1 /* 2 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "classfile/classLoader.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/vmSymbols.hpp" 29 #include "code/icBuffer.hpp" 30 #include "code/vtableStubs.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "compiler/disassembler.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "jvm_linux.h" 35 #include "logging/log.hpp" 36 #include "memory/allocation.inline.hpp" 37 #include "memory/filemap.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "os_linux.inline.hpp" 40 #include "os_share_linux.hpp" 41 #include "prims/jniFastGetField.hpp" 42 #include "prims/jvm.h" 43 #include "prims/jvm_misc.hpp" 44 #include "runtime/arguments.hpp" 45 #include "runtime/atomic.hpp" 46 #include "runtime/extendedPC.hpp" 47 #include "runtime/globals.hpp" 48 #include "runtime/interfaceSupport.hpp" 49 #include "runtime/init.hpp" 50 #include "runtime/java.hpp" 51 #include "runtime/javaCalls.hpp" 52 #include "runtime/mutexLocker.hpp" 53 #include "runtime/objectMonitor.hpp" 54 #include "runtime/orderAccess.inline.hpp" 55 #include "runtime/osThread.hpp" 56 #include "runtime/perfMemory.hpp" 57 #include "runtime/sharedRuntime.hpp" 58 #include "runtime/statSampler.hpp" 59 #include "runtime/stubRoutines.hpp" 60 #include "runtime/thread.inline.hpp" 61 #include "runtime/threadCritical.hpp" 62 #include "runtime/timer.hpp" 63 #include "semaphore_posix.hpp" 64 #include "services/attachListener.hpp" 65 #include "services/memTracker.hpp" 66 #include "services/runtimeService.hpp" 67 #include "utilities/decoder.hpp" 68 #include "utilities/defaultStream.hpp" 69 #include "utilities/events.hpp" 70 #include "utilities/elfFile.hpp" 71 #include "utilities/growableArray.hpp" 72 #include "utilities/macros.hpp" 73 #include "utilities/vmError.hpp" 74 75 // put OS-includes here 76 # include <sys/types.h> 77 # include <sys/mman.h> 78 # include <sys/stat.h> 79 # include <sys/select.h> 80 # include <pthread.h> 81 # include <signal.h> 82 # include <errno.h> 83 # include <dlfcn.h> 84 # include <stdio.h> 85 # include <unistd.h> 86 # include <sys/resource.h> 87 # include <pthread.h> 88 # include <sys/stat.h> 89 # include <sys/time.h> 90 # include <sys/times.h> 91 # include <sys/utsname.h> 92 # include <sys/socket.h> 93 # include <sys/wait.h> 94 # include <pwd.h> 95 # include <poll.h> 96 # include <semaphore.h> 97 # include <fcntl.h> 98 # include <string.h> 99 # include <syscall.h> 100 # include <sys/sysinfo.h> 101 # include <gnu/libc-version.h> 102 # include <sys/ipc.h> 103 # include <sys/shm.h> 104 # include <link.h> 105 # include <stdint.h> 106 # include <inttypes.h> 107 # include <sys/ioctl.h> 108 109 #ifndef _GNU_SOURCE 110 #define _GNU_SOURCE 111 #include <sched.h> 112 #undef _GNU_SOURCE 113 #else 114 #include <sched.h> 115 #endif 116 117 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 118 // getrusage() is prepared to handle the associated failure. 119 #ifndef RUSAGE_THREAD 120 #define RUSAGE_THREAD (1) /* only the calling thread */ 121 #endif 122 123 #define MAX_PATH (2 * K) 124 125 #define MAX_SECS 100000000 126 127 // for timer info max values which include all bits 128 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 129 130 #define LARGEPAGES_BIT (1 << 6) 131 //////////////////////////////////////////////////////////////////////////////// 132 // global variables 133 julong os::Linux::_physical_memory = 0; 134 135 address os::Linux::_initial_thread_stack_bottom = NULL; 136 uintptr_t os::Linux::_initial_thread_stack_size = 0; 137 138 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 139 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 140 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 141 Mutex* os::Linux::_createThread_lock = NULL; 142 pthread_t os::Linux::_main_thread; 143 int os::Linux::_page_size = -1; 144 bool os::Linux::_supports_fast_thread_cpu_time = false; 145 uint32_t os::Linux::_os_version = 0; 146 const char * os::Linux::_glibc_version = NULL; 147 const char * os::Linux::_libpthread_version = NULL; 148 pthread_condattr_t os::Linux::_condattr[1]; 149 150 static jlong initial_time_count=0; 151 152 static int clock_tics_per_sec = 100; 153 154 // For diagnostics to print a message once. see run_periodic_checks 155 static sigset_t check_signal_done; 156 static bool check_signals = true; 157 158 // Signal number used to suspend/resume a thread 159 160 // do not use any signal number less than SIGSEGV, see 4355769 161 static int SR_signum = SIGUSR2; 162 sigset_t SR_sigset; 163 164 // Declarations 165 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 166 167 // utility functions 168 169 static int SR_initialize(); 170 171 julong os::available_memory() { 172 return Linux::available_memory(); 173 } 174 175 julong os::Linux::available_memory() { 176 // values in struct sysinfo are "unsigned long" 177 struct sysinfo si; 178 sysinfo(&si); 179 180 return (julong)si.freeram * si.mem_unit; 181 } 182 183 julong os::physical_memory() { 184 return Linux::physical_memory(); 185 } 186 187 // Return true if user is running as root. 188 189 bool os::have_special_privileges() { 190 static bool init = false; 191 static bool privileges = false; 192 if (!init) { 193 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 194 init = true; 195 } 196 return privileges; 197 } 198 199 200 #ifndef SYS_gettid 201 // i386: 224, ia64: 1105, amd64: 186, sparc 143 202 #ifdef __ia64__ 203 #define SYS_gettid 1105 204 #else 205 #ifdef __i386__ 206 #define SYS_gettid 224 207 #else 208 #ifdef __amd64__ 209 #define SYS_gettid 186 210 #else 211 #ifdef __sparc__ 212 #define SYS_gettid 143 213 #else 214 #error define gettid for the arch 215 #endif 216 #endif 217 #endif 218 #endif 219 #endif 220 221 222 // pid_t gettid() 223 // 224 // Returns the kernel thread id of the currently running thread. Kernel 225 // thread id is used to access /proc. 226 pid_t os::Linux::gettid() { 227 int rslt = syscall(SYS_gettid); 228 assert(rslt != -1, "must be."); // old linuxthreads implementation? 229 return (pid_t)rslt; 230 } 231 232 // Most versions of linux have a bug where the number of processors are 233 // determined by looking at the /proc file system. In a chroot environment, 234 // the system call returns 1. This causes the VM to act as if it is 235 // a single processor and elide locking (see is_MP() call). 236 static bool unsafe_chroot_detected = false; 237 static const char *unstable_chroot_error = "/proc file system not found.\n" 238 "Java may be unstable running multithreaded in a chroot " 239 "environment on Linux when /proc filesystem is not mounted."; 240 241 void os::Linux::initialize_system_info() { 242 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 243 if (processor_count() == 1) { 244 pid_t pid = os::Linux::gettid(); 245 char fname[32]; 246 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 247 FILE *fp = fopen(fname, "r"); 248 if (fp == NULL) { 249 unsafe_chroot_detected = true; 250 } else { 251 fclose(fp); 252 } 253 } 254 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 255 assert(processor_count() > 0, "linux error"); 256 } 257 258 void os::init_system_properties_values() { 259 // The next steps are taken in the product version: 260 // 261 // Obtain the JAVA_HOME value from the location of libjvm.so. 262 // This library should be located at: 263 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 264 // 265 // If "/jre/lib/" appears at the right place in the path, then we 266 // assume libjvm.so is installed in a JDK and we use this path. 267 // 268 // Otherwise exit with message: "Could not create the Java virtual machine." 269 // 270 // The following extra steps are taken in the debugging version: 271 // 272 // If "/jre/lib/" does NOT appear at the right place in the path 273 // instead of exit check for $JAVA_HOME environment variable. 274 // 275 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 276 // then we append a fake suffix "hotspot/libjvm.so" to this path so 277 // it looks like libjvm.so is installed there 278 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 279 // 280 // Otherwise exit. 281 // 282 // Important note: if the location of libjvm.so changes this 283 // code needs to be changed accordingly. 284 285 // See ld(1): 286 // The linker uses the following search paths to locate required 287 // shared libraries: 288 // 1: ... 289 // ... 290 // 7: The default directories, normally /lib and /usr/lib. 291 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 292 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 293 #else 294 #define DEFAULT_LIBPATH "/lib:/usr/lib" 295 #endif 296 297 // Base path of extensions installed on the system. 298 #define SYS_EXT_DIR "/usr/java/packages" 299 #define EXTENSIONS_DIR "/lib/ext" 300 301 // Buffer that fits several sprintfs. 302 // Note that the space for the colon and the trailing null are provided 303 // by the nulls included by the sizeof operator. 304 const size_t bufsize = 305 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 306 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 307 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 308 309 // sysclasspath, java_home, dll_dir 310 { 311 char *pslash; 312 os::jvm_path(buf, bufsize); 313 314 // Found the full path to libjvm.so. 315 // Now cut the path to <java_home>/jre if we can. 316 pslash = strrchr(buf, '/'); 317 if (pslash != NULL) { 318 *pslash = '\0'; // Get rid of /libjvm.so. 319 } 320 pslash = strrchr(buf, '/'); 321 if (pslash != NULL) { 322 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 323 } 324 Arguments::set_dll_dir(buf); 325 326 if (pslash != NULL) { 327 pslash = strrchr(buf, '/'); 328 if (pslash != NULL) { 329 *pslash = '\0'; // Get rid of /lib. 330 } 331 } 332 Arguments::set_java_home(buf); 333 set_boot_path('/', ':'); 334 } 335 336 // Where to look for native libraries. 337 // 338 // Note: Due to a legacy implementation, most of the library path 339 // is set in the launcher. This was to accomodate linking restrictions 340 // on legacy Linux implementations (which are no longer supported). 341 // Eventually, all the library path setting will be done here. 342 // 343 // However, to prevent the proliferation of improperly built native 344 // libraries, the new path component /usr/java/packages is added here. 345 // Eventually, all the library path setting will be done here. 346 { 347 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 348 // should always exist (until the legacy problem cited above is 349 // addressed). 350 const char *v = ::getenv("LD_LIBRARY_PATH"); 351 const char *v_colon = ":"; 352 if (v == NULL) { v = ""; v_colon = ""; } 353 // That's +1 for the colon and +1 for the trailing '\0'. 354 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 355 strlen(v) + 1 + 356 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 357 mtInternal); 358 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 359 Arguments::set_library_path(ld_library_path); 360 FREE_C_HEAP_ARRAY(char, ld_library_path); 361 } 362 363 // Extensions directories. 364 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 365 Arguments::set_ext_dirs(buf); 366 367 FREE_C_HEAP_ARRAY(char, buf); 368 369 #undef DEFAULT_LIBPATH 370 #undef SYS_EXT_DIR 371 #undef EXTENSIONS_DIR 372 } 373 374 //////////////////////////////////////////////////////////////////////////////// 375 // breakpoint support 376 377 void os::breakpoint() { 378 BREAKPOINT; 379 } 380 381 extern "C" void breakpoint() { 382 // use debugger to set breakpoint here 383 } 384 385 //////////////////////////////////////////////////////////////////////////////// 386 // signal support 387 388 debug_only(static bool signal_sets_initialized = false); 389 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 390 391 bool os::Linux::is_sig_ignored(int sig) { 392 struct sigaction oact; 393 sigaction(sig, (struct sigaction*)NULL, &oact); 394 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 395 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 396 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 397 return true; 398 } else { 399 return false; 400 } 401 } 402 403 void os::Linux::signal_sets_init() { 404 // Should also have an assertion stating we are still single-threaded. 405 assert(!signal_sets_initialized, "Already initialized"); 406 // Fill in signals that are necessarily unblocked for all threads in 407 // the VM. Currently, we unblock the following signals: 408 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 409 // by -Xrs (=ReduceSignalUsage)); 410 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 411 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 412 // the dispositions or masks wrt these signals. 413 // Programs embedding the VM that want to use the above signals for their 414 // own purposes must, at this time, use the "-Xrs" option to prevent 415 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 416 // (See bug 4345157, and other related bugs). 417 // In reality, though, unblocking these signals is really a nop, since 418 // these signals are not blocked by default. 419 sigemptyset(&unblocked_sigs); 420 sigemptyset(&allowdebug_blocked_sigs); 421 sigaddset(&unblocked_sigs, SIGILL); 422 sigaddset(&unblocked_sigs, SIGSEGV); 423 sigaddset(&unblocked_sigs, SIGBUS); 424 sigaddset(&unblocked_sigs, SIGFPE); 425 #if defined(PPC64) 426 sigaddset(&unblocked_sigs, SIGTRAP); 427 #endif 428 sigaddset(&unblocked_sigs, SR_signum); 429 430 if (!ReduceSignalUsage) { 431 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 432 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 433 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 434 } 435 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 436 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 437 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 438 } 439 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 440 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 441 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 442 } 443 } 444 // Fill in signals that are blocked by all but the VM thread. 445 sigemptyset(&vm_sigs); 446 if (!ReduceSignalUsage) { 447 sigaddset(&vm_sigs, BREAK_SIGNAL); 448 } 449 debug_only(signal_sets_initialized = true); 450 451 } 452 453 // These are signals that are unblocked while a thread is running Java. 454 // (For some reason, they get blocked by default.) 455 sigset_t* os::Linux::unblocked_signals() { 456 assert(signal_sets_initialized, "Not initialized"); 457 return &unblocked_sigs; 458 } 459 460 // These are the signals that are blocked while a (non-VM) thread is 461 // running Java. Only the VM thread handles these signals. 462 sigset_t* os::Linux::vm_signals() { 463 assert(signal_sets_initialized, "Not initialized"); 464 return &vm_sigs; 465 } 466 467 // These are signals that are blocked during cond_wait to allow debugger in 468 sigset_t* os::Linux::allowdebug_blocked_signals() { 469 assert(signal_sets_initialized, "Not initialized"); 470 return &allowdebug_blocked_sigs; 471 } 472 473 void os::Linux::hotspot_sigmask(Thread* thread) { 474 475 //Save caller's signal mask before setting VM signal mask 476 sigset_t caller_sigmask; 477 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 478 479 OSThread* osthread = thread->osthread(); 480 osthread->set_caller_sigmask(caller_sigmask); 481 482 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 483 484 if (!ReduceSignalUsage) { 485 if (thread->is_VM_thread()) { 486 // Only the VM thread handles BREAK_SIGNAL ... 487 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 488 } else { 489 // ... all other threads block BREAK_SIGNAL 490 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 491 } 492 } 493 } 494 495 ////////////////////////////////////////////////////////////////////////////// 496 // detecting pthread library 497 498 void os::Linux::libpthread_init() { 499 // Save glibc and pthread version strings. 500 #if !defined(_CS_GNU_LIBC_VERSION) || \ 501 !defined(_CS_GNU_LIBPTHREAD_VERSION) 502 #error "glibc too old (< 2.3.2)" 503 #endif 504 505 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 506 assert(n > 0, "cannot retrieve glibc version"); 507 char *str = (char *)malloc(n, mtInternal); 508 confstr(_CS_GNU_LIBC_VERSION, str, n); 509 os::Linux::set_glibc_version(str); 510 511 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 512 assert(n > 0, "cannot retrieve pthread version"); 513 str = (char *)malloc(n, mtInternal); 514 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 515 os::Linux::set_libpthread_version(str); 516 } 517 518 ///////////////////////////////////////////////////////////////////////////// 519 // thread stack expansion 520 521 // os::Linux::manually_expand_stack() takes care of expanding the thread 522 // stack. Note that this is normally not needed: pthread stacks allocate 523 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 524 // committed. Therefore it is not necessary to expand the stack manually. 525 // 526 // Manually expanding the stack was historically needed on LinuxThreads 527 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 528 // it is kept to deal with very rare corner cases: 529 // 530 // For one, user may run the VM on an own implementation of threads 531 // whose stacks are - like the old LinuxThreads - implemented using 532 // mmap(MAP_GROWSDOWN). 533 // 534 // Also, this coding may be needed if the VM is running on the primordial 535 // thread. Normally we avoid running on the primordial thread; however, 536 // user may still invoke the VM on the primordial thread. 537 // 538 // The following historical comment describes the details about running 539 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 540 541 542 // Force Linux kernel to expand current thread stack. If "bottom" is close 543 // to the stack guard, caller should block all signals. 544 // 545 // MAP_GROWSDOWN: 546 // A special mmap() flag that is used to implement thread stacks. It tells 547 // kernel that the memory region should extend downwards when needed. This 548 // allows early versions of LinuxThreads to only mmap the first few pages 549 // when creating a new thread. Linux kernel will automatically expand thread 550 // stack as needed (on page faults). 551 // 552 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 553 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 554 // region, it's hard to tell if the fault is due to a legitimate stack 555 // access or because of reading/writing non-exist memory (e.g. buffer 556 // overrun). As a rule, if the fault happens below current stack pointer, 557 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 558 // application (see Linux kernel fault.c). 559 // 560 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 561 // stack overflow detection. 562 // 563 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 564 // not use MAP_GROWSDOWN. 565 // 566 // To get around the problem and allow stack banging on Linux, we need to 567 // manually expand thread stack after receiving the SIGSEGV. 568 // 569 // There are two ways to expand thread stack to address "bottom", we used 570 // both of them in JVM before 1.5: 571 // 1. adjust stack pointer first so that it is below "bottom", and then 572 // touch "bottom" 573 // 2. mmap() the page in question 574 // 575 // Now alternate signal stack is gone, it's harder to use 2. For instance, 576 // if current sp is already near the lower end of page 101, and we need to 577 // call mmap() to map page 100, it is possible that part of the mmap() frame 578 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 579 // That will destroy the mmap() frame and cause VM to crash. 580 // 581 // The following code works by adjusting sp first, then accessing the "bottom" 582 // page to force a page fault. Linux kernel will then automatically expand the 583 // stack mapping. 584 // 585 // _expand_stack_to() assumes its frame size is less than page size, which 586 // should always be true if the function is not inlined. 587 588 static void NOINLINE _expand_stack_to(address bottom) { 589 address sp; 590 size_t size; 591 volatile char *p; 592 593 // Adjust bottom to point to the largest address within the same page, it 594 // gives us a one-page buffer if alloca() allocates slightly more memory. 595 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 596 bottom += os::Linux::page_size() - 1; 597 598 // sp might be slightly above current stack pointer; if that's the case, we 599 // will alloca() a little more space than necessary, which is OK. Don't use 600 // os::current_stack_pointer(), as its result can be slightly below current 601 // stack pointer, causing us to not alloca enough to reach "bottom". 602 sp = (address)&sp; 603 604 if (sp > bottom) { 605 size = sp - bottom; 606 p = (volatile char *)alloca(size); 607 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 608 p[0] = '\0'; 609 } 610 } 611 612 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 613 assert(t!=NULL, "just checking"); 614 assert(t->osthread()->expanding_stack(), "expand should be set"); 615 assert(t->stack_base() != NULL, "stack_base was not initialized"); 616 617 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 618 sigset_t mask_all, old_sigset; 619 sigfillset(&mask_all); 620 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 621 _expand_stack_to(addr); 622 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 623 return true; 624 } 625 return false; 626 } 627 628 ////////////////////////////////////////////////////////////////////////////// 629 // create new thread 630 631 // Thread start routine for all newly created threads 632 static void *thread_native_entry(Thread *thread) { 633 // Try to randomize the cache line index of hot stack frames. 634 // This helps when threads of the same stack traces evict each other's 635 // cache lines. The threads can be either from the same JVM instance, or 636 // from different JVM instances. The benefit is especially true for 637 // processors with hyperthreading technology. 638 static int counter = 0; 639 int pid = os::current_process_id(); 640 alloca(((pid ^ counter++) & 7) * 128); 641 642 thread->initialize_thread_current(); 643 644 OSThread* osthread = thread->osthread(); 645 Monitor* sync = osthread->startThread_lock(); 646 647 osthread->set_thread_id(os::current_thread_id()); 648 649 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 650 os::current_thread_id(), (uintx) pthread_self()); 651 652 if (UseNUMA) { 653 int lgrp_id = os::numa_get_group_id(); 654 if (lgrp_id != -1) { 655 thread->set_lgrp_id(lgrp_id); 656 } 657 } 658 // initialize signal mask for this thread 659 os::Linux::hotspot_sigmask(thread); 660 661 // initialize floating point control register 662 os::Linux::init_thread_fpu_state(); 663 664 // handshaking with parent thread 665 { 666 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 667 668 // notify parent thread 669 osthread->set_state(INITIALIZED); 670 sync->notify_all(); 671 672 // wait until os::start_thread() 673 while (osthread->get_state() == INITIALIZED) { 674 sync->wait(Mutex::_no_safepoint_check_flag); 675 } 676 } 677 678 // call one more level start routine 679 thread->run(); 680 681 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 682 os::current_thread_id(), (uintx) pthread_self()); 683 684 // If a thread has not deleted itself ("delete this") as part of its 685 // termination sequence, we have to ensure thread-local-storage is 686 // cleared before we actually terminate. No threads should ever be 687 // deleted asynchronously with respect to their termination. 688 if (Thread::current_or_null_safe() != NULL) { 689 assert(Thread::current_or_null_safe() == thread, "current thread is wrong"); 690 thread->clear_thread_current(); 691 } 692 693 return 0; 694 } 695 696 bool os::create_thread(Thread* thread, ThreadType thr_type, 697 size_t req_stack_size) { 698 assert(thread->osthread() == NULL, "caller responsible"); 699 700 // Allocate the OSThread object 701 OSThread* osthread = new OSThread(NULL, NULL); 702 if (osthread == NULL) { 703 return false; 704 } 705 706 // set the correct thread state 707 osthread->set_thread_type(thr_type); 708 709 // Initial state is ALLOCATED but not INITIALIZED 710 osthread->set_state(ALLOCATED); 711 712 thread->set_osthread(osthread); 713 714 // init thread attributes 715 pthread_attr_t attr; 716 pthread_attr_init(&attr); 717 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 718 719 // calculate stack size if it's not specified by caller 720 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 721 pthread_attr_setstacksize(&attr, stack_size); 722 723 // glibc guard page 724 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 725 726 ThreadState state; 727 728 { 729 pthread_t tid; 730 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 731 732 char buf[64]; 733 if (ret == 0) { 734 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 735 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 736 } else { 737 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 738 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 739 } 740 741 pthread_attr_destroy(&attr); 742 743 if (ret != 0) { 744 // Need to clean up stuff we've allocated so far 745 thread->set_osthread(NULL); 746 delete osthread; 747 return false; 748 } 749 750 // Store pthread info into the OSThread 751 osthread->set_pthread_id(tid); 752 753 // Wait until child thread is either initialized or aborted 754 { 755 Monitor* sync_with_child = osthread->startThread_lock(); 756 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 757 while ((state = osthread->get_state()) == ALLOCATED) { 758 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 759 } 760 } 761 } 762 763 // Aborted due to thread limit being reached 764 if (state == ZOMBIE) { 765 thread->set_osthread(NULL); 766 delete osthread; 767 return false; 768 } 769 770 // The thread is returned suspended (in state INITIALIZED), 771 // and is started higher up in the call chain 772 assert(state == INITIALIZED, "race condition"); 773 return true; 774 } 775 776 ///////////////////////////////////////////////////////////////////////////// 777 // attach existing thread 778 779 // bootstrap the main thread 780 bool os::create_main_thread(JavaThread* thread) { 781 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 782 return create_attached_thread(thread); 783 } 784 785 bool os::create_attached_thread(JavaThread* thread) { 786 #ifdef ASSERT 787 thread->verify_not_published(); 788 #endif 789 790 // Allocate the OSThread object 791 OSThread* osthread = new OSThread(NULL, NULL); 792 793 if (osthread == NULL) { 794 return false; 795 } 796 797 // Store pthread info into the OSThread 798 osthread->set_thread_id(os::Linux::gettid()); 799 osthread->set_pthread_id(::pthread_self()); 800 801 // initialize floating point control register 802 os::Linux::init_thread_fpu_state(); 803 804 // Initial thread state is RUNNABLE 805 osthread->set_state(RUNNABLE); 806 807 thread->set_osthread(osthread); 808 809 if (UseNUMA) { 810 int lgrp_id = os::numa_get_group_id(); 811 if (lgrp_id != -1) { 812 thread->set_lgrp_id(lgrp_id); 813 } 814 } 815 816 if (os::Linux::is_initial_thread()) { 817 // If current thread is initial thread, its stack is mapped on demand, 818 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 819 // the entire stack region to avoid SEGV in stack banging. 