1 /* 2 * Copyright (c) 1999, 2011, 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 "interpreter/interpreter.hpp" 33 #include "jvm_linux.h" 34 #include "memory/allocation.inline.hpp" 35 #include "memory/filemap.hpp" 36 #include "mutex_linux.inline.hpp" 37 #include "oops/oop.inline.hpp" 38 #include "os_share_linux.hpp" 39 #include "prims/jniFastGetField.hpp" 40 #include "prims/jvm.h" 41 #include "prims/jvm_misc.hpp" 42 #include "runtime/arguments.hpp" 43 #include "runtime/extendedPC.hpp" 44 #include "runtime/globals.hpp" 45 #include "runtime/interfaceSupport.hpp" 46 #include "runtime/java.hpp" 47 #include "runtime/javaCalls.hpp" 48 #include "runtime/mutexLocker.hpp" 49 #include "runtime/objectMonitor.hpp" 50 #include "runtime/osThread.hpp" 51 #include "runtime/perfMemory.hpp" 52 #include "runtime/sharedRuntime.hpp" 53 #include "runtime/statSampler.hpp" 54 #include "runtime/stubRoutines.hpp" 55 #include "runtime/threadCritical.hpp" 56 #include "runtime/timer.hpp" 57 #include "services/attachListener.hpp" 58 #include "services/runtimeService.hpp" 59 #include "thread_linux.inline.hpp" 60 #include "utilities/decoder.hpp" 61 #include "utilities/defaultStream.hpp" 62 #include "utilities/events.hpp" 63 #include "utilities/growableArray.hpp" 64 #include "utilities/vmError.hpp" 65 #ifdef TARGET_ARCH_x86 66 # include "assembler_x86.inline.hpp" 67 # include "nativeInst_x86.hpp" 68 #endif 69 #ifdef TARGET_ARCH_sparc 70 # include "assembler_sparc.inline.hpp" 71 # include "nativeInst_sparc.hpp" 72 #endif 73 #ifdef TARGET_ARCH_zero 74 # include "assembler_zero.inline.hpp" 75 # include "nativeInst_zero.hpp" 76 #endif 77 #ifdef TARGET_ARCH_arm 78 # include "assembler_arm.inline.hpp" 79 # include "nativeInst_arm.hpp" 80 #endif 81 #ifdef TARGET_ARCH_ppc 82 # include "assembler_ppc.inline.hpp" 83 # include "nativeInst_ppc.hpp" 84 #endif 85 #ifdef COMPILER1 86 #include "c1/c1_Runtime1.hpp" 87 #endif 88 #ifdef COMPILER2 89 #include "opto/runtime.hpp" 90 #endif 91 92 // put OS-includes here 93 # include <sys/types.h> 94 # include <sys/mman.h> 95 # include <sys/stat.h> 96 # include <sys/select.h> 97 # include <pthread.h> 98 # include <signal.h> 99 # include <errno.h> 100 # include <dlfcn.h> 101 # include <stdio.h> 102 # include <unistd.h> 103 # include <sys/resource.h> 104 # include <pthread.h> 105 # include <sys/stat.h> 106 # include <sys/time.h> 107 # include <sys/times.h> 108 # include <sys/utsname.h> 109 # include <sys/socket.h> 110 # include <sys/wait.h> 111 # include <pwd.h> 112 # include <poll.h> 113 # include <semaphore.h> 114 # include <fcntl.h> 115 # include <string.h> 116 # include <syscall.h> 117 # include <sys/sysinfo.h> 118 # include <gnu/libc-version.h> 119 # include <sys/ipc.h> 120 # include <sys/shm.h> 121 # include <link.h> 122 # include <stdint.h> 123 # include <inttypes.h> 124 # include <sys/ioctl.h> 125 126 #define MAX_PATH (2 * K) 127 128 // for timer info max values which include all bits 129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 130 #define SEC_IN_NANOSECS 1000000000LL 131 132 #define LARGEPAGES_BIT (1 << 6) 133 //////////////////////////////////////////////////////////////////////////////// 134 // global variables 135 julong os::Linux::_physical_memory = 0; 136 137 address os::Linux::_initial_thread_stack_bottom = NULL; 138 uintptr_t os::Linux::_initial_thread_stack_size = 0; 139 140 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 141 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 142 Mutex* os::Linux::_createThread_lock = NULL; 143 pthread_t os::Linux::_main_thread; 144 int os::Linux::_page_size = -1; 145 bool os::Linux::_is_floating_stack = false; 146 bool os::Linux::_is_NPTL = false; 147 bool os::Linux::_supports_fast_thread_cpu_time = false; 148 const char * os::Linux::_glibc_version = NULL; 149 const char * os::Linux::_libpthread_version = NULL; 150 151 static jlong initial_time_count=0; 152 153 static int clock_tics_per_sec = 100; 154 155 // For diagnostics to print a message once. see run_periodic_checks 156 static sigset_t check_signal_done; 157 static bool check_signals = true;; 158 159 static pid_t _initial_pid = 0; 160 161 /* Signal number used to suspend/resume a thread */ 162 163 /* do not use any signal number less than SIGSEGV, see 4355769 */ 164 static int SR_signum = SIGUSR2; 165 sigset_t SR_sigset; 166 167 /* Used to protect dlsym() calls */ 168 static pthread_mutex_t dl_mutex; 169 170 #ifdef JAVASE_EMBEDDED 171 class MemNotifyThread: public Thread { 172 friend class VMStructs; 173 public: 174 virtual void run(); 175 176 private: 177 static MemNotifyThread* _memnotify_thread; 178 int _fd; 179 180 public: 181 182 // Constructor 183 MemNotifyThread(int fd); 184 185 // Tester 186 bool is_memnotify_thread() const { return true; } 187 188 // Printing 189 char* name() const { return (char*)"Linux MemNotify Thread"; } 190 191 // Returns the single instance of the MemNotifyThread 192 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; } 193 194 // Create and start the single instance of MemNotifyThread 195 static void start(); 196 }; 197 #endif // JAVASE_EMBEDDED 198 199 // utility functions 200 201 static int SR_initialize(); 202 static int SR_finalize(); 203 204 julong os::available_memory() { 205 return Linux::available_memory(); 206 } 207 208 julong os::Linux::available_memory() { 209 // values in struct sysinfo are "unsigned long" 210 struct sysinfo si; 211 sysinfo(&si); 212 213 return (julong)si.freeram * si.mem_unit; 214 } 215 216 julong os::physical_memory() { 217 return Linux::physical_memory(); 218 } 219 220 julong os::allocatable_physical_memory(julong size) { 221 #ifdef _LP64 222 return size; 223 #else 224 julong result = MIN2(size, (julong)3800*M); 225 if (!is_allocatable(result)) { 226 // See comments under solaris for alignment considerations 227 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size(); 228 result = MIN2(size, reasonable_size); 229 } 230 return result; 231 #endif // _LP64 232 } 233 234 //////////////////////////////////////////////////////////////////////////////// 235 // environment support 236 237 bool os::getenv(const char* name, char* buf, int len) { 238 const char* val = ::getenv(name); 239 if (val != NULL && strlen(val) < (size_t)len) { 240 strcpy(buf, val); 241 return true; 242 } 243 if (len > 0) buf[0] = 0; // return a null string 244 return false; 245 } 246 247 248 // Return true if user is running as root. 249 250 bool os::have_special_privileges() { 251 static bool init = false; 252 static bool privileges = false; 253 if (!init) { 254 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 255 init = true; 256 } 257 return privileges; 258 } 259 260 261 #ifndef SYS_gettid 262 // i386: 224, ia64: 1105, amd64: 186, sparc 143 263 #ifdef __ia64__ 264 #define SYS_gettid 1105 265 #elif __i386__ 266 #define SYS_gettid 224 267 #elif __amd64__ 268 #define SYS_gettid 186 269 #elif __sparc__ 270 #define SYS_gettid 143 271 #else 272 #error define gettid for the arch 273 #endif 274 #endif 275 276 // Cpu architecture string 277 #if defined(ZERO) 278 static char cpu_arch[] = ZERO_LIBARCH; 279 #elif defined(IA64) 280 static char cpu_arch[] = "ia64"; 281 #elif defined(IA32) 282 static char cpu_arch[] = "i386"; 283 #elif defined(AMD64) 284 static char cpu_arch[] = "amd64"; 285 #elif defined(ARM) 286 static char cpu_arch[] = "arm"; 287 #elif defined(PPC) 288 static char cpu_arch[] = "ppc"; 289 #elif defined(SPARC) 290 # ifdef _LP64 291 static char cpu_arch[] = "sparcv9"; 292 # else 293 static char cpu_arch[] = "sparc"; 294 # endif 295 #else 296 #error Add appropriate cpu_arch setting 297 #endif 298 299 300 // pid_t gettid() 301 // 302 // Returns the kernel thread id of the currently running thread. Kernel 303 // thread id is used to access /proc. 304 // 305 // (Note that getpid() on LinuxThreads returns kernel thread id too; but 306 // on NPTL, it returns the same pid for all threads, as required by POSIX.) 307 // 308 pid_t os::Linux::gettid() { 309 int rslt = syscall(SYS_gettid); 310 if (rslt == -1) { 311 // old kernel, no NPTL support 312 return getpid(); 313 } else { 314 return (pid_t)rslt; 315 } 316 } 317 318 // Most versions of linux have a bug where the number of processors are 319 // determined by looking at the /proc file system. In a chroot environment, 320 // the system call returns 1. This causes the VM to act as if it is 321 // a single processor and elide locking (see is_MP() call). 322 static bool unsafe_chroot_detected = false; 323 static const char *unstable_chroot_error = "/proc file system not found.\n" 324 "Java may be unstable running multithreaded in a chroot " 325 "environment on Linux when /proc filesystem is not mounted."; 326 327 void os::Linux::initialize_system_info() { 328 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 329 if (processor_count() == 1) { 330 pid_t pid = os::Linux::gettid(); 331 char fname[32]; 332 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 333 FILE *fp = fopen(fname, "r"); 334 if (fp == NULL) { 335 unsafe_chroot_detected = true; 336 } else { 337 fclose(fp); 338 } 339 } 340 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 341 assert(processor_count() > 0, "linux error"); 342 } 343 344 void os::init_system_properties_values() { 345 // char arch[12]; 346 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch)); 347 348 // The next steps are taken in the product version: 349 // 350 // Obtain the JAVA_HOME value from the location of libjvm[_g].so. 351 // This library should be located at: 352 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so. 353 // 354 // If "/jre/lib/" appears at the right place in the path, then we 355 // assume libjvm[_g].so is installed in a JDK and we use this path. 356 // 357 // Otherwise exit with message: "Could not create the Java virtual machine." 358 // 359 // The following extra steps are taken in the debugging version: 360 // 361 // If "/jre/lib/" does NOT appear at the right place in the path 362 // instead of exit check for $JAVA_HOME environment variable. 363 // 364 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 365 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so 366 // it looks like libjvm[_g].so is installed there 367 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so. 368 // 369 // Otherwise exit. 370 // 371 // Important note: if the location of libjvm.so changes this 372 // code needs to be changed accordingly. 373 374 // The next few definitions allow the code to be verbatim: 375 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n)) 376 #define getenv(n) ::getenv(n) 377 378 /* 379 * See ld(1): 380 * The linker uses the following search paths to locate required 381 * shared libraries: 382 * 1: ... 383 * ... 384 * 7: The default directories, normally /lib and /usr/lib. 385 */ 386 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 387 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 388 #else 389 #define DEFAULT_LIBPATH "/lib:/usr/lib" 390 #endif 391 392 #define EXTENSIONS_DIR "/lib/ext" 393 #define ENDORSED_DIR "/lib/endorsed" 394 #define REG_DIR "/usr/java/packages" 395 396 { 397 /* sysclasspath, java_home, dll_dir */ 398 { 399 char *home_path; 400 char *dll_path; 401 char *pslash; 402 char buf[MAXPATHLEN]; 403 os::jvm_path(buf, sizeof(buf)); 404 405 // Found the full path to libjvm.so. 406 // Now cut the path to <java_home>/jre if we can. 407 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */ 408 pslash = strrchr(buf, '/'); 409 if (pslash != NULL) 410 *pslash = '\0'; /* get rid of /{client|server|hotspot} */ 411 dll_path = malloc(strlen(buf) + 1); 412 if (dll_path == NULL) 413 return; 414 strcpy(dll_path, buf); 415 Arguments::set_dll_dir(dll_path); 416 417 if (pslash != NULL) { 418 pslash = strrchr(buf, '/'); 419 if (pslash != NULL) { 420 *pslash = '\0'; /* get rid of /<arch> */ 421 pslash = strrchr(buf, '/'); 422 if (pslash != NULL) 423 *pslash = '\0'; /* get rid of /lib */ 424 } 425 } 426 427 home_path = malloc(strlen(buf) + 1); 428 if (home_path == NULL) 429 return; 430 strcpy(home_path, buf); 431 Arguments::set_java_home(home_path); 432 433 if (!set_boot_path('/', ':')) 434 return; 435 } 436 437 /* 438 * Where to look for native libraries 439 * 440 * Note: Due to a legacy implementation, most of the library path 441 * is set in the launcher. This was to accomodate linking restrictions 442 * on legacy Linux implementations (which are no longer supported). 443 * Eventually, all the library path setting will be done here. 444 * 445 * However, to prevent the proliferation of improperly built native 446 * libraries, the new path component /usr/java/packages is added here. 447 * Eventually, all the library path setting will be done here. 448 */ 449 { 450 char *ld_library_path; 451 452 /* 453 * Construct the invariant part of ld_library_path. Note that the 454 * space for the colon and the trailing null are provided by the 455 * nulls included by the sizeof operator (so actually we allocate 456 * a byte more than necessary). 457 */ 458 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") + 459 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH)); 460 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch); 461 462 /* 463 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It 464 * should always exist (until the legacy problem cited above is 465 * addressed). 466 */ 467 char *v = getenv("LD_LIBRARY_PATH"); 468 if (v != NULL) { 469 char *t = ld_library_path; 470 /* That's +1 for the colon and +1 for the trailing '\0' */ 471 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1); 472 sprintf(ld_library_path, "%s:%s", v, t); 473 } 474 Arguments::set_library_path(ld_library_path); 475 } 476 477 /* 478 * Extensions directories. 479 * 480 * Note that the space for the colon and the trailing null are provided 481 * by the nulls included by the sizeof operator (so actually one byte more 482 * than necessary is allocated). 483 */ 484 { 485 char *buf = malloc(strlen(Arguments::get_java_home()) + 486 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR)); 487 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR, 488 Arguments::get_java_home()); 489 Arguments::set_ext_dirs(buf); 490 } 491 492 /* Endorsed standards default directory. */ 493 { 494 char * buf; 495 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR)); 496 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home()); 497 Arguments::set_endorsed_dirs(buf); 498 } 499 } 500 501 #undef malloc 502 #undef getenv 503 #undef EXTENSIONS_DIR 504 #undef ENDORSED_DIR 505 506 // Done 507 return; 508 } 509 510 //////////////////////////////////////////////////////////////////////////////// 511 // breakpoint support 512 513 void os::breakpoint() { 514 BREAKPOINT; 515 } 516 517 extern "C" void breakpoint() { 518 // use debugger to set breakpoint here 519 } 520 521 //////////////////////////////////////////////////////////////////////////////// 522 // signal support 523 524 debug_only(static bool signal_sets_initialized = false); 525 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 526 527 bool os::Linux::is_sig_ignored(int sig) { 528 struct sigaction oact; 529 sigaction(sig, (struct sigaction*)NULL, &oact); 530 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 531 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 532 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) 533 return true; 534 else 535 return false; 536 } 537 538 void os::Linux::signal_sets_init() { 539 // Should also have an assertion stating we are still single-threaded. 540 assert(!signal_sets_initialized, "Already initialized"); 541 // Fill in signals that are necessarily unblocked for all threads in 542 // the VM. Currently, we unblock the following signals: 543 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 544 // by -Xrs (=ReduceSignalUsage)); 545 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 546 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 547 // the dispositions or masks wrt these signals. 548 // Programs embedding the VM that want to use the above signals for their 549 // own purposes must, at this time, use the "-Xrs" option to prevent 550 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 551 // (See bug 4345157, and other related bugs). 552 // In reality, though, unblocking these signals is really a nop, since 553 // these signals are not blocked by default. 554 sigemptyset(&unblocked_sigs); 555 sigemptyset(&allowdebug_blocked_sigs); 556 sigaddset(&unblocked_sigs, SIGILL); 557 sigaddset(&unblocked_sigs, SIGSEGV); 558 sigaddset(&unblocked_sigs, SIGBUS); 559 sigaddset(&unblocked_sigs, SIGFPE); 560 sigaddset(&unblocked_sigs, SR_signum); 561 562 if (!ReduceSignalUsage) { 563 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 564 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 565 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 566 } 567 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 568 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 569 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 570 } 571 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 572 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 573 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 574 } 575 } 576 // Fill in signals that are blocked by all but the VM thread. 577 sigemptyset(&vm_sigs); 578 if (!ReduceSignalUsage) 579 sigaddset(&vm_sigs, BREAK_SIGNAL); 580 debug_only(signal_sets_initialized = true); 581 582 } 583 584 // These are signals that are unblocked while a thread is running Java. 585 // (For some reason, they get blocked by default.) 586 sigset_t* os::Linux::unblocked_signals() { 587 assert(signal_sets_initialized, "Not initialized"); 588 return &unblocked_sigs; 589 } 590 591 // These are the signals that are blocked while a (non-VM) thread is 592 // running Java. Only the VM thread handles these signals. 593 sigset_t* os::Linux::vm_signals() { 594 assert(signal_sets_initialized, "Not initialized"); 595 return &vm_sigs; 596 } 597 598 // These are signals that are blocked during cond_wait to allow debugger in 599 sigset_t* os::Linux::allowdebug_blocked_signals() { 600 assert(signal_sets_initialized, "Not initialized"); 601 return &allowdebug_blocked_sigs; 602 } 603 604 void os::Linux::hotspot_sigmask(Thread* thread) { 605 606 //Save caller's signal mask before setting VM signal mask 607 sigset_t caller_sigmask; 608 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 609 610 OSThread* osthread = thread->osthread(); 611 osthread->set_caller_sigmask(caller_sigmask); 612 613 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 614 615 if (!ReduceSignalUsage) { 616 if (thread->is_VM_thread()) { 617 // Only the VM thread handles BREAK_SIGNAL ... 618 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 619 } else { 620 // ... all other threads block BREAK_SIGNAL 621 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 622 } 623 } 624 } 625 626 ////////////////////////////////////////////////////////////////////////////// 627 // detecting pthread library 628 629 void os::Linux::libpthread_init() { 630 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION 631 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a 632 // generic name for earlier versions. 633 // Define macros here so we can build HotSpot on old systems. 634 # ifndef _CS_GNU_LIBC_VERSION 635 # define _CS_GNU_LIBC_VERSION 2 636 # endif 637 # ifndef _CS_GNU_LIBPTHREAD_VERSION 638 # define _CS_GNU_LIBPTHREAD_VERSION 3 639 # endif 640 641 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 642 if (n > 0) { 643 char *str = (char *)malloc(n); 644 confstr(_CS_GNU_LIBC_VERSION, str, n); 645 os::Linux::set_glibc_version(str); 646 } else { 647 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version() 648 static char _gnu_libc_version[32]; 649 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version), 650 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release()); 651 os::Linux::set_glibc_version(_gnu_libc_version); 652 } 653 654 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 655 if (n > 0) { 656 char *str = (char *)malloc(n); 657 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 658 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells 659 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this 660 // is the case. LinuxThreads has a hard limit on max number of threads. 661 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value. 662 // On the other hand, NPTL does not have such a limit, sysconf() 663 // will return -1 and errno is not changed. Check if it is really NPTL. 664 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 && 665 strstr(str, "NPTL") && 666 sysconf(_SC_THREAD_THREADS_MAX) > 0) { 667 free(str); 668 os::Linux::set_libpthread_version("linuxthreads"); 669 } else { 670 os::Linux::set_libpthread_version(str); 671 } 672 } else { 673 // glibc before 2.3.2 only has LinuxThreads. 674 os::Linux::set_libpthread_version("linuxthreads"); 675 } 676 677 if (strstr(libpthread_version(), "NPTL")) { 678 os::Linux::set_is_NPTL(); 679 } else { 680 os::Linux::set_is_LinuxThreads(); 681 } 682 683 // LinuxThreads have two flavors: floating-stack mode, which allows variable 684 // stack size; and fixed-stack mode. NPTL is always floating-stack. 685 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) { 686 os::Linux::set_is_floating_stack(); 687 } 688 } 689 690 ///////////////////////////////////////////////////////////////////////////// 691 // thread stack 692 693 // Force Linux kernel to expand current thread stack. If "bottom" is close 694 // to the stack guard, caller should block all signals. 695 // 696 // MAP_GROWSDOWN: 697 // A special mmap() flag that is used to implement thread stacks. It tells 698 // kernel that the memory region should extend downwards when needed. This 699 // allows early versions of LinuxThreads to only mmap the first few pages 700 // when creating a new thread. Linux kernel will automatically expand thread 701 // stack as needed (on page faults). 702 // 703 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 704 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 705 // region, it's hard to tell if the fault is due to a legitimate stack 706 // access or because of reading/writing non-exist memory (e.g. buffer 707 // overrun). As a rule, if the fault happens below current stack pointer, 708 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 709 // application (see Linux kernel fault.c). 710 // 711 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 712 // stack overflow detection. 713 // 714 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 715 // not use this flag. However, the stack of initial thread is not created 716 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though 717 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack 718 // and then attach the thread to JVM. 719 // 720 // To get around the problem and allow stack banging on Linux, we need to 721 // manually expand thread stack after receiving the SIGSEGV. 