguments 5750 timespec absTime; 5751 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5752 return; 5753 } 5754 if (time > 0) { 5755 unpackTime(&absTime, isAbsolute, time); 5756 } 5757 5758 5759 // Enter safepoint region 5760 // Beware of deadlocks such as 6317397. 5761 // The per-thread Parker:: mutex is a classic leaf-lock. 5762 // In particular a thread must never block on the Threads_lock while 5763 // holding the Parker:: mutex. If safepoints are pending both the 5764 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5765 ThreadBlockInVM tbivm(jt); 5766 5767 // Don't wait if cannot get lock since interference arises from 5768 // unblocking. Also. check interrupt before trying wait 5769 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5770 return; 5771 } 5772 5773 int status; 5774 if (_counter > 0) { // no wait needed 5775 _counter = 0; 5776 status = pthread_mutex_unlock(_mutex); 5777 assert(status == 0, "invariant"); 5778 // Paranoia to ensure our locked and lock-free paths interact 5779 // correctly with each other and Java-level accesses. 5780 OrderAccess::fence(); 5781 return; 5782 } 5783 5784#ifdef ASSERT 5785 // Don't catch signals while blocked; let the running threads have the signals. 5786 // (This allows a debugger to break into the running thread.) 5787 sigset_t oldsigs; 5788 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5789 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5790#endif 5791 5792 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5793 jt->set_suspend_equivalent(); 5794 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5795 5796 assert(_cur_index == -1, "invariant"); 5797 if (time == 0) { 5798 _cur_index = REL_INDEX; // arbitrary choice when not timed 5799 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5800 } else { 5801 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5802 status = os::Linux::safe_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5803 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5804 pthread_cond_destroy(&_cond[_cur_index]); 5805 pthread_cond_init(&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr()); 5806 } 5807 } 5808 _cur_index = -1; 5809 assert_status(status == 0 || status == EINTR || 5810 status == ETIME || status == ETIMEDOUT, 5811 status, "cond_timedwait"); 5812 5813#ifdef ASSERT 5814 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5815#endif 5816 5817 _counter = 0; 5818 status = pthread_mutex_unlock(_mutex); 5819 assert_status(status == 0, status, "invariant"); 5820 // Paranoia to ensure our locked and lock-free paths interact 5821 // correctly with each other and Java-level accesses. 5822 OrderAccess::fence(); 5823 5824 // If externally suspended while waiting, re-suspend 5825 if (jt->handle_special_suspend_equivalent_condition()) { 5826 jt->java_suspend_self(); 5827 } 5828} 5829 5830void Parker::unpark() { 5831 int status = pthread_mutex_lock(_mutex); 5832 assert(status == 0, "invariant"); 5833 const int s = _counter; 5834 _counter = 1; 5835 if (s < 1) { 5836 // thread might be parked 5837 if (_cur_index != -1) { 5838 // thread is definitely parked 5839 if (WorkAroundNPTLTimedWaitHang) { 5840 status = pthread_cond_signal(&_cond[_cur_index]); 5841 assert(status == 0, "invariant"); 5842 status = pthread_mutex_unlock(_mutex); 5843 assert(status == 0, "invariant"); 5844 } else { 5845 status = pthread_mutex_unlock(_mutex); 5846 assert(status == 0, "invariant"); 5847 status = pthread_cond_signal(&_cond[_cur_index]); 5848 assert(status == 0, "invariant"); 5849 } 5850 } else { 5851 pthread_mutex_unlock(_mutex); 5852 assert(status == 0, "invariant"); 5853 } 5854 } else { 5855 pthread_mutex_unlock(_mutex); 5856 assert(status == 0, "invariant"); 5857 } 5858} 5859 5860 5861extern char** environ; 5862 5863#ifndef __NR_fork 5864 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5865#endif 5866 5867#ifndef __NR_execve 5868 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5869#endif 5870 5871// Run the specified command in a separate process. Return its exit value, 5872// or -1 on failure (e.g. can't fork a new process). 