820 // It is also useful to get around the heap-stack-gap problem on SuSE 821 // kernel (see 4821821 for details). We first expand stack to the top 822 // of yellow zone, then enable stack yellow zone (order is significant, 823 // enabling yellow zone first will crash JVM on SuSE Linux), so there 824 // is no gap between the last two virtual memory regions. 825 826 JavaThread *jt = (JavaThread *)thread; 827 address addr = jt->stack_reserved_zone_base(); 828 assert(addr != NULL, "initialization problem?"); 829 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 830 831 osthread->set_expanding_stack(); 832 os::Linux::manually_expand_stack(jt, addr); 833 osthread->clear_expanding_stack(); 834 } 835 836 // initialize signal mask for this thread 837 // and save the caller's signal mask 838 os::Linux::hotspot_sigmask(thread); 839 840 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 841 os::current_thread_id(), (uintx) pthread_self()); 842 843 return true; 844 } 845 846 void os::pd_start_thread(Thread* thread) { 847 OSThread * osthread = thread->osthread(); 848 assert(osthread->get_state() != INITIALIZED, "just checking"); 849 Monitor* sync_with_child = osthread->startThread_lock(); 850 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 851 sync_with_child->notify(); 852 } 853 854 // Free Linux resources related to the OSThread 855 void os::free_thread(OSThread* osthread) { 856 assert(osthread != NULL, "osthread not set"); 857 858 // We are told to free resources of the argument thread, 859 // but we can only really operate on the current thread. 860 assert(Thread::current()->osthread() == osthread, 861 "os::free_thread but not current thread"); 862 863 #ifdef ASSERT 864 sigset_t current; 865 sigemptyset(¤t); 866 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 867 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 868 #endif 869 870 // Restore caller's signal mask 871 sigset_t sigmask = osthread->caller_sigmask(); 872 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 873 874 delete osthread; 875 } 876 877 ////////////////////////////////////////////////////////////////////////////// 878 // initial thread 879 880 // Check if current thread is the initial thread, similar to Solaris thr_main. 881 bool os::Linux::is_initial_thread(void) { 882 char dummy; 883 // If called before init complete, thread stack bottom will be null. 884 // Can be called if fatal error occurs before initialization. 885 if (initial_thread_stack_bottom() == NULL) return false; 886 assert(initial_thread_stack_bottom() != NULL && 887 initial_thread_stack_size() != 0, 888 "os::init did not locate initial thread's stack region"); 889 if ((address)&dummy >= initial_thread_stack_bottom() && 890 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 891 return true; 892 } else { 893 return false; 894 } 895 } 896 897 // Find the virtual memory area that contains addr 898 static bool find_vma(address addr, address* vma_low, address* vma_high) { 899 FILE *fp = fopen("/proc/self/maps", "r"); 900 if (fp) { 901 address low, high; 902 while (!feof(fp)) { 903 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 904 if (low <= addr && addr < high) { 905 if (vma_low) *vma_low = low; 906 if (vma_high) *vma_high = high; 907 fclose(fp); 908 return true; 909 } 910 } 911 for (;;) { 912 int ch = fgetc(fp); 913 if (ch == EOF || ch == (int)'\n') break; 914 } 915 } 916 fclose(fp); 917 } 918 return false; 919 } 920 921 // Locate initial thread stack. This special handling of initial thread stack 922 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 923 // bogus value for initial thread. 924 void os::Linux::capture_initial_stack(size_t max_size) { 925 // stack size is the easy part, get it from RLIMIT_STACK 926 struct rlimit rlim; 927 getrlimit(RLIMIT_STACK, &rlim); 928 size_t stack_size = rlim.rlim_cur; 929 930 // 6308388: a bug in ld.so will relocate its own .data section to the 931 // lower end of primordial stack; reduce ulimit -s value a little bit 932 // so we won't install guard page on ld.so's data section. 933 stack_size -= 2 * page_size(); 934 935 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 936 // 7.1, in both cases we will get 2G in return value. 937 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 938 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 939 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 940 // in case other parts in glibc still assumes 2M max stack size. 941 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 942 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 943 if (stack_size > 2 * K * K IA64_ONLY(*2)) { 944 stack_size = 2 * K * K IA64_ONLY(*2); 945 } 946 // Try to figure out where the stack base (top) is. This is harder. 947 // 948 // When an application is started, glibc saves the initial stack pointer in 949 // a global variable "__libc_stack_end", which is then used by system 950 // libraries. __libc_stack_end should be pretty close to stack top. The 951 // variable is available since the very early days. However, because it is 952 // a private interface, it could disappear in the future. 953 // 954 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 955 // to __libc_stack_end, it is very close to stack top, but isn't the real 956 // stack top. Note that /proc may not exist if VM is running as a chroot 957 // program, so reading /proc/<pid>/stat could fail. Also the contents of 958 // /proc/<pid>/stat could change in the future (though unlikely). 959 // 960 // We try __libc_stack_end first. If that doesn't work, look for 961 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 962 // as a hint, which should work well in most cases. 963 964 uintptr_t stack_start; 965 966 // try __libc_stack_end first 967 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 968 if (p && *p) { 969 stack_start = *p; 970 } else { 971 // see if we can get the start_stack field from /proc/self/stat 972 FILE *fp; 973 int pid; 974 char state; 975 int ppid; 976 int pgrp; 977 int session; 978 int nr; 979 int tpgrp; 980 unsigned long flags; 981 unsigned long minflt; 982 unsigned long cminflt; 983 unsigned long majflt; 984 unsigned long cmajflt; 985 unsigned long utime; 986 unsigned long stime; 987 long cutime; 988 long cstime; 989 long prio; 990 long nice; 991 long junk; 992 long it_real; 993 uintptr_t start; 994 uintptr_t vsize; 995 intptr_t rss; 996 uintptr_t rsslim; 997 uintptr_t scodes; 998 uintptr_t ecode; 999 int i; 1000 1001 // Figure what the primordial thread stack base is. Code is inspired 1002 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1003 // followed by command name surrounded by parentheses, state, etc. 1004 char stat[2048]; 1005 int statlen; 1006 1007 fp = fopen("/proc/self/stat", "r"); 1008 if (fp) { 1009 statlen = fread(stat, 1, 2047, fp); 1010 stat[statlen] = '\0'; 1011 fclose(fp); 1012 1013 // Skip pid and the command string. Note that we could be dealing with 1014 // weird command names, e.g. user could decide to rename java launcher 1015 // to "java 1.4.2 :)", then the stat file would look like 1016 // 1234 (java 1.4.2 :)) R ... ... 1017 // We don't really need to know the command string, just find the last 1018 // occurrence of ")" and then start parsing from there. See bug 4726580. 1019 char * s = strrchr(stat, ')'); 1020 1021 i = 0; 1022 if (s) { 1023 // Skip blank chars 1024 do { s++; } while (s && isspace(*s)); 1025 1026 #define _UFM UINTX_FORMAT 1027 #define _DFM INTX_FORMAT 1028 1029 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1030 // 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 1031 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, 1032 &state, // 3 %c 1033 &ppid, // 4 %d 1034 &pgrp, // 5 %d 1035 &session, // 6 %d 1036 &nr, // 7 %d 1037 &tpgrp, // 8 %d 1038 &flags, // 9 %lu 1039 &minflt, // 10 %lu 1040 &cminflt, // 11 %lu 1041 &majflt, // 12 %lu 1042 &cmajflt, // 13 %lu 1043 &utime, // 14 %lu 1044 &stime, // 15 %lu 1045 &cutime, // 16 %ld 1046 &cstime, // 17 %ld 1047 &prio, // 18 %ld 1048 &nice, // 19 %ld 1049 &junk, // 20 %ld 1050 &it_real, // 21 %ld 1051 &start, // 22 UINTX_FORMAT 1052 &vsize, // 23 UINTX_FORMAT 1053 &rss, // 24 INTX_FORMAT 1054 &rsslim, // 25 UINTX_FORMAT 1055 &scodes, // 26 UINTX_FORMAT 1056 &ecode, // 27 UINTX_FORMAT 1057 &stack_start); // 28 UINTX_FORMAT 1058 } 1059 1060 #undef _UFM 1061 #undef _DFM 1062 1063 if (i != 28 - 2) { 1064 assert(false, "Bad conversion from /proc/self/stat"); 1065 // product mode - assume we are the initial thread, good luck in the 1066 // embedded case. 1067 warning("Can't detect initial thread stack location - bad conversion"); 1068 stack_start = (uintptr_t) &rlim; 1069 } 1070 } else { 1071 // For some reason we can't open /proc/self/stat (for example, running on 1072 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1073 // most cases, so don't abort: 1074 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1075 stack_start = (uintptr_t) &rlim; 1076 } 1077 } 1078 1079 // Now we have a pointer (stack_start) very close to the stack top, the 1080 // next thing to do is to figure out the exact location of stack top. We 1081 // can find out the virtual memory area that contains stack_start by 1082 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1083 // and its upper limit is the real stack top. (again, this would fail if 1084 // running inside chroot, because /proc may not exist.) 1085 1086 uintptr_t stack_top; 1087 address low, high; 1088 if (find_vma((address)stack_start, &low, &high)) { 1089 // success, "high" is the true stack top. (ignore "low", because initial 1090 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1091 stack_top = (uintptr_t)high; 1092 } else { 1093 // failed, likely because /proc/self/maps does not exist 1094 warning("Can't detect initial thread stack location - find_vma failed"); 1095 // best effort: stack_start is normally within a few pages below the real 1096 // stack top, use it as stack top, and reduce stack size so we won't put 1097 // guard page outside stack. 1098 stack_top = stack_start; 1099 stack_size -= 16 * page_size(); 1100 } 1101 1102 // stack_top could be partially down the page so align it 1103 stack_top = align_size_up(stack_top, page_size()); 1104 1105 if (max_size && stack_size > max_size) { 1106 _initial_thread_stack_size = max_size; 1107 } else { 1108 _initial_thread_stack_size = stack_size; 1109 } 1110 1111 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1112 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1113 } 1114 1115 //////////////////////////////////////////////////////////////////////////////// 1116 // time support 1117 1118 // Time since start-up in seconds to a fine granularity. 1119 // Used by VMSelfDestructTimer and the MemProfiler. 1120 double os::elapsedTime() { 1121 1122 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1123 } 1124 1125 jlong os::elapsed_counter() { 1126 return javaTimeNanos() - initial_time_count; 1127 } 1128 1129 jlong os::elapsed_frequency() { 1130 return NANOSECS_PER_SEC; // nanosecond resolution 1131 } 1132 1133 bool os::supports_vtime() { return true; } 1134 bool os::enable_vtime() { return false; } 1135 bool os::vtime_enabled() { return false; } 1136 1137 double os::elapsedVTime() { 1138 struct rusage usage; 1139 int retval = getrusage(RUSAGE_THREAD, &usage); 1140 if (retval == 0) { 1141 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000); 1142 } else { 1143 // better than nothing, but not much 1144 return elapsedTime(); 1145 } 1146 } 1147 1148 jlong os::javaTimeMillis() { 1149 timeval time; 1150 int status = gettimeofday(&time, NULL); 1151 assert(status != -1, "linux error"); 1152 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1153 } 1154 1155 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1156 timeval time; 1157 int status = gettimeofday(&time, NULL); 1158 assert(status != -1, "linux error"); 1159 seconds = jlong(time.tv_sec); 1160 nanos = jlong(time.tv_usec) * 1000; 1161 } 1162 1163 1164 #ifndef CLOCK_MONOTONIC 1165 #define CLOCK_MONOTONIC (1) 1166 #endif 1167 1168 void os::Linux::clock_init() { 1169 // we do dlopen's in this particular order due to bug in linux 1170 // dynamical loader (see 6348968) leading to crash on exit 1171 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1172 if (handle == NULL) { 1173 handle = dlopen("librt.so", RTLD_LAZY); 1174 } 1175 1176 if (handle) { 1177 int (*clock_getres_func)(clockid_t, struct timespec*) = 1178 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1179 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1180 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1181 if (clock_getres_func && clock_gettime_func) { 1182 // See if monotonic clock is supported by the kernel. Note that some 1183 // early implementations simply return kernel jiffies (updated every 1184 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1185 // for nano time (though the monotonic property is still nice to have). 1186 // It's fixed in newer kernels, however clock_getres() still returns 1187 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1188 // resolution for now. Hopefully as people move to new kernels, this 1189 // won't be a problem. 1190 struct timespec res; 1191 struct timespec tp; 1192 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1193 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1194 // yes, monotonic clock is supported 1195 _clock_gettime = clock_gettime_func; 1196 return; 1197 } else { 1198 // close librt if there is no monotonic clock 1199 dlclose(handle); 1200 } 1201 } 1202 } 1203 warning("No monotonic clock was available - timed services may " \ 1204 "be adversely affected if the time-of-day clock changes"); 1205 } 1206 1207 #ifndef SYS_clock_getres 1208 #if defined(X86) || defined(PPC64) || defined(S390) 1209 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261) 1210 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1211 #else 1212 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1213 #define sys_clock_getres(x,y) -1 1214 #endif 1215 #else 1216 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1217 #endif 1218 1219 void os::Linux::fast_thread_clock_init() { 1220 if (!UseLinuxPosixThreadCPUClocks) { 1221 return; 1222 } 1223 clockid_t clockid; 1224 struct timespec tp; 1225 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1226 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1227 1228 // Switch to using fast clocks for thread cpu time if 1229 // the sys_clock_getres() returns 0 error code. 1230 // Note, that some kernels may support the current thread 1231 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1232 // returned by the pthread_getcpuclockid(). 1233 // If the fast Posix clocks are supported then the sys_clock_getres() 1234 // must return at least tp.tv_sec == 0 which means a resolution 1235 // better than 1 sec. This is extra check for reliability. 1236 1237 if (pthread_getcpuclockid_func && 1238 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1239 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1240 _supports_fast_thread_cpu_time = true; 1241 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1242 } 1243 } 1244 1245 jlong os::javaTimeNanos() { 1246 if (os::supports_monotonic_clock()) { 1247 struct timespec tp; 1248 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1249 assert(status == 0, "gettime error"); 1250 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1251 return result; 1252 } else { 1253 timeval time; 1254 int status = gettimeofday(&time, NULL); 1255 assert(status != -1, "linux error"); 1256 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1257 return 1000 * usecs; 1258 } 1259 } 1260 1261 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1262 if (os::supports_monotonic_clock()) { 1263 info_ptr->max_value = ALL_64_BITS; 1264 1265 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1266 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1267 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1268 } else { 1269 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1270 info_ptr->max_value = ALL_64_BITS; 1271 1272 // gettimeofday is a real time clock so it skips 1273 info_ptr->may_skip_backward = true; 1274 info_ptr->may_skip_forward = true; 1275 } 1276 1277 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1278 } 1279 1280 // Return the real, user, and system times in seconds from an 1281 // arbitrary fixed point in the past. 1282 bool os::getTimesSecs(double* process_real_time, 1283 double* process_user_time, 1284 double* process_system_time) { 1285 struct tms ticks; 1286 clock_t real_ticks = times(&ticks); 1287 1288 if (real_ticks == (clock_t) (-1)) { 1289 return false; 1290 } else { 1291 double ticks_per_second = (double) clock_tics_per_sec; 1292 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1293 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1294 *process_real_time = ((double) real_ticks) / ticks_per_second; 1295 1296 return true; 1297 } 1298 } 1299 1300 1301 char * os::local_time_string(char *buf, size_t buflen) { 1302 struct tm t; 1303 time_t long_time; 1304 time(&long_time); 1305 localtime_r(&long_time, &t); 1306 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1307 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1308 t.tm_hour, t.tm_min, t.tm_sec); 1309 return buf; 1310 } 1311 1312 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1313 return localtime_r(clock, res); 1314 } 1315 1316 //////////////////////////////////////////////////////////////////////////////// 1317 // runtime exit support 1318 1319 // Note: os::shutdown() might be called very early during initialization, or 1320 // called from signal handler. Before adding something to os::shutdown(), make 1321 // sure it is async-safe and can handle partially initialized VM. 1322 void os::shutdown() { 1323 1324 // allow PerfMemory to attempt cleanup of any persistent resources 1325 perfMemory_exit(); 1326 1327 // needs to remove object in file system 1328 AttachListener::abort(); 1329 1330 // flush buffered output, finish log files 1331 ostream_abort(); 1332 1333 // Check for abort hook 1334 abort_hook_t abort_hook = Arguments::abort_hook(); 1335 if (abort_hook != NULL) { 1336 abort_hook(); 1337 } 1338 1339 } 1340 1341 // Note: os::abort() might be called very early during initialization, or 1342 // called from signal handler. Before adding something to os::abort(), make 1343 // sure it is async-safe and can handle partially initialized VM. 1344 void os::abort(bool dump_core, void* siginfo, const void* context) { 1345 os::shutdown(); 1346 if (dump_core) { 1347 #ifndef PRODUCT 1348 fdStream out(defaultStream::output_fd()); 1349 out.print_raw("Current thread is "); 1350 char buf[16]; 1351 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1352 out.print_raw_cr(buf); 1353 out.print_raw_cr("Dumping core ..."); 1354 #endif 1355 ::abort(); // dump core 1356 } 1357 1358 ::exit(1); 1359 } 1360 1361 // Die immediately, no exit hook, no abort hook, no cleanup. 1362 void os::die() { 1363 ::abort(); 1364 } 1365 1366 1367 // This method is a copy of JDK's sysGetLastErrorString 1368 // from src/solaris/hpi/src/system_md.c 1369 1370 size_t os::lasterror(char *buf, size_t len) { 1371 if (errno == 0) return 0; 1372 1373 const char *s = os::strerror(errno); 1374 size_t n = ::strlen(s); 1375 if (n >= len) { 1376 n = len - 1; 1377 } 1378 ::strncpy(buf, s, n); 1379 buf[n] = '\0'; 1380 return n; 1381 } 1382 1383 // thread_id is kernel thread id (similar to Solaris LWP id) 1384 intx os::current_thread_id() { return os::Linux::gettid(); } 1385 int os::current_process_id() { 1386 return ::getpid(); 1387 } 1388 1389 // DLL functions 1390 1391 const char* os::dll_file_extension() { return ".so"; } 1392 1393 // This must be hard coded because it's the system's temporary 1394 // directory not the java application's temp directory, ala java.io.tmpdir. 1395 const char* os::get_temp_directory() { return "/tmp"; } 1396 1397 static bool file_exists(const char* filename) { 1398 struct stat statbuf; 1399 if (filename == NULL || strlen(filename) == 0) { 1400 return false; 1401 } 1402 return os::stat(filename, &statbuf) == 0; 1403 } 1404 1405 bool os::dll_build_name(char* buffer, size_t buflen, 1406 const char* pname, const char* fname) { 1407 bool retval = false; 1408 // Copied from libhpi 1409 const size_t pnamelen = pname ? strlen(pname) : 0; 1410 1411 // Return error on buffer overflow. 1412 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1413 return retval; 1414 } 1415 1416 if (pnamelen == 0) { 1417 snprintf(buffer, buflen, "lib%s.so", fname); 1418 retval = true; 1419 } else if (strchr(pname, *os::path_separator()) != NULL) { 1420 int n; 1421 char** pelements = split_path(pname, &n); 1422 if (pelements == NULL) { 1423 return false; 1424 } 1425 for (int i = 0; i < n; i++) { 1426 // Really shouldn't be NULL, but check can't hurt 1427 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1428 continue; // skip the empty path values 1429 } 1430 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1431 if (file_exists(buffer)) { 1432 retval = true; 1433 break; 1434 } 1435 } 1436 // release the storage 1437 for (int i = 0; i < n; i++) { 1438 if (pelements[i] != NULL) { 1439 FREE_C_HEAP_ARRAY(char, pelements[i]); 1440 } 1441 } 1442 if (pelements != NULL) { 1443 FREE_C_HEAP_ARRAY(char*, pelements); 1444 } 1445 } else { 1446 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1447 retval = true; 1448 } 1449 return retval; 1450 } 1451 1452 // check if addr is inside libjvm.so 1453 bool os::address_is_in_vm(address addr) { 1454 static address libjvm_base_addr; 1455 Dl_info dlinfo; 1456 1457 if (libjvm_base_addr == NULL) { 1458 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1459 libjvm_base_addr = (address)dlinfo.dli_fbase; 1460 } 1461 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1462 } 1463 1464 if (dladdr((void *)addr, &dlinfo) != 0) { 1465 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1466 } 1467 1468 return false; 1469 } 1470 1471 bool os::dll_address_to_function_name(address addr, char *buf, 1472 int buflen, int *offset, 1473 bool demangle) { 1474 // buf is not optional, but offset is optional 1475 assert(buf != NULL, "sanity check"); 1476 1477 Dl_info dlinfo; 1478 1479 if (dladdr((void*)addr, &dlinfo) != 0) { 1480 // see if we have a matching symbol 1481 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1482 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1483 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1484 } 1485 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1486 return true; 1487 } 1488 // no matching symbol so try for just file info 1489 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1490 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1491 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1492 return true; 1493 } 1494 } 1495 } 1496 1497 buf[0] = '\0'; 1498 if (offset != NULL) *offset = -1; 1499 return false; 1500 } 1501 1502 struct _address_to_library_name { 1503 address addr; // input : memory address 1504 size_t buflen; // size of fname 1505 char* fname; // output: library name 1506 address base; // library base addr 1507 }; 1508 1509 static int address_to_library_name_callback(struct dl_phdr_info *info, 1510 size_t size, void *data) { 1511 int i; 1512 bool found = false; 1513 address libbase = NULL; 1514 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1515 1516 // iterate through all loadable segments 1517 for (i = 0; i < info->dlpi_phnum; i++) { 1518 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1519 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1520 // base address of a library is the lowest address of its loaded 1521 // segments. 1522 if (libbase == NULL || libbase > segbase) { 1523 libbase = segbase; 1524 } 1525 // see if 'addr' is within current segment 1526 if (segbase <= d->addr && 1527 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1528 found = true; 1529 } 1530 } 1531 } 1532 1533 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1534 // so dll_address_to_library_name() can fall through to use dladdr() which 1535 // can figure out executable name from argv[0]. 