722 // 723 // There are two ways to expand thread stack to address "bottom", we used 724 // both of them in JVM before 1.5: 725 // 1. adjust stack pointer first so that it is below "bottom", and then 726 // touch "bottom" 727 // 2. mmap() the page in question 728 // 729 // Now alternate signal stack is gone, it's harder to use 2. For instance, 730 // if current sp is already near the lower end of page 101, and we need to 731 // call mmap() to map page 100, it is possible that part of the mmap() frame 732 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 733 // That will destroy the mmap() frame and cause VM to crash. 734 // 735 // The following code works by adjusting sp first, then accessing the "bottom" 736 // page to force a page fault. Linux kernel will then automatically expand the 737 // stack mapping. 738 // 739 // _expand_stack_to() assumes its frame size is less than page size, which 740 // should always be true if the function is not inlined. 741 742 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 743 #define NOINLINE 744 #else 745 #define NOINLINE __attribute__ ((noinline)) 746 #endif 747 748 static void _expand_stack_to(address bottom) NOINLINE; 749 750 static void _expand_stack_to(address bottom) { 751 address sp; 752 size_t size; 753 volatile char *p; 754 755 // Adjust bottom to point to the largest address within the same page, it 756 // gives us a one-page buffer if alloca() allocates slightly more memory. 757 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 758 bottom += os::Linux::page_size() - 1; 759 760 // sp might be slightly above current stack pointer; if that's the case, we 761 // will alloca() a little more space than necessary, which is OK. Don't use 762 // os::current_stack_pointer(), as its result can be slightly below current 763 // stack pointer, causing us to not alloca enough to reach "bottom". 764 sp = (address)&sp; 765 766 if (sp > bottom) { 767 size = sp - bottom; 768 p = (volatile char *)alloca(size); 769 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 770 p[0] = '\0'; 771 } 772 } 773 774 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 775 assert(t!=NULL, "just checking"); 776 assert(t->osthread()->expanding_stack(), "expand should be set"); 777 assert(t->stack_base() != NULL, "stack_base was not initialized"); 778 779 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 780 sigset_t mask_all, old_sigset; 781 sigfillset(&mask_all); 782 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 783 _expand_stack_to(addr); 784 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 785 return true; 786 } 787 return false; 788 } 789 790 ////////////////////////////////////////////////////////////////////////////// 791 // create new thread 792 793 static address highest_vm_reserved_address(); 794 795 // check if it's safe to start a new thread 796 static bool _thread_safety_check(Thread* thread) { 797 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) { 798 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat) 799 // Heap is mmap'ed at lower end of memory space. Thread stacks are 800 // allocated (MAP_FIXED) from high address space. Every thread stack 801 // occupies a fixed size slot (usually 2Mbytes, but user can change 802 // it to other values if they rebuild LinuxThreads). 803 // 804 // Problem with MAP_FIXED is that mmap() can still succeed even part of 805 // the memory region has already been mmap'ed. That means if we have too 806 // many threads and/or very large heap, eventually thread stack will 807 // collide with heap. 808 // 809 // Here we try to prevent heap/stack collision by comparing current 810 // stack bottom with the highest address that has been mmap'ed by JVM 811 // plus a safety margin for memory maps created by native code. 812 // 813 // This feature can be disabled by setting ThreadSafetyMargin to 0 814 // 815 if (ThreadSafetyMargin > 0) { 816 address stack_bottom = os::current_stack_base() - os::current_stack_size(); 817 818 // not safe if our stack extends below the safety margin 819 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address(); 820 } else { 821 return true; 822 } 823 } else { 824 // Floating stack LinuxThreads or NPTL: 825 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When 826 // there's not enough space left, pthread_create() will fail. If we come 827 // here, that means enough space has been reserved for stack. 828 return true; 829 } 830 } 831 832 // Thread start routine for all newly created threads 833 static void *java_start(Thread *thread) { 834 // Try to randomize the cache line index of hot stack frames. 835 // This helps when threads of the same stack traces evict each other's 836 // cache lines. The threads can be either from the same JVM instance, or 837 // from different JVM instances. The benefit is especially true for 838 // processors with hyperthreading technology. 839 static int counter = 0; 840 int pid = os::current_process_id(); 841 alloca(((pid ^ counter++) & 7) * 128); 842 843 ThreadLocalStorage::set_thread(thread); 844 845 OSThread* osthread = thread->osthread(); 846 Monitor* sync = osthread->startThread_lock(); 847 848 // non floating stack LinuxThreads needs extra check, see above 849 if (!_thread_safety_check(thread)) { 850 // notify parent thread 851 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 852 osthread->set_state(ZOMBIE); 853 sync->notify_all(); 854 return NULL; 855 } 856 857 // thread_id is kernel thread id (similar to Solaris LWP id) 858 osthread->set_thread_id(os::Linux::gettid()); 859 860 if (UseNUMA) { 861 int lgrp_id = os::numa_get_group_id(); 862 if (lgrp_id != -1) { 863 thread->set_lgrp_id(lgrp_id); 864 } 865 } 866 // initialize signal mask for this thread 867 os::Linux::hotspot_sigmask(thread); 868 869 // initialize floating point control register 870 os::Linux::init_thread_fpu_state(); 871 872 // handshaking with parent thread 873 { 874 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 875 876 // notify parent thread 877 osthread->set_state(INITIALIZED); 878 sync->notify_all(); 879 880 // wait until os::start_thread() 881 while (osthread->get_state() == INITIALIZED) { 882 sync->wait(Mutex::_no_safepoint_check_flag); 883 } 884 } 885 886 // call one more level start routine 887 thread->run(); 888 889 return 0; 890 } 891 892 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) { 893 assert(thread->osthread() == NULL, "caller responsible"); 894 895 // Allocate the OSThread object 896 OSThread* osthread = new OSThread(NULL, NULL); 897 if (osthread == NULL) { 898 return false; 899 } 900 901 // set the correct thread state 902 osthread->set_thread_type(thr_type); 903 904 // Initial state is ALLOCATED but not INITIALIZED 905 osthread->set_state(ALLOCATED); 906 907 thread->set_osthread(osthread); 908 909 // init thread attributes 910 pthread_attr_t attr; 911 pthread_attr_init(&attr); 912 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 913 914 // stack size 915 if (os::Linux::supports_variable_stack_size()) { 916 // calculate stack size if it's not specified by caller 917 if (stack_size == 0) { 918 stack_size = os::Linux::default_stack_size(thr_type); 919 920 switch (thr_type) { 921 case os::java_thread: 922 // Java threads use ThreadStackSize which default value can be 923 // changed with the flag -Xss 924 assert (JavaThread::stack_size_at_create() > 0, "this should be set"); 925 stack_size = JavaThread::stack_size_at_create(); 926 break; 927 case os::compiler_thread: 928 if (CompilerThreadStackSize > 0) { 929 stack_size = (size_t)(CompilerThreadStackSize * K); 930 break; 931 } // else fall through: 932 // use VMThreadStackSize if CompilerThreadStackSize is not defined 933 case os::vm_thread: 934 case os::pgc_thread: 935 case os::cgc_thread: 936 case os::watcher_thread: 937 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 938 break; 939 } 940 } 941 942 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 943 pthread_attr_setstacksize(&attr, stack_size); 944 } else { 945 // let pthread_create() pick the default value. 946 } 947 948 // glibc guard page 949 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 950 951 ThreadState state; 952 953 { 954 // Serialize thread creation if we are running with fixed stack LinuxThreads 955 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack(); 956 if (lock) { 957 os::Linux::createThread_lock()->lock_without_safepoint_check(); 958 } 959 960 pthread_t tid; 961 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 962 963 pthread_attr_destroy(&attr); 964 965 if (ret != 0) { 966 if (PrintMiscellaneous && (Verbose || WizardMode)) { 967 perror("pthread_create()"); 968 } 969 // Need to clean up stuff we've allocated so far 970 thread->set_osthread(NULL); 971 delete osthread; 972 if (lock) os::Linux::createThread_lock()->unlock(); 973 return false; 974 } 975 976 // Store pthread info into the OSThread 977 osthread->set_pthread_id(tid); 978 979 // Wait until child thread is either initialized or aborted 980 { 981 Monitor* sync_with_child = osthread->startThread_lock(); 982 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 983 while ((state = osthread->get_state()) == ALLOCATED) { 984 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 985 } 986 } 987 988 if (lock) { 989 os::Linux::createThread_lock()->unlock(); 990 } 991 } 992 993 // Aborted due to thread limit being reached 994 if (state == ZOMBIE) { 995 thread->set_osthread(NULL); 996 delete osthread; 997 return false; 998 } 999 1000 // The thread is returned suspended (in state INITIALIZED), 1001 // and is started higher up in the call chain 1002 assert(state == INITIALIZED, "race condition"); 1003 return true; 1004 } 1005 1006 ///////////////////////////////////////////////////////////////////////////// 1007 // attach existing thread 1008 1009 // bootstrap the main thread 1010 bool os::create_main_thread(JavaThread* thread) { 1011 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 1012 return create_attached_thread(thread); 1013 } 1014 1015 bool os::create_attached_thread(JavaThread* thread) { 1016 #ifdef ASSERT 1017 thread->verify_not_published(); 1018 #endif 1019 1020 // Allocate the OSThread object 1021 OSThread* osthread = new OSThread(NULL, NULL); 1022 1023 if (osthread == NULL) { 1024 return false; 1025 } 1026 1027 // Store pthread info into the OSThread 1028 osthread->set_thread_id(os::Linux::gettid()); 1029 osthread->set_pthread_id(::pthread_self()); 1030 1031 // initialize floating point control register 1032 os::Linux::init_thread_fpu_state(); 1033 1034 // Initial thread state is RUNNABLE 1035 osthread->set_state(RUNNABLE); 1036 1037 thread->set_osthread(osthread); 1038 1039 if (UseNUMA) { 1040 int lgrp_id = os::numa_get_group_id(); 1041 if (lgrp_id != -1) { 1042 thread->set_lgrp_id(lgrp_id); 1043 } 1044 } 1045 1046 if (os::Linux::is_initial_thread()) { 1047 // If current thread is initial thread, its stack is mapped on demand, 1048 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 1049 // the entire stack region to avoid SEGV in stack banging. 1050 // It is also useful to get around the heap-stack-gap problem on SuSE 1051 // kernel (see 4821821 for details). We first expand stack to the top 1052 // of yellow zone, then enable stack yellow zone (order is significant, 1053 // enabling yellow zone first will crash JVM on SuSE Linux), so there 1054 // is no gap between the last two virtual memory regions. 1055 1056 JavaThread *jt = (JavaThread *)thread; 1057 address addr = jt->stack_yellow_zone_base(); 1058 assert(addr != NULL, "initialization problem?"); 1059 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 1060 1061 osthread->set_expanding_stack(); 1062 os::Linux::manually_expand_stack(jt, addr); 1063 osthread->clear_expanding_stack(); 1064 } 1065 1066 // initialize signal mask for this thread 1067 // and save the caller's signal mask 1068 os::Linux::hotspot_sigmask(thread); 1069 1070 return true; 1071 } 1072 1073 void os::pd_start_thread(Thread* thread) { 1074 OSThread * osthread = thread->osthread(); 1075 assert(osthread->get_state() != INITIALIZED, "just checking"); 1076 Monitor* sync_with_child = osthread->startThread_lock(); 1077 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 1078 sync_with_child->notify(); 1079 } 1080 1081 // Free Linux resources related to the OSThread 1082 void os::free_thread(OSThread* osthread) { 1083 assert(osthread != NULL, "osthread not set"); 1084 1085 if (Thread::current()->osthread() == osthread) { 1086 // Restore caller's signal mask 1087 sigset_t sigmask = osthread->caller_sigmask(); 1088 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 1089 } 1090 1091 delete osthread; 1092 } 1093 1094 ////////////////////////////////////////////////////////////////////////////// 1095 // thread local storage 1096 1097 int os::allocate_thread_local_storage() { 1098 pthread_key_t key; 1099 int rslt = pthread_key_create(&key, NULL); 1100 assert(rslt == 0, "cannot allocate thread local storage"); 1101 return (int)key; 1102 } 1103 1104 // Note: This is currently not used by VM, as we don't destroy TLS key 1105 // on VM exit. 1106 void os::free_thread_local_storage(int index) { 1107 int rslt = pthread_key_delete((pthread_key_t)index); 1108 assert(rslt == 0, "invalid index"); 1109 } 1110 1111 void os::thread_local_storage_at_put(int index, void* value) { 1112 int rslt = pthread_setspecific((pthread_key_t)index, value); 1113 assert(rslt == 0, "pthread_setspecific failed"); 1114 } 1115 1116 extern "C" Thread* get_thread() { 1117 return ThreadLocalStorage::thread(); 1118 } 1119 1120 ////////////////////////////////////////////////////////////////////////////// 1121 // initial thread 1122 1123 // Check if current thread is the initial thread, similar to Solaris thr_main. 1124 bool os::Linux::is_initial_thread(void) { 1125 char dummy; 1126 // If called before init complete, thread stack bottom will be null. 1127 // Can be called if fatal error occurs before initialization. 1128 if (initial_thread_stack_bottom() == NULL) return false; 1129 assert(initial_thread_stack_bottom() != NULL && 1130 initial_thread_stack_size() != 0, 1131 "os::init did not locate initial thread's stack region"); 1132 if ((address)&dummy >= initial_thread_stack_bottom() && 1133 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) 1134 return true; 1135 else return false; 1136 } 1137 1138 // Find the virtual memory area that contains addr 1139 static bool find_vma(address addr, address* vma_low, address* vma_high) { 1140 FILE *fp = fopen("/proc/self/maps", "r"); 1141 if (fp) { 1142 address low, high; 1143 while (!feof(fp)) { 1144 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 1145 if (low <= addr && addr < high) { 1146 if (vma_low) *vma_low = low; 1147 if (vma_high) *vma_high = high; 1148 fclose (fp); 1149 return true; 1150 } 1151 } 1152 for (;;) { 1153 int ch = fgetc(fp); 1154 if (ch == EOF || ch == (int)'\n') break; 1155 } 1156 } 1157 fclose(fp); 1158 } 1159 return false; 1160 } 1161 1162 // Locate initial thread stack. This special handling of initial thread stack 1163 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 1164 // bogus value for initial thread. 1165 void os::Linux::capture_initial_stack(size_t max_size) { 1166 // stack size is the easy part, get it from RLIMIT_STACK 1167 size_t stack_size; 1168 struct rlimit rlim; 1169 getrlimit(RLIMIT_STACK, &rlim); 1170 stack_size = rlim.rlim_cur; 1171 1172 // 6308388: a bug in ld.so will relocate its own .data section to the 1173 // lower end of primordial stack; reduce ulimit -s value a little bit 1174 // so we won't install guard page on ld.so's data section. 1175 stack_size -= 2 * page_size(); 1176 1177 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 1178 // 7.1, in both cases we will get 2G in return value. 1179 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 1180 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 1181 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 1182 // in case other parts in glibc still assumes 2M max stack size. 1183 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 1184 #ifndef IA64 1185 if (stack_size > 2 * K * K) stack_size = 2 * K * K; 1186 #else 1187 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 1188 if (stack_size > 4 * K * K) stack_size = 4 * K * K; 1189 #endif 1190 1191 // Try to figure out where the stack base (top) is. This is harder. 1192 // 1193 // When an application is started, glibc saves the initial stack pointer in 1194 // a global variable "__libc_stack_end", which is then used by system 1195 // libraries. __libc_stack_end should be pretty close to stack top. The 1196 // variable is available since the very early days. However, because it is 1197 // a private interface, it could disappear in the future. 1198 // 1199 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 1200 // to __libc_stack_end, it is very close to stack top, but isn't the real 1201 // stack top. Note that /proc may not exist if VM is running as a chroot 1202 // program, so reading /proc/<pid>/stat could fail. Also the contents of 1203 // /proc/<pid>/stat could change in the future (though unlikely). 1204 // 1205 // We try __libc_stack_end first. If that doesn't work, look for 1206 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 1207 // as a hint, which should work well in most cases. 1208 1209 uintptr_t stack_start; 1210 1211 // try __libc_stack_end first 1212 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1213 if (p && *p) { 1214 stack_start = *p; 1215 } else { 1216 // see if we can get the start_stack field from /proc/self/stat 1217 FILE *fp; 1218 int pid; 1219 char state; 1220 int ppid; 1221 int pgrp; 1222 int session; 1223 int nr; 1224 int tpgrp; 1225 unsigned long flags; 1226 unsigned long minflt; 1227 unsigned long cminflt; 1228 unsigned long majflt; 1229 unsigned long cmajflt; 1230 unsigned long utime; 1231 unsigned long stime; 1232 long cutime; 1233 long cstime; 1234 long prio; 1235 long nice; 1236 long junk; 1237 long it_real; 1238 uintptr_t start; 1239 uintptr_t vsize; 1240 intptr_t rss; 1241 uintptr_t rsslim; 1242 uintptr_t scodes; 1243 uintptr_t ecode; 1244 int i; 1245 1246 // Figure what the primordial thread stack base is. Code is inspired 1247 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1248 // followed by command name surrounded by parentheses, state, etc. 1249 char stat[2048]; 1250 int statlen; 1251 1252 fp = fopen("/proc/self/stat", "r"); 1253 if (fp) { 1254 statlen = fread(stat, 1, 2047, fp); 1255 stat[statlen] = '\0'; 1256 fclose(fp); 1257 1258 // Skip pid and the command string. Note that we could be dealing with 1259 // weird command names, e.g. user could decide to rename java launcher 1260 // to "java 1.4.2 :)", then the stat file would look like 1261 // 1234 (java 1.4.2 :)) R ... ... 1262 // We don't really need to know the command string, just find the last 1263 // occurrence of ")" and then start parsing from there. See bug 4726580. 1264 char * s = strrchr(stat, ')'); 1265 1266 i = 0; 1267 if (s) { 1268 // Skip blank chars 1269 do s++; while (isspace(*s)); 1270 1271 #define _UFM UINTX_FORMAT 1272 #define _DFM INTX_FORMAT 1273 1274 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */ 1275 /* 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 */ 1276 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, 1277 &state, /* 3 %c */ 1278 &ppid, /* 4 %d */ 1279 &pgrp, /* 5 %d */ 1280 &session, /* 6 %d */ 1281 &nr, /* 7 %d */ 1282 &tpgrp, /* 8 %d */ 1283 &flags, /* 9 %lu */ 1284 &minflt, /* 10 %lu */ 1285 &cminflt, /* 11 %lu */ 1286 &majflt, /* 12 %lu */ 1287 &cmajflt, /* 13 %lu */ 1288 &utime, /* 14 %lu */ 1289 &stime, /* 15 %lu */ 1290 &cutime, /* 16 %ld */ 1291 &cstime, /* 17 %ld */ 1292 &prio, /* 18 %ld */ 1293 &nice, /* 19 %ld */ 1294 &junk, /* 20 %ld */ 1295 &it_real, /* 21 %ld */ 1296 &start, /* 22 UINTX_FORMAT */ 1297 &vsize, /* 23 UINTX_FORMAT */ 1298 &rss, /* 24 INTX_FORMAT */ 1299 &rsslim, /* 25 UINTX_FORMAT */ 1300 &scodes, /* 26 UINTX_FORMAT */ 1301 &ecode, /* 27 UINTX_FORMAT */ 1302 &stack_start); /* 28 UINTX_FORMAT */ 1303 } 1304 1305 #undef _UFM 1306 #undef _DFM 1307 1308 if (i != 28 - 2) { 1309 assert(false, "Bad conversion from /proc/self/stat"); 1310 // product mode - assume we are the initial thread, good luck in the 1311 // embedded case. 1312 warning("Can't detect initial thread stack location - bad conversion"); 1313 stack_start = (uintptr_t) &rlim; 1314 } 1315 } else { 1316 // For some reason we can't open /proc/self/stat (for example, running on 1317 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1318 // most cases, so don't abort: 1319 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1320 stack_start = (uintptr_t) &rlim; 1321 } 1322 } 1323 1324 // Now we have a pointer (stack_start) very close to the stack top, the 1325 // next thing to do is to figure out the exact location of stack top. We 1326 // can find out the virtual memory area that contains stack_start by 1327 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1328 // and its upper limit is the real stack top. (again, this would fail if 1329 // running inside chroot, because /proc may not exist.) 1330 1331 uintptr_t stack_top; 1332 address low, high; 1333 if (find_vma((address)stack_start, &low, &high)) { 1334 // success, "high" is the true stack top. (ignore "low", because initial 1335 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1336 stack_top = (uintptr_t)high; 1337 } else { 1338 // failed, likely because /proc/self/maps does not exist 1339 warning("Can't detect initial thread stack location - find_vma failed"); 1340 // best effort: stack_start is normally within a few pages below the real 1341 // stack top, use it as stack top, and reduce stack size so we won't put 1342 // guard page outside stack. 1343 stack_top = stack_start; 1344 stack_size -= 16 * page_size(); 1345 } 1346 1347 // stack_top could be partially down the page so align it 1348 stack_top = align_size_up(stack_top, page_size()); 1349 1350 if (max_size && stack_size > max_size) { 1351 _initial_thread_stack_size = max_size; 1352 } else { 1353 _initial_thread_stack_size = stack_size; 1354 } 1355 1356 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1357 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1358 } 1359 1360 //////////////////////////////////////////////////////////////////////////////// 1361 // time support 1362 1363 // Time since start-up in seconds to a fine granularity. 1364 // Used by VMSelfDestructTimer and the MemProfiler. 1365 double os::elapsedTime() { 1366 1367 return (double)(os::elapsed_counter()) * 0.000001; 1368 } 1369 1370 jlong os::elapsed_counter() { 1371 timeval time; 1372 int status = gettimeofday(&time, NULL); 1373 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count; 1374 } 1375 1376 jlong os::elapsed_frequency() { 1377 return (1000 * 1000); 1378 } 1379 1380 // For now, we say that linux does not support vtime. I have no idea 1381 // whether it can actually be made to (DLD, 9/13/05). 