5873// Unlike system(), this function can be called from signal handler. It 5874// doesn't block SIGINT et al. 5875int os::fork_and_exec(char* cmd) { 5876 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5877 5878 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5879 // pthread_atfork handlers and reset pthread library. All we need is a 5880 // separate process to execve. Make a direct syscall to fork process. 5881 // On IA64 there's no fork syscall, we have to use fork() and hope for 5882 // the best... 5883 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5884 IA64_ONLY(fork();) 5885 5886 if (pid < 0) { 5887 // fork failed 5888 return -1; 5889 5890 } else if (pid == 0) { 5891 // child process 5892 5893 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5894 // first to kill every thread on the thread list. Because this list is 5895 // not reset by fork() (see notes above), execve() will instead kill 5896 // every thread in the parent process. We know this is the only thread 5897 // in the new process, so make a system call directly. 5898 // IA64 should use normal execve() from glibc to match the glibc fork() 5899 // above. 5900 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5901 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5902 5903 // execve failed 5904 _exit(-1); 5905 5906 } else { 5907 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5908 // care about the actual exit code, for now. 5909 5910 int status; 5911 5912 // Wait for the child process to exit. This returns immediately if 5913 // the child has already exited. */ 5914 while (waitpid(pid, &status, 0) < 0) { 5915 switch (errno) { 5916 case ECHILD: return 0; 5917 case EINTR: break; 5918 default: return -1; 5919 } 5920 } 5921 5922 if (WIFEXITED(status)) { 5923 // The child exited normally; get its exit code. 5924 return WEXITSTATUS(status); 5925 } else if (WIFSIGNALED(status)) { 5926 // The child exited because of a signal 5927 // The best value to return is 0x80 + signal number, 5928 // because that is what all Unix shells do, and because 5929 // it allows callers to distinguish between process exit and 5930 // process death by signal. 5931 return 0x80 + WTERMSIG(status); 5932 } else { 5933 // Unknown exit code; pass it through 5934 return status; 5935 } 5936 } 5937} 5938 5939// is_headless_jre() 5940// 5941// Test for the existence of xawt/libmawt.so or libawt_xawt.so 5942// in order to report if we are running in a headless jre 5943// 5944// Since JDK8 xawt/libmawt.so was moved into the same directory 5945// as libawt.so, and renamed libawt_xawt.so 5946// 5947bool os::is_headless_jre() { 5948 struct stat statbuf; 5949 char buf[MAXPATHLEN]; 5950 char libmawtpath[MAXPATHLEN]; 5951 const char *xawtstr = "/xawt/libmawt.so"; 5952 const char *new_xawtstr = "/libawt_xawt.so"; 5953 char *p; 5954 5955 // Get path to libjvm.so 5956 os::jvm_path(buf, sizeof(buf)); 5957 5958 // Get rid of libjvm.so 5959 p = strrchr(buf, '/'); 5960 if (p == NULL) { 5961 return false; 5962 } else { 5963 *p = '\0'; 5964 } 5965 5966 // Get rid of client or server 5967 p = strrchr(buf, '/'); 5968 if (p == NULL) { 5969 return false; 5970 } else { 5971 *p = '\0'; 5972 } 5973 5974 // check xawt/libmawt.so 5975 strcpy(libmawtpath, buf); 5976 strcat(libmawtpath, xawtstr); 5977 if (::stat(libmawtpath, &statbuf) == 0) return false; 5978 5979 // check libawt_xawt.so 5980 strcpy(libmawtpath, buf); 5981 strcat(libmawtpath, new_xawtstr); 5982 if (::stat(libmawtpath, &statbuf) == 0) return false; 5983 5984 return true; 5985} 5986 5987// Get the default path to the core file 5988// Returns the length of the string 5989int os::get_core_path(char* buffer, size_t bufferSize) { 5990 const char* p = get_current_directory(buffer, bufferSize); 5991 5992 if (p == NULL) { 5993 assert(p != NULL, "failed to get current directory"); 5994 return 0; 5995 } 5996 5997 return strlen(buffer); 5998} 5999 6000/////////////// Unit tests /////////////// 6001 6002#ifndef PRODUCT 6003 6004#define test_log(...) \ 