1536 if (found && info->dlpi_name && info->dlpi_name[0]) { 1537 d->base = libbase; 1538 if (d->fname) { 1539 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1540 } 1541 return 1; 1542 } 1543 return 0; 1544 } 1545 1546 bool os::dll_address_to_library_name(address addr, char* buf, 1547 int buflen, int* offset) { 1548 // buf is not optional, but offset is optional 1549 assert(buf != NULL, "sanity check"); 1550 1551 Dl_info dlinfo; 1552 struct _address_to_library_name data; 1553 1554 // There is a bug in old glibc dladdr() implementation that it could resolve 1555 // to wrong library name if the .so file has a base address != NULL. Here 1556 // we iterate through the program headers of all loaded libraries to find 1557 // out which library 'addr' really belongs to. This workaround can be 1558 // removed once the minimum requirement for glibc is moved to 2.3.x. 1559 data.addr = addr; 1560 data.fname = buf; 1561 data.buflen = buflen; 1562 data.base = NULL; 1563 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1564 1565 if (rslt) { 1566 // buf already contains library name 1567 if (offset) *offset = addr - data.base; 1568 return true; 1569 } 1570 if (dladdr((void*)addr, &dlinfo) != 0) { 1571 if (dlinfo.dli_fname != NULL) { 1572 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1573 } 1574 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1575 *offset = addr - (address)dlinfo.dli_fbase; 1576 } 1577 return true; 1578 } 1579 1580 buf[0] = '\0'; 1581 if (offset) *offset = -1; 1582 return false; 1583 } 1584 1585 // Loads .dll/.so and 1586 // in case of error it checks if .dll/.so was built for the 1587 // same architecture as Hotspot is running on 1588 1589 1590 // Remember the stack's state. The Linux dynamic linker will change 1591 // the stack to 'executable' at most once, so we must safepoint only once. 1592 bool os::Linux::_stack_is_executable = false; 1593 1594 // VM operation that loads a library. This is necessary if stack protection 1595 // of the Java stacks can be lost during loading the library. If we 1596 // do not stop the Java threads, they can stack overflow before the stacks 1597 // are protected again. 1598 class VM_LinuxDllLoad: public VM_Operation { 1599 private: 1600 const char *_filename; 1601 char *_ebuf; 1602 int _ebuflen; 1603 void *_lib; 1604 public: 1605 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1606 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1607 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1608 void doit() { 1609 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1610 os::Linux::_stack_is_executable = true; 1611 } 1612 void* loaded_library() { return _lib; } 1613 }; 1614 1615 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1616 void * result = NULL; 1617 bool load_attempted = false; 1618 1619 // Check whether the library to load might change execution rights 1620 // of the stack. If they are changed, the protection of the stack 1621 // guard pages will be lost. We need a safepoint to fix this. 1622 // 1623 // See Linux man page execstack(8) for more info. 1624 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1625 ElfFile ef(filename); 1626 if (!ef.specifies_noexecstack()) { 1627 if (!is_init_completed()) { 1628 os::Linux::_stack_is_executable = true; 1629 // This is OK - No Java threads have been created yet, and hence no 1630 // stack guard pages to fix. 1631 // 1632 // This should happen only when you are building JDK7 using a very 1633 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1634 // 1635 // Dynamic loader will make all stacks executable after 1636 // this function returns, and will not do that again. 1637 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1638 } else { 1639 warning("You have loaded library %s which might have disabled stack guard. " 1640 "The VM will try to fix the stack guard now.\n" 1641 "It's highly recommended that you fix the library with " 1642 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1643 filename); 1644 1645 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1646 JavaThread *jt = JavaThread::current(); 1647 if (jt->thread_state() != _thread_in_native) { 1648 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1649 // that requires ExecStack. Cannot enter safe point. Let's give up. 1650 warning("Unable to fix stack guard. Giving up."); 1651 } else { 1652 if (!LoadExecStackDllInVMThread) { 1653 // This is for the case where the DLL has an static 1654 // constructor function that executes JNI code. We cannot 1655 // load such DLLs in the VMThread. 1656 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1657 } 1658 1659 ThreadInVMfromNative tiv(jt); 1660 debug_only(VMNativeEntryWrapper vew;) 1661 1662 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1663 VMThread::execute(&op); 1664 if (LoadExecStackDllInVMThread) { 1665 result = op.loaded_library(); 1666 } 1667 load_attempted = true; 1668 } 1669 } 1670 } 1671 } 1672 1673 if (!load_attempted) { 1674 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1675 } 1676 1677 if (result != NULL) { 1678 // Successful loading 1679 return result; 1680 } 1681 1682 Elf32_Ehdr elf_head; 1683 int diag_msg_max_length=ebuflen-strlen(ebuf); 1684 char* diag_msg_buf=ebuf+strlen(ebuf); 1685 1686 if (diag_msg_max_length==0) { 1687 // No more space in ebuf for additional diagnostics message 1688 return NULL; 1689 } 1690 1691 1692 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1693 1694 if (file_descriptor < 0) { 1695 // Can't open library, report dlerror() message 1696 return NULL; 1697 } 1698 1699 bool failed_to_read_elf_head= 1700 (sizeof(elf_head)!= 1701 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1702 1703 ::close(file_descriptor); 1704 if (failed_to_read_elf_head) { 1705 // file i/o error - report dlerror() msg 1706 return NULL; 1707 } 1708 1709 typedef struct { 1710 Elf32_Half code; // Actual value as defined in elf.h 1711 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1712 unsigned char elf_class; // 32 or 64 bit 1713 unsigned char endianess; // MSB or LSB 1714 char* name; // String representation 1715 } arch_t; 1716 1717 #ifndef EM_486 1718 #define EM_486 6 /* Intel 80486 */ 1719 #endif 1720 #ifndef EM_AARCH64 1721 #define EM_AARCH64 183 /* ARM AARCH64 */ 1722 #endif 1723 1724 static const arch_t arch_array[]={ 1725 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1726 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1727 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1728 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1729 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1730 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1731 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1732 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1733 #if defined(VM_LITTLE_ENDIAN) 1734 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1735 #else 1736 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"}, 1737 #endif 1738 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1739 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1740 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1741 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1742 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1743 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1744 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1745 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1746 }; 1747 1748 #if (defined IA32) 1749 static Elf32_Half running_arch_code=EM_386; 1750 #elif (defined AMD64) 1751 static Elf32_Half running_arch_code=EM_X86_64; 1752 #elif (defined IA64) 1753 static Elf32_Half running_arch_code=EM_IA_64; 1754 #elif (defined __sparc) && (defined _LP64) 1755 static Elf32_Half running_arch_code=EM_SPARCV9; 1756 #elif (defined __sparc) && (!defined _LP64) 1757 static Elf32_Half running_arch_code=EM_SPARC; 1758 #elif (defined __powerpc64__) 1759 static Elf32_Half running_arch_code=EM_PPC64; 1760 #elif (defined __powerpc__) 1761 static Elf32_Half running_arch_code=EM_PPC; 1762 #elif (defined AARCH64) 1763 static Elf32_Half running_arch_code=EM_AARCH64; 1764 #elif (defined ARM) 1765 static Elf32_Half running_arch_code=EM_ARM; 1766 #elif (defined S390) 1767 static Elf32_Half running_arch_code=EM_S390; 1768 #elif (defined ALPHA) 1769 static Elf32_Half running_arch_code=EM_ALPHA; 1770 #elif (defined MIPSEL) 1771 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1772 #elif (defined PARISC) 1773 static Elf32_Half running_arch_code=EM_PARISC; 1774 #elif (defined MIPS) 1775 static Elf32_Half running_arch_code=EM_MIPS; 1776 #elif (defined M68K) 1777 static Elf32_Half running_arch_code=EM_68K; 1778 #else 1779 #error Method os::dll_load requires that one of following is defined:\ 1780 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, __sparc 1781 #endif 1782 1783 // Identify compatability class for VM's architecture and library's architecture 1784 // Obtain string descriptions for architectures 1785 1786 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1787 int running_arch_index=-1; 1788 1789 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1790 if (running_arch_code == arch_array[i].code) { 1791 running_arch_index = i; 1792 } 1793 if (lib_arch.code == arch_array[i].code) { 1794 lib_arch.compat_class = arch_array[i].compat_class; 1795 lib_arch.name = arch_array[i].name; 1796 } 1797 } 1798 1799 assert(running_arch_index != -1, 1800 "Didn't find running architecture code (running_arch_code) in arch_array"); 1801 if (running_arch_index == -1) { 1802 // Even though running architecture detection failed 1803 // we may still continue with reporting dlerror() message 1804 return NULL; 1805 } 1806 1807 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1808 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1809 return NULL; 1810 } 1811 1812 #ifndef S390 1813 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1814 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1815 return NULL; 1816 } 1817 #endif // !S390 1818 1819 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1820 if (lib_arch.name!=NULL) { 1821 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1822 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1823 lib_arch.name, arch_array[running_arch_index].name); 1824 } else { 1825 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1826 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1827 lib_arch.code, 1828 arch_array[running_arch_index].name); 1829 } 1830 } 1831 1832 return NULL; 1833 } 1834 1835 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1836 int ebuflen) { 1837 void * result = ::dlopen(filename, RTLD_LAZY); 1838 if (result == NULL) { 1839 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1840 ebuf[ebuflen-1] = '\0'; 1841 } 1842 return result; 1843 } 1844 1845 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1846 int ebuflen) { 1847 void * result = NULL; 1848 if (LoadExecStackDllInVMThread) { 1849 result = dlopen_helper(filename, ebuf, ebuflen); 1850 } 1851 1852 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1853 // library that requires an executable stack, or which does not have this 1854 // stack attribute set, dlopen changes the stack attribute to executable. The 1855 // read protection of the guard pages gets lost. 1856 // 1857 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1858 // may have been queued at the same time. 1859 1860 if (!_stack_is_executable) { 1861 JavaThread *jt = Threads::first(); 1862 1863 while (jt) { 1864 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1865 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1866 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1867 warning("Attempt to reguard stack yellow zone failed."); 1868 } 1869 } 1870 jt = jt->next(); 1871 } 1872 } 1873 1874 return result; 1875 } 1876 1877 void* os::dll_lookup(void* handle, const char* name) { 1878 void* res = dlsym(handle, name); 1879 return res; 1880 } 1881 1882 void* os::get_default_process_handle() { 1883 return (void*)::dlopen(NULL, RTLD_LAZY); 1884 } 1885 1886 static bool _print_ascii_file(const char* filename, outputStream* st) { 1887 int fd = ::open(filename, O_RDONLY); 1888 if (fd == -1) { 1889 return false; 1890 } 1891 1892 char buf[33]; 1893 int bytes; 1894 buf[32] = '\0'; 1895 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1896 st->print_raw(buf, bytes); 1897 } 1898 1899 ::close(fd); 1900 1901 return true; 1902 } 1903 1904 void os::print_dll_info(outputStream *st) { 1905 st->print_cr("Dynamic libraries:"); 1906 1907 char fname[32]; 1908 pid_t pid = os::Linux::gettid(); 1909 1910 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1911 1912 if (!_print_ascii_file(fname, st)) { 1913 st->print("Can not get library information for pid = %d\n", pid); 1914 } 1915 } 1916 1917 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1918 FILE *procmapsFile = NULL; 1919 1920 // Open the procfs maps file for the current process 1921 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1922 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1923 char line[PATH_MAX + 100]; 1924 1925 // Read line by line from 'file' 1926 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1927 u8 base, top, offset, inode; 1928 char permissions[5]; 1929 char device[6]; 1930 char name[PATH_MAX + 1]; 1931 1932 // Parse fields from line 1933 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1934 &base, &top, permissions, &offset, device, &inode, name); 1935 1936 // Filter by device id '00:00' so that we only get file system mapped files. 1937 if (strcmp(device, "00:00") != 0) { 1938 1939 // Call callback with the fields of interest 1940 if(callback(name, (address)base, (address)top, param)) { 1941 // Oops abort, callback aborted 1942 fclose(procmapsFile); 1943 return 1; 1944 } 1945 } 1946 } 1947 fclose(procmapsFile); 1948 } 1949 return 0; 1950 } 1951 1952 void os::print_os_info_brief(outputStream* st) { 1953 os::Linux::print_distro_info(st); 1954 1955 os::Posix::print_uname_info(st); 1956 1957 os::Linux::print_libversion_info(st); 1958 1959 } 1960 1961 void os::print_os_info(outputStream* st) { 1962 st->print("OS:"); 1963 1964 os::Linux::print_distro_info(st); 1965 1966 os::Posix::print_uname_info(st); 1967 1968 // Print warning if unsafe chroot environment detected 1969 if (unsafe_chroot_detected) { 1970 st->print("WARNING!! "); 1971 st->print_cr("%s", unstable_chroot_error); 1972 } 1973 1974 os::Linux::print_libversion_info(st); 1975 1976 os::Posix::print_rlimit_info(st); 1977 1978 os::Posix::print_load_average(st); 1979 1980 os::Linux::print_full_memory_info(st); 1981 } 1982 1983 // Try to identify popular distros. 1984 // Most Linux distributions have a /etc/XXX-release file, which contains 1985 // the OS version string. Newer Linux distributions have a /etc/lsb-release 1986 // file that also contains the OS version string. Some have more than one 1987 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 1988 // /etc/redhat-release.), so the order is important. 1989 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 1990 // their own specific XXX-release file as well as a redhat-release file. 1991 // Because of this the XXX-release file needs to be searched for before the 1992 // redhat-release file. 1993 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 1994 // search for redhat-release / SuSE-release needs to be before lsb-release. 1995 // Since the lsb-release file is the new standard it needs to be searched 1996 // before the older style release files. 1997 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 1998 // next to last resort. The os-release file is a new standard that contains 1999 // distribution information and the system-release file seems to be an old 2000 // standard that has been replaced by the lsb-release and os-release files. 2001 // Searching for the debian_version file is the last resort. It contains 2002 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2003 // "Debian " is printed before the contents of the debian_version file. 2004 2005 const char* distro_files[] = { 2006 "/etc/oracle-release", 2007 "/etc/mandriva-release", 2008 "/etc/mandrake-release", 2009 "/etc/sun-release", 2010 "/etc/redhat-release", 2011 "/etc/SuSE-release", 2012 "/etc/lsb-release", 2013 "/etc/turbolinux-release", 2014 "/etc/gentoo-release", 2015 "/etc/ltib-release", 2016 "/etc/angstrom-version", 2017 "/etc/system-release", 2018 "/etc/os-release", 2019 NULL }; 2020 2021 void os::Linux::print_distro_info(outputStream* st) { 2022 for (int i = 0;; i++) { 2023 const char* file = distro_files[i]; 2024 if (file == NULL) { 2025 break; // done 2026 } 2027 // If file prints, we found it. 2028 if (_print_ascii_file(file, st)) { 2029 return; 2030 } 2031 } 2032 2033 if (file_exists("/etc/debian_version")) { 2034 st->print("Debian "); 2035 _print_ascii_file("/etc/debian_version", st); 2036 } else { 2037 st->print("Linux"); 2038 } 2039 st->cr(); 2040 } 2041 2042 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2043 char buf[256]; 2044 while (fgets(buf, sizeof(buf), fp)) { 2045 // Edit out extra stuff in expected format 2046 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2047 char* ptr = strstr(buf, "\""); // the name is in quotes 2048 if (ptr != NULL) { 2049 ptr++; // go beyond first quote 2050 char* nl = strchr(ptr, '\"'); 2051 if (nl != NULL) *nl = '\0'; 2052 strncpy(distro, ptr, length); 2053 } else { 2054 ptr = strstr(buf, "="); 2055 ptr++; // go beyond equals then 2056 char* nl = strchr(ptr, '\n'); 2057 if (nl != NULL) *nl = '\0'; 2058 strncpy(distro, ptr, length); 2059 } 2060 return; 2061 } else if (get_first_line) { 2062 char* nl = strchr(buf, '\n'); 2063 if (nl != NULL) *nl = '\0'; 2064 strncpy(distro, buf, length); 2065 return; 2066 } 2067 } 2068 // print last line and close 2069 char* nl = strchr(buf, '\n'); 2070 if (nl != NULL) *nl = '\0'; 2071 strncpy(distro, buf, length); 2072 } 2073 2074 static void parse_os_info(char* distro, size_t length, const char* file) { 2075 FILE* fp = fopen(file, "r"); 2076 if (fp != NULL) { 2077 // if suse format, print out first line 2078 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2079 parse_os_info_helper(fp, distro, length, get_first_line); 2080 fclose(fp); 2081 } 2082 } 2083 2084 void os::get_summary_os_info(char* buf, size_t buflen) { 2085 for (int i = 0;; i++) { 2086 const char* file = distro_files[i]; 2087 if (file == NULL) { 2088 break; // ran out of distro_files 2089 } 2090 if (file_exists(file)) { 2091 parse_os_info(buf, buflen, file); 2092 return; 2093 } 2094 } 2095 // special case for debian 2096 if (file_exists("/etc/debian_version")) { 2097 strncpy(buf, "Debian ", buflen); 2098 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2099 } else { 2100 strncpy(buf, "Linux", buflen); 2101 } 2102 } 2103 2104 void os::Linux::print_libversion_info(outputStream* st) { 2105 // libc, pthread 2106 st->print("libc:"); 2107 st->print("%s ", os::Linux::glibc_version()); 2108 st->print("%s ", os::Linux::libpthread_version()); 2109 st->cr(); 2110 } 2111 2112 void os::Linux::print_full_memory_info(outputStream* st) { 2113 st->print("\n/proc/meminfo:\n"); 2114 _print_ascii_file("/proc/meminfo", st); 2115 st->cr(); 2116 } 2117 2118 void os::print_memory_info(outputStream* st) { 2119 2120 st->print("Memory:"); 2121 st->print(" %dk page", os::vm_page_size()>>10); 2122 2123 // values in struct sysinfo are "unsigned long" 2124 struct sysinfo si; 2125 sysinfo(&si); 2126 2127 st->print(", physical " UINT64_FORMAT "k", 2128 os::physical_memory() >> 10); 2129 st->print("(" UINT64_FORMAT "k free)", 2130 os::available_memory() >> 10); 2131 st->print(", swap " UINT64_FORMAT "k", 2132 ((jlong)si.totalswap * si.mem_unit) >> 10); 2133 st->print("(" UINT64_FORMAT "k free)", 2134 ((jlong)si.freeswap * si.mem_unit) >> 10); 2135 st->cr(); 2136 } 2137 2138 // Print the first "model name" line and the first "flags" line 2139 // that we find and nothing more. We assume "model name" comes 2140 // before "flags" so if we find a second "model name", then the 2141 // "flags" field is considered missing. 2142 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2143 #if defined(IA32) || defined(AMD64) 2144 // Other platforms have less repetitive cpuinfo files 2145 FILE *fp = fopen("/proc/cpuinfo", "r"); 2146 if (fp) { 2147 while (!feof(fp)) { 2148 if (fgets(buf, buflen, fp)) { 2149 // Assume model name comes before flags 2150 bool model_name_printed = false; 2151 if (strstr(buf, "model name") != NULL) { 2152 if (!model_name_printed) { 2153 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2154 st->print_raw(buf); 2155 model_name_printed = true; 2156 } else { 2157 // model name printed but not flags? Odd, just return 2158 fclose(fp); 2159 return true; 2160 } 2161 } 2162 // print the flags line too 2163 if (strstr(buf, "flags") != NULL) { 2164 st->print_raw(buf); 2165 fclose(fp); 2166 return true; 2167 } 2168 } 2169 } 2170 fclose(fp); 2171 } 2172 #endif // x86 platforms 2173 return false; 2174 } 2175 2176 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2177 // Only print the model name if the platform provides this as a summary 2178 if (!print_model_name_and_flags(st, buf, buflen)) { 2179 st->print("\n/proc/cpuinfo:\n"); 2180 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2181 st->print_cr(" <Not Available>"); 2182 } 2183 } 2184 } 2185 2186 #if defined(AMD64) || defined(IA32) || defined(X32) 2187 const char* search_string = "model name"; 2188 #elif defined(PPC64) 2189 const char* search_string = "cpu"; 2190 #elif defined(S390) 2191 const char* search_string = "processor"; 2192 #elif defined(SPARC) 2193 const char* search_string = "cpu"; 2194 #else 2195 const char* search_string = "Processor"; 2196 #endif 2197 2198 // Parses the cpuinfo file for string representing the model name. 2199 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2200 FILE* fp = fopen("/proc/cpuinfo", "r"); 2201 if (fp != NULL) { 2202 while (!feof(fp)) { 2203 char buf[256]; 2204 if (fgets(buf, sizeof(buf), fp)) { 2205 char* start = strstr(buf, search_string); 2206 if (start != NULL) { 2207 char *ptr = start + strlen(search_string); 2208 char *end = buf + strlen(buf); 2209 while (ptr != end) { 2210 // skip whitespace and colon for the rest of the name. 2211 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2212 break; 2213 } 2214 ptr++; 2215 } 2216 if (ptr != end) { 2217 // reasonable string, get rid of newline and keep the rest 2218 char* nl = strchr(buf, '\n'); 2219 if (nl != NULL) *nl = '\0'; 2220 strncpy(cpuinfo, ptr, length); 2221 fclose(fp); 2222 return; 2223 } 2224 } 2225 } 2226 } 2227 fclose(fp); 2228 } 2229 // cpuinfo not found or parsing failed, just print generic string. The entire 2230 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2231 #if defined(AARCH64) 2232 strncpy(cpuinfo, "AArch64", length); 2233 #elif defined(AMD64) 2234 strncpy(cpuinfo, "x86_64", length); 2235 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2236 strncpy(cpuinfo, "ARM", length); 2237 #elif defined(IA32) 2238 strncpy(cpuinfo, "x86_32", length); 2239 #elif defined(IA64) 2240 strncpy(cpuinfo, "IA64", length); 2241 #elif defined(PPC) 2242 strncpy(cpuinfo, "PPC64", length); 2243 #elif defined(S390) 2244 strncpy(cpuinfo, "S390", length); 2245 #elif defined(SPARC) 2246 strncpy(cpuinfo, "sparcv9", length); 2247 #elif defined(ZERO_LIBARCH) 2248 strncpy(cpuinfo, ZERO_LIBARCH, length); 2249 #else 2250 strncpy(cpuinfo, "unknown", length); 2251 #endif 2252 } 2253 2254 static void print_signal_handler(outputStream* st, int sig, 2255 char* buf, size_t buflen); 2256 2257 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2258 st->print_cr("Signal Handlers:"); 2259 print_signal_handler(st, SIGSEGV, buf, buflen); 2260 print_signal_handler(st, SIGBUS , buf, buflen); 2261 print_signal_handler(st, SIGFPE , buf, buflen); 2262 print_signal_handler(st, SIGPIPE, buf, buflen); 2263 print_signal_handler(st, SIGXFSZ, buf, buflen); 2264 print_signal_handler(st, SIGILL , buf, buflen); 2265 print_signal_handler(st, SR_signum, buf, buflen); 2266 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2267 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2268 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2269 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2270 #if defined(PPC64) 2271 print_signal_handler(st, SIGTRAP, buf, buflen); 2272 #endif 2273 } 2274 2275 static char saved_jvm_path[MAXPATHLEN] = {0}; 2276 2277 // Find the full path to the current module, libjvm.so 2278 void os::jvm_path(char *buf, jint buflen) { 2279 // Error checking. 2280 if (buflen < MAXPATHLEN) { 2281 assert(false, "must use a large-enough buffer"); 2282 buf[0] = '\0'; 2283 return; 2284 } 2285 // Lazy resolve the path to current module. 2286 if (saved_jvm_path[0] != 0) { 2287 strcpy(buf, saved_jvm_path); 2288 return; 2289 } 2290 2291 char dli_fname[MAXPATHLEN]; 2292 bool ret = dll_address_to_library_name( 2293 CAST_FROM_FN_PTR(address, os::jvm_path), 2294 dli_fname, sizeof(dli_fname), NULL); 2295 assert(ret, "cannot locate libjvm"); 2296 char *rp = NULL; 2297 if (ret && dli_fname[0] != '\0') { 2298 rp = realpath(dli_fname, buf); 2299 } 2300 if (rp == NULL) { 2301 return; 2302 } 2303 2304 if (Arguments::sun_java_launcher_is_altjvm()) { 2305 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2306 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2307 // If "/jre/lib/" appears at the right place in the string, then 2308 // assume we are installed in a JDK and we're done. Otherwise, check 2309 // for a JAVA_HOME environment variable and fix up the path so it 2310 // looks like libjvm.so is installed there (append a fake suffix 2311 // hotspot/libjvm.so). 