1382 1383 bool os::supports_vtime() { return false; } 1384 bool os::enable_vtime() { return false; } 1385 bool os::vtime_enabled() { return false; } 1386 double os::elapsedVTime() { 1387 // better than nothing, but not much 1388 return elapsedTime(); 1389 } 1390 1391 jlong os::javaTimeMillis() { 1392 timeval time; 1393 int status = gettimeofday(&time, NULL); 1394 assert(status != -1, "linux error"); 1395 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1396 } 1397 1398 #ifndef CLOCK_MONOTONIC 1399 #define CLOCK_MONOTONIC (1) 1400 #endif 1401 1402 void os::Linux::clock_init() { 1403 // we do dlopen's in this particular order due to bug in linux 1404 // dynamical loader (see 6348968) leading to crash on exit 1405 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1406 if (handle == NULL) { 1407 handle = dlopen("librt.so", RTLD_LAZY); 1408 } 1409 1410 if (handle) { 1411 int (*clock_getres_func)(clockid_t, struct timespec*) = 1412 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1413 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1414 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1415 if (clock_getres_func && clock_gettime_func) { 1416 // See if monotonic clock is supported by the kernel. Note that some 1417 // early implementations simply return kernel jiffies (updated every 1418 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1419 // for nano time (though the monotonic property is still nice to have). 1420 // It's fixed in newer kernels, however clock_getres() still returns 1421 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1422 // resolution for now. Hopefully as people move to new kernels, this 1423 // won't be a problem. 1424 struct timespec res; 1425 struct timespec tp; 1426 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1427 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1428 // yes, monotonic clock is supported 1429 _clock_gettime = clock_gettime_func; 1430 } else { 1431 // close librt if there is no monotonic clock 1432 dlclose(handle); 1433 } 1434 } 1435 } 1436 } 1437 1438 #ifndef SYS_clock_getres 1439 1440 #if defined(IA32) || defined(AMD64) 1441 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1442 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1443 #else 1444 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1445 #define sys_clock_getres(x,y) -1 1446 #endif 1447 1448 #else 1449 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1450 #endif 1451 1452 void os::Linux::fast_thread_clock_init() { 1453 if (!UseLinuxPosixThreadCPUClocks) { 1454 return; 1455 } 1456 clockid_t clockid; 1457 struct timespec tp; 1458 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1459 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1460 1461 // Switch to using fast clocks for thread cpu time if 1462 // the sys_clock_getres() returns 0 error code. 1463 // Note, that some kernels may support the current thread 1464 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1465 // returned by the pthread_getcpuclockid(). 1466 // If the fast Posix clocks are supported then the sys_clock_getres() 1467 // must return at least tp.tv_sec == 0 which means a resolution 1468 // better than 1 sec. This is extra check for reliability. 1469 1470 if(pthread_getcpuclockid_func && 1471 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1472 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1473 1474 _supports_fast_thread_cpu_time = true; 1475 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1476 } 1477 } 1478 1479 jlong os::javaTimeNanos() { 1480 if (Linux::supports_monotonic_clock()) { 1481 struct timespec tp; 1482 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1483 assert(status == 0, "gettime error"); 1484 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1485 return result; 1486 } else { 1487 timeval time; 1488 int status = gettimeofday(&time, NULL); 1489 assert(status != -1, "linux error"); 1490 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1491 return 1000 * usecs; 1492 } 1493 } 1494 1495 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1496 if (Linux::supports_monotonic_clock()) { 1497 info_ptr->max_value = ALL_64_BITS; 1498 1499 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1500 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1501 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1502 } else { 1503 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1504 info_ptr->max_value = ALL_64_BITS; 1505 1506 // gettimeofday is a real time clock so it skips 1507 info_ptr->may_skip_backward = true; 1508 info_ptr->may_skip_forward = true; 1509 } 1510 1511 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1512 } 1513 1514 // Return the real, user, and system times in seconds from an 1515 // arbitrary fixed point in the past. 1516 bool os::getTimesSecs(double* process_real_time, 1517 double* process_user_time, 1518 double* process_system_time) { 1519 struct tms ticks; 1520 clock_t real_ticks = times(&ticks); 1521 1522 if (real_ticks == (clock_t) (-1)) { 1523 return false; 1524 } else { 1525 double ticks_per_second = (double) clock_tics_per_sec; 1526 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1527 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1528 *process_real_time = ((double) real_ticks) / ticks_per_second; 1529 1530 return true; 1531 } 1532 } 1533 1534 1535 char * os::local_time_string(char *buf, size_t buflen) { 1536 struct tm t; 1537 time_t long_time; 1538 time(&long_time); 1539 localtime_r(&long_time, &t); 1540 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1541 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1542 t.tm_hour, t.tm_min, t.tm_sec); 1543 return buf; 1544 } 1545 1546 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1547 return localtime_r(clock, res); 1548 } 1549 1550 //////////////////////////////////////////////////////////////////////////////// 1551 // runtime exit support 1552 1553 // Note: os::shutdown() might be called very early during initialization, or 1554 // called from signal handler. Before adding something to os::shutdown(), make 1555 // sure it is async-safe and can handle partially initialized VM. 1556 void os::shutdown() { 1557 1558 // allow PerfMemory to attempt cleanup of any persistent resources 1559 perfMemory_exit(); 1560 1561 // needs to remove object in file system 1562 AttachListener::abort(); 1563 1564 // flush buffered output, finish log files 1565 ostream_abort(); 1566 1567 // Check for abort hook 1568 abort_hook_t abort_hook = Arguments::abort_hook(); 1569 if (abort_hook != NULL) { 1570 abort_hook(); 1571 } 1572 1573 } 1574 1575 // Note: os::abort() might be called very early during initialization, or 1576 // called from signal handler. Before adding something to os::abort(), make 1577 // sure it is async-safe and can handle partially initialized VM. 1578 void os::abort(bool dump_core) { 1579 os::shutdown(); 1580 if (dump_core) { 1581 #ifndef PRODUCT 1582 fdStream out(defaultStream::output_fd()); 1583 out.print_raw("Current thread is "); 1584 char buf[16]; 1585 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1586 out.print_raw_cr(buf); 1587 out.print_raw_cr("Dumping core ..."); 1588 #endif 1589 ::abort(); // dump core 1590 } 1591 1592 ::exit(1); 1593 } 1594 1595 // Die immediately, no exit hook, no abort hook, no cleanup. 1596 void os::die() { 1597 // _exit() on LinuxThreads only kills current thread 1598 ::abort(); 1599 } 1600 1601 // unused on linux for now. 1602 void os::set_error_file(const char *logfile) {} 1603 1604 1605 // This method is a copy of JDK's sysGetLastErrorString 1606 // from src/solaris/hpi/src/system_md.c 1607 1608 size_t os::lasterror(char *buf, size_t len) { 1609 1610 if (errno == 0) return 0; 1611 1612 const char *s = ::strerror(errno); 1613 size_t n = ::strlen(s); 1614 if (n >= len) { 1615 n = len - 1; 1616 } 1617 ::strncpy(buf, s, n); 1618 buf[n] = '\0'; 1619 return n; 1620 } 1621 1622 intx os::current_thread_id() { return (intx)pthread_self(); } 1623 int os::current_process_id() { 1624 1625 // Under the old linux thread library, linux gives each thread 1626 // its own process id. Because of this each thread will return 1627 // a different pid if this method were to return the result 1628 // of getpid(2). Linux provides no api that returns the pid 1629 // of the launcher thread for the vm. This implementation 1630 // returns a unique pid, the pid of the launcher thread 1631 // that starts the vm 'process'. 1632 1633 // Under the NPTL, getpid() returns the same pid as the 1634 // launcher thread rather than a unique pid per thread. 1635 // Use gettid() if you want the old pre NPTL behaviour. 1636 1637 // if you are looking for the result of a call to getpid() that 1638 // returns a unique pid for the calling thread, then look at the 1639 // OSThread::thread_id() method in osThread_linux.hpp file 1640 1641 return (int)(_initial_pid ? _initial_pid : getpid()); 1642 } 1643 1644 // DLL functions 1645 1646 const char* os::dll_file_extension() { return ".so"; } 1647 1648 // This must be hard coded because it's the system's temporary 1649 // directory not the java application's temp directory, ala java.io.tmpdir. 1650 const char* os::get_temp_directory() { return "/tmp"; } 1651 1652 static bool file_exists(const char* filename) { 1653 struct stat statbuf; 1654 if (filename == NULL || strlen(filename) == 0) { 1655 return false; 1656 } 1657 return os::stat(filename, &statbuf) == 0; 1658 } 1659 1660 void os::dll_build_name(char* buffer, size_t buflen, 1661 const char* pname, const char* fname) { 1662 // Copied from libhpi 1663 const size_t pnamelen = pname ? strlen(pname) : 0; 1664 1665 // Quietly truncate on buffer overflow. Should be an error. 1666 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1667 *buffer = '\0'; 1668 return; 1669 } 1670 1671 if (pnamelen == 0) { 1672 snprintf(buffer, buflen, "lib%s.so", fname); 1673 } else if (strchr(pname, *os::path_separator()) != NULL) { 1674 int n; 1675 char** pelements = split_path(pname, &n); 1676 for (int i = 0 ; i < n ; i++) { 1677 // Really shouldn't be NULL, but check can't hurt 1678 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1679 continue; // skip the empty path values 1680 } 1681 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1682 if (file_exists(buffer)) { 1683 break; 1684 } 1685 } 1686 // release the storage 1687 for (int i = 0 ; i < n ; i++) { 1688 if (pelements[i] != NULL) { 1689 FREE_C_HEAP_ARRAY(char, pelements[i]); 1690 } 1691 } 1692 if (pelements != NULL) { 1693 FREE_C_HEAP_ARRAY(char*, pelements); 1694 } 1695 } else { 1696 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1697 } 1698 } 1699 1700 const char* os::get_current_directory(char *buf, int buflen) { 1701 return getcwd(buf, buflen); 1702 } 1703 1704 // check if addr is inside libjvm[_g].so 1705 bool os::address_is_in_vm(address addr) { 1706 static address libjvm_base_addr; 1707 Dl_info dlinfo; 1708 1709 if (libjvm_base_addr == NULL) { 1710 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo); 1711 libjvm_base_addr = (address)dlinfo.dli_fbase; 1712 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1713 } 1714 1715 if (dladdr((void *)addr, &dlinfo)) { 1716 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1717 } 1718 1719 return false; 1720 } 1721 1722 bool os::dll_address_to_function_name(address addr, char *buf, 1723 int buflen, int *offset) { 1724 Dl_info dlinfo; 1725 1726 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) { 1727 if (buf != NULL) { 1728 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) { 1729 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1730 } 1731 } 1732 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1733 return true; 1734 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) { 1735 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1736 buf, buflen, offset, dlinfo.dli_fname)) { 1737 return true; 1738 } 1739 } 1740 1741 if (buf != NULL) buf[0] = '\0'; 1742 if (offset != NULL) *offset = -1; 1743 return false; 1744 } 1745 1746 struct _address_to_library_name { 1747 address addr; // input : memory address 1748 size_t buflen; // size of fname 1749 char* fname; // output: library name 1750 address base; // library base addr 1751 }; 1752 1753 static int address_to_library_name_callback(struct dl_phdr_info *info, 1754 size_t size, void *data) { 1755 int i; 1756 bool found = false; 1757 address libbase = NULL; 1758 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1759 1760 // iterate through all loadable segments 1761 for (i = 0; i < info->dlpi_phnum; i++) { 1762 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1763 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1764 // base address of a library is the lowest address of its loaded 1765 // segments. 1766 if (libbase == NULL || libbase > segbase) { 1767 libbase = segbase; 1768 } 1769 // see if 'addr' is within current segment 1770 if (segbase <= d->addr && 1771 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1772 found = true; 1773 } 1774 } 1775 } 1776 1777 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1778 // so dll_address_to_library_name() can fall through to use dladdr() which 1779 // can figure out executable name from argv[0]. 1780 if (found && info->dlpi_name && info->dlpi_name[0]) { 1781 d->base = libbase; 1782 if (d->fname) { 1783 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1784 } 1785 return 1; 1786 } 1787 return 0; 1788 } 1789 1790 bool os::dll_address_to_library_name(address addr, char* buf, 1791 int buflen, int* offset) { 1792 Dl_info dlinfo; 1793 struct _address_to_library_name data; 1794 1795 // There is a bug in old glibc dladdr() implementation that it could resolve 1796 // to wrong library name if the .so file has a base address != NULL. Here 1797 // we iterate through the program headers of all loaded libraries to find 1798 // out which library 'addr' really belongs to. This workaround can be 1799 // removed once the minimum requirement for glibc is moved to 2.3.x. 1800 data.addr = addr; 1801 data.fname = buf; 1802 data.buflen = buflen; 1803 data.base = NULL; 1804 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1805 1806 if (rslt) { 1807 // buf already contains library name 1808 if (offset) *offset = addr - data.base; 1809 return true; 1810 } else if (dladdr((void*)addr, &dlinfo)){ 1811 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1812 if (offset) *offset = addr - (address)dlinfo.dli_fbase; 1813 return true; 1814 } else { 1815 if (buf) buf[0] = '\0'; 1816 if (offset) *offset = -1; 1817 return false; 1818 } 1819 } 1820 1821 // Loads .dll/.so and 1822 // in case of error it checks if .dll/.so was built for the 1823 // same architecture as Hotspot is running on 1824 1825 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) 1826 { 1827 void * result= ::dlopen(filename, RTLD_LAZY); 1828 if (result != NULL) { 1829 // Successful loading 1830 return result; 1831 } 1832 1833 Elf32_Ehdr elf_head; 1834 1835 // Read system error message into ebuf 1836 // It may or may not be overwritten below 1837 ::strncpy(ebuf, ::dlerror(), ebuflen-1); 1838 ebuf[ebuflen-1]='\0'; 1839 int diag_msg_max_length=ebuflen-strlen(ebuf); 1840 char* diag_msg_buf=ebuf+strlen(ebuf); 1841 1842 if (diag_msg_max_length==0) { 1843 // No more space in ebuf for additional diagnostics message 1844 return NULL; 1845 } 1846 1847 1848 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1849 1850 if (file_descriptor < 0) { 1851 // Can't open library, report dlerror() message 1852 return NULL; 1853 } 1854 1855 bool failed_to_read_elf_head= 1856 (sizeof(elf_head)!= 1857 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ; 1858 1859 ::close(file_descriptor); 1860 if (failed_to_read_elf_head) { 1861 // file i/o error - report dlerror() msg 1862 return NULL; 1863 } 1864 1865 typedef struct { 1866 Elf32_Half code; // Actual value as defined in elf.h 1867 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1868 char elf_class; // 32 or 64 bit 1869 char endianess; // MSB or LSB 1870 char* name; // String representation 1871 } arch_t; 1872 1873 #ifndef EM_486 1874 #define EM_486 6 /* Intel 80486 */ 1875 #endif 1876 1877 static const arch_t arch_array[]={ 1878 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1879 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1880 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1881 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1882 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1883 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1884 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1885 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1886 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1887 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1888 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1889 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1890 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1891 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1892 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1893 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"} 1894 }; 1895 1896 #if (defined IA32) 1897 static Elf32_Half running_arch_code=EM_386; 1898 #elif (defined AMD64) 1899 static Elf32_Half running_arch_code=EM_X86_64; 1900 #elif (defined IA64) 1901 static Elf32_Half running_arch_code=EM_IA_64; 1902 #elif (defined __sparc) && (defined _LP64) 1903 static Elf32_Half running_arch_code=EM_SPARCV9; 1904 #elif (defined __sparc) && (!defined _LP64) 1905 static Elf32_Half running_arch_code=EM_SPARC; 1906 #elif (defined __powerpc64__) 1907 static Elf32_Half running_arch_code=EM_PPC64; 1908 #elif (defined __powerpc__) 1909 static Elf32_Half running_arch_code=EM_PPC; 1910 #elif (defined ARM) 1911 static Elf32_Half running_arch_code=EM_ARM; 1912 #elif (defined S390) 1913 static Elf32_Half running_arch_code=EM_S390; 1914 #elif (defined ALPHA) 1915 static Elf32_Half running_arch_code=EM_ALPHA; 1916 #elif (defined MIPSEL) 1917 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1918 #elif (defined PARISC) 1919 static Elf32_Half running_arch_code=EM_PARISC; 1920 #elif (defined MIPS) 1921 static Elf32_Half running_arch_code=EM_MIPS; 1922 #elif (defined M68K) 1923 static Elf32_Half running_arch_code=EM_68K; 1924 #else 1925 #error Method os::dll_load requires that one of following is defined:\ 1926 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K 1927 #endif 1928 1929 // Identify compatability class for VM's architecture and library's architecture 1930 // Obtain string descriptions for architectures 1931 1932 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1933 int running_arch_index=-1; 1934 1935 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) { 1936 if (running_arch_code == arch_array[i].code) { 1937 running_arch_index = i; 1938 } 1939 if (lib_arch.code == arch_array[i].code) { 1940 lib_arch.compat_class = arch_array[i].compat_class; 1941 lib_arch.name = arch_array[i].name; 1942 } 1943 } 1944 1945 assert(running_arch_index != -1, 1946 "Didn't find running architecture code (running_arch_code) in arch_array"); 1947 if (running_arch_index == -1) { 1948 // Even though running architecture detection failed 1949 // we may still continue with reporting dlerror() message 1950 return NULL; 1951 } 1952 1953 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1954 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1955 return NULL; 1956 } 1957 1958 #ifndef S390 1959 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1960 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1961 return NULL; 1962 } 1963 #endif // !S390 1964 1965 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1966 if ( lib_arch.name!=NULL ) { 1967 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1968 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1969 lib_arch.name, arch_array[running_arch_index].name); 1970 } else { 1971 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1972 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1973 lib_arch.code, 1974 arch_array[running_arch_index].name); 1975 } 1976 } 1977 1978 return NULL; 1979 } 1980 1981 /* 1982 * glibc-2.0 libdl is not MT safe. If you are building with any glibc, 1983 * chances are you might want to run the generated bits against glibc-2.0 1984 * libdl.so, so always use locking for any version of glibc. 1985 */ 1986 void* os::dll_lookup(void* handle, const char* name) { 1987 pthread_mutex_lock(&dl_mutex); 1988 void* res = dlsym(handle, name); 1989 pthread_mutex_unlock(&dl_mutex); 1990 return res; 1991 } 1992 1993 1994 static bool _print_ascii_file(const char* filename, outputStream* st) { 1995 int fd = ::open(filename, O_RDONLY); 1996 if (fd == -1) { 1997 return false; 1998 } 1999 2000 char buf[32]; 2001 int bytes; 2002 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 2003 st->print_raw(buf, bytes); 2004 } 2005 2006 ::close(fd); 2007 2008 return true; 2009 } 2010 2011 void os::print_dll_info(outputStream *st) { 2012 st->print_cr("Dynamic libraries:"); 2013 2014 char fname[32]; 2015 pid_t pid = os::Linux::gettid(); 2016 2017 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 2018 2019 if (!_print_ascii_file(fname, st)) { 2020 st->print("Can not get library information for pid = %d\n", pid); 2021 } 2022 } 2023 2024 2025 void os::print_os_info(outputStream* st) { 2026 st->print("OS:"); 2027 2028 // Try to identify popular distros. 2029 // Most Linux distributions have /etc/XXX-release file, which contains 2030 // the OS version string. Some have more than one /etc/XXX-release file 2031 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.), 2032 // so the order is important. 2033 if (!_print_ascii_file("/etc/mandrake-release", st) && 2034 !_print_ascii_file("/etc/sun-release", st) && 2035 !_print_ascii_file("/etc/redhat-release", st) && 2036 !_print_ascii_file("/etc/SuSE-release", st) && 2037 !_print_ascii_file("/etc/turbolinux-release", st) && 2038 !_print_ascii_file("/etc/gentoo-release", st) && 2039 !_print_ascii_file("/etc/debian_version", st) && 2040 !_print_ascii_file("/etc/ltib-release", st) && 2041 !