6005 do { \ 6006 if (VerboseInternalVMTests) { \ 6007 tty->print_cr(__VA_ARGS__); \ 6008 tty->flush(); \ 6009 } \ 6010 } while (false) 6011 6012class TestReserveMemorySpecial : AllStatic { 6013 public: 6014 static void small_page_write(void* addr, size_t size) { 6015 size_t page_size = os::vm_page_size(); 6016 6017 char* end = (char*)addr + size; 6018 for (char* p = (char*)addr; p < end; p += page_size) { 6019 *p = 1; 6020 } 6021 } 6022 6023 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6024 if (!UseHugeTLBFS) { 6025 return; 6026 } 6027 6028 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6029 6030 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6031 6032 if (addr != NULL) { 6033 small_page_write(addr, size); 6034 6035 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6036 } 6037 } 6038 6039 static void test_reserve_memory_special_huge_tlbfs_only() { 6040 if (!UseHugeTLBFS) { 6041 return; 6042 } 6043 6044 size_t lp = os::large_page_size(); 6045 6046 for (size_t size = lp; size <= lp * 10; size += lp) { 6047 test_reserve_memory_special_huge_tlbfs_only(size); 6048 } 6049 } 6050 6051 static void test_reserve_memory_special_huge_tlbfs_mixed(size_t size, size_t alignment) { 6052 if (!UseHugeTLBFS) { 6053 return; 6054 } 6055 6056 test_log("test_reserve_memory_special_huge_tlbfs_mixed(" SIZE_FORMAT ", " SIZE_FORMAT ")", 6057 size, alignment); 6058 6059 assert(size >= os::large_page_size(), "Incorrect input to test"); 6060 6061 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6062 6063 if (addr != NULL) { 6064 small_page_write(addr, size); 6065 6066 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6067 } 6068 } 6069 6070 static void test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(size_t size) { 6071 size_t lp = os::large_page_size(); 6072 size_t ag = os::vm_allocation_granularity(); 6073 6074 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6075 test_reserve_memory_special_huge_tlbfs_mixed(size, alignment); 6076 } 6077 } 6078 6079 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6080 size_t lp = os::large_page_size(); 6081 size_t ag = os::vm_allocation_granularity(); 6082 6083 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp); 6084 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + ag); 6085 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + lp / 2); 6086 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2); 6087 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + ag); 6088 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 - ag); 6089 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + lp / 2); 6090 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10); 6091 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10 + lp / 2); 6092 } 6093 6094 static void test_reserve_memory_special_huge_tlbfs() { 6095 if (!UseHugeTLBFS) { 6096 return; 6097 } 6098 6099 test_reserve_memory_special_huge_tlbfs_only(); 6100 test_reserve_memory_special_huge_tlbfs_mixed(); 6101 } 6102 6103 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6104 if (!UseSHM) { 6105 return; 6106 } 6107 6108 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6109 6110 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6111 6112 if (addr != NULL) { 6113 assert(is_ptr_aligned(addr, alignment), "Check"); 6114 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6115 6116 small_page_write(addr, size); 6117 6118 os::Linux::release_memory_special_shm(addr, size); 6119 } 6120 } 6121 6122 static void test_reserve_memory_special_shm() { 6123 size_t lp = os::large_page_size(); 6124 size_t ag = os::vm_allocation_granularity(); 6125 6126 for (size_t size = ag; size < lp * 3; size += ag) { 6127 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6128 test_reserve_memory_special_shm(size, alignment); 6129 } 6130 } 6131 } 6132 6133 static void test() { 6134 test_reserve_memory_special_huge_tlbfs(); 6135 test_reserve_memory_special_shm(); 6136 } 6137}; 6138 6139void TestReserveMemorySpecial_test() { 6140 TestReserveMemorySpecial::test(); 6141} 6142 6143#endif 6144