2312 const char *p = buf + strlen(buf) - 1; 2313 for (int count = 0; p > buf && count < 5; ++count) { 2314 for (--p; p > buf && *p != '/'; --p) 2315 /* empty */ ; 2316 } 2317 2318 if (strncmp(p, "/jre/lib/", 9) != 0) { 2319 // Look for JAVA_HOME in the environment. 2320 char* java_home_var = ::getenv("JAVA_HOME"); 2321 if (java_home_var != NULL && java_home_var[0] != 0) { 2322 char* jrelib_p; 2323 int len; 2324 2325 // Check the current module name "libjvm.so". 2326 p = strrchr(buf, '/'); 2327 if (p == NULL) { 2328 return; 2329 } 2330 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2331 2332 rp = realpath(java_home_var, buf); 2333 if (rp == NULL) { 2334 return; 2335 } 2336 2337 // determine if this is a legacy image or modules image 2338 // modules image doesn't have "jre" subdirectory 2339 len = strlen(buf); 2340 assert(len < buflen, "Ran out of buffer room"); 2341 jrelib_p = buf + len; 2342 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2343 if (0 != access(buf, F_OK)) { 2344 snprintf(jrelib_p, buflen-len, "/lib"); 2345 } 2346 2347 if (0 == access(buf, F_OK)) { 2348 // Use current module name "libjvm.so" 2349 len = strlen(buf); 2350 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2351 } else { 2352 // Go back to path of .so 2353 rp = realpath(dli_fname, buf); 2354 if (rp == NULL) { 2355 return; 2356 } 2357 } 2358 } 2359 } 2360 } 2361 2362 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2363 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2364 } 2365 2366 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2367 // no prefix required, not even "_" 2368 } 2369 2370 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2371 // no suffix required 2372 } 2373 2374 //////////////////////////////////////////////////////////////////////////////// 2375 // sun.misc.Signal support 2376 2377 static volatile jint sigint_count = 0; 2378 2379 static void UserHandler(int sig, void *siginfo, void *context) { 2380 // 4511530 - sem_post is serialized and handled by the manager thread. When 2381 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2382 // don't want to flood the manager thread with sem_post requests. 2383 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2384 return; 2385 } 2386 2387 // Ctrl-C is pressed during error reporting, likely because the error 2388 // handler fails to abort. Let VM die immediately. 2389 if (sig == SIGINT && is_error_reported()) { 2390 os::die(); 2391 } 2392 2393 os::signal_notify(sig); 2394 } 2395 2396 void* os::user_handler() { 2397 return CAST_FROM_FN_PTR(void*, UserHandler); 2398 } 2399 2400 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2401 struct timespec ts; 2402 // Semaphore's are always associated with CLOCK_REALTIME 2403 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2404 // see unpackTime for discussion on overflow checking 2405 if (sec >= MAX_SECS) { 2406 ts.tv_sec += MAX_SECS; 2407 ts.tv_nsec = 0; 2408 } else { 2409 ts.tv_sec += sec; 2410 ts.tv_nsec += nsec; 2411 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2412 ts.tv_nsec -= NANOSECS_PER_SEC; 2413 ++ts.tv_sec; // note: this must be <= max_secs 2414 } 2415 } 2416 2417 return ts; 2418 } 2419 2420 extern "C" { 2421 typedef void (*sa_handler_t)(int); 2422 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2423 } 2424 2425 void* os::signal(int signal_number, void* handler) { 2426 struct sigaction sigAct, oldSigAct; 2427 2428 sigfillset(&(sigAct.sa_mask)); 2429 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2430 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2431 2432 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2433 // -1 means registration failed 2434 return (void *)-1; 2435 } 2436 2437 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2438 } 2439 2440 void os::signal_raise(int signal_number) { 2441 ::raise(signal_number); 2442 } 2443 2444 // The following code is moved from os.cpp for making this 2445 // code platform specific, which it is by its very nature. 2446 2447 // Will be modified when max signal is changed to be dynamic 2448 int os::sigexitnum_pd() { 2449 return NSIG; 2450 } 2451 2452 // a counter for each possible signal value 2453 static volatile jint pending_signals[NSIG+1] = { 0 }; 2454 2455 // Linux(POSIX) specific hand shaking semaphore. 2456 static sem_t sig_sem; 2457 static PosixSemaphore sr_semaphore; 2458 2459 void os::signal_init_pd() { 2460 // Initialize signal structures 2461 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2462 2463 // Initialize signal semaphore 2464 ::sem_init(&sig_sem, 0, 0); 2465 } 2466 2467 void os::signal_notify(int sig) { 2468 Atomic::inc(&pending_signals[sig]); 2469 ::sem_post(&sig_sem); 2470 } 2471 2472 static int check_pending_signals(bool wait) { 2473 Atomic::store(0, &sigint_count); 2474 for (;;) { 2475 for (int i = 0; i < NSIG + 1; i++) { 2476 jint n = pending_signals[i]; 2477 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2478 return i; 2479 } 2480 } 2481 if (!wait) { 2482 return -1; 2483 } 2484 JavaThread *thread = JavaThread::current(); 2485 ThreadBlockInVM tbivm(thread); 2486 2487 bool threadIsSuspended; 2488 do { 2489 thread->set_suspend_equivalent(); 2490 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2491 ::sem_wait(&sig_sem); 2492 2493 // were we externally suspended while we were waiting? 2494 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2495 if (threadIsSuspended) { 2496 // The semaphore has been incremented, but while we were waiting 2497 // another thread suspended us. We don't want to continue running 2498 // while suspended because that would surprise the thread that 2499 // suspended us. 2500 ::sem_post(&sig_sem); 2501 2502 thread->java_suspend_self(); 2503 } 2504 } while (threadIsSuspended); 2505 } 2506 } 2507 2508 int os::signal_lookup() { 2509 return check_pending_signals(false); 2510 } 2511 2512 int os::signal_wait() { 2513 return check_pending_signals(true); 2514 } 2515 2516 //////////////////////////////////////////////////////////////////////////////// 2517 // Virtual Memory 2518 2519 int os::vm_page_size() { 2520 // Seems redundant as all get out 2521 assert(os::Linux::page_size() != -1, "must call os::init"); 2522 return os::Linux::page_size(); 2523 } 2524 2525 // Solaris allocates memory by pages. 2526 int os::vm_allocation_granularity() { 2527 assert(os::Linux::page_size() != -1, "must call os::init"); 2528 return os::Linux::page_size(); 2529 } 2530 2531 // Rationale behind this function: 2532 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2533 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2534 // samples for JITted code. Here we create private executable mapping over the code cache 2535 // and then we can use standard (well, almost, as mapping can change) way to provide 2536 // info for the reporting script by storing timestamp and location of symbol 2537 void linux_wrap_code(char* base, size_t size) { 2538 static volatile jint cnt = 0; 2539 2540 if (!UseOprofile) { 2541 return; 2542 } 2543 2544 char buf[PATH_MAX+1]; 2545 int num = Atomic::add(1, &cnt); 2546 2547 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2548 os::get_temp_directory(), os::current_process_id(), num); 2549 unlink(buf); 2550 2551 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2552 2553 if (fd != -1) { 2554 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2555 if (rv != (off_t)-1) { 2556 if (::write(fd, "", 1) == 1) { 2557 mmap(base, size, 2558 PROT_READ|PROT_WRITE|PROT_EXEC, 2559 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2560 } 2561 } 2562 ::close(fd); 2563 unlink(buf); 2564 } 2565 } 2566 2567 static bool recoverable_mmap_error(int err) { 2568 // See if the error is one we can let the caller handle. This 2569 // list of errno values comes from JBS-6843484. I can't find a 2570 // Linux man page that documents this specific set of errno 2571 // values so while this list currently matches Solaris, it may 2572 // change as we gain experience with this failure mode. 2573 switch (err) { 2574 case EBADF: 2575 case EINVAL: 2576 case ENOTSUP: 2577 // let the caller deal with these errors 2578 return true; 2579 2580 default: 2581 // Any remaining errors on this OS can cause our reserved mapping 2582 // to be lost. That can cause confusion where different data 2583 // structures think they have the same memory mapped. The worst 2584 // scenario is if both the VM and a library think they have the 2585 // same memory mapped. 2586 return false; 2587 } 2588 } 2589 2590 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2591 int err) { 2592 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2593 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2594 os::strerror(err), err); 2595 } 2596 2597 static void warn_fail_commit_memory(char* addr, size_t size, 2598 size_t alignment_hint, bool exec, 2599 int err) { 2600 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2601 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2602 alignment_hint, exec, os::strerror(err), err); 2603 } 2604 2605 // NOTE: Linux kernel does not really reserve the pages for us. 2606 // All it does is to check if there are enough free pages 2607 // left at the time of mmap(). This could be a potential 2608 // problem. 2609 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2610 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2611 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2612 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2613 if (res != (uintptr_t) MAP_FAILED) { 2614 if (UseNUMAInterleaving) { 2615 numa_make_global(addr, size); 2616 } 2617 return 0; 2618 } 2619 2620 int err = errno; // save errno from mmap() call above 2621 2622 if (!recoverable_mmap_error(err)) { 2623 warn_fail_commit_memory(addr, size, exec, err); 2624 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2625 } 2626 2627 return err; 2628 } 2629 2630 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2631 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2632 } 2633 2634 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2635 const char* mesg) { 2636 assert(mesg != NULL, "mesg must be specified"); 2637 int err = os::Linux::commit_memory_impl(addr, size, exec); 2638 if (err != 0) { 2639 // the caller wants all commit errors to exit with the specified mesg: 2640 warn_fail_commit_memory(addr, size, exec, err); 2641 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2642 } 2643 } 2644 2645 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2646 #ifndef MAP_HUGETLB 2647 #define MAP_HUGETLB 0x40000 2648 #endif 2649 2650 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2651 #ifndef MADV_HUGEPAGE 2652 #define MADV_HUGEPAGE 14 2653 #endif 2654 2655 int os::Linux::commit_memory_impl(char* addr, size_t size, 2656 size_t alignment_hint, bool exec) { 2657 int err = os::Linux::commit_memory_impl(addr, size, exec); 2658 if (err == 0) { 2659 realign_memory(addr, size, alignment_hint); 2660 } 2661 return err; 2662 } 2663 2664 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2665 bool exec) { 2666 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2667 } 2668 2669 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2670 size_t alignment_hint, bool exec, 2671 const char* mesg) { 2672 assert(mesg != NULL, "mesg must be specified"); 2673 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2674 if (err != 0) { 2675 // the caller wants all commit errors to exit with the specified mesg: 2676 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2677 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2678 } 2679 } 2680 2681 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2682 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2683 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2684 // be supported or the memory may already be backed by huge pages. 2685 ::madvise(addr, bytes, MADV_HUGEPAGE); 2686 } 2687 } 2688 2689 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2690 // This method works by doing an mmap over an existing mmaping and effectively discarding 2691 // the existing pages. However it won't work for SHM-based large pages that cannot be 2692 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2693 // small pages on top of the SHM segment. This method always works for small pages, so we 2694 // allow that in any case. 2695 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2696 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2697 } 2698 } 2699 2700 void os::numa_make_global(char *addr, size_t bytes) { 2701 Linux::numa_interleave_memory(addr, bytes); 2702 } 2703 2704 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2705 // bind policy to MPOL_PREFERRED for the current thread. 2706 #define USE_MPOL_PREFERRED 0 2707 2708 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2709 // To make NUMA and large pages more robust when both enabled, we need to ease 2710 // the requirements on where the memory should be allocated. MPOL_BIND is the 2711 // default policy and it will force memory to be allocated on the specified 2712 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2713 // the specified node, but will not force it. Using this policy will prevent 2714 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2715 // free large pages. 2716 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2717 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2718 } 2719 2720 bool os::numa_topology_changed() { return false; } 2721 2722 size_t os::numa_get_groups_num() { 2723 int max_node = Linux::numa_max_node(); 2724 return max_node > 0 ? max_node + 1 : 1; 2725 } 2726 2727 int os::numa_get_group_id() { 2728 int cpu_id = Linux::sched_getcpu(); 2729 if (cpu_id != -1) { 2730 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2731 if (lgrp_id != -1) { 2732 return lgrp_id; 2733 } 2734 } 2735 return 0; 2736 } 2737 2738 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2739 for (size_t i = 0; i < size; i++) { 2740 ids[i] = i; 2741 } 2742 return size; 2743 } 2744 2745 bool os::get_page_info(char *start, page_info* info) { 2746 return false; 2747 } 2748 2749 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2750 page_info* page_found) { 2751 return end; 2752 } 2753 2754 2755 int os::Linux::sched_getcpu_syscall(void) { 2756 unsigned int cpu = 0; 2757 int retval = -1; 2758 2759 #if defined(IA32) 2760 #ifndef SYS_getcpu 2761 #define SYS_getcpu 318 2762 #endif 2763 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2764 #elif defined(AMD64) 2765 // Unfortunately we have to bring all these macros here from vsyscall.h 2766 // to be able to compile on old linuxes. 2767 #define __NR_vgetcpu 2 2768 #define VSYSCALL_START (-10UL << 20) 2769 #define VSYSCALL_SIZE 1024 2770 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2771 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2772 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2773 retval = vgetcpu(&cpu, NULL, NULL); 2774 #endif 2775 2776 return (retval == -1) ? retval : cpu; 2777 } 2778 2779 // Something to do with the numa-aware allocator needs these symbols 2780 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2781 extern "C" JNIEXPORT void numa_error(char *where) { } 2782 2783 2784 // If we are running with libnuma version > 2, then we should 2785 // be trying to use symbols with versions 1.1 2786 // If we are running with earlier version, which did not have symbol versions, 2787 // we should use the base version. 2788 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2789 void *f = dlvsym(handle, name, "libnuma_1.1"); 2790 if (f == NULL) { 2791 f = dlsym(handle, name); 2792 } 2793 return f; 2794 } 2795 2796 bool os::Linux::libnuma_init() { 2797 // sched_getcpu() should be in libc. 2798 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2799 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2800 2801 // If it's not, try a direct syscall. 2802 if (sched_getcpu() == -1) { 2803 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2804 (void*)&sched_getcpu_syscall)); 2805 } 2806 2807 if (sched_getcpu() != -1) { // Does it work? 2808 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2809 if (handle != NULL) { 2810 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2811 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2812 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2813 libnuma_dlsym(handle, "numa_max_node"))); 2814 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2815 libnuma_dlsym(handle, "numa_available"))); 2816 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2817 libnuma_dlsym(handle, "numa_tonode_memory"))); 2818 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2819 libnuma_dlsym(handle, "numa_interleave_memory"))); 2820 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2821 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2822 2823 2824 if (numa_available() != -1) { 2825 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2826 // Create a cpu -> node mapping 2827 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2828 rebuild_cpu_to_node_map(); 2829 return true; 2830 } 2831 } 2832 } 2833 return false; 2834 } 2835 2836 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2837 // The table is later used in get_node_by_cpu(). 2838 void os::Linux::rebuild_cpu_to_node_map() { 2839 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2840 // in libnuma (possible values are starting from 16, 2841 // and continuing up with every other power of 2, but less 2842 // than the maximum number of CPUs supported by kernel), and 2843 // is a subject to change (in libnuma version 2 the requirements 2844 // are more reasonable) we'll just hardcode the number they use 2845 // in the library. 2846 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2847 2848 size_t cpu_num = processor_count(); 2849 size_t cpu_map_size = NCPUS / BitsPerCLong; 2850 size_t cpu_map_valid_size = 2851 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2852 2853 cpu_to_node()->clear(); 2854 cpu_to_node()->at_grow(cpu_num - 1); 2855 size_t node_num = numa_get_groups_num(); 2856 2857 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2858 for (size_t i = 0; i < node_num; i++) { 2859 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2860 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2861 if (cpu_map[j] != 0) { 2862 for (size_t k = 0; k < BitsPerCLong; k++) { 2863 if (cpu_map[j] & (1UL << k)) { 2864 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2865 } 2866 } 2867 } 2868 } 2869 } 2870 } 2871 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2872 } 2873 2874 int os::Linux::get_node_by_cpu(int cpu_id) { 2875 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2876 return cpu_to_node()->at(cpu_id); 2877 } 2878 return -1; 2879 } 2880 2881 GrowableArray<int>* os::Linux::_cpu_to_node; 2882 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2883 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2884 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2885 os::Linux::numa_available_func_t os::Linux::_numa_available; 2886 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2887 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2888 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2889 unsigned long* os::Linux::_numa_all_nodes; 2890 2891 bool os::pd_uncommit_memory(char* addr, size_t size) { 2892 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2893 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2894 return res != (uintptr_t) MAP_FAILED; 2895 } 2896 2897 static address get_stack_commited_bottom(address bottom, size_t size) { 2898 address nbot = bottom; 2899 address ntop = bottom + size; 2900 2901 size_t page_sz = os::vm_page_size(); 2902 unsigned pages = size / page_sz; 2903 2904 unsigned char vec[1]; 2905 unsigned imin = 1, imax = pages + 1, imid; 2906 int mincore_return_value = 0; 2907 2908 assert(imin <= imax, "Unexpected page size"); 2909 2910 while (imin < imax) { 2911 imid = (imax + imin) / 2; 2912 nbot = ntop - (imid * page_sz); 2913 2914 // Use a trick with mincore to check whether the page is mapped or not. 2915 // mincore sets vec to 1 if page resides in memory and to 0 if page 2916 // is swapped output but if page we are asking for is unmapped 2917 // it returns -1,ENOMEM 2918 mincore_return_value = mincore(nbot, page_sz, vec); 2919 2920 if (mincore_return_value == -1) { 2921 // Page is not mapped go up 2922 // to find first mapped page 2923 if (errno != EAGAIN) { 2924 assert(errno == ENOMEM, "Unexpected mincore errno"); 2925 imax = imid; 2926 } 2927 } else { 2928 // Page is mapped go down 2929 // to find first not mapped page 2930 imin = imid + 1; 2931 } 2932 } 2933 2934 nbot = nbot + page_sz; 2935 2936 // Adjust stack bottom one page up if last checked page is not mapped 2937 if (mincore_return_value == -1) { 2938 nbot = nbot + page_sz; 2939 } 2940 2941 return nbot; 2942 } 2943 2944 2945 // Linux uses a growable mapping for the stack, and if the mapping for 2946 // the stack guard pages is not removed when we detach a thread the 2947 // stack cannot grow beyond the pages where the stack guard was 2948 // mapped. If at some point later in the process the stack expands to 2949 // that point, the Linux kernel cannot expand the stack any further 2950 // because the guard pages are in the way, and a segfault occurs. 2951 // 2952 // However, it's essential not to split the stack region by unmapping 2953 // a region (leaving a hole) that's already part of the stack mapping, 2954 // so if the stack mapping has already grown beyond the guard pages at 2955 // the time we create them, we have to truncate the stack mapping. 2956 // So, we need to know the extent of the stack mapping when 2957 // create_stack_guard_pages() is called. 2958 2959 // We only need this for stacks that are growable: at the time of 2960 // writing thread stacks don't use growable mappings (i.e. those 2961 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 2962 // only applies to the main thread. 2963 2964 // If the (growable) stack mapping already extends beyond the point 2965 // where we're going to put our guard pages, truncate the mapping at 2966 // that point by munmap()ping it. This ensures that when we later 2967 // munmap() the guard pages we don't leave a hole in the stack 2968 // mapping. This only affects the main/initial thread 2969 2970 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 2971 if (os::Linux::is_initial_thread()) { 2972 // As we manually grow stack up to bottom inside create_attached_thread(), 2973 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 2974 // we don't need to do anything special. 2975 // Check it first, before calling heavy function. 2976 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 2977 unsigned char vec[1]; 2978 2979 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 2980 // Fallback to slow path on all errors, including EAGAIN 2981 stack_extent = (uintptr_t) get_stack_commited_bottom( 2982 os::Linux::initial_thread_stack_bottom(), 2983 (size_t)addr - stack_extent); 2984 } 2985 2986 if (stack_extent < (uintptr_t)addr) { 2987 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 2988 } 2989 } 2990 2991 return os::commit_memory(addr, size, !ExecMem); 2992 } 2993 2994 // If this is a growable mapping, remove the guard pages entirely by 2995 // munmap()ping them. If not, just call uncommit_memory(). This only 2996 // affects the main/initial thread, but guard against future OS changes 2997 // It's safe to always unmap guard pages for initial thread because we 2998 // always place it right after end of the mapped region 2999 3000 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3001 uintptr_t stack_extent, stack_base; 3002 3003 if (os::Linux::is_initial_thread()) { 3004 return ::munmap(addr, size) == 0; 3005 } 3006 3007 return os::uncommit_memory(addr, size); 3008 } 3009 3010 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3011 // at 'requested_addr'. If there are existing memory mappings at the same 3012 // location, however, they will be overwritten. If 'fixed' is false, 3013 // 'requested_addr' is only treated as a hint, the return value may or 3014 // may not start from the requested address. Unlike Linux mmap(), this 3015 // function returns NULL to indicate failure. 3016 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3017 char * addr; 3018 int flags; 3019 3020 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3021 if (fixed) { 3022 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3023 flags |= MAP_FIXED; 3024 } 3025 3026 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3027 // touch an uncommitted page. Otherwise, the read/write might 3028 // succeed if we have enough swap space to back the physical page. 3029 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3030 flags, -1, 0); 3031 3032 return addr == MAP_FAILED ? NULL : addr; 3033 } 3034 3035 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3036 // (req_addr != NULL) or with a given alignment. 3037 // - bytes shall be a multiple of alignment. 3038 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3039 // - alignment sets the alignment at which memory shall be allocated. 3040 // It must be a multiple of allocation granularity. 