_print_ascii_file("/etc/angstrom-version", st)) { 2042 st->print("Linux"); 2043 } 2044 st->cr(); 2045 2046 // kernel 2047 st->print("uname:"); 2048 struct utsname name; 2049 uname(&name); 2050 st->print(name.sysname); st->print(" "); 2051 st->print(name.release); st->print(" "); 2052 st->print(name.version); st->print(" "); 2053 st->print(name.machine); 2054 st->cr(); 2055 2056 // Print warning if unsafe chroot environment detected 2057 if (unsafe_chroot_detected) { 2058 st->print("WARNING!! "); 2059 st->print_cr(unstable_chroot_error); 2060 } 2061 2062 // libc, pthread 2063 st->print("libc:"); 2064 st->print(os::Linux::glibc_version()); st->print(" "); 2065 st->print(os::Linux::libpthread_version()); st->print(" "); 2066 if (os::Linux::is_LinuxThreads()) { 2067 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed"); 2068 } 2069 st->cr(); 2070 2071 // rlimit 2072 st->print("rlimit:"); 2073 struct rlimit rlim; 2074 2075 st->print(" STACK "); 2076 getrlimit(RLIMIT_STACK, &rlim); 2077 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2078 else st->print("%uk", rlim.rlim_cur >> 10); 2079 2080 st->print(", CORE "); 2081 getrlimit(RLIMIT_CORE, &rlim); 2082 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2083 else st->print("%uk", rlim.rlim_cur >> 10); 2084 2085 st->print(", NPROC "); 2086 getrlimit(RLIMIT_NPROC, &rlim); 2087 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2088 else st->print("%d", rlim.rlim_cur); 2089 2090 st->print(", NOFILE "); 2091 getrlimit(RLIMIT_NOFILE, &rlim); 2092 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2093 else st->print("%d", rlim.rlim_cur); 2094 2095 st->print(", AS "); 2096 getrlimit(RLIMIT_AS, &rlim); 2097 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); 2098 else st->print("%uk", rlim.rlim_cur >> 10); 2099 st->cr(); 2100 2101 // load average 2102 st->print("load average:"); 2103 double loadavg[3]; 2104 os::loadavg(loadavg, 3); 2105 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]); 2106 st->cr(); 2107 2108 // meminfo 2109 st->print("\n/proc/meminfo:\n"); 2110 _print_ascii_file("/proc/meminfo", st); 2111 st->cr(); 2112 } 2113 2114 void os::pd_print_cpu_info(outputStream* st) { 2115 st->print("\n/proc/cpuinfo:\n"); 2116 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2117 st->print(" <Not Available>"); 2118 } 2119 st->cr(); 2120 } 2121 2122 void os::print_memory_info(outputStream* st) { 2123 2124 st->print("Memory:"); 2125 st->print(" %dk page", os::vm_page_size()>>10); 2126 2127 // values in struct sysinfo are "unsigned long" 2128 struct sysinfo si; 2129 sysinfo(&si); 2130 2131 st->print(", physical " UINT64_FORMAT "k", 2132 os::physical_memory() >> 10); 2133 st->print("(" UINT64_FORMAT "k free)", 2134 os::available_memory() >> 10); 2135 st->print(", swap " UINT64_FORMAT "k", 2136 ((jlong)si.totalswap * si.mem_unit) >> 10); 2137 st->print("(" UINT64_FORMAT "k free)", 2138 ((jlong)si.freeswap * si.mem_unit) >> 10); 2139 st->cr(); 2140 } 2141 2142 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific 2143 // but they're the same for all the linux arch that we support 2144 // and they're the same for solaris but there's no common place to put this. 2145 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR", 2146 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG", 2147 "ILL_COPROC", "ILL_BADSTK" }; 2148 2149 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV", 2150 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES", 2151 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" }; 2152 2153 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" }; 2154 2155 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" }; 2156 2157 void os::print_siginfo(outputStream* st, void* siginfo) { 2158 st->print("siginfo:"); 2159 2160 const int buflen = 100; 2161 char buf[buflen]; 2162 siginfo_t *si = (siginfo_t*)siginfo; 2163 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen)); 2164 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) { 2165 st->print("si_errno=%s", buf); 2166 } else { 2167 st->print("si_errno=%d", si->si_errno); 2168 } 2169 const int c = si->si_code; 2170 assert(c > 0, "unexpected si_code"); 2171 switch (si->si_signo) { 2172 case SIGILL: 2173 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]); 2174 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2175 break; 2176 case SIGFPE: 2177 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]); 2178 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2179 break; 2180 case SIGSEGV: 2181 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]); 2182 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2183 break; 2184 case SIGBUS: 2185 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]); 2186 st->print(", si_addr=" PTR_FORMAT, si->si_addr); 2187 break; 2188 default: 2189 st->print(", si_code=%d", si->si_code); 2190 // no si_addr 2191 } 2192 2193 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2194 UseSharedSpaces) { 2195 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2196 if (mapinfo->is_in_shared_space(si->si_addr)) { 2197 st->print("\n\nError accessing class data sharing archive." \ 2198 " Mapped file inaccessible during execution, " \ 2199 " possible disk/network problem."); 2200 } 2201 } 2202 st->cr(); 2203 } 2204 2205 2206 static void print_signal_handler(outputStream* st, int sig, 2207 char* buf, size_t buflen); 2208 2209 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2210 st->print_cr("Signal Handlers:"); 2211 print_signal_handler(st, SIGSEGV, buf, buflen); 2212 print_signal_handler(st, SIGBUS , buf, buflen); 2213 print_signal_handler(st, SIGFPE , buf, buflen); 2214 print_signal_handler(st, SIGPIPE, buf, buflen); 2215 print_signal_handler(st, SIGXFSZ, buf, buflen); 2216 print_signal_handler(st, SIGILL , buf, buflen); 2217 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen); 2218 print_signal_handler(st, SR_signum, buf, buflen); 2219 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2220 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2221 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2222 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2223 } 2224 2225 static char saved_jvm_path[MAXPATHLEN] = {0}; 2226 2227 // Find the full path to the current module, libjvm.so or libjvm_g.so 2228 void os::jvm_path(char *buf, jint buflen) { 2229 // Error checking. 2230 if (buflen < MAXPATHLEN) { 2231 assert(false, "must use a large-enough buffer"); 2232 buf[0] = '\0'; 2233 return; 2234 } 2235 // Lazy resolve the path to current module. 2236 if (saved_jvm_path[0] != 0) { 2237 strcpy(buf, saved_jvm_path); 2238 return; 2239 } 2240 2241 char dli_fname[MAXPATHLEN]; 2242 bool ret = dll_address_to_library_name( 2243 CAST_FROM_FN_PTR(address, os::jvm_path), 2244 dli_fname, sizeof(dli_fname), NULL); 2245 assert(ret != 0, "cannot locate libjvm"); 2246 char *rp = realpath(dli_fname, buf); 2247 if (rp == NULL) 2248 return; 2249 2250 if (Arguments::created_by_gamma_launcher()) { 2251 // Support for the gamma launcher. Typical value for buf is 2252 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at 2253 // the right place in the string, then assume we are installed in a JDK and 2254 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix 2255 // up the path so it looks like libjvm.so is installed there (append a 2256 // fake suffix hotspot/libjvm.so). 2257 const char *p = buf + strlen(buf) - 1; 2258 for (int count = 0; p > buf && count < 5; ++count) { 2259 for (--p; p > buf && *p != '/'; --p) 2260 /* empty */ ; 2261 } 2262 2263 if (strncmp(p, "/jre/lib/", 9) != 0) { 2264 // Look for JAVA_HOME in the environment. 2265 char* java_home_var = ::getenv("JAVA_HOME"); 2266 if (java_home_var != NULL && java_home_var[0] != 0) { 2267 char* jrelib_p; 2268 int len; 2269 2270 // Check the current module name "libjvm.so" or "libjvm_g.so". 2271 p = strrchr(buf, '/'); 2272 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2273 p = strstr(p, "_g") ? "_g" : ""; 2274 2275 rp = realpath(java_home_var, buf); 2276 if (rp == NULL) 2277 return; 2278 2279 // determine if this is a legacy image or modules image 2280 // modules image doesn't have "jre" subdirectory 2281 len = strlen(buf); 2282 jrelib_p = buf + len; 2283 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2284 if (0 != access(buf, F_OK)) { 2285 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2286 } 2287 2288 if (0 == access(buf, F_OK)) { 2289 // Use current module name "libjvm[_g].so" instead of 2290 // "libjvm"debug_only("_g")".so" since for fastdebug version 2291 // we should have "libjvm.so" but debug_only("_g") adds "_g"! 2292 len = strlen(buf); 2293 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p); 2294 } else { 2295 // Go back to path of .so 2296 rp = realpath(dli_fname, buf); 2297 if (rp == NULL) 2298 return; 2299 } 2300 } 2301 } 2302 } 2303 2304 strcpy(saved_jvm_path, buf); 2305 } 2306 2307 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2308 // no prefix required, not even "_" 2309 } 2310 2311 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2312 // no suffix required 2313 } 2314 2315 //////////////////////////////////////////////////////////////////////////////// 2316 // sun.misc.Signal support 2317 2318 static volatile jint sigint_count = 0; 2319 2320 static void 2321 UserHandler(int sig, void *siginfo, void *context) { 2322 // 4511530 - sem_post is serialized and handled by the manager thread. When 2323 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2324 // don't want to flood the manager thread with sem_post requests. 2325 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) 2326 return; 2327 2328 // Ctrl-C is pressed during error reporting, likely because the error 2329 // handler fails to abort. Let VM die immediately. 2330 if (sig == SIGINT && is_error_reported()) { 2331 os::die(); 2332 } 2333 2334 os::signal_notify(sig); 2335 } 2336 2337 void* os::user_handler() { 2338 return CAST_FROM_FN_PTR(void*, UserHandler); 2339 } 2340 2341 extern "C" { 2342 typedef void (*sa_handler_t)(int); 2343 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2344 } 2345 2346 void* os::signal(int signal_number, void* handler) { 2347 struct sigaction sigAct, oldSigAct; 2348 2349 sigfillset(&(sigAct.sa_mask)); 2350 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2351 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2352 2353 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2354 // -1 means registration failed 2355 return (void *)-1; 2356 } 2357 2358 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2359 } 2360 2361 void os::signal_raise(int signal_number) { 2362 ::raise(signal_number); 2363 } 2364 2365 /* 2366 * The following code is moved from os.cpp for making this 2367 * code platform specific, which it is by its very nature. 2368 */ 2369 2370 // Will be modified when max signal is changed to be dynamic 2371 int os::sigexitnum_pd() { 2372 return NSIG; 2373 } 2374 2375 // a counter for each possible signal value 2376 static volatile jint pending_signals[NSIG+1] = { 0 }; 2377 2378 // Linux(POSIX) specific hand shaking semaphore. 2379 static sem_t sig_sem; 2380 2381 void os::signal_init_pd() { 2382 // Initialize signal structures 2383 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2384 2385 // Initialize signal semaphore 2386 ::sem_init(&sig_sem, 0, 0); 2387 } 2388 2389 void os::signal_notify(int sig) { 2390 Atomic::inc(&pending_signals[sig]); 2391 ::sem_post(&sig_sem); 2392 } 2393 2394 static int check_pending_signals(bool wait) { 2395 Atomic::store(0, &sigint_count); 2396 for (;;) { 2397 for (int i = 0; i < NSIG + 1; i++) { 2398 jint n = pending_signals[i]; 2399 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2400 return i; 2401 } 2402 } 2403 if (!wait) { 2404 return -1; 2405 } 2406 JavaThread *thread = JavaThread::current(); 2407 ThreadBlockInVM tbivm(thread); 2408 2409 bool threadIsSuspended; 2410 do { 2411 thread->set_suspend_equivalent(); 2412 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2413 ::sem_wait(&sig_sem); 2414 2415 // were we externally suspended while we were waiting? 2416 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2417 if (threadIsSuspended) { 2418 // 2419 // The semaphore has been incremented, but while we were waiting 2420 // another thread suspended us. We don't want to continue running 2421 // while suspended because that would surprise the thread that 2422 // suspended us. 2423 // 2424 ::sem_post(&sig_sem); 2425 2426 thread->java_suspend_self(); 2427 } 2428 } while (threadIsSuspended); 2429 } 2430 } 2431 2432 int os::signal_lookup() { 2433 return check_pending_signals(false); 2434 } 2435 2436 int os::signal_wait() { 2437 return check_pending_signals(true); 2438 } 2439 2440 //////////////////////////////////////////////////////////////////////////////// 2441 // Virtual Memory 2442 2443 int os::vm_page_size() { 2444 // Seems redundant as all get out 2445 assert(os::Linux::page_size() != -1, "must call os::init"); 2446 return os::Linux::page_size(); 2447 } 2448 2449 // Solaris allocates memory by pages. 2450 int os::vm_allocation_granularity() { 2451 assert(os::Linux::page_size() != -1, "must call os::init"); 2452 return os::Linux::page_size(); 2453 } 2454 2455 // Rationale behind this function: 2456 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2457 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2458 // samples for JITted code. Here we create private executable mapping over the code cache 2459 // and then we can use standard (well, almost, as mapping can change) way to provide 2460 // info for the reporting script by storing timestamp and location of symbol 2461 void linux_wrap_code(char* base, size_t size) { 2462 static volatile jint cnt = 0; 2463 2464 if (!UseOprofile) { 2465 return; 2466 } 2467 2468 char buf[PATH_MAX+1]; 2469 int num = Atomic::add(1, &cnt); 2470 2471 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2472 os::get_temp_directory(), os::current_process_id(), num); 2473 unlink(buf); 2474 2475 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2476 2477 if (fd != -1) { 2478 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2479 if (rv != (off_t)-1) { 2480 if (::write(fd, "", 1) == 1) { 2481 mmap(base, size, 2482 PROT_READ|PROT_WRITE|PROT_EXEC, 2483 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2484 } 2485 } 2486 ::close(fd); 2487 unlink(buf); 2488 } 2489 } 2490 2491 // NOTE: Linux kernel does not really reserve the pages for us. 2492 // All it does is to check if there are enough free pages 2493 // left at the time of mmap(). This could be a potential 2494 // problem. 2495 bool os::commit_memory(char* addr, size_t size, bool exec) { 2496 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2497 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2498 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2499 if (res != (uintptr_t) MAP_FAILED) { 2500 if (UseNUMAInterleaving) { 2501 numa_make_global(addr, size); 2502 } 2503 return true; 2504 } 2505 return false; 2506 } 2507 2508 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2509 #ifndef MAP_HUGETLB 2510 #define MAP_HUGETLB 0x40000 2511 #endif 2512 2513 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2514 #ifndef MADV_HUGEPAGE 2515 #define MADV_HUGEPAGE 14 2516 #endif 2517 2518 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 2519 bool exec) { 2520 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2521 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2522 uintptr_t res = 2523 (uintptr_t) ::mmap(addr, size, prot, 2524 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB, 2525 -1, 0); 2526 if (res != (uintptr_t) MAP_FAILED) { 2527 if (UseNUMAInterleaving) { 2528 numa_make_global(addr, size); 2529 } 2530 return true; 2531 } 2532 // Fall through and try to use small pages 2533 } 2534 2535 if (commit_memory(addr, size, exec)) { 2536 realign_memory(addr, size, alignment_hint); 2537 return true; 2538 } 2539 return false; 2540 } 2541 2542 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2543 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) { 2544 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2545 // be supported or the memory may already be backed by huge pages. 2546 ::madvise(addr, bytes, MADV_HUGEPAGE); 2547 } 2548 } 2549 2550 void os::free_memory(char *addr, size_t bytes) { 2551 commit_memory(addr, bytes, false); 2552 } 2553 2554 void os::numa_make_global(char *addr, size_t bytes) { 2555 Linux::numa_interleave_memory(addr, bytes); 2556 } 2557 2558 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2559 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2560 } 2561 2562 bool os::numa_topology_changed() { return false; } 2563 2564 size_t os::numa_get_groups_num() { 2565 int max_node = Linux::numa_max_node(); 2566 return max_node > 0 ? max_node + 1 : 1; 2567 } 2568 2569 int os::numa_get_group_id() { 2570 int cpu_id = Linux::sched_getcpu(); 2571 if (cpu_id != -1) { 2572 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2573 if (lgrp_id != -1) { 2574 return lgrp_id; 2575 } 2576 } 2577 return 0; 2578 } 2579 2580 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2581 for (size_t i = 0; i < size; i++) { 2582 ids[i] = i; 2583 } 2584 return size; 2585 } 2586 2587 bool os::get_page_info(char *start, page_info* info) { 2588 return false; 2589 } 2590 2591 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) { 2592 return end; 2593 } 2594 2595 2596 int os::Linux::sched_getcpu_syscall(void) { 2597 unsigned int cpu; 2598 int retval = -1; 2599 2600 #if defined(IA32) 2601 # ifndef SYS_getcpu 2602 # define SYS_getcpu 318 2603 # endif 2604 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2605 #elif defined(AMD64) 2606 // Unfortunately we have to bring all these macros here from vsyscall.h 2607 // to be able to compile on old linuxes. 2608 # define __NR_vgetcpu 2 2609 # define VSYSCALL_START (-10UL << 20) 2610 # define VSYSCALL_SIZE 1024 2611 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2612 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2613 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2614 retval = vgetcpu(&cpu, NULL, NULL); 2615 #endif 2616 2617 return (retval == -1) ? retval : cpu; 2618 } 2619 2620 // Something to do with the numa-aware allocator needs these symbols 2621 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2622 extern "C" JNIEXPORT void numa_error(char *where) { } 2623 extern "C" JNIEXPORT int fork1() { return fork(); } 2624 2625 2626 // If we are running with libnuma version > 2, then we should 2627 // be trying to use symbols with versions 1.1 2628 // If we are running with earlier version, which did not have symbol versions, 2629 // we should use the base version. 2630 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2631 void *f = dlvsym(handle, name, "libnuma_1.1"); 2632 if (f == NULL) { 2633 f = dlsym(handle, name); 2634 } 2635 return f; 2636 } 2637 2638 bool os::Linux::libnuma_init() { 2639 // sched_getcpu() should be in libc. 2640 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2641 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2642 2643 // If it's not, try a direct syscall. 2644 if (sched_getcpu() == -1) 2645 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall)); 2646 2647 if (sched_getcpu() != -1) { // Does it work? 2648 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2649 if (handle != NULL) { 2650 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2651 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2652 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2653 libnuma_dlsym(handle, "numa_max_node"))); 2654 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2655 libnuma_dlsym(handle, "numa_available"))); 2656 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2657 libnuma_dlsym(handle, "numa_tonode_memory"))); 2658 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2659 libnuma_dlsym(handle, "numa_interleave_memory"))); 2660 2661 2662 if (numa_available() != -1) { 2663 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2664 // Create a cpu -> node mapping 2665 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true); 2666 rebuild_cpu_to_node_map(); 2667 return true; 2668 } 2669 } 2670 } 2671 return false; 2672 } 2673 2674 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2675 // The table is later used in get_node_by_cpu(). 2676 void os::Linux::rebuild_cpu_to_node_map() { 2677 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2678 // in libnuma (possible values are starting from 16, 2679 // and continuing up with every other power of 2, but less 2680 // than the maximum number of CPUs supported by kernel), and 2681 // is a subject to change (in libnuma version 2 the requirements 2682 // are more reasonable) we'll just hardcode the number they use 2683 // in the library. 2684 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2685 2686 size_t cpu_num = os::active_processor_count(); 2687 size_t cpu_map_size = NCPUS / BitsPerCLong; 2688 size_t cpu_map_valid_size = 2689 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2690 2691 cpu_to_node()->clear(); 2692 cpu_to_node()->at_grow(cpu_num - 1); 2693 size_t node_num = numa_get_groups_num(); 2694 2695 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size); 2696 for (size_t i = 0; i < node_num; i++) { 2697 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2698 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2699 if (cpu_map[j] != 0) { 2700 for (size_t k = 0; k < BitsPerCLong; k++) { 2701 if (cpu_map[j] & (1UL << k)) { 2702 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2703 } 2704 } 2705 } 2706 } 2707 } 2708 } 2709 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2710 } 2711 2712 int os::Linux::get_node_by_cpu(int cpu_id) { 2713 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2714 return cpu_to_node()->at(cpu_id); 2715 } 2716 return -1; 2717 } 2718 2719 GrowableArray<int>* os::Linux::_cpu_to_node; 2720 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2721 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2722 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2723 os::Linux::numa_available_func_t os::Linux::_numa_available; 2724 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2725 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2726 unsigned long* os::Linux::_numa_all_nodes; 2727 2728 bool os::uncommit_memory(char* addr, size_t size) { 2729 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2730 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2731 return res != (uintptr_t) MAP_FAILED; 2732 } 2733 2734 // Linux uses a growable mapping for the stack, and if the mapping for 2735 // the stack guard pages is not removed when we detach a thread the 2736 // stack cannot grow beyond the pages where the stack guard was 2737 // mapped. If at some point later in the process the stack expands to 2738 // that point, the Linux kernel cannot expand the stack any further 2739 // because the guard pages are in the way, and a segfault occurs. 2740 // 2741 // However, it's essential not to split the stack region by unmapping 2742 // a region (leaving a hole) that's already part of the stack mapping, 2743 // so if the stack mapping has already grown beyond the guard pages at 2744 // the time we create them, we have to truncate the stack mapping. 2745 // So, we need to know the extent of the stack mapping when 2746 // create_stack_guard_pages() is called. 2747 2748 // Find the bounds of the stack mapping. Return true for success. 2749 // 2750 // We only need this for stacks that are growable: at the time of 2751 // writing thread stacks don't use growable mappings (i.e. those 2752 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2753 // only applies to the main thread. 