3041 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3042 // req_addr or NULL. 3043 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3044 3045 size_t extra_size = bytes; 3046 if (req_addr == NULL && alignment > 0) { 3047 extra_size += alignment; 3048 } 3049 3050 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3051 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3052 -1, 0); 3053 if (start == MAP_FAILED) { 3054 start = NULL; 3055 } else { 3056 if (req_addr != NULL) { 3057 if (start != req_addr) { 3058 ::munmap(start, extra_size); 3059 start = NULL; 3060 } 3061 } else { 3062 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3063 char* const end_aligned = start_aligned + bytes; 3064 char* const end = start + extra_size; 3065 if (start_aligned > start) { 3066 ::munmap(start, start_aligned - start); 3067 } 3068 if (end_aligned < end) { 3069 ::munmap(end_aligned, end - end_aligned); 3070 } 3071 start = start_aligned; 3072 } 3073 } 3074 return start; 3075 } 3076 3077 static int anon_munmap(char * addr, size_t size) { 3078 return ::munmap(addr, size) == 0; 3079 } 3080 3081 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3082 size_t alignment_hint) { 3083 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3084 } 3085 3086 bool os::pd_release_memory(char* addr, size_t size) { 3087 return anon_munmap(addr, size); 3088 } 3089 3090 static bool linux_mprotect(char* addr, size_t size, int prot) { 3091 // Linux wants the mprotect address argument to be page aligned. 3092 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3093 3094 // According to SUSv3, mprotect() should only be used with mappings 3095 // established by mmap(), and mmap() always maps whole pages. Unaligned 3096 // 'addr' likely indicates problem in the VM (e.g. trying to change 3097 // protection of malloc'ed or statically allocated memory). Check the 3098 // caller if you hit this assert. 3099 assert(addr == bottom, "sanity check"); 3100 3101 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3102 return ::mprotect(bottom, size, prot) == 0; 3103 } 3104 3105 // Set protections specified 3106 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3107 bool is_committed) { 3108 unsigned int p = 0; 3109 switch (prot) { 3110 case MEM_PROT_NONE: p = PROT_NONE; break; 3111 case MEM_PROT_READ: p = PROT_READ; break; 3112 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3113 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3114 default: 3115 ShouldNotReachHere(); 3116 } 3117 // is_committed is unused. 3118 return linux_mprotect(addr, bytes, p); 3119 } 3120 3121 bool os::guard_memory(char* addr, size_t size) { 3122 return linux_mprotect(addr, size, PROT_NONE); 3123 } 3124 3125 bool os::unguard_memory(char* addr, size_t size) { 3126 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3127 } 3128 3129 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3130 size_t page_size) { 3131 bool result = false; 3132 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3133 MAP_ANONYMOUS|MAP_PRIVATE, 3134 -1, 0); 3135 if (p != MAP_FAILED) { 3136 void *aligned_p = align_ptr_up(p, page_size); 3137 3138 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3139 3140 munmap(p, page_size * 2); 3141 } 3142 3143 if (warn && !result) { 3144 warning("TransparentHugePages is not supported by the operating system."); 3145 } 3146 3147 return result; 3148 } 3149 3150 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3151 bool result = false; 3152 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3153 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3154 -1, 0); 3155 3156 if (p != MAP_FAILED) { 3157 // We don't know if this really is a huge page or not. 3158 FILE *fp = fopen("/proc/self/maps", "r"); 3159 if (fp) { 3160 while (!feof(fp)) { 3161 char chars[257]; 3162 long x = 0; 3163 if (fgets(chars, sizeof(chars), fp)) { 3164 if (sscanf(chars, "%lx-%*x", &x) == 1 3165 && x == (long)p) { 3166 if (strstr (chars, "hugepage")) { 3167 result = true; 3168 break; 3169 } 3170 } 3171 } 3172 } 3173 fclose(fp); 3174 } 3175 munmap(p, page_size); 3176 } 3177 3178 if (warn && !result) { 3179 warning("HugeTLBFS is not supported by the operating system."); 3180 } 3181 3182 return result; 3183 } 3184 3185 // Set the coredump_filter bits to include largepages in core dump (bit 6) 3186 // 3187 // From the coredump_filter documentation: 3188 // 3189 // - (bit 0) anonymous private memory 3190 // - (bit 1) anonymous shared memory 3191 // - (bit 2) file-backed private memory 3192 // - (bit 3) file-backed shared memory 3193 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3194 // effective only if the bit 2 is cleared) 3195 // - (bit 5) hugetlb private memory 3196 // - (bit 6) hugetlb shared memory 3197 // 3198 static void set_coredump_filter(void) { 3199 FILE *f; 3200 long cdm; 3201 3202 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3203 return; 3204 } 3205 3206 if (fscanf(f, "%lx", &cdm) != 1) { 3207 fclose(f); 3208 return; 3209 } 3210 3211 rewind(f); 3212 3213 if ((cdm & LARGEPAGES_BIT) == 0) { 3214 cdm |= LARGEPAGES_BIT; 3215 fprintf(f, "%#lx", cdm); 3216 } 3217 3218 fclose(f); 3219 } 3220 3221 // Large page support 3222 3223 static size_t _large_page_size = 0; 3224 3225 size_t os::Linux::find_large_page_size() { 3226 size_t large_page_size = 0; 3227 3228 // large_page_size on Linux is used to round up heap size. x86 uses either 3229 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3230 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3231 // page as large as 256M. 3232 // 3233 // Here we try to figure out page size by parsing /proc/meminfo and looking 3234 // for a line with the following format: 3235 // Hugepagesize: 2048 kB 3236 // 3237 // If we can't determine the value (e.g. /proc is not mounted, or the text 3238 // format has been changed), we'll use the largest page size supported by 3239 // the processor. 3240 3241 #ifndef ZERO 3242 large_page_size = 3243 AARCH64_ONLY(2 * M) 3244 AMD64_ONLY(2 * M) 3245 ARM32_ONLY(2 * M) 3246 IA32_ONLY(4 * M) 3247 IA64_ONLY(256 * M) 3248 PPC_ONLY(4 * M) 3249 S390_ONLY(1 * M) 3250 SPARC_ONLY(4 * M); 3251 #endif // ZERO 3252 3253 FILE *fp = fopen("/proc/meminfo", "r"); 3254 if (fp) { 3255 while (!feof(fp)) { 3256 int x = 0; 3257 char buf[16]; 3258 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3259 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3260 large_page_size = x * K; 3261 break; 3262 } 3263 } else { 3264 // skip to next line 3265 for (;;) { 3266 int ch = fgetc(fp); 3267 if (ch == EOF || ch == (int)'\n') break; 3268 } 3269 } 3270 } 3271 fclose(fp); 3272 } 3273 3274 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3275 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3276 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3277 proper_unit_for_byte_size(large_page_size)); 3278 } 3279 3280 return large_page_size; 3281 } 3282 3283 size_t os::Linux::setup_large_page_size() { 3284 _large_page_size = Linux::find_large_page_size(); 3285 const size_t default_page_size = (size_t)Linux::page_size(); 3286 if (_large_page_size > default_page_size) { 3287 _page_sizes[0] = _large_page_size; 3288 _page_sizes[1] = default_page_size; 3289 _page_sizes[2] = 0; 3290 } 3291 3292 return _large_page_size; 3293 } 3294 3295 bool os::Linux::setup_large_page_type(size_t page_size) { 3296 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3297 FLAG_IS_DEFAULT(UseSHM) && 3298 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3299 3300 // The type of large pages has not been specified by the user. 3301 3302 // Try UseHugeTLBFS and then UseSHM. 3303 UseHugeTLBFS = UseSHM = true; 3304 3305 // Don't try UseTransparentHugePages since there are known 3306 // performance issues with it turned on. This might change in the future. 3307 UseTransparentHugePages = false; 3308 } 3309 3310 if (UseTransparentHugePages) { 3311 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3312 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3313 UseHugeTLBFS = false; 3314 UseSHM = false; 3315 return true; 3316 } 3317 UseTransparentHugePages = false; 3318 } 3319 3320 if (UseHugeTLBFS) { 3321 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3322 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3323 UseSHM = false; 3324 return true; 3325 } 3326 UseHugeTLBFS = false; 3327 } 3328 3329 return UseSHM; 3330 } 3331 3332 void os::large_page_init() { 3333 if (!UseLargePages && 3334 !UseTransparentHugePages && 3335 !UseHugeTLBFS && 3336 !UseSHM) { 3337 // Not using large pages. 3338 return; 3339 } 3340 3341 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3342 // The user explicitly turned off large pages. 3343 // Ignore the rest of the large pages flags. 3344 UseTransparentHugePages = false; 3345 UseHugeTLBFS = false; 3346 UseSHM = false; 3347 return; 3348 } 3349 3350 size_t large_page_size = Linux::setup_large_page_size(); 3351 UseLargePages = Linux::setup_large_page_type(large_page_size); 3352 3353 set_coredump_filter(); 3354 } 3355 3356 #ifndef SHM_HUGETLB 3357 #define SHM_HUGETLB 04000 3358 #endif 3359 3360 #define shm_warning_format(format, ...) \ 3361 do { \ 3362 if (UseLargePages && \ 3363 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3364 !FLAG_IS_DEFAULT(UseSHM) || \ 3365 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3366 warning(format, __VA_ARGS__); \ 3367 } \ 3368 } while (0) 3369 3370 #define shm_warning(str) shm_warning_format("%s", str) 3371 3372 #define shm_warning_with_errno(str) \ 3373 do { \ 3374 int err = errno; \ 3375 shm_warning_format(str " (error = %d)", err); \ 3376 } while (0) 3377 3378 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3379 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment"); 3380 3381 if (!is_size_aligned(alignment, SHMLBA)) { 3382 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3383 return NULL; 3384 } 3385 3386 // To ensure that we get 'alignment' aligned memory from shmat, 3387 // we pre-reserve aligned virtual memory and then attach to that. 3388 3389 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3390 if (pre_reserved_addr == NULL) { 3391 // Couldn't pre-reserve aligned memory. 3392 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3393 return NULL; 3394 } 3395 3396 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3397 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3398 3399 if ((intptr_t)addr == -1) { 3400 int err = errno; 3401 shm_warning_with_errno("Failed to attach shared memory."); 3402 3403 assert(err != EACCES, "Unexpected error"); 3404 assert(err != EIDRM, "Unexpected error"); 3405 assert(err != EINVAL, "Unexpected error"); 3406 3407 // Since we don't know if the kernel unmapped the pre-reserved memory area 3408 // we can't unmap it, since that would potentially unmap memory that was 3409 // mapped from other threads. 3410 return NULL; 3411 } 3412 3413 return addr; 3414 } 3415 3416 static char* shmat_at_address(int shmid, char* req_addr) { 3417 if (!is_ptr_aligned(req_addr, SHMLBA)) { 3418 assert(false, "Requested address needs to be SHMLBA aligned"); 3419 return NULL; 3420 } 3421 3422 char* addr = (char*)shmat(shmid, req_addr, 0); 3423 3424 if ((intptr_t)addr == -1) { 3425 shm_warning_with_errno("Failed to attach shared memory."); 3426 return NULL; 3427 } 3428 3429 return addr; 3430 } 3431 3432 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3433 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3434 if (req_addr != NULL) { 3435 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3436 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3437 return shmat_at_address(shmid, req_addr); 3438 } 3439 3440 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3441 // return large page size aligned memory addresses when req_addr == NULL. 3442 // However, if the alignment is larger than the large page size, we have 3443 // to manually ensure that the memory returned is 'alignment' aligned. 3444 if (alignment > os::large_page_size()) { 3445 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3446 return shmat_with_alignment(shmid, bytes, alignment); 3447 } else { 3448 return shmat_at_address(shmid, NULL); 3449 } 3450 } 3451 3452 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3453 char* req_addr, bool exec) { 3454 // "exec" is passed in but not used. Creating the shared image for 3455 // the code cache doesn't have an SHM_X executable permission to check. 3456 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3457 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3458 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address"); 3459 3460 if (!is_size_aligned(bytes, os::large_page_size())) { 3461 return NULL; // Fallback to small pages. 3462 } 3463 3464 // Create a large shared memory region to attach to based on size. 3465 // Currently, size is the total size of the heap. 3466 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3467 if (shmid == -1) { 3468 // Possible reasons for shmget failure: 3469 // 1. shmmax is too small for Java heap. 3470 // > check shmmax value: cat /proc/sys/kernel/shmmax 3471 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3472 // 2. not enough large page memory. 3473 // > check available large pages: cat /proc/meminfo 3474 // > increase amount of large pages: 3475 // echo new_value > /proc/sys/vm/nr_hugepages 3476 // Note 1: different Linux may use different name for this property, 3477 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3478 // Note 2: it's possible there's enough physical memory available but 3479 // they are so fragmented after a long run that they can't 3480 // coalesce into large pages. Try to reserve large pages when 3481 // the system is still "fresh". 3482 shm_warning_with_errno("Failed to reserve shared memory."); 3483 return NULL; 3484 } 3485 3486 // Attach to the region. 3487 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3488 3489 // Remove shmid. If shmat() is successful, the actual shared memory segment 3490 // will be deleted when it's detached by shmdt() or when the process 3491 // terminates. If shmat() is not successful this will remove the shared 3492 // segment immediately. 3493 shmctl(shmid, IPC_RMID, NULL); 3494 3495 return addr; 3496 } 3497 3498 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3499 int error) { 3500 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3501 3502 bool warn_on_failure = UseLargePages && 3503 (!FLAG_IS_DEFAULT(UseLargePages) || 3504 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3505 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3506 3507 if (warn_on_failure) { 3508 char msg[128]; 3509 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3510 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3511 warning("%s", msg); 3512 } 3513 } 3514 3515 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3516 char* req_addr, 3517 bool exec) { 3518 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3519 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3520 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3521 3522 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3523 char* addr = (char*)::mmap(req_addr, bytes, prot, 3524 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3525 -1, 0); 3526 3527 if (addr == MAP_FAILED) { 3528 warn_on_large_pages_failure(req_addr, bytes, errno); 3529 return NULL; 3530 } 3531 3532 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3533 3534 return addr; 3535 } 3536 3537 // Reserve memory using mmap(MAP_HUGETLB). 3538 // - bytes shall be a multiple of alignment. 3539 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3540 // - alignment sets the alignment at which memory shall be allocated. 3541 // It must be a multiple of allocation granularity. 3542 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3543 // req_addr or NULL. 3544 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3545 size_t alignment, 3546 char* req_addr, 3547 bool exec) { 3548 size_t large_page_size = os::large_page_size(); 3549 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3550 3551 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3552 assert(is_size_aligned(bytes, alignment), "Must be"); 3553 3554 // First reserve - but not commit - the address range in small pages. 3555 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3556 3557 if (start == NULL) { 3558 return NULL; 3559 } 3560 3561 assert(is_ptr_aligned(start, alignment), "Must be"); 3562 3563 char* end = start + bytes; 3564 3565 // Find the regions of the allocated chunk that can be promoted to large pages. 3566 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3567 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3568 3569 size_t lp_bytes = lp_end - lp_start; 3570 3571 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3572 3573 if (lp_bytes == 0) { 3574 // The mapped region doesn't even span the start and the end of a large page. 3575 // Fall back to allocate a non-special area. 3576 ::munmap(start, end - start); 3577 return NULL; 3578 } 3579 3580 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3581 3582 void* result; 3583 3584 // Commit small-paged leading area. 3585 if (start != lp_start) { 3586 result = ::mmap(start, lp_start - start, prot, 3587 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3588 -1, 0); 3589 if (result == MAP_FAILED) { 3590 ::munmap(lp_start, end - lp_start); 3591 return NULL; 3592 } 3593 } 3594 3595 // Commit large-paged area. 3596 result = ::mmap(lp_start, lp_bytes, prot, 3597 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3598 -1, 0); 3599 if (result == MAP_FAILED) { 3600 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3601 // If the mmap above fails, the large pages region will be unmapped and we 3602 // have regions before and after with small pages. Release these regions. 3603 // 3604 // | mapped | unmapped | mapped | 3605 // ^ ^ ^ ^ 3606 // start lp_start lp_end end 3607 // 3608 ::munmap(start, lp_start - start); 3609 ::munmap(lp_end, end - lp_end); 3610 return NULL; 3611 } 3612 3613 // Commit small-paged trailing area. 3614 if (lp_end != end) { 3615 result = ::mmap(lp_end, end - lp_end, prot, 3616 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3617 -1, 0); 3618 if (result == MAP_FAILED) { 3619 ::munmap(start, lp_end - start); 3620 return NULL; 3621 } 3622 } 3623 3624 return start; 3625 } 3626 3627 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3628 size_t alignment, 3629 char* req_addr, 3630 bool exec) { 3631 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3632 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3633 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3634 assert(is_power_of_2(os::large_page_size()), "Must be"); 3635 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3636 3637 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3638 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3639 } else { 3640 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3641 } 3642 } 3643 3644 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3645 char* req_addr, bool exec) { 3646 assert(UseLargePages, "only for large pages"); 3647 3648 char* addr; 3649 if (UseSHM) { 3650 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3651 } else { 3652 assert(UseHugeTLBFS, "must be"); 3653 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3654 } 3655 3656 if (addr != NULL) { 3657 if (UseNUMAInterleaving) { 3658 numa_make_global(addr, bytes); 3659 } 3660 3661 // The memory is committed 3662 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3663 } 3664 3665 return addr; 3666 } 3667 3668 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3669 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3670 return shmdt(base) == 0; 3671 } 3672 3673 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3674 return pd_release_memory(base, bytes); 3675 } 3676 3677 bool os::release_memory_special(char* base, size_t bytes) { 3678 bool res; 3679 if (MemTracker::tracking_level() > NMT_minimal) { 3680 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3681 res = os::Linux::release_memory_special_impl(base, bytes); 3682 if (res) { 3683 tkr.record((address)base, bytes); 3684 } 3685 3686 } else { 3687 res = os::Linux::release_memory_special_impl(base, bytes); 3688 } 3689 return res; 3690 } 3691 3692 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3693 assert(UseLargePages, "only for large pages"); 3694 bool res; 3695 3696 if (UseSHM) { 3697 res = os::Linux::release_memory_special_shm(base, bytes); 3698 } else { 3699 assert(UseHugeTLBFS, "must be"); 3700 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3701 } 3702 return res; 3703 } 3704 3705 size_t os::large_page_size() { 3706 return _large_page_size; 3707 } 3708 3709 // With SysV SHM the entire memory region must be allocated as shared 3710 // memory. 3711 // HugeTLBFS allows application to commit large page memory on demand. 3712 // However, when committing memory with HugeTLBFS fails, the region 3713 // that was supposed to be committed will lose the old reservation 3714 // and allow other threads to steal that memory region. Because of this 3715 // behavior we can't commit HugeTLBFS memory. 3716 bool os::can_commit_large_page_memory() { 3717 return UseTransparentHugePages; 3718 } 3719 3720 bool os::can_execute_large_page_memory() { 3721 return UseTransparentHugePages || UseHugeTLBFS; 3722 } 3723 3724 // Reserve memory at an arbitrary address, only if that area is 3725 // available (and not reserved for something else). 3726 3727 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3728 const int max_tries = 10; 3729 char* base[max_tries]; 3730 size_t size[max_tries]; 3731 const size_t gap = 0x000000; 3732 3733 // Assert only that the size is a multiple of the page size, since 3734 // that's all that mmap requires, and since that's all we really know 3735 // about at this low abstraction level. If we need higher alignment, 3736 // we can either pass an alignment to this method or verify alignment 3737 // in one of the methods further up the call chain. See bug 5044738. 3738 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3739 3740 // Repeatedly allocate blocks until the block is allocated at the 3741 // right spot. 3742 3743 // Linux mmap allows caller to pass an address as hint; give it a try first, 3744 // if kernel honors the hint then we can return immediately. 3745 char * addr = anon_mmap(requested_addr, bytes, false); 3746 if (addr == requested_addr) { 3747 return requested_addr; 3748 } 3749 3750 if (addr != NULL) { 3751 // mmap() is successful but it fails to reserve at the requested address 3752 anon_munmap(addr, bytes); 3753 } 3754 3755 int i; 3756 for (i = 0; i < max_tries; ++i) { 3757 base[i] = reserve_memory(bytes); 3758 3759 if (base[i] != NULL) { 3760 // Is this the block we wanted? 3761 if (base[i] == requested_addr) { 3762 size[i] = bytes; 3763 break; 3764 } 3765 3766 // Does this overlap the block we wanted? Give back the overlapped 3767 // parts and try again. 3768 3769 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3770 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3771 unmap_memory(base[i], top_overlap); 3772 base[i] += top_overlap; 3773 size[i] = bytes - top_overlap; 3774 } else { 3775 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3776 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3777 unmap_memory(requested_addr, bottom_overlap); 3778 size[i] = bytes - bottom_overlap; 3779 } else { 3780 size[i] = bytes; 3781 } 3782 } 3783 } 3784 } 3785 3786 // Give back the unused reserved pieces. 3787 3788 for (int j = 0; j < i; ++j) { 3789 if (base[j] != NULL) { 3790 unmap_memory(base[j], size[j]); 3791 } 3792 } 3793 3794 if (i < max_tries) { 3795 return requested_addr; 3796 } else { 3797 return NULL; 3798 } 3799 } 3800 3801 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3802 return ::read(fd, buf, nBytes); 3803 } 3804 3805 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3806 return ::pread(fd, buf, nBytes, offset); 3807 } 3808 3809 // Short sleep, direct OS call. 3810 // 3811 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3812 // sched_yield(2) will actually give up the CPU: 3813 // 3814 // * Alone on this pariticular CPU, keeps running. 3815 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 3816 // (pre 2.6.39). 3817 // 3818 // So calling this with 0 is an alternative. 3819 // 3820 void os::naked_short_sleep(jlong ms) { 3821 struct timespec req; 3822 3823 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3824 req.tv_sec = 0; 3825 if (ms > 0) { 3826 req.tv_nsec = (ms % 1000) * 1000000; 3827 } else { 3828 req.tv_nsec = 1; 3829 } 3830 3831 nanosleep(&req, NULL); 3832 3833 return; 3834 } 3835 3836 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3837 void os::infinite_sleep() { 3838 while (true) { // sleep forever ... 3839 ::sleep(100); // ... 100 seconds at a time 3840 } 3841 } 3842 3843 // Used to convert frequent JVM_Yield() to nops 3844 bool os::dont_yield() { 3845 return DontYieldALot; 3846 } 3847 3848 void os::naked_yield() { 3849 sched_yield(); 3850 } 3851 3852 //////////////////////////////////////////////////////////////////////////////// 3853 // thread priority support 3854 3855 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3856 // only supports dynamic priority, static priority must be zero. For real-time 3857 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3858 // However, for large multi-threaded applications, SCHED_RR is not only slower 3859 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3860 // of 5 runs - Sep 2005). 3861 // 3862 // The following code actually changes the niceness of kernel-thread/LWP. It 3863 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3864 // not the entire user process, and user level threads are 1:1 mapped to kernel 3865 // threads. It has always been the case, but could change in the future. For 3866 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3867 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3868 3869 int os::java_to_os_priority[CriticalPriority + 1] = { 3870 19, // 0 Entry should never be used 3871 3872 4, // 1 MinPriority 3873 3, // 2 3874 2, // 3 3875 3876 1, // 4 3877 0, // 5 NormPriority 3878 -1, // 6 3879 3880 -2, // 7 3881 -3, // 8 3882 -4, // 9 NearMaxPriority 3883 3884 -5, // 10 MaxPriority 3885 3886 -5 // 11 CriticalPriority 3887 }; 3888 3889 static int prio_init() { 3890 if (ThreadPriorityPolicy == 1) { 3891 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3892 // if effective uid is not root. Perhaps, a more elegant way of doing 3893 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3894 if (geteuid() != 0) { 3895 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3896 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3897 } 3898 ThreadPriorityPolicy = 0; 3899 } 3900 } 3901 if (UseCriticalJavaThreadPriority) { 3902 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3903 } 3904 return 0; 3905 } 3906 3907 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3908 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3909 3910 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3911 return (ret == 0) ? OS_OK : OS_ERR; 3912 } 3913 3914 OSReturn os::get_native_priority(const Thread* const thread, 3915 int *priority_ptr) { 3916 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3917 *priority_ptr = java_to_os_priority[NormPriority]; 3918 return OS_OK; 3919 } 3920 3921 errno = 0; 3922 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3923 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3924 } 3925 3926 // Hint to the underlying OS that a task switch would not be good. 3927 // Void return because it's a hint and can fail. 3928 void os::hint_no_preempt() {} 3929 3930 //////////////////////////////////////////////////////////////////////////////// 3931 // suspend/resume support 3932 3933 // the low-level signal-based suspend/resume support is a remnant from the 3934 // old VM-suspension that used to be for java-suspension, safepoints etc, 3935 // within hotspot. Now there is a single use-case for this: 3936 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3937 // that runs in the watcher thread. 3938 // The remaining code is greatly simplified from the more general suspension 3939 // code that used to be used. 3940 // 3941 // The protocol is quite simple: 3942 // - suspend: 3943 // - sends a signal to the target thread 3944 // - polls the suspend state of the osthread using a yield loop 3945 // - target thread signal handler (SR_handler) sets suspend state 3946 // and blocks in sigsuspend until continued 3947 // - resume: 3948 // - sets target osthread state to continue 3949 // - sends signal to end the sigsuspend loop in the SR_handler 3950 // 3951 // Note that the SR_lock plays no role in this suspend/resume protocol, 3952 // but is checked for NULL in SR_handler as a thread termination indicator. 3953 3954 static void resume_clear_context(OSThread *osthread) { 3955 osthread->set_ucontext(NULL); 3956 osthread->set_siginfo(NULL); 3957 } 3958 3959 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 3960 ucontext_t* context) { 3961 osthread->set_ucontext(context); 3962 osthread->set_siginfo(siginfo); 3963 } 3964 3965 // Handler function invoked when a thread's execution is suspended or 3966 // resumed. We have to be careful that only async-safe functions are 3967 // called here (Note: most pthread functions are not async safe and 3968 // should be avoided.) 3969 // 3970 // Note: sigwait() is a more natural fit than sigsuspend() from an 3971 // interface point of view, but sigwait() prevents the signal hander 3972 // from being run. libpthread would get very confused by not having 3973 // its signal handlers run and prevents sigwait()'s use with the 3974 // mutex granting granting signal. 3975 // 3976 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 3977 // 3978 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3979 // Save and restore errno to avoid confusing native code with EINTR 3980 // after sigsuspend. 3981 int old_errno = errno; 3982 3983 Thread* thread = Thread::current_or_null_safe(); 3984 assert(thread != NULL, "Missing current thread in SR_handler"); 3985 3986 // On some systems we have seen signal delivery get "stuck" until the signal 3987 // mask is changed as part of thread termination. Check that the current thread 3988 // has not already terminated (via SR_lock()) - else the following assertion 3989 // will fail because the thread is no longer a JavaThread as the ~JavaThread 3990 // destructor has completed. 3991 3992 if (thread->SR_lock() == NULL) { 3993 return; 3994 } 3995 3996 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 3997 3998 OSThread* osthread = thread->osthread(); 3999 4000 os::SuspendResume::State current = osthread->sr.state(); 4001 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4002 suspend_save_context(osthread, siginfo, context); 4003 4004 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4005 os::SuspendResume::State state = osthread->sr.suspended(); 4006 if (state == os::SuspendResume::SR_SUSPENDED) { 4007 sigset_t suspend_set; // signals for sigsuspend() 4008 sigemptyset(&suspend_set); 4009 // get current set of blocked signals and unblock resume signal 4010 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4011 sigdelset(&suspend_set, SR_signum); 4012 4013 sr_semaphore.signal(); 4014 // wait here until we are resumed 4015 while (1) { 4016 sigsuspend(&suspend_set); 4017 4018 os::SuspendResume::State result = osthread->sr.running(); 4019 if (result == os::SuspendResume::SR_RUNNING) { 4020 sr_semaphore.signal(); 4021 break; 4022 } 4023 } 4024 4025 } else if (state == os::SuspendResume::SR_RUNNING) { 4026 // request was cancelled, continue 4027 } else { 4028 ShouldNotReachHere(); 4029 } 4030 4031 resume_clear_context(osthread); 4032 } else if (current == os::SuspendResume::SR_RUNNING) { 4033 // request was cancelled, continue 4034 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4035 // ignore 4036 } else { 4037 // ignore 4038 } 4039 4040 errno = old_errno; 4041 } 4042 4043 static int SR_initialize() { 4044 struct sigaction act; 4045 char *s; 4046 4047 // Get signal number to use for suspend/resume 4048 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4049 int sig = ::strtol(s, 0, 10); 4050 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4051 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4052 SR_signum = sig; 4053 } else { 4054 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4055 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4056 } 4057 } 4058 4059 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4060 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4061 4062 sigemptyset(&SR_sigset); 4063 sigaddset(&SR_sigset, SR_signum); 4064 4065 // Set up signal handler for suspend/resume 4066 act.sa_flags = SA_RESTART|SA_SIGINFO; 4067 act.sa_handler = (void (*)(int)) SR_handler; 4068 4069 // SR_signum is blocked by default. 4070 // 4528190 - We also need to block pthread restart signal (32 on all 4071 // supported Linux platforms). Note that LinuxThreads need to block 4072 // this signal for all threads to work properly. So we don't have 4073 // to use hard-coded signal number when setting up the mask. 4074 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4075 4076 if (sigaction(SR_signum, &act, 0) == -1) { 4077 return -1; 4078 } 4079 4080 // Save signal flag 4081 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4082 return 0; 4083 } 4084 4085 static int sr_notify(OSThread* osthread) { 4086 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4087 assert_status(status == 0, status, "pthread_kill"); 4088 return status; 4089 } 4090 4091 // "Randomly" selected value for how long we want to spin 4092 // before bailing out on suspending a thread, also how often 4093 // we send a signal to a thread we want to resume 4094 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4095 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4096 4097 // returns true on success and false on error - really an error is fatal 4098 // but this seems the normal response to library errors 4099 static bool do_suspend(OSThread* osthread) { 4100 assert(osthread->sr.is_running(), "thread should be running"); 4101 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4102 4103 // mark as suspended and send signal 4104 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4105 // failed to switch, state wasn't running? 4106 ShouldNotReachHere(); 4107 return false; 4108 } 4109 4110 if (sr_notify(osthread) != 0) { 4111 ShouldNotReachHere(); 4112 } 4113 4114 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4115 while (true) { 4116 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4117 break; 4118 } else { 4119 // timeout 4120 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4121 if (cancelled == os::SuspendResume::SR_RUNNING) { 4122 return false; 4123 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4124 // make sure that we consume the signal on the semaphore as well 4125 sr_semaphore.wait(); 4126 break; 4127 } else { 4128 ShouldNotReachHere(); 4129 return false; 4130 } 4131 } 4132 } 4133 4134 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4135 return true; 4136 } 4137 4138 static void do_resume(OSThread* osthread) { 4139 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4140 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4141 4142 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4143 // failed to switch to WAKEUP_REQUEST 4144 ShouldNotReachHere(); 4145 return; 4146 } 4147 4148 while (true) { 4149 if (sr_notify(osthread) == 0) { 4150 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4151 if (osthread->sr.is_running()) { 4152 return; 4153 } 4154 } 4155 } else { 4156 ShouldNotReachHere(); 4157 } 4158 } 4159 4160 guarantee(osthread->sr.is_running(), "Must be running!"); 4161 } 4162 4163 /////////////////////////////////////////////////////////////////////////////////// 4164 // signal handling (except suspend/resume) 4165 4166 // This routine may be used by user applications as a "hook" to catch signals. 4167 // The user-defined signal handler must pass unrecognized signals to this 4168 // routine, and if it returns true (non-zero), then the signal handler must 4169 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4170 // routine will never retun false (zero), but instead will execute a VM panic 4171 // routine kill the process. 4172 // 4173 // If this routine returns false, it is OK to call it again. This allows 4174 // the user-defined signal handler to perform checks either before or after 4175 // the VM performs its own checks. Naturally, the user code would be making 4176 // a serious error if it tried to handle an exception (such as a null check 4177 // or breakpoint) that the VM was generating for its own correct operation. 4178 // 4179 // This routine may recognize any of the following kinds of signals: 4180 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4181 // It should be consulted by handlers for any of those signals. 4182 // 4183 // The caller of this routine must pass in the three arguments supplied 4184 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4185 // field of the structure passed to sigaction(). This routine assumes that 4186 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4187 // 4188 // Note that the VM will print warnings if it detects conflicting signal 4189 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4190 // 4191 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4192 siginfo_t* siginfo, 4193 void* ucontext, 4194 int abort_if_unrecognized); 4195 4196 void signalHandler(int sig, siginfo_t* info, void* uc) { 4197 assert(info != NULL && uc != NULL, "it must be old kernel"); 4198 int orig_errno = errno; // Preserve errno value over signal handler. 4199 JVM_handle_linux_signal(sig, info, uc, true); 4200 errno = orig_errno; 4201 } 4202 4203 4204 // This boolean allows users to forward their own non-matching signals 4205 // to JVM_handle_linux_signal, harmlessly. 4206 bool os::Linux::signal_handlers_are_installed = false; 4207 4208 // For signal-chaining 4209 struct sigaction sigact[NSIG]; 4210 uint64_t sigs = 0; 4211 #if (64 < NSIG-1) 4212 #error "Not all signals can be encoded in sigs. Adapt its type!" 4213 #endif 4214 bool os::Linux::libjsig_is_loaded = false; 4215 typedef struct sigaction *(*get_signal_t)(int); 4216 get_signal_t os::Linux::get_signal_action = NULL; 4217 4218 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4219 struct sigaction *actp = NULL; 4220 4221 if (libjsig_is_loaded) { 4222 // Retrieve the old signal handler from libjsig 4223 actp = (*get_signal_action)(sig); 4224 } 4225 if (actp == NULL) { 4226 // Retrieve the preinstalled signal handler from jvm 4227 actp = get_preinstalled_handler(sig); 4228 } 4229 4230 return actp; 4231 } 4232 4233 static bool call_chained_handler(struct sigaction *actp, int sig, 4234 siginfo_t *siginfo, void *context) { 4235 // Call the old signal handler 4236 if (actp->sa_handler == SIG_DFL) { 4237 // It's more reasonable to let jvm treat it as an unexpected exception 4238 // instead of taking the default action. 4239 return false; 4240 } else if (actp->sa_handler != SIG_IGN) { 4241 if ((actp->sa_flags & SA_NODEFER) == 0) { 4242 // automaticlly block the signal 4243 sigaddset(&(actp->sa_mask), sig); 4244 } 4245 4246 sa_handler_t hand = NULL; 4247 sa_sigaction_t sa = NULL; 4248 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4249 // retrieve the chained handler 4250 if (siginfo_flag_set) { 4251 sa = actp->sa_sigaction; 4252 } else { 4253 hand = actp->sa_handler; 4254 } 4255 4256 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4257 actp->sa_handler = SIG_DFL; 4258 } 4259 4260 // try to honor the signal mask 4261 sigset_t oset; 4262 sigemptyset(&oset); 4263 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4264 4265 // call into the chained handler 4266 if (siginfo_flag_set) { 4267 (*sa)(sig, siginfo, context); 4268 } else { 4269 (*hand)(sig); 4270 } 4271 4272 // restore the signal mask 4273 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4274 } 4275 // Tell jvm's signal handler the signal is taken care of. 4276 return true; 4277 } 4278 4279 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4280 bool chained = false; 4281 // signal-chaining 4282 if (UseSignalChaining) { 4283 struct sigaction *actp = get_chained_signal_action(sig); 4284 if (actp != NULL) { 4285 chained = call_chained_handler(actp, sig, siginfo, context); 4286 } 4287 } 4288 return chained; 4289 } 4290 4291 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4292 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4293 return &sigact[sig]; 4294 } 4295 return NULL; 4296 } 4297 4298 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4299 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4300 sigact[sig] = oldAct; 4301 sigs |= (uint64_t)1 << (sig-1); 4302 } 4303 4304 // for diagnostic 4305 int sigflags[NSIG]; 4306 4307 int os::Linux::get_our_sigflags(int sig) { 4308 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4309 return sigflags[sig]; 4310 } 4311 4312 void os::Linux::set_our_sigflags(int sig, int flags) { 4313 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4314 if (sig > 0 && sig < NSIG) { 4315 sigflags[sig] = flags; 4316 } 4317 } 4318 4319 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4320 // Check for overwrite. 4321 struct sigaction oldAct; 4322 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4323 4324 void* oldhand = oldAct.sa_sigaction 4325 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4326 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4327 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4328 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4329 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4330 if (AllowUserSignalHandlers || !set_installed) { 4331 // Do not overwrite; user takes responsibility to forward to us. 4332 return; 4333 } else if (UseSignalChaining) { 4334 // save the old handler in jvm 4335 save_preinstalled_handler(sig, oldAct); 4336 // libjsig also interposes the sigaction() call below and saves the 4337 // old sigaction on it own. 4338 } else { 4339 fatal("Encountered unexpected pre-existing sigaction handler " 4340 "%#lx for signal %d.", (long)oldhand, sig); 4341 } 4342 } 4343 4344 struct sigaction sigAct; 4345 sigfillset(&(sigAct.sa_mask)); 4346 sigAct.sa_handler = SIG_DFL; 4347 if (!set_installed) { 4348 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4349 } else { 4350 sigAct.sa_sigaction = signalHandler; 4351 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4352 } 4353 // Save flags, which are set by ours 4354 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4355 sigflags[sig] = sigAct.sa_flags; 4356 4357 int ret = sigaction(sig, &sigAct, &oldAct); 4358 assert(ret == 0, "check"); 4359 4360 void* oldhand2 = oldAct.sa_sigaction 4361 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4362 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4363 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4364 } 4365 4366 // install signal handlers for signals that HotSpot needs to 4367 // handle in order to support Java-level exception handling. 4368 4369 void os::Linux::install_signal_handlers() { 4370 if (!signal_handlers_are_installed) { 4371 signal_handlers_are_installed = true; 4372 4373 // signal-chaining 4374 typedef void (*signal_setting_t)(); 4375 signal_setting_t begin_signal_setting = NULL; 4376 signal_setting_t end_signal_setting = NULL; 4377 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4378 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4379 if (begin_signal_setting != NULL) { 4380 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4381 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4382 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4383 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4384 libjsig_is_loaded = true; 4385 assert(UseSignalChaining, "should enable signal-chaining"); 4386 } 4387 if (libjsig_is_loaded) { 4388 // Tell libjsig jvm is setting signal handlers 4389 (*begin_signal_setting)(); 4390 } 4391 4392 set_signal_handler(SIGSEGV, true); 4393 set_signal_handler(SIGPIPE, true); 4394 set_signal_handler(SIGBUS, true); 4395 set_signal_handler(SIGILL, true); 4396 set_signal_handler(SIGFPE, true); 4397 #if defined(PPC64) 4398 set_signal_handler(SIGTRAP, true); 4399 #endif 4400 set_signal_handler(SIGXFSZ, true); 4401 4402 if (libjsig_is_loaded) { 4403 // Tell libjsig jvm finishes setting signal handlers 4404 (*end_signal_setting)(); 4405 } 4406 4407 // We don't activate signal checker if libjsig is in place, we trust ourselves 4408 // and if UserSignalHandler is installed all bets are off. 4409 // Log that signal checking is off only if -verbose:jni is specified. 4410 if (CheckJNICalls) { 4411 if (libjsig_is_loaded) { 4412 if (PrintJNIResolving) { 4413 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4414 } 4415 check_signals = false; 4416 } 4417 if (AllowUserSignalHandlers) { 4418 if (PrintJNIResolving) { 4419 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4420 } 4421 check_signals = false; 4422 } 4423 } 4424 } 4425 } 4426 4427 // This is the fastest way to get thread cpu time on Linux. 4428 // Returns cpu time (user+sys) for any thread, not only for current. 4429 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4430 // It might work on 2.6.10+ with a special kernel/glibc patch. 4431 // For reference, please, see IEEE Std 1003.1-2004: 4432 // http://www.unix.org/single_unix_specification 4433 4434 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4435 struct timespec tp; 4436 int rc = os::Linux::clock_gettime(clockid, &tp); 4437 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4438 4439 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4440 } 4441 4442 void os::Linux::initialize_os_info() { 4443 assert(_os_version == 0, "OS info already initialized"); 4444 4445 struct utsname _uname; 4446 4447 uint32_t major; 4448 uint32_t minor; 4449 uint32_t fix; 4450 4451 int rc; 4452 4453 // Kernel version is unknown if 4454 // verification below fails. 4455 _os_version = 0x01000000; 4456 4457 rc = uname(&_uname); 4458 if (rc != -1) { 4459 4460 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4461 if (rc == 3) { 4462 4463 if (major < 256 && minor < 256 && fix < 256) { 4464 // Kernel version format is as expected, 4465 // set it overriding unknown state. 4466 _os_version = (major << 16) | 4467 (minor << 8 ) | 4468 (fix << 0 ) ; 4469 } 4470 } 4471 } 4472 } 4473 4474 uint32_t os::Linux::os_version() { 4475 assert(_os_version != 0, "not initialized"); 4476 return _os_version & 0x00FFFFFF; 4477 } 4478 4479 bool os::Linux::os_version_is_known() { 4480 assert(_os_version != 0, "not initialized"); 4481 return _os_version & 0x01000000 ? false : true; 4482 } 4483 4484 ///// 4485 // glibc on Linux platform uses non-documented flag 4486 // to indicate, that some special sort of signal 4487 // trampoline is used. 4488 // We will never set this flag, and we should 4489 // ignore this flag in our diagnostic 4490 #ifdef SIGNIFICANT_SIGNAL_MASK 4491 #undef SIGNIFICANT_SIGNAL_MASK 4492 #endif 4493 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4494 4495 static const char* get_signal_handler_name(address handler, 4496 char* buf, int buflen) { 4497 int offset = 0; 4498 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4499 if (found) { 4500 // skip directory names 4501 const char *p1, *p2; 4502 p1 = buf; 4503 size_t len = strlen(os::file_separator()); 4504 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4505 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4506 } else { 4507 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4508 } 4509 return buf; 4510 } 4511 4512 static void print_signal_handler(outputStream* st, int sig, 4513 char* buf, size_t buflen) { 4514 struct sigaction sa; 4515 4516 sigaction(sig, NULL, &sa); 4517 4518 // See comment for SIGNIFICANT_SIGNAL_MASK define 4519 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4520 4521 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4522 4523 address handler = (sa.sa_flags & SA_SIGINFO) 4524 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4525 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4526 4527 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4528 st->print("SIG_DFL"); 4529 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4530 st->print("SIG_IGN"); 4531 } else { 4532 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4533 } 4534 4535 st->print(", sa_mask[0]="); 4536 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4537 4538 address rh = VMError::get_resetted_sighandler(sig); 4539 // May be, handler was resetted by VMError? 4540 if (rh != NULL) { 4541 handler = rh; 4542 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4543 } 4544 4545 st->print(", sa_flags="); 4546 os::Posix::print_sa_flags(st, sa.sa_flags); 4547 4548 // Check: is it our handler? 