2754 2755 static 2756 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) { 2757 2758 char buf[128]; 2759 int fd, sz; 2760 2761 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) { 2762 return false; 2763 } 2764 2765 const char kw[] = "[stack]"; 2766 const int kwlen = sizeof(kw)-1; 2767 2768 // Address part of /proc/self/maps couldn't be more than 128 bytes 2769 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) { 2770 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) { 2771 // Extract addresses 2772 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) { 2773 uintptr_t sp = (uintptr_t) __builtin_frame_address(0); 2774 if (sp >= *bottom && sp <= *top) { 2775 ::close(fd); 2776 return true; 2777 } 2778 } 2779 } 2780 } 2781 2782 ::close(fd); 2783 return false; 2784 } 2785 2786 2787 // If the (growable) stack mapping already extends beyond the point 2788 // where we're going to put our guard pages, truncate the mapping at 2789 // that point by munmap()ping it. This ensures that when we later 2790 // munmap() the guard pages we don't leave a hole in the stack 2791 // mapping. This only affects the main/initial thread, but guard 2792 // against future OS changes 2793 bool os::create_stack_guard_pages(char* addr, size_t size) { 2794 uintptr_t stack_extent, stack_base; 2795 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2796 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2797 assert(os::Linux::is_initial_thread(), 2798 "growable stack in non-initial thread"); 2799 if (stack_extent < (uintptr_t)addr) 2800 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); 2801 } 2802 2803 return os::commit_memory(addr, size); 2804 } 2805 2806 // If this is a growable mapping, remove the guard pages entirely by 2807 // munmap()ping them. If not, just call uncommit_memory(). This only 2808 // affects the main/initial thread, but guard against future OS changes 2809 bool os::remove_stack_guard_pages(char* addr, size_t size) { 2810 uintptr_t stack_extent, stack_base; 2811 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true); 2812 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) { 2813 assert(os::Linux::is_initial_thread(), 2814 "growable stack in non-initial thread"); 2815 2816 return ::munmap(addr, size) == 0; 2817 } 2818 2819 return os::uncommit_memory(addr, size); 2820 } 2821 2822 static address _highest_vm_reserved_address = NULL; 2823 2824 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 2825 // at 'requested_addr'. If there are existing memory mappings at the same 2826 // location, however, they will be overwritten. If 'fixed' is false, 2827 // 'requested_addr' is only treated as a hint, the return value may or 2828 // may not start from the requested address. Unlike Linux mmap(), this 2829 // function returns NULL to indicate failure. 2830 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 2831 char * addr; 2832 int flags; 2833 2834 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 2835 if (fixed) { 2836 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 2837 flags |= MAP_FIXED; 2838 } 2839 2840 // Map uncommitted pages PROT_READ and PROT_WRITE, change access 2841 // to PROT_EXEC if executable when we commit the page. 2842 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE, 2843 flags, -1, 0); 2844 2845 if (addr != MAP_FAILED) { 2846 // anon_mmap() should only get called during VM initialization, 2847 // don't need lock (actually we can skip locking even it can be called 2848 // from multiple threads, because _highest_vm_reserved_address is just a 2849 // hint about the upper limit of non-stack memory regions.) 2850 if ((address)addr + bytes > _highest_vm_reserved_address) { 2851 _highest_vm_reserved_address = (address)addr + bytes; 2852 } 2853 } 2854 2855 return addr == MAP_FAILED ? NULL : addr; 2856 } 2857 2858 // Don't update _highest_vm_reserved_address, because there might be memory 2859 // regions above addr + size. If so, releasing a memory region only creates 2860 // a hole in the address space, it doesn't help prevent heap-stack collision. 2861 // 2862 static int anon_munmap(char * addr, size_t size) { 2863 return ::munmap(addr, size) == 0; 2864 } 2865 2866 char* os::reserve_memory(size_t bytes, char* requested_addr, 2867 size_t alignment_hint) { 2868 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 2869 } 2870 2871 bool os::release_memory(char* addr, size_t size) { 2872 return anon_munmap(addr, size); 2873 } 2874 2875 static address highest_vm_reserved_address() { 2876 return _highest_vm_reserved_address; 2877 } 2878 2879 static bool linux_mprotect(char* addr, size_t size, int prot) { 2880 // Linux wants the mprotect address argument to be page aligned. 2881 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 2882 2883 // According to SUSv3, mprotect() should only be used with mappings 2884 // established by mmap(), and mmap() always maps whole pages. Unaligned 2885 // 'addr' likely indicates problem in the VM (e.g. trying to change 2886 // protection of malloc'ed or statically allocated memory). Check the 2887 // caller if you hit this assert. 2888 assert(addr == bottom, "sanity check"); 2889 2890 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 2891 return ::mprotect(bottom, size, prot) == 0; 2892 } 2893 2894 // Set protections specified 2895 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 2896 bool is_committed) { 2897 unsigned int p = 0; 2898 switch (prot) { 2899 case MEM_PROT_NONE: p = PROT_NONE; break; 2900 case MEM_PROT_READ: p = PROT_READ; break; 2901 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 2902 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 2903 default: 2904 ShouldNotReachHere(); 2905 } 2906 // is_committed is unused. 2907 return linux_mprotect(addr, bytes, p); 2908 } 2909 2910 bool os::guard_memory(char* addr, size_t size) { 2911 return linux_mprotect(addr, size, PROT_NONE); 2912 } 2913 2914 bool os::unguard_memory(char* addr, size_t size) { 2915 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 2916 } 2917 2918 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 2919 bool result = false; 2920 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE, 2921 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 2922 -1, 0); 2923 2924 if (p != (void *) -1) { 2925 // We don't know if this really is a huge page or not. 2926 FILE *fp = fopen("/proc/self/maps", "r"); 2927 if (fp) { 2928 while (!feof(fp)) { 2929 char chars[257]; 2930 long x = 0; 2931 if (fgets(chars, sizeof(chars), fp)) { 2932 if (sscanf(chars, "%lx-%*x", &x) == 1 2933 && x == (long)p) { 2934 if (strstr (chars, "hugepage")) { 2935 result = true; 2936 break; 2937 } 2938 } 2939 } 2940 } 2941 fclose(fp); 2942 } 2943 munmap (p, page_size); 2944 if (result) 2945 return true; 2946 } 2947 2948 if (warn) { 2949 warning("HugeTLBFS is not supported by the operating system."); 2950 } 2951 2952 return result; 2953 } 2954 2955 /* 2956 * Set the coredump_filter bits to include largepages in core dump (bit 6) 2957 * 2958 * From the coredump_filter documentation: 2959 * 2960 * - (bit 0) anonymous private memory 2961 * - (bit 1) anonymous shared memory 2962 * - (bit 2) file-backed private memory 2963 * - (bit 3) file-backed shared memory 2964 * - (bit 4) ELF header pages in file-backed private memory areas (it is 2965 * effective only if the bit 2 is cleared) 2966 * - (bit 5) hugetlb private memory 2967 * - (bit 6) hugetlb shared memory 2968 */ 2969 static void set_coredump_filter(void) { 2970 FILE *f; 2971 long cdm; 2972 2973 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 2974 return; 2975 } 2976 2977 if (fscanf(f, "%lx", &cdm) != 1) { 2978 fclose(f); 2979 return; 2980 } 2981 2982 rewind(f); 2983 2984 if ((cdm & LARGEPAGES_BIT) == 0) { 2985 cdm |= LARGEPAGES_BIT; 2986 fprintf(f, "%#lx", cdm); 2987 } 2988 2989 fclose(f); 2990 } 2991 2992 // Large page support 2993 2994 static size_t _large_page_size = 0; 2995 2996 void os::large_page_init() { 2997 if (!UseLargePages) { 2998 UseHugeTLBFS = false; 2999 UseSHM = false; 3000 return; 3001 } 3002 3003 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) { 3004 // If UseLargePages is specified on the command line try both methods, 3005 // if it's default, then try only HugeTLBFS. 3006 if (FLAG_IS_DEFAULT(UseLargePages)) { 3007 UseHugeTLBFS = true; 3008 } else { 3009 UseHugeTLBFS = UseSHM = true; 3010 } 3011 } 3012 3013 if (LargePageSizeInBytes) { 3014 _large_page_size = LargePageSizeInBytes; 3015 } else { 3016 // large_page_size on Linux is used to round up heap size. x86 uses either 3017 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3018 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3019 // page as large as 256M. 3020 // 3021 // Here we try to figure out page size by parsing /proc/meminfo and looking 3022 // for a line with the following format: 3023 // Hugepagesize: 2048 kB 3024 // 3025 // If we can't determine the value (e.g. /proc is not mounted, or the text 3026 // format has been changed), we'll use the largest page size supported by 3027 // the processor. 3028 3029 #ifndef ZERO 3030 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3031 ARM_ONLY(2 * M) PPC_ONLY(4 * M); 3032 #endif // ZERO 3033 3034 FILE *fp = fopen("/proc/meminfo", "r"); 3035 if (fp) { 3036 while (!feof(fp)) { 3037 int x = 0; 3038 char buf[16]; 3039 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3040 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3041 _large_page_size = x * K; 3042 break; 3043 } 3044 } else { 3045 // skip to next line 3046 for (;;) { 3047 int ch = fgetc(fp); 3048 if (ch == EOF || ch == (int)'\n') break; 3049 } 3050 } 3051 } 3052 fclose(fp); 3053 } 3054 } 3055 3056 // print a warning if any large page related flag is specified on command line 3057 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3058 3059 const size_t default_page_size = (size_t)Linux::page_size(); 3060 if (_large_page_size > default_page_size) { 3061 _page_sizes[0] = _large_page_size; 3062 _page_sizes[1] = default_page_size; 3063 _page_sizes[2] = 0; 3064 } 3065 UseHugeTLBFS = UseHugeTLBFS && 3066 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size); 3067 3068 if (UseHugeTLBFS) 3069 UseSHM = false; 3070 3071 UseLargePages = UseHugeTLBFS || UseSHM; 3072 3073 set_coredump_filter(); 3074 } 3075 3076 #ifndef SHM_HUGETLB 3077 #define SHM_HUGETLB 04000 3078 #endif 3079 3080 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) { 3081 // "exec" is passed in but not used. Creating the shared image for 3082 // the code cache doesn't have an SHM_X executable permission to check. 3083 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3084 3085 key_t key = IPC_PRIVATE; 3086 char *addr; 3087 3088 bool warn_on_failure = UseLargePages && 3089 (!FLAG_IS_DEFAULT(UseLargePages) || 3090 !FLAG_IS_DEFAULT(LargePageSizeInBytes) 3091 ); 3092 char msg[128]; 3093 3094 // Create a large shared memory region to attach to based on size. 3095 // Currently, size is the total size of the heap 3096 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3097 if (shmid == -1) { 3098 // Possible reasons for shmget failure: 3099 // 1. shmmax is too small for Java heap. 3100 // > check shmmax value: cat /proc/sys/kernel/shmmax 3101 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3102 // 2. not enough large page memory. 3103 // > check available large pages: cat /proc/meminfo 3104 // > increase amount of large pages: 3105 // echo new_value > /proc/sys/vm/nr_hugepages 3106 // Note 1: different Linux may use different name for this property, 3107 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3108 // Note 2: it's possible there's enough physical memory available but 3109 // they are so fragmented after a long run that they can't 3110 // coalesce into large pages. Try to reserve large pages when 3111 // the system is still "fresh". 3112 if (warn_on_failure) { 3113 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3114 warning(msg); 3115 } 3116 return NULL; 3117 } 3118 3119 // attach to the region 3120 addr = (char*)shmat(shmid, req_addr, 0); 3121 int err = errno; 3122 3123 // Remove shmid. If shmat() is successful, the actual shared memory segment 3124 // will be deleted when it's detached by shmdt() or when the process 3125 // terminates. If shmat() is not successful this will remove the shared 3126 // segment immediately. 3127 shmctl(shmid, IPC_RMID, NULL); 3128 3129 if ((intptr_t)addr == -1) { 3130 if (warn_on_failure) { 3131 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3132 warning(msg); 3133 } 3134 return NULL; 3135 } 3136 3137 if ((addr != NULL) && UseNUMAInterleaving) { 3138 numa_make_global(addr, bytes); 3139 } 3140 3141 return addr; 3142 } 3143 3144 bool os::release_memory_special(char* base, size_t bytes) { 3145 // detaching the SHM segment will also delete it, see reserve_memory_special() 3146 int rslt = shmdt(base); 3147 return rslt == 0; 3148 } 3149 3150 size_t os::large_page_size() { 3151 return _large_page_size; 3152 } 3153 3154 // HugeTLBFS allows application to commit large page memory on demand; 3155 // with SysV SHM the entire memory region must be allocated as shared 3156 // memory. 3157 bool os::can_commit_large_page_memory() { 3158 return UseHugeTLBFS; 3159 } 3160 3161 bool os::can_execute_large_page_memory() { 3162 return UseHugeTLBFS; 3163 } 3164 3165 // Reserve memory at an arbitrary address, only if that area is 3166 // available (and not reserved for something else). 3167 3168 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3169 const int max_tries = 10; 3170 char* base[max_tries]; 3171 size_t size[max_tries]; 3172 const size_t gap = 0x000000; 3173 3174 // Assert only that the size is a multiple of the page size, since 3175 // that's all that mmap requires, and since that's all we really know 3176 // about at this low abstraction level. If we need higher alignment, 3177 // we can either pass an alignment to this method or verify alignment 3178 // in one of the methods further up the call chain. See bug 5044738. 3179 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3180 3181 // Repeatedly allocate blocks until the block is allocated at the 3182 // right spot. Give up after max_tries. Note that reserve_memory() will 3183 // automatically update _highest_vm_reserved_address if the call is 3184 // successful. The variable tracks the highest memory address every reserved 3185 // by JVM. It is used to detect heap-stack collision if running with 3186 // fixed-stack LinuxThreads. Because here we may attempt to reserve more 3187 // space than needed, it could confuse the collision detecting code. To 3188 // solve the problem, save current _highest_vm_reserved_address and 3189 // calculate the correct value before return. 3190 address old_highest = _highest_vm_reserved_address; 3191 3192 // Linux mmap allows caller to pass an address as hint; give it a try first, 3193 // if kernel honors the hint then we can return immediately. 3194 char * addr = anon_mmap(requested_addr, bytes, false); 3195 if (addr == requested_addr) { 3196 return requested_addr; 3197 } 3198 3199 if (addr != NULL) { 3200 // mmap() is successful but it fails to reserve at the requested address 3201 anon_munmap(addr, bytes); 3202 } 3203 3204 int i; 3205 for (i = 0; i < max_tries; ++i) { 3206 base[i] = reserve_memory(bytes); 3207 3208 if (base[i] != NULL) { 3209 // Is this the block we wanted? 3210 if (base[i] == requested_addr) { 3211 size[i] = bytes; 3212 break; 3213 } 3214 3215 // Does this overlap the block we wanted? Give back the overlapped 3216 // parts and try again. 3217 3218 size_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3219 if (top_overlap >= 0 && top_overlap < bytes) { 3220 unmap_memory(base[i], top_overlap); 3221 base[i] += top_overlap; 3222 size[i] = bytes - top_overlap; 3223 } else { 3224 size_t bottom_overlap = base[i] + bytes - requested_addr; 3225 if (bottom_overlap >= 0 && bottom_overlap < bytes) { 3226 unmap_memory(requested_addr, bottom_overlap); 3227 size[i] = bytes - bottom_overlap; 3228 } else { 3229 size[i] = bytes; 3230 } 3231 } 3232 } 3233 } 3234 3235 // Give back the unused reserved pieces. 3236 3237 for (int j = 0; j < i; ++j) { 3238 if (base[j] != NULL) { 3239 unmap_memory(base[j], size[j]); 3240 } 3241 } 3242 3243 if (i < max_tries) { 3244 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes); 3245 return requested_addr; 3246 } else { 3247 _highest_vm_reserved_address = old_highest; 3248 return NULL; 3249 } 3250 } 3251 3252 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3253 return ::read(fd, buf, nBytes); 3254 } 3255 3256 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation. 3257 // Solaris uses poll(), linux uses park(). 3258 // Poll() is likely a better choice, assuming that Thread.interrupt() 3259 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with 3260 // SIGSEGV, see 4355769. 3261 3262 const int NANOSECS_PER_MILLISECS = 1000000; 3263 3264 int os::sleep(Thread* thread, jlong millis, bool interruptible) { 3265 assert(thread == Thread::current(), "thread consistency check"); 3266 3267 ParkEvent * const slp = thread->_SleepEvent ; 3268 slp->reset() ; 3269 OrderAccess::fence() ; 3270 3271 if (interruptible) { 3272 jlong prevtime = javaTimeNanos(); 3273 3274 for (;;) { 3275 if (os::is_interrupted(thread, true)) { 3276 return OS_INTRPT; 3277 } 3278 3279 jlong newtime = javaTimeNanos(); 3280 3281 if (newtime - prevtime < 0) { 3282 // time moving backwards, should only happen if no monotonic clock 3283 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3284 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3285 } else { 3286 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3287 } 3288 3289 if(millis <= 0) { 3290 return OS_OK; 3291 } 3292 3293 prevtime = newtime; 3294 3295 { 3296 assert(thread->is_Java_thread(), "sanity check"); 3297 JavaThread *jt = (JavaThread *) thread; 3298 ThreadBlockInVM tbivm(jt); 3299 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */); 3300 3301 jt->set_suspend_equivalent(); 3302 // cleared by handle_special_suspend_equivalent_condition() or 3303 // java_suspend_self() via check_and_wait_while_suspended() 3304 3305 slp->park(millis); 3306 3307 // were we externally suspended while we were waiting? 3308 jt->check_and_wait_while_suspended(); 3309 } 3310 } 3311 } else { 3312 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 3313 jlong prevtime = javaTimeNanos(); 3314 3315 for (;;) { 3316 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on 3317 // the 1st iteration ... 3318 jlong newtime = javaTimeNanos(); 3319 3320 if (newtime - prevtime < 0) { 3321 // time moving backwards, should only happen if no monotonic clock 3322 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3323 assert(!Linux::supports_monotonic_clock(), "time moving backwards"); 3324 } else { 3325 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS; 3326 } 3327 3328 if(millis <= 0) break ; 3329 3330 prevtime = newtime; 3331 slp->park(millis); 3332 } 3333 return OS_OK ; 3334 } 3335 } 3336 3337 int os::naked_sleep() { 3338 // %% make the sleep time an integer flag. for now use 1 millisec. 3339 return os::sleep(Thread::current(), 1, false); 3340 } 3341 3342 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3343 void os::infinite_sleep() { 3344 while (true) { // sleep forever ... 3345 ::sleep(100); // ... 100 seconds at a time 3346 } 3347 } 3348 3349 // Used to convert frequent JVM_Yield() to nops 3350 bool os::dont_yield() { 3351 return DontYieldALot; 3352 } 3353 3354 void os::yield() { 3355 sched_yield(); 3356 } 3357 3358 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;} 3359 3360 void os::yield_all(int attempts) { 3361 // Yields to all threads, including threads with lower priorities 3362 // Threads on Linux are all with same priority. The Solaris style 3363 // os::yield_all() with nanosleep(1ms) is not necessary. 3364 sched_yield(); 3365 } 3366 3367 // Called from the tight loops to possibly influence time-sharing heuristics 3368 void os::loop_breaker(int attempts) { 3369 os::yield_all(attempts); 3370 } 3371 3372 //////////////////////////////////////////////////////////////////////////////// 3373 // thread priority support 3374 3375 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3376 // only supports dynamic priority, static priority must be zero. For real-time 3377 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3378 // However, for large multi-threaded applications, SCHED_RR is not only slower 3379 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3380 // of 5 runs - Sep 2005). 3381 // 3382 // The following code actually changes the niceness of kernel-thread/LWP. It 3383 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3384 // not the entire user process, and user level threads are 1:1 mapped to kernel 3385 // threads. It has always been the case, but could change in the future. For 3386 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3387 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3388 3389 int os::java_to_os_priority[MaxPriority + 1] = { 3390 19, // 0 Entry should never be used 3391 3392 4, // 1 MinPriority 3393 3, // 2 3394 2, // 3 3395 3396 1, // 4 3397 0, // 5 NormPriority 3398 -1, // 6 3399 3400 -2, // 7 3401 -3, // 8 3402 -4, // 9 NearMaxPriority 3403 3404 -5 // 10 MaxPriority 3405 }; 3406 3407 static int prio_init() { 3408 if (ThreadPriorityPolicy == 1) { 3409 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3410 // if effective uid is not root. Perhaps, a more elegant way of doing 3411 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3412 if (geteuid() != 0) { 3413 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3414 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3415 } 3416 ThreadPriorityPolicy = 0; 3417 } 3418 } 3419 return 0; 3420 } 3421 3422 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3423 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK; 3424 3425 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3426 return (ret == 0) ? OS_OK : OS_ERR; 3427 } 3428 3429 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) { 3430 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) { 3431 *priority_ptr = java_to_os_priority[NormPriority]; 3432 return OS_OK; 3433 } 3434 3435 errno = 0; 3436 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3437 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3438 } 3439 3440 // Hint to the underlying OS that a task switch would not be good. 3441 // Void return because it's a hint and can fail. 3442 void os::hint_no_preempt() {} 3443 3444 //////////////////////////////////////////////////////////////////////////////// 3445 // suspend/resume support 3446 3447 // the low-level signal-based suspend/resume support is a remnant from the 3448 // old VM-suspension that used to be for java-suspension, safepoints etc, 3449 // within hotspot. Now there is a single use-case for this: 3450 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3451 // that runs in the watcher thread. 3452 // The remaining code is greatly simplified from the more general suspension 3453 // code that used to be used. 3454 // 3455 // The protocol is quite simple: 3456 // - suspend: 3457 // - sends a signal to the target thread 3458 // - polls the suspend state of the osthread using a yield loop 3459 // - target thread signal handler (SR_handler) sets suspend state 3460 // and blocks in sigsuspend until continued 3461 // - resume: 3462 // - sets target osthread state to continue 3463 // - sends signal to end the sigsuspend loop in the SR_handler 3464 // 3465 // Note that the SR_lock plays no role in this suspend/resume protocol. 3466 // 3467 3468 static void resume_clear_context(OSThread *osthread) { 3469 osthread->set_ucontext(NULL); 3470 osthread->set_siginfo(NULL); 3471 3472 // notify the suspend action is completed, we have now resumed 3473 osthread->sr.clear_suspended(); 3474 } 3475 3476 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) { 3477 osthread->set_ucontext(context); 3478 osthread->set_siginfo(siginfo); 3479 } 3480 3481 // 3482 // Handler function invoked when a thread's execution is suspended or 3483 // resumed. We have to be careful that only async-safe functions are 3484 // called here (Note: most pthread functions are not async safe and 3485 // should be avoided.) 