4549 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4550 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4551 // It is our signal handler 4552 // check for flags, reset system-used one! 4553 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4554 st->print( 4555 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4556 os::Linux::get_our_sigflags(sig)); 4557 } 4558 } 4559 st->cr(); 4560 } 4561 4562 4563 #define DO_SIGNAL_CHECK(sig) \ 4564 do { \ 4565 if (!sigismember(&check_signal_done, sig)) { \ 4566 os::Linux::check_signal_handler(sig); \ 4567 } \ 4568 } while (0) 4569 4570 // This method is a periodic task to check for misbehaving JNI applications 4571 // under CheckJNI, we can add any periodic checks here 4572 4573 void os::run_periodic_checks() { 4574 if (check_signals == false) return; 4575 4576 // SEGV and BUS if overridden could potentially prevent 4577 // generation of hs*.log in the event of a crash, debugging 4578 // such a case can be very challenging, so we absolutely 4579 // check the following for a good measure: 4580 DO_SIGNAL_CHECK(SIGSEGV); 4581 DO_SIGNAL_CHECK(SIGILL); 4582 DO_SIGNAL_CHECK(SIGFPE); 4583 DO_SIGNAL_CHECK(SIGBUS); 4584 DO_SIGNAL_CHECK(SIGPIPE); 4585 DO_SIGNAL_CHECK(SIGXFSZ); 4586 #if defined(PPC64) 4587 DO_SIGNAL_CHECK(SIGTRAP); 4588 #endif 4589 4590 // ReduceSignalUsage allows the user to override these handlers 4591 // see comments at the very top and jvm_solaris.h 4592 if (!ReduceSignalUsage) { 4593 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4594 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4595 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4596 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4597 } 4598 4599 DO_SIGNAL_CHECK(SR_signum); 4600 } 4601 4602 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4603 4604 static os_sigaction_t os_sigaction = NULL; 4605 4606 void os::Linux::check_signal_handler(int sig) { 4607 char buf[O_BUFLEN]; 4608 address jvmHandler = NULL; 4609 4610 4611 struct sigaction act; 4612 if (os_sigaction == NULL) { 4613 // only trust the default sigaction, in case it has been interposed 4614 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4615 if (os_sigaction == NULL) return; 4616 } 4617 4618 os_sigaction(sig, (struct sigaction*)NULL, &act); 4619 4620 4621 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4622 4623 address thisHandler = (act.sa_flags & SA_SIGINFO) 4624 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4625 : CAST_FROM_FN_PTR(address, act.sa_handler); 4626 4627 4628 switch (sig) { 4629 case SIGSEGV: 4630 case SIGBUS: 4631 case SIGFPE: 4632 case SIGPIPE: 4633 case SIGILL: 4634 case SIGXFSZ: 4635 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4636 break; 4637 4638 case SHUTDOWN1_SIGNAL: 4639 case SHUTDOWN2_SIGNAL: 4640 case SHUTDOWN3_SIGNAL: 4641 case BREAK_SIGNAL: 4642 jvmHandler = (address)user_handler(); 4643 break; 4644 4645 default: 4646 if (sig == SR_signum) { 4647 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4648 } else { 4649 return; 4650 } 4651 break; 4652 } 4653 4654 if (thisHandler != jvmHandler) { 4655 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4656 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4657 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4658 // No need to check this sig any longer 4659 sigaddset(&check_signal_done, sig); 4660 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4661 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4662 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4663 exception_name(sig, buf, O_BUFLEN)); 4664 } 4665 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4666 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4667 tty->print("expected:"); 4668 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4669 tty->cr(); 4670 tty->print(" found:"); 4671 os::Posix::print_sa_flags(tty, act.sa_flags); 4672 tty->cr(); 4673 // No need to check this sig any longer 4674 sigaddset(&check_signal_done, sig); 4675 } 4676 4677 // Dump all the signal 4678 if (sigismember(&check_signal_done, sig)) { 4679 print_signal_handlers(tty, buf, O_BUFLEN); 4680 } 4681 } 4682 4683 extern void report_error(char* file_name, int line_no, char* title, 4684 char* format, ...); 4685 4686 // this is called _before_ the most of global arguments have been parsed 4687 void os::init(void) { 4688 char dummy; // used to get a guess on initial stack address 4689 // first_hrtime = gethrtime(); 4690 4691 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4692 4693 init_random(1234567); 4694 4695 ThreadCritical::initialize(); 4696 4697 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4698 if (Linux::page_size() == -1) { 4699 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4700 os::strerror(errno)); 4701 } 4702 init_page_sizes((size_t) Linux::page_size()); 4703 4704 Linux::initialize_system_info(); 4705 4706 Linux::initialize_os_info(); 4707 4708 // main_thread points to the aboriginal thread 4709 Linux::_main_thread = pthread_self(); 4710 4711 Linux::clock_init(); 4712 initial_time_count = javaTimeNanos(); 4713 4714 // pthread_condattr initialization for monotonic clock 4715 int status; 4716 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4717 if ((status = pthread_condattr_init(_condattr)) != 0) { 4718 fatal("pthread_condattr_init: %s", os::strerror(status)); 4719 } 4720 // Only set the clock if CLOCK_MONOTONIC is available 4721 if (os::supports_monotonic_clock()) { 4722 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4723 if (status == EINVAL) { 4724 warning("Unable to use monotonic clock with relative timed-waits" \ 4725 " - changes to the time-of-day clock may have adverse affects"); 4726 } else { 4727 fatal("pthread_condattr_setclock: %s", os::strerror(status)); 4728 } 4729 } 4730 } 4731 // else it defaults to CLOCK_REALTIME 4732 4733 // retrieve entry point for pthread_setname_np 4734 Linux::_pthread_setname_np = 4735 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4736 4737 } 4738 4739 // To install functions for atexit system call 4740 extern "C" { 4741 static void perfMemory_exit_helper() { 4742 perfMemory_exit(); 4743 } 4744 } 4745 4746 // this is called _after_ the global arguments have been parsed 4747 jint os::init_2(void) { 4748 Linux::fast_thread_clock_init(); 4749 4750 // Allocate a single page and mark it as readable for safepoint polling 4751 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4752 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4753 4754 os::set_polling_page(polling_page); 4755 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page)); 4756 4757 if (!UseMembar) { 4758 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4759 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4760 os::set_memory_serialize_page(mem_serialize_page); 4761 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page)); 4762 } 4763 4764 // initialize suspend/resume support - must do this before signal_sets_init() 4765 if (SR_initialize() != 0) { 4766 perror("SR_initialize failed"); 4767 return JNI_ERR; 4768 } 4769 4770 Linux::signal_sets_init(); 4771 Linux::install_signal_handlers(); 4772 4773 // Check and sets minimum stack sizes against command line options 4774 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 4775 return JNI_ERR; 4776 } 4777 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4778 4779 #if defined(IA32) 4780 workaround_expand_exec_shield_cs_limit(); 4781 #endif 4782 4783 Linux::libpthread_init(); 4784 log_info(os)("HotSpot is running with %s, %s", 4785 Linux::glibc_version(), Linux::libpthread_version()); 4786 4787 if (UseNUMA) { 4788 if (!Linux::libnuma_init()) { 4789 UseNUMA = false; 4790 } else { 4791 if ((Linux::numa_max_node() < 1)) { 4792 // There's only one node(they start from 0), disable NUMA. 4793 UseNUMA = false; 4794 } 4795 } 4796 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4797 // we can make the adaptive lgrp chunk resizing work. If the user specified 4798 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4799 // disable adaptive resizing. 4800 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4801 if (FLAG_IS_DEFAULT(UseNUMA)) { 4802 UseNUMA = false; 4803 } else { 4804 if (FLAG_IS_DEFAULT(UseLargePages) && 4805 FLAG_IS_DEFAULT(UseSHM) && 4806 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4807 UseLargePages = false; 4808 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4809 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4810 UseAdaptiveSizePolicy = false; 4811 UseAdaptiveNUMAChunkSizing = false; 4812 } 4813 } 4814 } 4815 if (!UseNUMA && ForceNUMA) { 4816 UseNUMA = true; 4817 } 4818 } 4819 4820 if (MaxFDLimit) { 4821 // set the number of file descriptors to max. print out error 4822 // if getrlimit/setrlimit fails but continue regardless. 4823 struct rlimit nbr_files; 4824 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4825 if (status != 0) { 4826 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 4827 } else { 4828 nbr_files.rlim_cur = nbr_files.rlim_max; 4829 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4830 if (status != 0) { 4831 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 4832 } 4833 } 4834 } 4835 4836 // Initialize lock used to serialize thread creation (see os::create_thread) 4837 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4838 4839 // at-exit methods are called in the reverse order of their registration. 4840 // atexit functions are called on return from main or as a result of a 4841 // call to exit(3C). There can be only 32 of these functions registered 4842 // and atexit() does not set errno. 4843 4844 if (PerfAllowAtExitRegistration) { 4845 // only register atexit functions if PerfAllowAtExitRegistration is set. 4846 // atexit functions can be delayed until process exit time, which 4847 // can be problematic for embedded VM situations. Embedded VMs should 4848 // call DestroyJavaVM() to assure that VM resources are released. 4849 4850 // note: perfMemory_exit_helper atexit function may be removed in 4851 // the future if the appropriate cleanup code can be added to the 4852 // VM_Exit VMOperation's doit method. 4853 if (atexit(perfMemory_exit_helper) != 0) { 4854 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4855 } 4856 } 4857 4858 // initialize thread priority policy 4859 prio_init(); 4860 4861 return JNI_OK; 4862 } 4863 4864 // Mark the polling page as unreadable 4865 void os::make_polling_page_unreadable(void) { 4866 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4867 fatal("Could not disable polling page"); 4868 } 4869 } 4870 4871 // Mark the polling page as readable 4872 void os::make_polling_page_readable(void) { 4873 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4874 fatal("Could not enable polling page"); 4875 } 4876 } 4877 4878 // older glibc versions don't have this macro (which expands to 4879 // an optimized bit-counting function) so we have to roll our own 4880 #ifndef CPU_COUNT 4881 4882 static int _cpu_count(const cpu_set_t* cpus) { 4883 int count = 0; 4884 // only look up to the number of configured processors 4885 for (int i = 0; i < os::processor_count(); i++) { 4886 if (CPU_ISSET(i, cpus)) { 4887 count++; 4888 } 4889 } 4890 return count; 4891 } 4892 4893 #define CPU_COUNT(cpus) _cpu_count(cpus) 4894 4895 #endif // CPU_COUNT 4896 4897 // Get the current number of available processors for this process. 4898 // This value can change at any time during a process's lifetime. 4899 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 4900 // If it appears there may be more than 1024 processors then we do a 4901 // dynamic check - see 6515172 for details. 4902 // If anything goes wrong we fallback to returning the number of online 4903 // processors - which can be greater than the number available to the process. 4904 int os::active_processor_count() { 4905 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 4906 cpu_set_t* cpus_p = &cpus; 4907 int cpus_size = sizeof(cpu_set_t); 4908 4909 int configured_cpus = processor_count(); // upper bound on available cpus 4910 int cpu_count = 0; 4911 4912 // old build platforms may not support dynamic cpu sets 4913 #ifdef CPU_ALLOC 4914 4915 // To enable easy testing of the dynamic path on different platforms we 4916 // introduce a diagnostic flag: UseCpuAllocPath 4917 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 4918 // kernel may use a mask bigger than cpu_set_t 4919 log_trace(os)("active_processor_count: using dynamic path %s" 4920 "- configured processors: %d", 4921 UseCpuAllocPath ? "(forced) " : "", 4922 configured_cpus); 4923 cpus_p = CPU_ALLOC(configured_cpus); 4924 if (cpus_p != NULL) { 4925 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 4926 // zero it just to be safe 4927 CPU_ZERO_S(cpus_size, cpus_p); 4928 } 4929 else { 4930 // failed to allocate so fallback to online cpus 4931 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4932 log_trace(os)("active_processor_count: " 4933 "CPU_ALLOC failed (%s) - using " 4934 "online processor count: %d", 4935 os::strerror(errno), online_cpus); 4936 return online_cpus; 4937 } 4938 } 4939 else { 4940 log_trace(os)("active_processor_count: using static path - configured processors: %d", 4941 configured_cpus); 4942 } 4943 #else // CPU_ALLOC 4944 // these stubs won't be executed 4945 #define CPU_COUNT_S(size, cpus) -1 4946 #define CPU_FREE(cpus) 4947 4948 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 4949 configured_cpus); 4950 #endif // CPU_ALLOC 4951 4952 // pid 0 means the current thread - which we have to assume represents the process 4953 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 4954 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 4955 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 4956 } 4957 else { 4958 cpu_count = CPU_COUNT(cpus_p); 4959 } 4960 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 4961 } 4962 else { 4963 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 4964 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 4965 "which may exceed available processors", os::strerror(errno), cpu_count); 4966 } 4967 4968 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 4969 CPU_FREE(cpus_p); 4970 } 4971 4972 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check"); 4973 return cpu_count; 4974 } 4975 4976 void os::set_native_thread_name(const char *name) { 4977 if (Linux::_pthread_setname_np) { 4978 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 4979 snprintf(buf, sizeof(buf), "%s", name); 4980 buf[sizeof(buf) - 1] = '\0'; 4981 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 4982 // ERANGE should not happen; all other errors should just be ignored. 4983 assert(rc != ERANGE, "pthread_setname_np failed"); 4984 } 4985 } 4986 4987 bool os::distribute_processes(uint length, uint* distribution) { 4988 // Not yet implemented. 4989 return false; 4990 } 4991 4992 bool os::bind_to_processor(uint processor_id) { 4993 // Not yet implemented. 4994 return false; 4995 } 4996 4997 /// 4998 4999 void os::SuspendedThreadTask::internal_do_task() { 5000 if (do_suspend(_thread->osthread())) { 5001 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5002 do_task(context); 5003 do_resume(_thread->osthread()); 5004 } 5005 } 5006 5007 class PcFetcher : public os::SuspendedThreadTask { 5008 public: 5009 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 5010 ExtendedPC result(); 5011 protected: 5012 void do_task(const os::SuspendedThreadTaskContext& context); 5013 private: 5014 ExtendedPC _epc; 5015 }; 5016 5017 ExtendedPC PcFetcher::result() { 5018 guarantee(is_done(), "task is not done yet."); 5019 return _epc; 5020 } 5021 5022 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 5023 Thread* thread = context.thread(); 5024 OSThread* osthread = thread->osthread(); 5025 if (osthread->ucontext() != NULL) { 5026 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext()); 5027 } else { 5028 // NULL context is unexpected, double-check this is the VMThread 5029 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 5030 } 5031 } 5032 5033 // Suspends the target using the signal mechanism and then grabs the PC before 5034 // resuming the target. Used by the flat-profiler only 5035 ExtendedPC os::get_thread_pc(Thread* thread) { 5036 // Make sure that it is called by the watcher for the VMThread 5037 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 5038 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 5039 5040 PcFetcher fetcher(thread); 5041 fetcher.run(); 5042 return fetcher.result(); 5043 } 5044 5045 //////////////////////////////////////////////////////////////////////////////// 5046 // debug support 5047 5048 bool os::find(address addr, outputStream* st) { 5049 Dl_info dlinfo; 5050 memset(&dlinfo, 0, sizeof(dlinfo)); 5051 if (dladdr(addr, &dlinfo) != 0) { 5052 st->print(PTR_FORMAT ": ", p2i(addr)); 5053 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5054 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5055 p2i(addr) - p2i(dlinfo.dli_saddr)); 5056 } else if (dlinfo.dli_fbase != NULL) { 5057 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5058 } else { 5059 st->print("<absolute address>"); 5060 } 5061 if (dlinfo.dli_fname != NULL) { 5062 st->print(" in %s", dlinfo.dli_fname); 5063 } 5064 if (dlinfo.dli_fbase != NULL) { 5065 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5066 } 5067 st->cr(); 5068 5069 if (Verbose) { 5070 // decode some bytes around the PC 5071 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5072 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5073 address lowest = (address) dlinfo.dli_sname; 5074 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5075 if (begin < lowest) begin = lowest; 5076 Dl_info dlinfo2; 5077 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5078 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5079 end = (address) dlinfo2.dli_saddr; 5080 } 5081 Disassembler::decode(begin, end, st); 5082 } 5083 return true; 5084 } 5085 return false; 5086 } 5087 5088 //////////////////////////////////////////////////////////////////////////////// 5089 // misc 5090 5091 // This does not do anything on Linux. This is basically a hook for being 5092 // able to use structured exception handling (thread-local exception filters) 5093 // on, e.g., Win32. 5094 void 5095 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5096 JavaCallArguments* args, Thread* thread) { 5097 f(value, method, args, thread); 5098 } 5099 5100 void os::print_statistics() { 5101 } 5102 5103 bool os::message_box(const char* title, const char* message) { 5104 int i; 5105 fdStream err(defaultStream::error_fd()); 5106 for (i = 0; i < 78; i++) err.print_raw("="); 5107 err.cr(); 5108 err.print_raw_cr(title); 5109 for (i = 0; i < 78; i++) err.print_raw("-"); 5110 err.cr(); 5111 err.print_raw_cr(message); 5112 for (i = 0; i < 78; i++) err.print_raw("="); 5113 err.cr(); 5114 5115 char buf[16]; 5116 // Prevent process from exiting upon "read error" without consuming all CPU 5117 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5118 5119 return buf[0] == 'y' || buf[0] == 'Y'; 5120 } 5121 5122 int os::stat(const char *path, struct stat *sbuf) { 5123 char pathbuf[MAX_PATH]; 5124 if (strlen(path) > MAX_PATH - 1) { 5125 errno = ENAMETOOLONG; 5126 return -1; 5127 } 5128 os::native_path(strcpy(pathbuf, path)); 5129 return ::stat(pathbuf, sbuf); 5130 } 5131 5132 // Is a (classpath) directory empty? 5133 bool os::dir_is_empty(const char* path) { 5134 DIR *dir = NULL; 5135 struct dirent *ptr; 5136 5137 dir = opendir(path); 5138 if (dir == NULL) return true; 5139 5140 // Scan the directory 5141 bool result = true; 5142 char buf[sizeof(struct dirent) + MAX_PATH]; 5143 while (result && (ptr = ::readdir(dir)) != NULL) { 5144 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5145 result = false; 5146 } 5147 } 5148 closedir(dir); 5149 return result; 5150 } 5151 5152 // This code originates from JDK's sysOpen and open64_w 5153 // from src/solaris/hpi/src/system_md.c 5154 5155 int os::open(const char *path, int oflag, int mode) { 5156 if (strlen(path) > MAX_PATH - 1) { 5157 errno = ENAMETOOLONG; 5158 return -1; 5159 } 5160 5161 // All file descriptors that are opened in the Java process and not 5162 // specifically destined for a subprocess should have the close-on-exec 5163 // flag set. If we don't set it, then careless 3rd party native code 5164 // might fork and exec without closing all appropriate file descriptors 5165 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5166 // turn might: 5167 // 5168 // - cause end-of-file to fail to be detected on some file 5169 // descriptors, resulting in mysterious hangs, or 5170 // 5171 // - might cause an fopen in the subprocess to fail on a system 5172 // suffering from bug 1085341. 5173 // 5174 // (Yes, the default setting of the close-on-exec flag is a Unix 5175 // design flaw) 5176 // 5177 // See: 5178 // 1085341: 32-bit stdio routines should support file descriptors >255 5179 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5180 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5181 // 5182 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5183 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5184 // because it saves a system call and removes a small window where the flag 5185 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5186 // and we fall back to using FD_CLOEXEC (see below). 5187 #ifdef O_CLOEXEC 5188 oflag |= O_CLOEXEC; 5189 #endif 5190 5191 int fd = ::open64(path, oflag, mode); 5192 if (fd == -1) return -1; 5193 5194 //If the open succeeded, the file might still be a directory 5195 { 5196 struct stat64 buf64; 5197 int ret = ::fstat64(fd, &buf64); 5198 int st_mode = buf64.st_mode; 5199 5200 if (ret != -1) { 5201 if ((st_mode & S_IFMT) == S_IFDIR) { 5202 errno = EISDIR; 5203 ::close(fd); 5204 return -1; 5205 } 5206 } else { 5207 ::close(fd); 5208 return -1; 5209 } 5210 } 5211 5212 #ifdef FD_CLOEXEC 5213 // Validate that the use of the O_CLOEXEC flag on open above worked. 5214 // With recent kernels, we will perform this check exactly once. 5215 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5216 if (!O_CLOEXEC_is_known_to_work) { 5217 int flags = ::fcntl(fd, F_GETFD); 5218 if (flags != -1) { 5219 if ((flags & FD_CLOEXEC) != 0) 5220 O_CLOEXEC_is_known_to_work = 1; 5221 else 5222 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5223 } 5224 } 5225 #endif 5226 5227 return fd; 5228 } 5229 5230 5231 // create binary file, rewriting existing file if required 5232 int os::create_binary_file(const char* path, bool rewrite_existing) { 5233 int oflags = O_WRONLY | O_CREAT; 5234 if (!rewrite_existing) { 5235 oflags |= O_EXCL; 5236 } 5237 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5238 } 5239 5240 // return current position of file pointer 5241 jlong os::current_file_offset(int fd) { 5242 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5243 } 5244 5245 // move file pointer to the specified offset 5246 jlong os::seek_to_file_offset(int fd, jlong offset) { 5247 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5248 } 5249 5250 // This code originates from JDK's sysAvailable 5251 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5252 5253 int os::available(int fd, jlong *bytes) { 5254 jlong cur, end; 5255 int mode; 5256 struct stat64 buf64; 5257 5258 if (::fstat64(fd, &buf64) >= 0) { 5259 mode = buf64.st_mode; 5260 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5261 int n; 5262 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5263 *bytes = n; 5264 return 1; 5265 } 5266 } 5267 } 5268 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5269 return 0; 5270 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5271 return 0; 5272 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5273 return 0; 5274 } 5275 *bytes = end - cur; 5276 return 1; 5277 } 5278 5279 // Map a block of memory. 5280 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5281 char *addr, size_t bytes, bool read_only, 5282 bool allow_exec) { 5283 int prot; 5284 int flags = MAP_PRIVATE; 5285 5286 if (read_only) { 5287 prot = PROT_READ; 5288 } else { 5289 prot = PROT_READ | PROT_WRITE; 5290 } 5291 5292 if (allow_exec) { 5293 prot |= PROT_EXEC; 5294 } 5295 5296 if (addr != NULL) { 5297 flags |= MAP_FIXED; 5298 } 5299 5300 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5301 fd, file_offset); 5302 if (mapped_address == MAP_FAILED) { 5303 return NULL; 5304 } 5305 return mapped_address; 5306 } 5307 5308 5309 // Remap a block of memory. 5310 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5311 char *addr, size_t bytes, bool read_only, 5312 bool allow_exec) { 5313 // same as map_memory() on this OS 5314 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5315 allow_exec); 5316 } 5317 5318 5319 // Unmap a block of memory. 5320 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5321 return munmap(addr, bytes) == 0; 5322 } 5323 5324 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5325 5326 static clockid_t thread_cpu_clockid(Thread* thread) { 5327 pthread_t tid = thread->osthread()->pthread_id(); 5328 clockid_t clockid; 5329 5330 // Get thread clockid 5331 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5332 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5333 return clockid; 5334 } 5335 5336 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5337 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5338 // of a thread. 5339 // 5340 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5341 // the fast estimate available on the platform. 5342 5343 jlong os::current_thread_cpu_time() { 5344 if (os::Linux::supports_fast_thread_cpu_time()) { 5345 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5346 } else { 5347 // return user + sys since the cost is the same 5348 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5349 } 5350 } 5351 5352 jlong os::thread_cpu_time(Thread* thread) { 5353 // consistent with what current_thread_cpu_time() returns 5354 if (os::Linux::supports_fast_thread_cpu_time()) { 5355 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5356 } else { 5357 return slow_thread_cpu_time(thread, true /* user + sys */); 5358 } 5359 } 5360 5361 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5362 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5363 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5364 } else { 5365 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5366 } 5367 } 5368 5369 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5370 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5371 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5372 } else { 5373 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5374 } 5375 } 5376 5377 // -1 on error. 5378 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5379 pid_t tid = thread->osthread()->thread_id(); 5380 char *s; 5381 char stat[2048]; 5382 int statlen; 5383 char proc_name[64]; 5384 int count; 5385 long sys_time, user_time; 5386 char cdummy; 5387 int idummy; 5388 long ldummy; 5389 FILE *fp; 5390 5391 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5392 fp = fopen(proc_name, "r"); 5393 if (fp == NULL) return -1; 5394 statlen = fread(stat, 1, 2047, fp); 5395 stat[statlen] = '\0'; 5396 fclose(fp); 5397 5398 // Skip pid and the command string. Note that we could be dealing with 5399 // weird command names, e.g. user could decide to rename java launcher 5400 // to "java 1.4.2 :)", then the stat file would look like 5401 // 1234 (java 1.4.2 :)) R ... ... 5402 // We don't really need to know the command string, just find the last 5403 // occurrence of ")" and then start parsing from there. See bug 4726580. 5404 s = strrchr(stat, ')'); 5405 if (s == NULL) return -1; 5406 5407 // Skip blank chars 5408 do { s++; } while (s && isspace(*s)); 5409 5410 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5411 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5412 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5413 &user_time, &sys_time); 5414 if (count != 13) return -1; 5415 if (user_sys_cpu_time) { 5416 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5417 } else { 5418 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5419 } 5420 } 5421 5422 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5423 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5424 info_ptr->may_skip_backward = false; // elapsed time not wall time 5425 info_ptr->may_skip_forward = false; // elapsed time not wall time 5426 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5427 } 5428 5429 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5430 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5431 info_ptr->may_skip_backward = false; // elapsed time not wall time 5432 info_ptr->may_skip_forward = false; // elapsed time not wall time 5433 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5434 } 5435 5436 bool os::is_thread_cpu_time_supported() { 5437 return true; 5438 } 5439 5440 // System loadavg support. Returns -1 if load average cannot be obtained. 