3486 // 3487 // Note: sigwait() is a more natural fit than sigsuspend() from an 3488 // interface point of view, but sigwait() prevents the signal hander 3489 // from being run. libpthread would get very confused by not having 3490 // its signal handlers run and prevents sigwait()'s use with the 3491 // mutex granting granting signal. 3492 // 3493 // Currently only ever called on the VMThread 3494 // 3495 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3496 // Save and restore errno to avoid confusing native code with EINTR 3497 // after sigsuspend. 3498 int old_errno = errno; 3499 3500 Thread* thread = Thread::current(); 3501 OSThread* osthread = thread->osthread(); 3502 assert(thread->is_VM_thread(), "Must be VMThread"); 3503 // read current suspend action 3504 int action = osthread->sr.suspend_action(); 3505 if (action == SR_SUSPEND) { 3506 suspend_save_context(osthread, siginfo, context); 3507 3508 // Notify the suspend action is about to be completed. do_suspend() 3509 // waits until SR_SUSPENDED is set and then returns. We will wait 3510 // here for a resume signal and that completes the suspend-other 3511 // action. do_suspend/do_resume is always called as a pair from 3512 // the same thread - so there are no races 3513 3514 // notify the caller 3515 osthread->sr.set_suspended(); 3516 3517 sigset_t suspend_set; // signals for sigsuspend() 3518 3519 // get current set of blocked signals and unblock resume signal 3520 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3521 sigdelset(&suspend_set, SR_signum); 3522 3523 // wait here until we are resumed 3524 do { 3525 sigsuspend(&suspend_set); 3526 // ignore all returns until we get a resume signal 3527 } while (osthread->sr.suspend_action() != SR_CONTINUE); 3528 3529 resume_clear_context(osthread); 3530 3531 } else { 3532 assert(action == SR_CONTINUE, "unexpected sr action"); 3533 // nothing special to do - just leave the handler 3534 } 3535 3536 errno = old_errno; 3537 } 3538 3539 3540 static int SR_initialize() { 3541 struct sigaction act; 3542 char *s; 3543 /* Get signal number to use for suspend/resume */ 3544 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3545 int sig = ::strtol(s, 0, 10); 3546 if (sig > 0 || sig < _NSIG) { 3547 SR_signum = sig; 3548 } 3549 } 3550 3551 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 3552 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 3553 3554 sigemptyset(&SR_sigset); 3555 sigaddset(&SR_sigset, SR_signum); 3556 3557 /* Set up signal handler for suspend/resume */ 3558 act.sa_flags = SA_RESTART|SA_SIGINFO; 3559 act.sa_handler = (void (*)(int)) SR_handler; 3560 3561 // SR_signum is blocked by default. 3562 // 4528190 - We also need to block pthread restart signal (32 on all 3563 // supported Linux platforms). Note that LinuxThreads need to block 3564 // this signal for all threads to work properly. So we don't have 3565 // to use hard-coded signal number when setting up the mask. 3566 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 3567 3568 if (sigaction(SR_signum, &act, 0) == -1) { 3569 return -1; 3570 } 3571 3572 // Save signal flag 3573 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 3574 return 0; 3575 } 3576 3577 static int SR_finalize() { 3578 return 0; 3579 } 3580 3581 3582 // returns true on success and false on error - really an error is fatal 3583 // but this seems the normal response to library errors 3584 static bool do_suspend(OSThread* osthread) { 3585 // mark as suspended and send signal 3586 osthread->sr.set_suspend_action(SR_SUSPEND); 3587 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3588 assert_status(status == 0, status, "pthread_kill"); 3589 3590 // check status and wait until notified of suspension 3591 if (status == 0) { 3592 for (int i = 0; !osthread->sr.is_suspended(); i++) { 3593 os::yield_all(i); 3594 } 3595 osthread->sr.set_suspend_action(SR_NONE); 3596 return true; 3597 } 3598 else { 3599 osthread->sr.set_suspend_action(SR_NONE); 3600 return false; 3601 } 3602 } 3603 3604 static void do_resume(OSThread* osthread) { 3605 assert(osthread->sr.is_suspended(), "thread should be suspended"); 3606 osthread->sr.set_suspend_action(SR_CONTINUE); 3607 3608 int status = pthread_kill(osthread->pthread_id(), SR_signum); 3609 assert_status(status == 0, status, "pthread_kill"); 3610 // check status and wait unit notified of resumption 3611 if (status == 0) { 3612 for (int i = 0; osthread->sr.is_suspended(); i++) { 3613 os::yield_all(i); 3614 } 3615 } 3616 osthread->sr.set_suspend_action(SR_NONE); 3617 } 3618 3619 //////////////////////////////////////////////////////////////////////////////// 3620 // interrupt support 3621 3622 void os::interrupt(Thread* thread) { 3623 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3624 "possibility of dangling Thread pointer"); 3625 3626 OSThread* osthread = thread->osthread(); 3627 3628 if (!osthread->interrupted()) { 3629 osthread->set_interrupted(true); 3630 // More than one thread can get here with the same value of osthread, 3631 // resulting in multiple notifications. We do, however, want the store 3632 // to interrupted() to be visible to other threads before we execute unpark(). 3633 OrderAccess::fence(); 3634 ParkEvent * const slp = thread->_SleepEvent ; 3635 if (slp != NULL) slp->unpark() ; 3636 } 3637 3638 // For JSR166. Unpark even if interrupt status already was set 3639 if (thread->is_Java_thread()) 3640 ((JavaThread*)thread)->parker()->unpark(); 3641 3642 ParkEvent * ev = thread->_ParkEvent ; 3643 if (ev != NULL) ev->unpark() ; 3644 3645 } 3646 3647 bool os::is_interrupted(Thread* thread, bool clear_interrupted) { 3648 assert(Thread::current() == thread || Threads_lock->owned_by_self(), 3649 "possibility of dangling Thread pointer"); 3650 3651 OSThread* osthread = thread->osthread(); 3652 3653 bool interrupted = osthread->interrupted(); 3654 3655 if (interrupted && clear_interrupted) { 3656 osthread->set_interrupted(false); 3657 // consider thread->_SleepEvent->reset() ... optional optimization 3658 } 3659 3660 return interrupted; 3661 } 3662 3663 /////////////////////////////////////////////////////////////////////////////////// 3664 // signal handling (except suspend/resume) 3665 3666 // This routine may be used by user applications as a "hook" to catch signals. 3667 // The user-defined signal handler must pass unrecognized signals to this 3668 // routine, and if it returns true (non-zero), then the signal handler must 3669 // return immediately. If the flag "abort_if_unrecognized" is true, then this 3670 // routine will never retun false (zero), but instead will execute a VM panic 3671 // routine kill the process. 3672 // 3673 // If this routine returns false, it is OK to call it again. This allows 3674 // the user-defined signal handler to perform checks either before or after 3675 // the VM performs its own checks. Naturally, the user code would be making 3676 // a serious error if it tried to handle an exception (such as a null check 3677 // or breakpoint) that the VM was generating for its own correct operation. 3678 // 3679 // This routine may recognize any of the following kinds of signals: 3680 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 3681 // It should be consulted by handlers for any of those signals. 3682 // 3683 // The caller of this routine must pass in the three arguments supplied 3684 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 3685 // field of the structure passed to sigaction(). This routine assumes that 3686 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 3687 // 3688 // Note that the VM will print warnings if it detects conflicting signal 3689 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 3690 // 3691 extern "C" JNIEXPORT int 3692 JVM_handle_linux_signal(int signo, siginfo_t* siginfo, 3693 void* ucontext, int abort_if_unrecognized); 3694 3695 void signalHandler(int sig, siginfo_t* info, void* uc) { 3696 assert(info != NULL && uc != NULL, "it must be old kernel"); 3697 JVM_handle_linux_signal(sig, info, uc, true); 3698 } 3699 3700 3701 // This boolean allows users to forward their own non-matching signals 3702 // to JVM_handle_linux_signal, harmlessly. 3703 bool os::Linux::signal_handlers_are_installed = false; 3704 3705 // For signal-chaining 3706 struct sigaction os::Linux::sigact[MAXSIGNUM]; 3707 unsigned int os::Linux::sigs = 0; 3708 bool os::Linux::libjsig_is_loaded = false; 3709 typedef struct sigaction *(*get_signal_t)(int); 3710 get_signal_t os::Linux::get_signal_action = NULL; 3711 3712 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 3713 struct sigaction *actp = NULL; 3714 3715 if (libjsig_is_loaded) { 3716 // Retrieve the old signal handler from libjsig 3717 actp = (*get_signal_action)(sig); 3718 } 3719 if (actp == NULL) { 3720 // Retrieve the preinstalled signal handler from jvm 3721 actp = get_preinstalled_handler(sig); 3722 } 3723 3724 return actp; 3725 } 3726 3727 static bool call_chained_handler(struct sigaction *actp, int sig, 3728 siginfo_t *siginfo, void *context) { 3729 // Call the old signal handler 3730 if (actp->sa_handler == SIG_DFL) { 3731 // It's more reasonable to let jvm treat it as an unexpected exception 3732 // instead of taking the default action. 3733 return false; 3734 } else if (actp->sa_handler != SIG_IGN) { 3735 if ((actp->sa_flags & SA_NODEFER) == 0) { 3736 // automaticlly block the signal 3737 sigaddset(&(actp->sa_mask), sig); 3738 } 3739 3740 sa_handler_t hand; 3741 sa_sigaction_t sa; 3742 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 3743 // retrieve the chained handler 3744 if (siginfo_flag_set) { 3745 sa = actp->sa_sigaction; 3746 } else { 3747 hand = actp->sa_handler; 3748 } 3749 3750 if ((actp->sa_flags & SA_RESETHAND) != 0) { 3751 actp->sa_handler = SIG_DFL; 3752 } 3753 3754 // try to honor the signal mask 3755 sigset_t oset; 3756 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 3757 3758 // call into the chained handler 3759 if (siginfo_flag_set) { 3760 (*sa)(sig, siginfo, context); 3761 } else { 3762 (*hand)(sig); 3763 } 3764 3765 // restore the signal mask 3766 pthread_sigmask(SIG_SETMASK, &oset, 0); 3767 } 3768 // Tell jvm's signal handler the signal is taken care of. 3769 return true; 3770 } 3771 3772 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 3773 bool chained = false; 3774 // signal-chaining 3775 if (UseSignalChaining) { 3776 struct sigaction *actp = get_chained_signal_action(sig); 3777 if (actp != NULL) { 3778 chained = call_chained_handler(actp, sig, siginfo, context); 3779 } 3780 } 3781 return chained; 3782 } 3783 3784 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 3785 if ((( (unsigned int)1 << sig ) & sigs) != 0) { 3786 return &sigact[sig]; 3787 } 3788 return NULL; 3789 } 3790 3791 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 3792 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3793 sigact[sig] = oldAct; 3794 sigs |= (unsigned int)1 << sig; 3795 } 3796 3797 // for diagnostic 3798 int os::Linux::sigflags[MAXSIGNUM]; 3799 3800 int os::Linux::get_our_sigflags(int sig) { 3801 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3802 return sigflags[sig]; 3803 } 3804 3805 void os::Linux::set_our_sigflags(int sig, int flags) { 3806 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3807 sigflags[sig] = flags; 3808 } 3809 3810 void os::Linux::set_signal_handler(int sig, bool set_installed) { 3811 // Check for overwrite. 3812 struct sigaction oldAct; 3813 sigaction(sig, (struct sigaction*)NULL, &oldAct); 3814 3815 void* oldhand = oldAct.sa_sigaction 3816 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3817 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3818 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 3819 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 3820 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 3821 if (AllowUserSignalHandlers || !set_installed) { 3822 // Do not overwrite; user takes responsibility to forward to us. 3823 return; 3824 } else if (UseSignalChaining) { 3825 // save the old handler in jvm 3826 save_preinstalled_handler(sig, oldAct); 3827 // libjsig also interposes the sigaction() call below and saves the 3828 // old sigaction on it own. 3829 } else { 3830 fatal(err_msg("Encountered unexpected pre-existing sigaction handler " 3831 "%#lx for signal %d.", (long)oldhand, sig)); 3832 } 3833 } 3834 3835 struct sigaction sigAct; 3836 sigfillset(&(sigAct.sa_mask)); 3837 sigAct.sa_handler = SIG_DFL; 3838 if (!set_installed) { 3839 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3840 } else { 3841 sigAct.sa_sigaction = signalHandler; 3842 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 3843 } 3844 // Save flags, which are set by ours 3845 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range"); 3846 sigflags[sig] = sigAct.sa_flags; 3847 3848 int ret = sigaction(sig, &sigAct, &oldAct); 3849 assert(ret == 0, "check"); 3850 3851 void* oldhand2 = oldAct.sa_sigaction 3852 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 3853 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 3854 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 3855 } 3856 3857 // install signal handlers for signals that HotSpot needs to 3858 // handle in order to support Java-level exception handling. 3859 3860 void os::Linux::install_signal_handlers() { 3861 if (!signal_handlers_are_installed) { 3862 signal_handlers_are_installed = true; 3863 3864 // signal-chaining 3865 typedef void (*signal_setting_t)(); 3866 signal_setting_t begin_signal_setting = NULL; 3867 signal_setting_t end_signal_setting = NULL; 3868 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3869 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 3870 if (begin_signal_setting != NULL) { 3871 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 3872 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 3873 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 3874 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 3875 libjsig_is_loaded = true; 3876 assert(UseSignalChaining, "should enable signal-chaining"); 3877 } 3878 if (libjsig_is_loaded) { 3879 // Tell libjsig jvm is setting signal handlers 3880 (*begin_signal_setting)(); 3881 } 3882 3883 set_signal_handler(SIGSEGV, true); 3884 set_signal_handler(SIGPIPE, true); 3885 set_signal_handler(SIGBUS, true); 3886 set_signal_handler(SIGILL, true); 3887 set_signal_handler(SIGFPE, true); 3888 set_signal_handler(SIGXFSZ, true); 3889 3890 if (libjsig_is_loaded) { 3891 // Tell libjsig jvm finishes setting signal handlers 3892 (*end_signal_setting)(); 3893 } 3894 3895 // We don't activate signal checker if libjsig is in place, we trust ourselves 3896 // and if UserSignalHandler is installed all bets are off. 3897 // Log that signal checking is off only if -verbose:jni is specified. 3898 if (CheckJNICalls) { 3899 if (libjsig_is_loaded) { 3900 if (PrintJNIResolving) { 3901 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 3902 } 3903 check_signals = false; 3904 } 3905 if (AllowUserSignalHandlers) { 3906 if (PrintJNIResolving) { 3907 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 3908 } 3909 check_signals = false; 3910 } 3911 } 3912 } 3913 } 3914 3915 // This is the fastest way to get thread cpu time on Linux. 3916 // Returns cpu time (user+sys) for any thread, not only for current. 3917 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 3918 // It might work on 2.6.10+ with a special kernel/glibc patch. 3919 // For reference, please, see IEEE Std 1003.1-2004: 3920 // http://www.unix.org/single_unix_specification 3921 3922 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 3923 struct timespec tp; 3924 int rc = os::Linux::clock_gettime(clockid, &tp); 3925 assert(rc == 0, "clock_gettime is expected to return 0 code"); 3926 3927 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec; 3928 } 3929 3930 ///// 3931 // glibc on Linux platform uses non-documented flag 3932 // to indicate, that some special sort of signal 3933 // trampoline is used. 3934 // We will never set this flag, and we should 3935 // ignore this flag in our diagnostic 3936 #ifdef SIGNIFICANT_SIGNAL_MASK 3937 #undef SIGNIFICANT_SIGNAL_MASK 3938 #endif 3939 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 3940 3941 static const char* get_signal_handler_name(address handler, 3942 char* buf, int buflen) { 3943 int offset; 3944 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 3945 if (found) { 3946 // skip directory names 3947 const char *p1, *p2; 3948 p1 = buf; 3949 size_t len = strlen(os::file_separator()); 3950 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 3951 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 3952 } else { 3953 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 3954 } 3955 return buf; 3956 } 3957 3958 static void print_signal_handler(outputStream* st, int sig, 3959 char* buf, size_t buflen) { 3960 struct sigaction sa; 3961 3962 sigaction(sig, NULL, &sa); 3963 3964 // See comment for SIGNIFICANT_SIGNAL_MASK define 3965 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 3966 3967 st->print("%s: ", os::exception_name(sig, buf, buflen)); 3968 3969 address handler = (sa.sa_flags & SA_SIGINFO) 3970 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 3971 : CAST_FROM_FN_PTR(address, sa.sa_handler); 3972 3973 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 3974 st->print("SIG_DFL"); 3975 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 3976 st->print("SIG_IGN"); 3977 } else { 3978 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 3979 } 3980 3981 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask); 3982 3983 address rh = VMError::get_resetted_sighandler(sig); 3984 // May be, handler was resetted by VMError? 3985 if(rh != NULL) { 3986 handler = rh; 3987 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 3988 } 3989 3990 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags); 3991 3992 // Check: is it our handler? 3993 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 3994 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 3995 // It is our signal handler 3996 // check for flags, reset system-used one! 3997 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 3998 st->print( 3999 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4000 os::Linux::get_our_sigflags(sig)); 4001 } 4002 } 4003 st->cr(); 4004 } 4005 4006 4007 #define DO_SIGNAL_CHECK(sig) \ 4008 if (!sigismember(&check_signal_done, sig)) \ 4009 os::Linux::check_signal_handler(sig) 4010 4011 // This method is a periodic task to check for misbehaving JNI applications 4012 // under CheckJNI, we can add any periodic checks here 4013 4014 void os::run_periodic_checks() { 4015 4016 if (check_signals == false) return; 4017 4018 // SEGV and BUS if overridden could potentially prevent 4019 // generation of hs*.log in the event of a crash, debugging 4020 // such a case can be very challenging, so we absolutely 4021 // check the following for a good measure: 4022 DO_SIGNAL_CHECK(SIGSEGV); 4023 DO_SIGNAL_CHECK(SIGILL); 4024 DO_SIGNAL_CHECK(SIGFPE); 4025 DO_SIGNAL_CHECK(SIGBUS); 4026 DO_SIGNAL_CHECK(SIGPIPE); 4027 DO_SIGNAL_CHECK(SIGXFSZ); 4028 4029 4030 // ReduceSignalUsage allows the user to override these handlers 4031 // see comments at the very top and jvm_solaris.h 4032 if (!ReduceSignalUsage) { 4033 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4034 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4035 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4036 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4037 } 4038 4039 DO_SIGNAL_CHECK(SR_signum); 4040 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL); 4041 } 4042 4043 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4044 4045 static os_sigaction_t os_sigaction = NULL; 4046 4047 void os::Linux::check_signal_handler(int sig) { 4048 char buf[O_BUFLEN]; 4049 address jvmHandler = NULL; 4050 4051 4052 struct sigaction act; 4053 if (os_sigaction == NULL) { 4054 // only trust the default sigaction, in case it has been interposed 4055 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4056 if (os_sigaction == NULL) return; 4057 } 4058 4059 os_sigaction(sig, (struct sigaction*)NULL, &act); 4060 4061 4062 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4063 4064 address thisHandler = (act.sa_flags & SA_SIGINFO) 4065 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4066 : CAST_FROM_FN_PTR(address, act.sa_handler) ; 4067 4068 4069 switch(sig) { 4070 case SIGSEGV: 4071 case SIGBUS: 4072 case SIGFPE: 4073 case SIGPIPE: 4074 case SIGILL: 4075 case SIGXFSZ: 4076 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4077 break; 4078 4079 case SHUTDOWN1_SIGNAL: 4080 case SHUTDOWN2_SIGNAL: 4081 case SHUTDOWN3_SIGNAL: 4082 case BREAK_SIGNAL: 4083 jvmHandler = (address)user_handler(); 4084 break; 4085 4086 case INTERRUPT_SIGNAL: 4087 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL); 4088 break; 4089 4090 default: 4091 if (sig == SR_signum) { 4092 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4093 } else { 4094 return; 4095 } 4096 break; 4097 } 4098 4099 if (thisHandler != jvmHandler) { 4100 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4101 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4102 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4103 // No need to check this sig any longer 4104 sigaddset(&check_signal_done, sig); 4105 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4106 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4107 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4108 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4109 // No need to check this sig any longer 4110 sigaddset(&check_signal_done, sig); 4111 } 4112 4113 // Dump all the signal 4114 if (sigismember(&check_signal_done, sig)) { 4115 print_signal_handlers(tty, buf, O_BUFLEN); 4116 } 4117 } 4118 4119 extern void report_error(char* file_name, int line_no, char* title, char* format, ...); 4120 4121 extern bool signal_name(int signo, char* buf, size_t len); 4122 4123 const char* os::exception_name(int exception_code, char* buf, size_t size) { 4124 if (0 < exception_code && exception_code <= SIGRTMAX) { 4125 // signal 4126 if (!signal_name(exception_code, buf, size)) { 4127 jio_snprintf(buf, size, "SIG%d", exception_code); 4128 } 4129 return buf; 4130 } else { 4131 return NULL; 4132 } 4133 } 4134 4135 // this is called _before_ the most of global arguments have been parsed 4136 void os::init(void) { 4137 char dummy; /* used to get a guess on initial stack address */ 4138 // first_hrtime = gethrtime(); 4139 4140 // With LinuxThreads the JavaMain thread pid (primordial thread) 4141 // is different than the pid of the java launcher thread. 4142 // So, on Linux, the launcher thread pid is passed to the VM 4143 // via the sun.java.launcher.pid property. 4144 // Use this property instead of getpid() if it was correctly passed. 4145 // See bug 6351349. 4146 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid(); 4147 4148 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid(); 4149 4150 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4151 4152 init_random(1234567); 4153 4154 ThreadCritical::initialize(); 4155 4156 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4157 if (Linux::page_size() == -1) { 4158 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)", 4159 strerror(errno))); 4160 } 4161 init_page_sizes((size_t) Linux::page_size()); 4162 4163 Linux::initialize_system_info(); 4164 4165 // main_thread points to the aboriginal thread 4166 Linux::_main_thread = pthread_self(); 4167 4168 Linux::clock_init(); 4169 initial_time_count = os::elapsed_counter(); 4170 pthread_mutex_init(&dl_mutex, NULL); 4171 } 4172 4173 // To install functions for atexit system call 4174 extern "C" { 4175 static void perfMemory_exit_helper() { 4176 perfMemory_exit(); 4177 } 4178 } 4179 4180 // this is called _after_ the global arguments have been parsed 4181 jint os::init_2(void) 4182 { 4183 Linux::fast_thread_clock_init(); 4184 4185 // Allocate a single page and mark it as readable for safepoint polling 4186 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4187 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" ); 4188 4189 os::set_polling_page( polling_page ); 4190 4191 #ifndef PRODUCT 4192 if(Verbose && PrintMiscellaneous) 4193 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page); 4194 #endif 4195 4196 if (!UseMembar) { 4197 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4198 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page"); 4199 os::set_memory_serialize_page( mem_serialize_page ); 4200 4201 #ifndef PRODUCT 4202 if(Verbose && PrintMiscellaneous) 4203 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page); 4204 #endif 4205 } 4206 4207 os::large_page_init(); 4208 4209 // initialize suspend/resume support - must do this before signal_sets_init() 4210 if (SR_initialize() != 0) { 4211 perror("SR_initialize failed"); 4212 return JNI_ERR; 4213 } 4214 4215 Linux::signal_sets_init(); 4216 Linux::install_signal_handlers(); 4217 4218 // Check minimum allowable stack size for thread creation and to initialize 4219 // the java system classes, including StackOverflowError - depends on page 4220 // size. Add a page for compiler2 recursion in main thread. 4221 // Add in 2*BytesPerWord times page size to account for VM stack during 4222 // class initialization depending on 32 or 64 bit VM. 4223 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4224 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+ 4225 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size()); 4226 4227 size_t threadStackSizeInBytes = ThreadStackSize * K; 4228 if (threadStackSizeInBytes != 0 && 4229 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4230 tty->print_cr("\nThe stack size specified is too small, " 4231 "Specify at least %dk", 4232 os::Linux::min_stack_allowed/ K); 4233 return JNI_ERR; 4234 } 4235 4236 // Make the stack size a multiple of the page size so that 4237 // the yellow/red zones can be guarded. 4238 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4239 vm_page_size())); 4240 4241 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4242 4243 Linux::libpthread_init(); 4244 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4245 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n", 4246 Linux::glibc_version(), Linux::libpthread_version(), 4247 Linux::is_floating_stack() ? "floating stack" : "fixed stack"); 4248 } 4249 4250 if (UseNUMA) { 4251 if (!Linux::libnuma_init()) { 4252 UseNUMA = false; 4253 } else { 4254 if ((Linux::numa_max_node() < 1)) { 4255 // There's only one node(they start from 0), disable NUMA. 4256 UseNUMA = false; 4257 } 4258 } 4259 // With SHM large pages we cannot uncommit a page, so there's not way 4260 // we can make the adaptive lgrp chunk resizing work. If the user specified 4261 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and 4262 // disable adaptive resizing. 4263 if (UseNUMA && UseLargePages && UseSHM) { 4264 if (!FLAG_IS_DEFAULT(UseNUMA)) { 4265 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) { 4266 UseLargePages = false; 4267 } else { 4268 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing"); 4269 UseAdaptiveSizePolicy = false; 4270 UseAdaptiveNUMAChunkSizing = false; 4271 } 4272 } else { 4273 UseNUMA = false; 4274 } 4275 } 4276 if (!UseNUMA && ForceNUMA) { 4277 UseNUMA = true; 4278 } 4279 } 4280 4281 if (MaxFDLimit) { 4282 // set the number of file descriptors to max. print out error 4283 // if getrlimit/setrlimit fails but continue regardless. 4284 struct rlimit nbr_files; 4285 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4286 if (status != 0) { 4287 if (PrintMiscellaneous && (Verbose || WizardMode)) 4288 perror("os::init_2 getrlimit failed"); 4289 } else { 4290 nbr_files.rlim_cur = nbr_files.rlim_max; 4291 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4292 if (status != 0) { 4293 if (PrintMiscellaneous && (Verbose || WizardMode)) 4294 perror("os::init_2 setrlimit failed"); 4295 } 4296 } 4297 } 4298 4299 // Initialize lock used to serialize thread creation (see os::create_thread) 4300 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4301 4302 // at-exit methods are called in the reverse order of their registration. 4303 // atexit functions are called on return from main or as a result of a 4304 // call to exit(3C). There can be only 32 of these functions registered 4305 // and atexit() does not set errno. 4306 4307 if (PerfAllowAtExitRegistration) { 4308 // only register atexit functions if PerfAllowAtExitRegistration is set. 4309 // atexit functions can be delayed until process exit time, which 4310 // can be problematic for embedded VM situations. Embedded VMs should 4311 // call DestroyJavaVM() to assure that VM resources are released. 4312 4313 // note: perfMemory_exit_helper atexit function may be removed in 4314 // the future if the appropriate cleanup code can be added to the 4315 // VM_Exit VMOperation's doit method. 4316 if (atexit(perfMemory_exit_helper) != 0) { 4317 warning("os::init2 atexit(perfMemory_exit_helper) failed"); 4318 } 4319 } 4320 4321 // initialize thread priority policy 4322 prio_init(); 4323 4324 return JNI_OK; 4325 } 4326 4327 // this is called at the end of vm_initialization 4328 void os::init_3(void) 4329 { 4330 #ifdef JAVASE_EMBEDDED 4331 // Start the MemNotifyThread 4332 if (LowMemoryProtection) { 4333 MemNotifyThread::start(); 4334 } 4335 return; 4336 #endif 4337 } 4338 4339 // Mark the polling page as unreadable 4340 void os::make_polling_page_unreadable(void) { 4341 if( !guard_memory((char*)_polling_page, Linux::page_size()) ) 4342 fatal("Could not disable polling page"); 4343 }; 4344 4345 // Mark the polling page as readable 4346 void os::make_polling_page_readable(void) { 4347 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4348 fatal("Could not enable polling page"); 4349 } 4350 }; 4351 4352 int os::active_processor_count() { 4353 // Linux doesn't yet have a (official) notion of processor sets, 4354 // so just return the number of online processors. 4355 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4356 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4357 return online_cpus; 4358 } 4359 4360 bool os::distribute_processes(uint length, uint* distribution) { 4361 // Not yet implemented. 4362 return false; 4363 } 4364 4365 bool os::bind_to_processor(uint processor_id) { 4366 // Not yet implemented. 4367 return false; 4368 } 4369 4370 /// 4371 4372 // Suspends the target using the signal mechanism and then grabs the PC before 4373 // resuming the target. Used by the flat-profiler only 4374 ExtendedPC os::get_thread_pc(Thread* thread) { 4375 // Make sure that it is called by the watcher for the VMThread 4376 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4377 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4378 4379 ExtendedPC epc; 4380 4381 OSThread* osthread = thread->osthread(); 4382 if (do_suspend(osthread)) { 4383 if (osthread->ucontext() != NULL) { 4384 epc = os::Linux::ucontext_get_pc(osthread->ucontext()); 4385 } else { 4386 // NULL context is unexpected, double-check this is the VMThread 4387 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4388 } 4389 do_resume(osthread); 4390 } 4391 // failure means pthread_kill failed for some reason - arguably this is 4392 // a fatal problem, but such problems are ignored elsewhere 4393 4394 return epc; 4395 } 4396 4397 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime) 4398 { 4399 if (is_NPTL()) { 4400 return pthread_cond_timedwait(_cond, _mutex, _abstime); 4401 } else { 4402 #ifndef IA64 4403 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control 4404 // word back to default 64bit precision if condvar is signaled. Java 4405 // wants 53bit precision. Save and restore current value. 4406 int fpu = get_fpu_control_word(); 4407 #endif // IA64 4408 int status = pthread_cond_timedwait(_cond, _mutex, _abstime); 4409 #ifndef IA64 4410 set_fpu_control_word(fpu); 4411 #endif // IA64 4412 return status; 4413 } 4414 } 4415 4416 //////////////////////////////////////////////////////////////////////////////// 4417 // debug support 4418 4419 static address same_page(address x, address y) { 4420 int page_bits = -os::vm_page_size(); 4421 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits)) 4422 return x; 4423 else if (x > y) 4424 return (address)(intptr_t(y) | ~page_bits) + 1; 4425 else 4426 return (address)(intptr_t(y) & page_bits); 4427 } 4428 4429 bool os::find(address addr, outputStream* st) { 4430 Dl_info dlinfo; 4431 memset(&dlinfo, 0, sizeof(dlinfo)); 4432 if (dladdr(addr, &dlinfo)) { 4433 st->print(PTR_FORMAT ": ", addr); 4434 if (dlinfo.dli_sname != NULL) { 4435 st->print("%s+%#x", dlinfo.dli_sname, 4436 addr - (intptr_t)dlinfo.dli_saddr); 4437 } else if (dlinfo.dli_fname) { 4438 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase); 4439 } else { 4440 st->print("<absolute address>"); 4441 } 4442 if (dlinfo.dli_fname) { 4443 st->print(" in %s", dlinfo.dli_fname); 4444 } 4445 if (dlinfo.dli_fbase) { 4446 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase); 4447 } 4448 st->cr(); 4449 4450 if (Verbose) { 4451 // decode some bytes around the PC 4452 address begin = same_page(addr-40, addr); 4453 address end = same_page(addr+40, addr); 4454 address lowest = (address) dlinfo.dli_sname; 4455 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4456 if (begin < lowest) begin = lowest; 4457 Dl_info dlinfo2; 4458 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr 4459 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) 4460 end = (address) dlinfo2.dli_saddr; 4461 Disassembler::decode(begin, end, st); 4462 } 4463 return true; 4464 } 4465 return false; 4466 } 4467 4468 //////////////////////////////////////////////////////////////////////////////// 4469 // misc 4470 4471 // This does not do anything on Linux. This is basically a hook for being 4472 // able to use structured exception handling (thread-local exception filters) 4473 // on, e.g., Win32. 4474 void 4475 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, 4476 JavaCallArguments* args, Thread* thread) { 4477 f(value, method, args, thread); 4478 } 4479 4480 void os::print_statistics() { 4481 } 4482 4483 int os::message_box(const char* title, const char* message) { 4484 int i; 4485 fdStream err(defaultStream::error_fd()); 4486 for (i = 0; i < 78; i++) err.print_raw("="); 4487 err.cr(); 4488 err.print_raw_cr(title); 4489 for (i = 0; i < 78; i++) err.print_raw("-"); 4490 err.cr(); 4491 err.print_raw_cr(message); 4492 for (i = 0; i < 78; i++) err.print_raw("="); 4493 err.cr(); 4494 4495 char buf[16]; 4496 // Prevent process from exiting upon "read error" without consuming all CPU 4497 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4498 4499 return buf[0] == 'y' || buf[0] == 'Y'; 4500 } 4501 4502 int os::stat(const char *path, struct stat *sbuf) { 4503 char pathbuf[MAX_PATH]; 4504 if (strlen(path) > MAX_PATH - 1) { 4505 errno = ENAMETOOLONG; 4506 return -1; 4507 } 4508 os::native_path(strcpy(pathbuf, path)); 4509 return ::stat(pathbuf, sbuf); 4510 } 4511 4512 bool os::check_heap(bool force) { 4513 return true; 4514 } 4515 4516 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) { 4517 return ::vsnprintf(buf, count, format, args); 4518 } 4519 4520 // Is a (classpath) directory empty? 4521 bool os::dir_is_empty(const char* path) { 4522 DIR *dir = NULL; 4523 struct dirent *ptr; 4524 4525 dir = opendir(path); 4526 if (dir == NULL) return true; 4527 4528 /* Scan the directory */ 4529 bool result = true; 4530 char buf[sizeof(struct dirent) + MAX_PATH]; 4531 while (result && (ptr = ::readdir(dir)) != NULL) { 4532 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 4533 result = false; 4534 } 4535 } 4536 closedir(dir); 4537 return result; 4538 } 4539 4540 // This code originates from JDK's sysOpen and open64_w 4541 // from src/solaris/hpi/src/system_md.c 4542 4543 #ifndef O_DELETE 4544 #define O_DELETE 0x10000 4545 #endif 4546 4547 // Open a file. Unlink the file immediately after open returns 4548 // if the specified oflag has the O_DELETE flag set. 4549 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c 4550 4551 int os::open(const char *path, int oflag, int mode) { 4552 4553 if (strlen(path) > MAX_PATH - 1) { 4554 errno = ENAMETOOLONG; 4555 return -1; 4556 } 4557 int fd; 4558 int o_delete = (oflag & O_DELETE); 4559 oflag = oflag & ~O_DELETE; 4560 4561 fd = ::open64(path, oflag, mode); 4562 if (fd == -1) return -1; 4563 4564 //If the open succeeded, the file might still be a directory 4565 { 4566 struct stat64 buf64; 4567 int ret = ::fstat64(fd, &buf64); 4568 int st_mode = buf64.st_mode; 4569 4570 if (ret != -1) { 4571 if ((st_mode & S_IFMT) == S_IFDIR) { 4572 errno = EISDIR; 4573 ::close(fd); 4574 return -1; 4575 } 4576 } else { 4577 ::close(fd); 4578 return -1; 4579 } 4580 } 4581 4582 /* 4583 * All file descriptors that are opened in the JVM and not 4584 * specifically destined for a subprocess should have the 4585 * close-on-exec flag set. If we don't set it, then careless 3rd 4586 * party native code might fork and exec without closing all 4587 * appropriate file descriptors (e.g. as we do in closeDescriptors in 4588 * UNIXProcess.c), and this in turn might: 4589 * 4590 * - cause end-of-file to fail to be detected on some file 4591 * descriptors, resulting in mysterious hangs, or 4592 * 4593 * - might cause an fopen in the subprocess to fail on a system 4594 * suffering from bug 1085341. 4595 * 4596 * (Yes, the default setting of the close-on-exec flag is a Unix 4597 * design flaw) 4598 * 4599 * See: 4600 * 1085341: 32-bit stdio routines should support file descriptors >255 4601 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed 4602 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 4603 */ 4604 #ifdef FD_CLOEXEC 4605 { 4606 int flags = ::fcntl(fd, F_GETFD); 4607 if (flags != -1) 4608 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 4609 } 4610 #endif 4611 4612 if (o_delete != 0) { 4613 ::unlink(path); 4614 } 4615 return fd; 4616 } 4617 4618 4619 // create binary file, rewriting existing file if required 4620 int os::create_binary_file(const char* path, bool rewrite_existing) { 4621 int oflags = O_WRONLY | O_CREAT; 4622 if (!rewrite_existing) { 4623 oflags |= O_EXCL; 4624 } 4625 return ::open64(path, oflags, S_IREAD | S_IWRITE); 4626 } 4627 4628 // return current position of file pointer 4629 jlong os::current_file_offset(int fd) { 4630 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 4631 } 4632 4633 // move file pointer to the specified offset 4634 jlong os::seek_to_file_offset(int fd, jlong offset) { 4635 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 4636 } 4637 4638 // This code originates from JDK's sysAvailable 4639 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 4640 4641 int os::available(int fd, jlong *bytes) { 4642 jlong cur, end; 4643 int mode; 4644 struct stat64 buf64; 4645 4646 if (::fstat64(fd, &buf64) >= 0) { 4647 mode = buf64.st_mode; 4648 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 4649 /* 4650 * XXX: is the following call interruptible? If so, this might 4651 * need to go through the INTERRUPT_IO() wrapper as for other 4652 * blocking, interruptible calls in this file. 4653 */ 4654 int n; 4655 if (::ioctl(fd, FIONREAD, &n) >= 0) { 4656 *bytes = n; 4657 return 1; 4658 } 4659 } 4660 } 4661 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 4662 return 0; 4663 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 4664 return 0; 4665 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 4666 return 0; 4667 } 4668 *bytes = end - cur; 4669 return 1; 4670 } 4671 4672 int os::socket_available(int fd, jint *pbytes) { 4673 // Linux doc says EINTR not returned, unlike Solaris 4674 int ret = ::ioctl(fd, FIONREAD, pbytes); 4675 4676 //%% note ioctl can return 0 when successful, JVM_SocketAvailable 4677 // is expected to return 0 on failure and 1 on success to the jdk. 4678 return (ret < 0) ? 0 : 1; 4679 } 4680 4681 // Map a block of memory. 4682 char* os::map_memory(int fd, const char* file_name, size_t file_offset, 4683 char *addr, size_t bytes, bool read_only, 4684 bool allow_exec) { 4685 int prot; 4686 int flags; 4687 4688 if (read_only) { 4689 prot = PROT_READ; 4690 flags = MAP_SHARED; 4691 } else { 4692 prot = PROT_READ | PROT_WRITE; 4693 flags = MAP_PRIVATE; 4694 } 4695 4696 if (allow_exec) { 4697 prot |= PROT_EXEC; 4698 } 4699 4700 if (addr != NULL) { 4701 flags |= MAP_FIXED; 4702 } 4703 4704 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 4705 fd, file_offset); 4706 if (mapped_address == MAP_FAILED) { 4707 return NULL; 4708 } 4709 return mapped_address; 4710 } 4711 4712 4713 // Remap a block of memory. 4714 char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 4715 char *addr, size_t bytes, bool read_only, 4716 bool allow_exec) { 4717 // same as map_memory() on this OS 4718 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 4719 allow_exec); 4720 } 4721 4722 4723 // Unmap a block of memory. 4724 bool os::unmap_memory(char* addr, size_t bytes) { 4725 return munmap(addr, bytes) == 0; 4726 } 4727 4728 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 4729 4730 static clockid_t thread_cpu_clockid(Thread* thread) { 4731 pthread_t tid = thread->osthread()->pthread_id(); 4732 clockid_t clockid; 4733 4734 // Get thread clockid 4735 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 4736 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 4737 return clockid; 4738 } 4739 4740 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 4741 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 4742 // of a thread. 4743 // 4744 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 4745 // the fast estimate available on the platform. 4746 4747 jlong os::current_thread_cpu_time() { 4748 if (os::Linux::supports_fast_thread_cpu_time()) { 4749 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4750 } else { 4751 // return user + sys since the cost is the same 4752 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 4753 } 4754 } 4755 4756 jlong os::thread_cpu_time(Thread* thread) { 4757 // consistent with what current_thread_cpu_time() returns 4758 if (os::Linux::supports_fast_thread_cpu_time()) { 4759 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4760 } else { 4761 return slow_thread_cpu_time(thread, true /* user + sys */); 4762 } 4763 } 4764 4765 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 4766 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4767 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 4768 } else { 4769 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 4770 } 4771 } 4772 4773 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4774 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 4775 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 4776 } else { 4777 return slow_thread_cpu_time(thread, user_sys_cpu_time); 4778 } 4779 } 4780 4781 // 4782 // -1 on error. 4783 // 4784 4785 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 4786 static bool proc_pid_cpu_avail = true; 4787 static bool proc_task_unchecked = true; 4788 static const char *proc_stat_path = "/proc/%d/stat"; 4789 pid_t tid = thread->osthread()->thread_id(); 4790 int i; 4791 char *s; 4792 char stat[2048]; 4793 int statlen; 4794 char proc_name[64]; 4795 int count; 4796 long sys_time, user_time; 4797 char string[64]; 4798 char cdummy; 4799 int idummy; 4800 long ldummy; 4801 FILE *fp; 4802 4803 // We first try accessing /proc/<pid>/cpu since this is faster to 4804 // process. If this file is not present (linux kernels 2.5 and above) 4805 // then we open /proc/<pid>/stat. 4806 if ( proc_pid_cpu_avail ) { 4807 sprintf(proc_name, "/proc/%d/cpu", tid); 4808 fp = fopen(proc_name, "r"); 4809 if ( fp != NULL ) { 4810 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time); 4811 fclose(fp); 4812 if ( count != 3 ) return -1; 4813 4814 if (user_sys_cpu_time) { 4815 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4816 } else { 4817 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4818 } 4819 } 4820 else proc_pid_cpu_avail = false; 4821 } 4822 4823 // The /proc/<tid>/stat aggregates per-process usage on 4824 // new Linux kernels 2.6+ where NPTL is supported. 4825 // The /proc/self/task/<tid>/stat still has the per-thread usage. 4826 // See bug 6328462. 4827 // There can be no directory /proc/self/task on kernels 2.4 with NPTL 4828 // and possibly in some other cases, so we check its availability. 4829 if (proc_task_unchecked && os::Linux::is_NPTL()) { 4830 // This is executed only once 4831 proc_task_unchecked = false; 4832 fp = fopen("/proc/self/task", "r"); 4833 if (fp != NULL) { 4834 proc_stat_path = "/proc/self/task/%d/stat"; 4835 fclose(fp); 4836 } 4837 } 4838 4839 sprintf(proc_name, proc_stat_path, tid); 4840 fp = fopen(proc_name, "r"); 4841 if ( fp == NULL ) return -1; 4842 statlen = fread(stat, 1, 2047, fp); 4843 stat[statlen] = '\0'; 4844 fclose(fp); 4845 4846 // Skip pid and the command string. Note that we could be dealing with 4847 // weird command names, e.g. user could decide to rename java launcher 4848 // to "java 1.4.2 :)", then the stat file would look like 4849 // 1234 (java 1.4.2 :)) R ... ... 4850 // We don't really need to know the command string, just find the last 4851 // occurrence of ")" and then start parsing from there. See bug 4726580. 4852 s = strrchr(stat, ')'); 4853 i = 0; 4854 if (s == NULL ) return -1; 4855 4856 // Skip blank chars 4857 do s++; while (isspace(*s)); 4858 4859 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 4860 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 4861 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 4862 &user_time, &sys_time); 4863 if ( count != 13 ) return -1; 4864 if (user_sys_cpu_time) { 4865 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 4866 } else { 4867 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 4868 } 4869 } 4870 4871 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4872 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4873 info_ptr->may_skip_backward = false; // elapsed time not wall time 4874 info_ptr->may_skip_forward = false; // elapsed time not wall time 4875 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4876 } 4877 4878 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 4879 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 4880 info_ptr->may_skip_backward = false; // elapsed time not wall time 4881 info_ptr->may_skip_forward = false; // elapsed time not wall time 4882 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 4883 } 4884 4885 bool os::is_thread_cpu_time_supported() { 4886 return true; 4887 } 4888 4889 // System loadavg support. Returns -1 if load average cannot be obtained. 4890 // Linux doesn't yet have a (official) notion of processor sets, 4891 // so just return the system wide load average. 4892 int os::loadavg(double loadavg[], int nelem) { 4893 return ::getloadavg(loadavg, nelem); 4894 } 4895 4896 void os::pause() { 4897 char filename[MAX_PATH]; 4898 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 4899 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile); 4900 } else { 4901 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 4902 } 4903 4904 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 4905 if (fd != -1) { 4906 struct stat buf; 4907 ::close(fd); 4908 while (::stat(filename, &buf) == 0) { 4909 (void)::poll(NULL, 0, 100); 4910 } 4911 } else { 4912 jio_fprintf(stderr, 4913 "Could not open pause file '%s', continuing immediately.\n", filename); 4914 } 4915 } 4916 4917 4918 // Refer to the comments in os_solaris.cpp park-unpark. 4919 // 4920 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 4921 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 4922 // For specifics regarding the bug see GLIBC BUGID 261237 : 4923 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 4924 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 4925 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 4926 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 4927 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 4928 // and monitorenter when we're using 1-0 locking. All those operations may result in 4929 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 4930 // of libpthread avoids the problem, but isn't practical. 4931 // 4932 // Possible remedies: 4933 // 4934 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 4935 // This is palliative and probabilistic, however. If the thread is preempted 4936 // between the call to compute_abstime() and pthread_cond_timedwait(), more 4937 // than the minimum period may have passed, and the abstime may be stale (in the 4938 // past) resultin in a hang. Using this technique reduces the odds of a hang 4939 // but the JVM is still vulnerable, particularly on heavily loaded systems. 4940 // 4941 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 4942 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 4943 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 4944 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 4945 // thread. 4946 // 4947 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 4948 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 4949 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 4950 // This also works well. In fact it avoids kernel-level scalability impediments 4951 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 4952 // timers in a graceful fashion. 4953 // 4954 // 4. When the abstime value is in the past it appears that control returns 4955 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 4956 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 4957 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 4958 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 4959 // It may be possible to avoid reinitialization by checking the return 4960 // value from pthread_cond_timedwait(). In addition to reinitializing the 4961 // condvar we must establish the invariant that cond_signal() is only called 4962 // within critical sections protected by the adjunct mutex. This prevents 4963 // cond_signal() from "seeing" a condvar that's in the midst of being 4964 // reinitialized or that is corrupt. Sadly, this invariant obviates the 4965 // desirable signal-after-unlock optimization that avoids futile context switching. 4966 // 4967 // I'm also concerned that some versions of NTPL might allocate an auxilliary 4968 // structure when a condvar is used or initialized. cond_destroy() would 4969 // release the helper structure. Our reinitialize-after-timedwait fix 4970 // put excessive stress on malloc/free and locks protecting the c-heap. 4971 // 4972 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 4973 // It may be possible to refine (4) by checking the kernel and NTPL verisons 4974 // and only enabling the work-around for vulnerable environments. 4975 4976 // utility to compute the abstime argument to timedwait: 4977 // millis is the relative timeout time 4978 // abstime will be the absolute timeout time 4979 // TODO: replace compute_abstime() with unpackTime() 4980 4981 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 4982 if (millis < 0) millis = 0; 4983 struct timeval now; 4984 int status = gettimeofday(&now, NULL); 4985 assert(status == 0, "gettimeofday"); 4986 jlong seconds = millis / 1000; 4987 millis %= 1000; 4988 if (seconds > 50000000) { // see man cond_timedwait(3T) 4989 seconds = 50000000; 4990 } 4991 abstime->tv_sec = now.tv_sec + seconds; 4992 long usec = now.tv_usec + millis * 1000; 4993 if (usec >= 1000000) { 4994 abstime->tv_sec += 1; 4995 usec -= 1000000; 4996 } 4997 abstime->tv_nsec = usec * 1000; 4998 return abstime; 4999 } 5000 5001 5002 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately. 5003 // Conceptually TryPark() should be equivalent to park(0). 5004 5005 int os::PlatformEvent::TryPark() { 5006 for (;;) { 5007 const int v = _Event ; 5008 guarantee ((v == 0) || (v == 1), "invariant") ; 5009 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ; 5010 } 5011 } 5012 5013 void os::PlatformEvent::park() { // AKA "down()" 5014 // Invariant: Only the thread associated with the Event/PlatformEvent 5015 // may call park(). 5016 // TODO: assert that _Assoc != NULL or _Assoc == Self 5017 int v ; 5018 for (;;) { 5019 v = _Event ; 5020 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5021 } 5022 guarantee (v >= 0, "invariant") ; 5023 if (v == 0) { 5024 // Do this the hard way by blocking ... 5025 int status = pthread_mutex_lock(_mutex); 5026 assert_status(status == 0, status, "mutex_lock"); 5027 guarantee (_nParked == 0, "invariant") ; 5028 ++ _nParked ; 5029 while (_Event < 0) { 5030 status = pthread_cond_wait(_cond, _mutex); 5031 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5032 // Treat this the same as if the wait was interrupted 5033 if (status == ETIME) { status = EINTR; } 5034 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5035 } 5036 -- _nParked ; 5037 5038 // In theory we could move the ST of 0 into _Event past the unlock(), 5039 // but then we'd need a MEMBAR after the ST. 5040 _Event = 0 ; 5041 status = pthread_mutex_unlock(_mutex); 5042 assert_status(status == 0, status, "mutex_unlock"); 5043 } 5044 guarantee (_Event >= 0, "invariant") ; 5045 } 5046 5047 int os::PlatformEvent::park(jlong millis) { 5048 guarantee (_nParked == 0, "invariant") ; 5049 5050 int v ; 5051 for (;;) { 5052 v = _Event ; 5053 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ; 5054 } 5055 guarantee (v >= 0, "invariant") ; 5056 if (v != 0) return OS_OK ; 5057 5058 // We do this the hard way, by blocking the thread. 5059 // Consider enforcing a minimum timeout value. 5060 struct timespec abst; 5061 compute_abstime(&abst, millis); 5062 5063 int ret = OS_TIMEOUT; 5064 int status = pthread_mutex_lock(_mutex); 5065 assert_status(status == 0, status, "mutex_lock"); 5066 guarantee (_nParked == 0, "invariant") ; 5067 ++_nParked ; 5068 5069 // Object.wait(timo) will return because of 5070 // (a) notification 5071 // (b) timeout 5072 // (c) thread.interrupt 5073 // 5074 // Thread.interrupt and object.notify{All} both call Event::set. 5075 // That is, we treat thread.interrupt as a special case of notification. 5076 // The underlying Solaris implementation, cond_timedwait, admits 5077 // spurious/premature wakeups, but the JLS/JVM spec prevents the 5078 // JVM from making those visible to Java code. As such, we must 5079 // filter out spurious wakeups. We assume all ETIME returns are valid. 5080 // 5081 // TODO: properly differentiate simultaneous notify+interrupt. 5082 // In that case, we should propagate the notify to another waiter. 5083 5084 while (_Event < 0) { 5085 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst); 5086 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5087 pthread_cond_destroy (_cond); 5088 pthread_cond_init (_cond, NULL) ; 5089 } 5090 assert_status(status == 0 || status == EINTR || 5091 status == ETIME || status == ETIMEDOUT, 5092 status, "cond_timedwait"); 5093 if (!FilterSpuriousWakeups) break ; // previous semantics 5094 if (status == ETIME || status == ETIMEDOUT) break ; 5095 // We consume and ignore EINTR and spurious wakeups. 5096 } 5097 --_nParked ; 5098 if (_Event >= 0) { 5099 ret = OS_OK; 5100 } 5101 _Event = 0 ; 5102 status = pthread_mutex_unlock(_mutex); 5103 assert_status(status == 0, status, "mutex_unlock"); 5104 assert (_nParked == 0, "invariant") ; 5105 return ret; 5106 } 5107 5108 void os::PlatformEvent::unpark() { 5109 int v, AnyWaiters ; 5110 for (;;) { 5111 v = _Event ; 5112 if (v > 0) { 5113 // The LD of _Event could have reordered or be satisfied 5114 // by a read-aside from this processor's write buffer. 5115 // To avoid problems execute a barrier and then 5116 // ratify the value. 5117 OrderAccess::fence() ; 5118 if (_Event == v) return ; 5119 continue ; 5120 } 5121 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ; 5122 } 5123 if (v < 0) { 5124 // Wait for the thread associated with the event to vacate 5125 int status = pthread_mutex_lock(_mutex); 5126 assert_status(status == 0, status, "mutex_lock"); 5127 AnyWaiters = _nParked ; 5128 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ; 5129 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5130 AnyWaiters = 0 ; 5131 pthread_cond_signal (_cond); 5132 } 5133 status = pthread_mutex_unlock(_mutex); 5134 assert_status(status == 0, status, "mutex_unlock"); 5135 if (AnyWaiters != 0) { 5136 status = pthread_cond_signal(_cond); 5137 assert_status(status == 0, status, "cond_signal"); 5138 } 5139 } 5140 5141 // Note that we signal() _after dropping the lock for "immortal" Events. 5142 // This is safe and avoids a common class of futile wakeups. In rare 5143 // circumstances this can cause a thread to return prematurely from 5144 // cond_{timed}wait() but the spurious wakeup is benign and the victim will 5145 // simply re-test the condition and re-park itself. 5146 } 5147 5148 5149 // JSR166 5150 // ------------------------------------------------------- 5151 5152 /* 5153 * The solaris and linux implementations of park/unpark are fairly 5154 * conservative for now, but can be improved. They currently use a 5155 * mutex/condvar pair, plus a a count. 5156 * Park decrements count if > 0, else does a condvar wait. Unpark 5157 * sets count to 1 and signals condvar. Only one thread ever waits 5158 * on the condvar. Contention seen when trying to park implies that someone 5159 * is unparking you, so don't wait. And spurious returns are fine, so there 5160 * is no need to track notifications. 5161 */ 5162 5163 5164 #define NANOSECS_PER_SEC 1000000000 5165 #define NANOSECS_PER_MILLISEC 1000000 5166 #define MAX_SECS 100000000 5167 /* 5168 * This code is common to linux and solaris and will be moved to a 5169 * common place in dolphin. 5170 * 5171 * The passed in time value is either a relative time in nanoseconds 5172 * or an absolute time in milliseconds. Either way it has to be unpacked 5173 * into suitable seconds and nanoseconds components and stored in the 5174 * given timespec structure. 5175 * Given time is a 64-bit value and the time_t used in the timespec is only 5176 * a signed-32-bit value (except on 64-bit Linux) we have to watch for 5177 * overflow if times way in the future are given. Further on Solaris versions 5178 * prior to 10 there is a restriction (see cond_timedwait) that the specified 5179 * number of seconds, in abstime, is less than current_time + 100,000,000. 5180 * As it will be 28 years before "now + 100000000" will overflow we can 5181 * ignore overflow and just impose a hard-limit on seconds using the value 5182 * of "now + 100,000,000". This places a limit on the timeout of about 3.17 5183 * years from "now". 5184 */ 5185 5186 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5187 assert (time > 0, "convertTime"); 5188 5189 struct timeval now; 5190 int status = gettimeofday(&now, NULL); 5191 assert(status == 0, "gettimeofday"); 5192 5193 time_t max_secs = now.tv_sec + MAX_SECS; 5194 5195 if (isAbsolute) { 5196 jlong secs = time / 1000; 5197 if (secs > max_secs) { 5198 absTime->tv_sec = max_secs; 5199 } 5200 else { 5201 absTime->tv_sec = secs; 5202 } 5203 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5204 } 5205 else { 5206 jlong secs = time / NANOSECS_PER_SEC; 5207 if (secs >= MAX_SECS) { 5208 absTime->tv_sec = max_secs; 5209 absTime->tv_nsec = 0; 5210 } 5211 else { 5212 absTime->tv_sec = now.tv_sec + secs; 5213 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5214 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5215 absTime->tv_nsec -= NANOSECS_PER_SEC; 5216 ++absTime->tv_sec; // note: this must be <= max_secs 5217 } 5218 } 5219 } 5220 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5221 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5222 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5223 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5224 } 5225 5226 void Parker::park(bool isAbsolute, jlong time) { 5227 // Optional fast-path check: 5228 // Return immediately if a permit is available. 5229 if (_counter > 0) { 5230 _counter = 0 ; 5231 OrderAccess::fence(); 5232 return ; 5233 } 5234 5235 Thread* thread = Thread::current(); 5236 assert(thread->is_Java_thread(), "Must be JavaThread"); 5237 JavaThread *jt = (JavaThread *)thread; 5238 5239 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5240 // Check interrupt before trying to wait 5241 if (Thread::is_interrupted(thread, false)) { 5242 return; 5243 } 5244 5245 // Next, demultiplex/decode time arguments 5246 timespec absTime; 5247 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all 5248 return; 5249 } 5250 if (time > 0) { 5251 unpackTime(&absTime, isAbsolute, time); 5252 } 5253 5254 5255 // Enter safepoint region 5256 // Beware of deadlocks such as 6317397. 5257 // The per-thread Parker:: mutex is a classic leaf-lock. 5258 // In particular a thread must never block on the Threads_lock while 5259 // holding the Parker:: mutex. If safepoints are pending both the 5260 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5261 ThreadBlockInVM tbivm(jt); 5262 5263 // Don't wait if cannot get lock since interference arises from 5264 // unblocking. Also. check interrupt before trying wait 5265 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5266 return; 5267 } 5268 5269 int status ; 5270 if (_counter > 0) { // no wait needed 5271 _counter = 0; 5272 status = pthread_mutex_unlock(_mutex); 5273 assert (status == 0, "invariant") ; 5274 OrderAccess::fence(); 5275 return; 5276 } 5277 5278 #ifdef ASSERT 5279 // Don't catch signals while blocked; let the running threads have the signals. 5280 // (This allows a debugger to break into the running thread.) 5281 sigset_t oldsigs; 5282 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5283 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5284 #endif 5285 5286 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5287 jt->set_suspend_equivalent(); 5288 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5289 5290 if (time == 0) { 5291 status = pthread_cond_wait (_cond, _mutex) ; 5292 } else { 5293 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ; 5294 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5295 pthread_cond_destroy (_cond) ; 5296 pthread_cond_init (_cond, NULL); 5297 } 5298 } 5299 assert_status(status == 0 || status == EINTR || 5300 status == ETIME || status == ETIMEDOUT, 5301 status, "cond_timedwait"); 5302 5303 #ifdef ASSERT 5304 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5305 #endif 5306 5307 _counter = 0 ; 5308 status = pthread_mutex_unlock(_mutex) ; 5309 assert_status(status == 0, status, "invariant") ; 5310 // If externally suspended while waiting, re-suspend 5311 if (jt->handle_special_suspend_equivalent_condition()) { 5312 jt->java_suspend_self(); 5313 } 5314 5315 OrderAccess::fence(); 5316 } 5317 5318 void Parker::unpark() { 5319 int s, status ; 5320 status = pthread_mutex_lock(_mutex); 5321 assert (status == 0, "invariant") ; 5322 s = _counter; 5323 _counter = 1; 5324 if (s < 1) { 5325 if (WorkAroundNPTLTimedWaitHang) { 5326 status = pthread_cond_signal (_cond) ; 5327 assert (status == 0, "invariant") ; 5328 status = pthread_mutex_unlock(_mutex); 5329 assert (status == 0, "invariant") ; 5330 } else { 5331 status = pthread_mutex_unlock(_mutex); 5332 assert (status == 0, "invariant") ; 5333 status = pthread_cond_signal (_cond) ; 5334 assert (status == 0, "invariant") ; 5335 } 5336 } else { 5337 pthread_mutex_unlock(_mutex); 5338 assert (status == 0, "invariant") ; 5339 } 5340 } 5341 5342 5343 extern char** environ; 5344 5345 #ifndef __NR_fork 5346 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) 5347 #endif 5348 5349 #ifndef __NR_execve 5350 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) 5351 #endif 5352 5353 // Run the specified command in a separate process. Return its exit value, 5354 // or -1 on failure (e.g. can't fork a new process). 5355 // Unlike system(), this function can be called from signal handler. It 5356 // doesn't block SIGINT et al. 5357 int os::fork_and_exec(char* cmd) { 5358 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5359 5360 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run 5361 // pthread_atfork handlers and reset pthread library. All we need is a 5362 // separate process to execve. Make a direct syscall to fork process. 5363 // On IA64 there's no fork syscall, we have to use fork() and hope for 5364 // the best... 5365 pid_t pid = NOT_IA64(syscall(__NR_fork);) 5366 IA64_ONLY(fork();) 5367 5368 if (pid < 0) { 5369 // fork failed 5370 return -1; 5371 5372 } else if (pid == 0) { 5373 // child process 5374 5375 // execve() in LinuxThreads will call pthread_kill_other_threads_np() 5376 // first to kill every thread on the thread list. Because this list is 5377 // not reset by fork() (see notes above), execve() will instead kill 5378 // every thread in the parent process. We know this is the only thread 5379 // in the new process, so make a system call directly. 5380 // IA64 should use normal execve() from glibc to match the glibc fork() 5381 // above. 5382 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);) 5383 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);) 5384 5385 // execve failed 5386 _exit(-1); 5387 5388 } else { 5389 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5390 // care about the actual exit code, for now. 5391 5392 int status; 5393 5394 // Wait for the child process to exit. This returns immediately if 5395 // the child has already exited. */ 5396 while (waitpid(pid, &status, 0) < 0) { 5397 switch (errno) { 5398 case ECHILD: return 0; 5399 case EINTR: break; 5400 default: return -1; 5401 } 5402 } 5403 5404 if (WIFEXITED(status)) { 5405 // The child exited normally; get its exit code. 5406 return WEXITSTATUS(status); 5407 } else if (WIFSIGNALED(status)) { 5408 // The child exited because of a signal 5409 // The best value to return is 0x80 + signal number, 5410 // because that is what all Unix shells do, and because 5411 // it allows callers to distinguish between process exit and 5412 // process death by signal. 5413 return 0x80 + WTERMSIG(status); 5414 } else { 5415 // Unknown exit code; pass it through 5416 return status; 5417 } 5418 } 5419 } 5420 5421 // is_headless_jre() 5422 // 5423 // Test for the existence of libmawt in motif21 or xawt directories 5424 // in order to report if we are running in a headless jre 5425 // 5426 bool os::is_headless_jre() { 5427 struct stat statbuf; 5428 char buf[MAXPATHLEN]; 5429 char libmawtpath[MAXPATHLEN]; 5430 const char *xawtstr = "/xawt/libmawt.so"; 5431 const char *motifstr = "/motif21/libmawt.so"; 5432 char *p; 5433 5434 // Get path to libjvm.so 5435 os::jvm_path(buf, sizeof(buf)); 5436 5437 // Get rid of libjvm.so 5438 p = strrchr(buf, '/'); 5439 if (p == NULL) return false; 5440 else *p = '\0'; 5441 5442 // Get rid of client or server 5443 p = strrchr(buf, '/'); 5444 if (p == NULL) return false; 5445 else *p = '\0'; 5446 5447 // check xawt/libmawt.so 5448 strcpy(libmawtpath, buf); 5449 strcat(libmawtpath, xawtstr); 5450 if (::stat(libmawtpath, &statbuf) == 0) return false; 5451 5452 // check motif21/libmawt.so 5453 strcpy(libmawtpath, buf); 5454 strcat(libmawtpath, motifstr); 5455 if (::stat(libmawtpath, &statbuf) == 0) return false; 5456 5457 return true; 5458 } 5459 5460 5461 #ifdef JAVASE_EMBEDDED 5462 // 5463 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory. 5464 // 5465 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL; 5466 5467 // ctor 5468 // 5469 MemNotifyThread::MemNotifyThread(int fd): Thread() { 5470 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread"); 5471 _fd = fd; 5472 5473 if (os::create_thread(this, os::os_thread)) { 5474 _memnotify_thread = this; 5475 os::set_priority(this, NearMaxPriority); 5476 os::start_thread(this); 5477 } 5478 } 5479 5480 // Where all the work gets done 5481 // 5482 void MemNotifyThread::run() { 5483 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread"); 5484 5485 // Set up the select arguments 5486 fd_set rfds; 5487 if (_fd != -1) { 5488 FD_ZERO(&rfds); 5489 FD_SET(_fd, &rfds); 5490 } 5491 5492 // Now wait for the mem_notify device to wake up 5493 while (1) { 5494 // Wait for the mem_notify device to signal us.. 5495 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL); 5496 if (rc == -1) { 5497 perror("select!\n"); 5498 break; 5499 } else if (rc) { 5500 //ssize_t free_before = os::available_memory(); 5501 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024); 5502 5503 // The kernel is telling us there is not much memory left... 5504 // try to do something about that 5505 5506 // If we are not already in a GC, try one. 5507 if (!Universe::heap()->is_gc_active()) { 5508 Universe::heap()->collect(GCCause::_allocation_failure); 5509 5510 //ssize_t free_after = os::available_memory(); 5511 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024); 5512 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024); 5513 } 5514 // We might want to do something like the following if we find the GC's are not helping... 5515 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true); 5516 } 5517 } 5518 } 5519 5520 // 5521 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it. 5522 // 5523 void MemNotifyThread::start() { 5524 int fd; 5525 fd = open ("/dev/mem_notify", O_RDONLY, 0); 5526 if (fd < 0) { 5527 return; 5528 } 5529 5530 if (memnotify_thread() == NULL) { 5531 new MemNotifyThread(fd); 5532 } 5533 } 5534 #endif // JAVASE_EMBEDDED