5441 // Linux doesn't yet have a (official) notion of processor sets, 5442 // so just return the system wide load average. 5443 int os::loadavg(double loadavg[], int nelem) { 5444 return ::getloadavg(loadavg, nelem); 5445 } 5446 5447 void os::pause() { 5448 char filename[MAX_PATH]; 5449 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5450 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5451 } else { 5452 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5453 } 5454 5455 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5456 if (fd != -1) { 5457 struct stat buf; 5458 ::close(fd); 5459 while (::stat(filename, &buf) == 0) { 5460 (void)::poll(NULL, 0, 100); 5461 } 5462 } else { 5463 jio_fprintf(stderr, 5464 "Could not open pause file '%s', continuing immediately.\n", filename); 5465 } 5466 } 5467 5468 5469 // Refer to the comments in os_solaris.cpp park-unpark. The next two 5470 // comment paragraphs are worth repeating here: 5471 // 5472 // Assumption: 5473 // Only one parker can exist on an event, which is why we allocate 5474 // them per-thread. Multiple unparkers can coexist. 5475 // 5476 // _Event serves as a restricted-range semaphore. 5477 // -1 : thread is blocked, i.e. there is a waiter 5478 // 0 : neutral: thread is running or ready, 5479 // could have been signaled after a wait started 5480 // 1 : signaled - thread is running or ready 5481 // 5482 5483 // utility to compute the abstime argument to timedwait: 5484 // millis is the relative timeout time 5485 // abstime will be the absolute timeout time 5486 // TODO: replace compute_abstime() with unpackTime() 5487 5488 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5489 if (millis < 0) millis = 0; 5490 5491 jlong seconds = millis / 1000; 5492 millis %= 1000; 5493 if (seconds > 50000000) { // see man cond_timedwait(3T) 5494 seconds = 50000000; 5495 } 5496 5497 if (os::supports_monotonic_clock()) { 5498 struct timespec now; 5499 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5500 assert_status(status == 0, status, "clock_gettime"); 5501 abstime->tv_sec = now.tv_sec + seconds; 5502 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5503 if (nanos >= NANOSECS_PER_SEC) { 5504 abstime->tv_sec += 1; 5505 nanos -= NANOSECS_PER_SEC; 5506 } 5507 abstime->tv_nsec = nanos; 5508 } else { 5509 struct timeval now; 5510 int status = gettimeofday(&now, NULL); 5511 assert(status == 0, "gettimeofday"); 5512 abstime->tv_sec = now.tv_sec + seconds; 5513 long usec = now.tv_usec + millis * 1000; 5514 if (usec >= 1000000) { 5515 abstime->tv_sec += 1; 5516 usec -= 1000000; 5517 } 5518 abstime->tv_nsec = usec * 1000; 5519 } 5520 return abstime; 5521 } 5522 5523 void os::PlatformEvent::park() { // AKA "down()" 5524 // Transitions for _Event: 5525 // -1 => -1 : illegal 5526 // 1 => 0 : pass - return immediately 5527 // 0 => -1 : block; then set _Event to 0 before returning 5528 5529 // Invariant: Only the thread associated with the Event/PlatformEvent 5530 // may call park(). 5531 // TODO: assert that _Assoc != NULL or _Assoc == Self 5532 assert(_nParked == 0, "invariant"); 5533 5534 int v; 5535 for (;;) { 5536 v = _Event; 5537 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5538 } 5539 guarantee(v >= 0, "invariant"); 5540 if (v == 0) { 5541 // Do this the hard way by blocking ... 5542 int status = pthread_mutex_lock(_mutex); 5543 assert_status(status == 0, status, "mutex_lock"); 5544 guarantee(_nParked == 0, "invariant"); 5545 ++_nParked; 5546 while (_Event < 0) { 5547 status = pthread_cond_wait(_cond, _mutex); 5548 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5549 // Treat this the same as if the wait was interrupted 5550 if (status == ETIME) { status = EINTR; } 5551 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5552 } 5553 --_nParked; 5554 5555 _Event = 0; 5556 status = pthread_mutex_unlock(_mutex); 5557 assert_status(status == 0, status, "mutex_unlock"); 5558 // Paranoia to ensure our locked and lock-free paths interact 5559 // correctly with each other. 5560 OrderAccess::fence(); 5561 } 5562 guarantee(_Event >= 0, "invariant"); 5563 } 5564 5565 int os::PlatformEvent::park(jlong millis) { 5566 // Transitions for _Event: 5567 // -1 => -1 : illegal 5568 // 1 => 0 : pass - return immediately 5569 // 0 => -1 : block; then set _Event to 0 before returning 5570 5571 guarantee(_nParked == 0, "invariant"); 5572 5573 int v; 5574 for (;;) { 5575 v = _Event; 5576 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5577 } 5578 guarantee(v >= 0, "invariant"); 5579 if (v != 0) return OS_OK; 5580 5581 // We do this the hard way, by blocking the thread. 5582 // Consider enforcing a minimum timeout value. 5583 struct timespec abst; 5584 compute_abstime(&abst, millis); 5585 5586 int ret = OS_TIMEOUT; 5587 int status = pthread_mutex_lock(_mutex); 5588 assert_status(status == 0, status, "mutex_lock"); 5589 guarantee(_nParked == 0, "invariant"); 5590 ++_nParked; 5591 5592 // Object.wait(timo) will return because of 5593 // (a) notification 5594 // (b) timeout 5595 // (c) thread.interrupt 5596 // 5597 // Thread.interrupt and object.notify{All} both call Event::set. 5598 // That is, we treat thread.interrupt as a special case of notification. 5599 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5600 // We assume all ETIME returns are valid. 5601 // 5602 // TODO: properly differentiate simultaneous notify+interrupt. 5603 // In that case, we should propagate the notify to another waiter. 5604 5605 while (_Event < 0) { 5606 status = pthread_cond_timedwait(_cond, _mutex, &abst); 5607 assert_status(status == 0 || status == EINTR || 5608 status == ETIME || status == ETIMEDOUT, 5609 status, "cond_timedwait"); 5610 if (!FilterSpuriousWakeups) break; // previous semantics 5611 if (status == ETIME || status == ETIMEDOUT) break; 5612 // We consume and ignore EINTR and spurious wakeups. 5613 } 5614 --_nParked; 5615 if (_Event >= 0) { 5616 ret = OS_OK; 5617 } 5618 _Event = 0; 5619 status = pthread_mutex_unlock(_mutex); 5620 assert_status(status == 0, status, "mutex_unlock"); 5621 assert(_nParked == 0, "invariant"); 5622 // Paranoia to ensure our locked and lock-free paths interact 5623 // correctly with each other. 5624 OrderAccess::fence(); 5625 return ret; 5626 } 5627 5628 void os::PlatformEvent::unpark() { 5629 // Transitions for _Event: 5630 // 0 => 1 : just return 5631 // 1 => 1 : just return 5632 // -1 => either 0 or 1; must signal target thread 5633 // That is, we can safely transition _Event from -1 to either 5634 // 0 or 1. 5635 // See also: "Semaphores in Plan 9" by Mullender & Cox 5636 // 5637 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5638 // that it will take two back-to-back park() calls for the owning 5639 // thread to block. This has the benefit of forcing a spurious return 5640 // from the first park() call after an unpark() call which will help 5641 // shake out uses of park() and unpark() without condition variables. 5642 5643 if (Atomic::xchg(1, &_Event) >= 0) return; 5644 5645 // Wait for the thread associated with the event to vacate 5646 int status = pthread_mutex_lock(_mutex); 5647 assert_status(status == 0, status, "mutex_lock"); 5648 int AnyWaiters = _nParked; 5649 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5650 status = pthread_mutex_unlock(_mutex); 5651 assert_status(status == 0, status, "mutex_unlock"); 5652 if (AnyWaiters != 0) { 5653 // Note that we signal() *after* dropping the lock for "immortal" Events. 5654 // This is safe and avoids a common class of futile wakeups. In rare 5655 // circumstances this can cause a thread to return prematurely from 5656 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5657 // will simply re-test the condition and re-park itself. 5658 // This provides particular benefit if the underlying platform does not 5659 // provide wait morphing. 5660 status = pthread_cond_signal(_cond); 5661 assert_status(status == 0, status, "cond_signal"); 5662 } 5663 } 5664 5665 5666 // JSR166 5667 // ------------------------------------------------------- 5668 5669 // The solaris and linux implementations of park/unpark are fairly 5670 // conservative for now, but can be improved. They currently use a 5671 // mutex/condvar pair, plus a a count. 5672 // Park decrements count if > 0, else does a condvar wait. Unpark 5673 // sets count to 1 and signals condvar. Only one thread ever waits 5674 // on the condvar. Contention seen when trying to park implies that someone 5675 // is unparking you, so don't wait. And spurious returns are fine, so there 5676 // is no need to track notifications. 5677 5678 // This code is common to linux and solaris and will be moved to a 5679 // common place in dolphin. 5680 // 5681 // The passed in time value is either a relative time in nanoseconds 5682 // or an absolute time in milliseconds. Either way it has to be unpacked 5683 // into suitable seconds and nanoseconds components and stored in the 5684 // given timespec structure. 5685 // Given time is a 64-bit value and the time_t used in the timespec is only 5686 // a signed-32-bit value (except on 64-bit Linux) we have to watch for 5687 // overflow if times way in the future are given. Further on Solaris versions 5688 // prior to 10 there is a restriction (see cond_timedwait) that the specified 5689 // number of seconds, in abstime, is less than current_time + 100,000,000. 5690 // As it will be 28 years before "now + 100000000" will overflow we can 5691 // ignore overflow and just impose a hard-limit on seconds using the value 5692 // of "now + 100,000,000". This places a limit on the timeout of about 3.17 5693 // years from "now". 5694 5695 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5696 assert(time > 0, "convertTime"); 5697 time_t max_secs = 0; 5698 5699 if (!os::supports_monotonic_clock() || isAbsolute) { 5700 struct timeval now; 5701 int status = gettimeofday(&now, NULL); 5702 assert(status == 0, "gettimeofday"); 5703 5704 max_secs = now.tv_sec + MAX_SECS; 5705 5706 if (isAbsolute) { 5707 jlong secs = time / 1000; 5708 if (secs > max_secs) { 5709 absTime->tv_sec = max_secs; 5710 } else { 5711 absTime->tv_sec = secs; 5712 } 5713 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5714 } else { 5715 jlong secs = time / NANOSECS_PER_SEC; 5716 if (secs >= MAX_SECS) { 5717 absTime->tv_sec = max_secs; 5718 absTime->tv_nsec = 0; 5719 } else { 5720 absTime->tv_sec = now.tv_sec + secs; 5721 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5722 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5723 absTime->tv_nsec -= NANOSECS_PER_SEC; 5724 ++absTime->tv_sec; // note: this must be <= max_secs 5725 } 5726 } 5727 } 5728 } else { 5729 // must be relative using monotonic clock 5730 struct timespec now; 5731 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5732 assert_status(status == 0, status, "clock_gettime"); 5733 max_secs = now.tv_sec + MAX_SECS; 5734 jlong secs = time / NANOSECS_PER_SEC; 5735 if (secs >= MAX_SECS) { 5736 absTime->tv_sec = max_secs; 5737 absTime->tv_nsec = 0; 5738 } else { 5739 absTime->tv_sec = now.tv_sec + secs; 5740 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5741 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5742 absTime->tv_nsec -= NANOSECS_PER_SEC; 5743 ++absTime->tv_sec; // note: this must be <= max_secs 5744 } 5745 } 5746 } 5747 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5748 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5749 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5750 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5751 } 5752 5753 void Parker::park(bool isAbsolute, jlong time) { 5754 // Ideally we'd do something useful while spinning, such 5755 // as calling unpackTime(). 5756 5757 // Optional fast-path check: 5758 // Return immediately if a permit is available. 5759 // We depend on Atomic::xchg() having full barrier semantics 5760 // since we are doing a lock-free update to _counter. 5761 if (Atomic::xchg(0, &_counter) > 0) return; 5762 5763 Thread* thread = Thread::current(); 5764 assert(thread->is_Java_thread(), "Must be JavaThread"); 5765 JavaThread *jt = (JavaThread *)thread; 5766 5767 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5768 // Check interrupt before trying to wait 5769 if (Thread::is_interrupted(thread, false)) { 5770 return; 5771 } 5772 5773 // Next, demultiplex/decode time arguments 5774 timespec absTime; 5775 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5776 return; 5777 } 5778 if (time > 0) { 5779 unpackTime(&absTime, isAbsolute, time); 5780 } 5781 5782 5783 // Enter safepoint region 5784 // Beware of deadlocks such as 6317397. 5785 // The per-thread Parker:: mutex is a classic leaf-lock. 5786 // In particular a thread must never block on the Threads_lock while 5787 // holding the Parker:: mutex. If safepoints are pending both the 5788 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5789 ThreadBlockInVM tbivm(jt); 5790 5791 // Don't wait if cannot get lock since interference arises from 5792 // unblocking. Also. check interrupt before trying wait 5793 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5794 return; 5795 } 5796 5797 int status; 5798 if (_counter > 0) { // no wait needed 5799 _counter = 0; 5800 status = pthread_mutex_unlock(_mutex); 5801 assert_status(status == 0, status, "invariant"); 5802 // Paranoia to ensure our locked and lock-free paths interact 5803 // correctly with each other and Java-level accesses. 5804 OrderAccess::fence(); 5805 return; 5806 } 5807 5808 #ifdef ASSERT 5809 // Don't catch signals while blocked; let the running threads have the signals. 5810 // (This allows a debugger to break into the running thread.) 5811 sigset_t oldsigs; 5812 sigemptyset(&oldsigs); 5813 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5814 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5815 #endif 5816 5817 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5818 jt->set_suspend_equivalent(); 5819 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5820 5821 assert(_cur_index == -1, "invariant"); 5822 if (time == 0) { 5823 _cur_index = REL_INDEX; // arbitrary choice when not timed 5824 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5825 } else { 5826 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5827 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5828 } 5829 _cur_index = -1; 5830 assert_status(status == 0 || status == EINTR || 5831 status == ETIME || status == ETIMEDOUT, 5832 status, "cond_timedwait"); 5833 5834 #ifdef ASSERT 5835 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5836 #endif 5837 5838 _counter = 0; 5839 status = pthread_mutex_unlock(_mutex); 5840 assert_status(status == 0, status, "invariant"); 5841 // Paranoia to ensure our locked and lock-free paths interact 5842 // correctly with each other and Java-level accesses. 5843 OrderAccess::fence(); 5844 5845 // If externally suspended while waiting, re-suspend 5846 if (jt->handle_special_suspend_equivalent_condition()) { 5847 jt->java_suspend_self(); 5848 } 5849 } 5850 5851 void Parker::unpark() { 5852 int status = pthread_mutex_lock(_mutex); 5853 assert_status(status == 0, status, "invariant"); 5854 const int s = _counter; 5855 _counter = 1; 5856 // must capture correct index before unlocking 5857 int index = _cur_index; 5858 status = pthread_mutex_unlock(_mutex); 5859 assert_status(status == 0, status, "invariant"); 5860 if (s < 1 && index != -1) { 5861 // thread is definitely parked 5862 status = pthread_cond_signal(&_cond[index]); 5863 assert_status(status == 0, status, "invariant"); 5864 } 5865 } 5866 5867 5868 extern char** environ; 5869 5870 // Run the specified command in a separate process. Return its exit value, 5871 // or -1 on failure (e.g. can't fork a new process). 5872 // Unlike system(), this function can be called from signal handler. It 5873 // doesn't block SIGINT et al. 5874 int os::fork_and_exec(char* cmd) { 5875 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5876 5877 pid_t pid = fork(); 5878 5879 if (pid < 0) { 5880 // fork failed 5881 return -1; 5882 5883 } else if (pid == 0) { 5884 // child process 5885 5886 execve("/bin/sh", (char* const*)argv, environ); 5887 5888 // execve failed 5889 _exit(-1); 5890 5891 } else { 5892 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5893 // care about the actual exit code, for now. 5894 5895 int status; 5896 5897 // Wait for the child process to exit. This returns immediately if 5898 // the child has already exited. */ 5899 while (waitpid(pid, &status, 0) < 0) { 5900 switch (errno) { 5901 case ECHILD: return 0; 5902 case EINTR: break; 5903 default: return -1; 5904 } 5905 } 5906 5907 if (WIFEXITED(status)) { 5908 // The child exited normally; get its exit code. 5909 return WEXITSTATUS(status); 5910 } else if (WIFSIGNALED(status)) { 5911 // The child exited because of a signal 5912 // The best value to return is 0x80 + signal number, 5913 // because that is what all Unix shells do, and because 5914 // it allows callers to distinguish between process exit and 5915 // process death by signal. 5916 return 0x80 + WTERMSIG(status); 5917 } else { 5918 // Unknown exit code; pass it through 5919 return status; 5920 } 5921 } 5922 } 5923 5924 // is_headless_jre() 5925 // 5926 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 5927 // in order to report if we are running in a headless jre 5928 // 5929 // Since JDK8 xawt/libmawt.so was moved into the same directory 5930 // as libawt.so, and renamed libawt_xawt.so 5931 // 5932 bool os::is_headless_jre() { 5933 struct stat statbuf; 5934 char buf[MAXPATHLEN]; 5935 char libmawtpath[MAXPATHLEN]; 5936 const char *xawtstr = "/xawt/libmawt.so"; 5937 const char *new_xawtstr = "/libawt_xawt.so"; 5938 char *p; 5939 5940 // Get path to libjvm.so 5941 os::jvm_path(buf, sizeof(buf)); 5942 5943 // Get rid of libjvm.so 5944 p = strrchr(buf, '/'); 5945 if (p == NULL) { 5946 return false; 5947 } else { 5948 *p = '\0'; 5949 } 5950 5951 // Get rid of client or server 5952 p = strrchr(buf, '/'); 5953 if (p == NULL) { 5954 return false; 5955 } else { 5956 *p = '\0'; 5957 } 5958 5959 // check xawt/libmawt.so 5960 strcpy(libmawtpath, buf); 5961 strcat(libmawtpath, xawtstr); 5962 if (::stat(libmawtpath, &statbuf) == 0) return false; 5963 5964 // check libawt_xawt.so 5965 strcpy(libmawtpath, buf); 5966 strcat(libmawtpath, new_xawtstr); 5967 if (::stat(libmawtpath, &statbuf) == 0) return false; 5968 5969 return true; 5970 } 5971 5972 // Get the default path to the core file 5973 // Returns the length of the string 5974 int os::get_core_path(char* buffer, size_t bufferSize) { 5975 /* 5976 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5977 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5978 */ 5979 const int core_pattern_len = 129; 5980 char core_pattern[core_pattern_len] = {0}; 5981 5982 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5983 if (core_pattern_file == -1) { 5984 return -1; 5985 } 5986 5987 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5988 ::close(core_pattern_file); 5989 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5990 return -1; 5991 } 5992 if (core_pattern[ret-1] == '\n') { 5993 core_pattern[ret-1] = '\0'; 5994 } else { 5995 core_pattern[ret] = '\0'; 5996 } 5997 5998 char *pid_pos = strstr(core_pattern, "%p"); 5999 int written; 6000 6001 if (core_pattern[0] == '/') { 6002 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 6003 } else { 6004 char cwd[PATH_MAX]; 6005 6006 const char* p = get_current_directory(cwd, PATH_MAX); 6007 if (p == NULL) { 6008 return -1; 6009 } 6010 6011 if (core_pattern[0] == '|') { 6012 written = jio_snprintf(buffer, bufferSize, 6013 "\"%s\" (or dumping to %s/core.%d)", 6014 &core_pattern[1], p, current_process_id()); 6015 } else { 6016 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 6017 } 6018 } 6019 6020 if (written < 0) { 6021 return -1; 6022 } 6023 6024 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 6025 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 6026 6027 if (core_uses_pid_file != -1) { 6028 char core_uses_pid = 0; 6029 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 6030 ::close(core_uses_pid_file); 6031 6032 if (core_uses_pid == '1') { 6033 jio_snprintf(buffer + written, bufferSize - written, 6034 ".%d", current_process_id()); 6035 } 6036 } 6037 } 6038 6039 return strlen(buffer); 6040 } 6041 6042 bool os::start_debugging(char *buf, int buflen) { 6043 int len = (int)strlen(buf); 6044 char *p = &buf[len]; 6045 6046 jio_snprintf(p, buflen-len, 6047 "\n\n" 6048 "Do you want to debug the problem?\n\n" 6049 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 6050 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 6051 "Otherwise, press RETURN to abort...", 6052 os::current_process_id(), os::current_process_id(), 6053 os::current_thread_id(), os::current_thread_id()); 6054 6055 bool yes = os::message_box("Unexpected Error", buf); 6056 6057 if (yes) { 6058 // yes, user asked VM to launch debugger 6059 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 6060 os::current_process_id(), os::current_process_id()); 6061 6062 os::fork_and_exec(buf); 6063 yes = false; 6064 } 6065 return yes; 6066 } 6067 6068 static inline struct timespec get_mtime(const char* filename) { 6069 struct stat st; 6070 int ret = os::stat(filename, &st); 6071 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno)); 6072 return st.st_mtim; 6073 } 6074 6075 int os::compare_file_modified_times(const char* file1, const char* file2) { 6076 struct timespec filetime1 = get_mtime(file1); 6077 struct timespec filetime2 = get_mtime(file2); 6078 int diff = filetime1.tv_sec - filetime2.tv_sec; 6079 if (diff == 0) { 6080 return filetime1.tv_nsec - filetime2.tv_nsec; 6081 } 6082 return diff; 6083 } 6084 6085 /////////////// Unit tests /////////////// 6086 6087 #ifndef PRODUCT 6088 6089 #define test_log(...) \ 6090 do { \ 6091 if (VerboseInternalVMTests) { \ 6092 tty->print_cr(__VA_ARGS__); \ 6093 tty->flush(); \ 6094 } \ 6095 } while (false) 6096 6097 class TestReserveMemorySpecial : AllStatic { 6098 public: 6099 static void small_page_write(void* addr, size_t size) { 6100 size_t page_size = os::vm_page_size(); 6101 6102 char* end = (char*)addr + size; 6103 for (char* p = (char*)addr; p < end; p += page_size) { 6104 *p = 1; 6105 } 6106 } 6107 6108 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6109 if (!UseHugeTLBFS) { 6110 return; 6111 } 6112 6113 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6114 6115 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6116 6117 if (addr != NULL) { 6118 small_page_write(addr, size); 6119 6120 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6121 } 6122 } 6123 6124 static void test_reserve_memory_special_huge_tlbfs_only() { 6125 if (!UseHugeTLBFS) { 6126 return; 6127 } 6128 6129 size_t lp = os::large_page_size(); 6130 6131 for (size_t size = lp; size <= lp * 10; size += lp) { 6132 test_reserve_memory_special_huge_tlbfs_only(size); 6133 } 6134 } 6135 6136 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6137 size_t lp = os::large_page_size(); 6138 size_t ag = os::vm_allocation_granularity(); 6139 6140 // sizes to test 6141 const size_t sizes[] = { 6142 lp, lp + ag, lp + lp / 2, lp * 2, 6143 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6144 lp * 10, lp * 10 + lp / 2 6145 }; 6146 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6147 6148 // For each size/alignment combination, we test three scenarios: 6149 // 1) with req_addr == NULL 6150 // 2) with a non-null req_addr at which we expect to successfully allocate 6151 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6152 // expect the allocation to either fail or to ignore req_addr 6153 6154 // Pre-allocate two areas; they shall be as large as the largest allocation 6155 // and aligned to the largest alignment we will be testing. 6156 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6157 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6158 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6159 -1, 0); 6160 assert(mapping1 != MAP_FAILED, "should work"); 6161 6162 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6163 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6164 -1, 0); 6165 assert(mapping2 != MAP_FAILED, "should work"); 6166 6167 // Unmap the first mapping, but leave the second mapping intact: the first 6168 // mapping will serve as a value for a "good" req_addr (case 2). The second 6169 // mapping, still intact, as "bad" req_addr (case 3). 6170 ::munmap(mapping1, mapping_size); 6171 6172 // Case 1 6173 test_log("%s, req_addr NULL:", __FUNCTION__); 6174 test_log("size align result"); 6175 6176 for (int i = 0; i < num_sizes; i++) { 6177 const size_t size = sizes[i]; 6178 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6179 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6180 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6181 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6182 if (p != NULL) { 6183 assert(is_ptr_aligned(p, alignment), "must be"); 6184 small_page_write(p, size); 6185 os::Linux::release_memory_special_huge_tlbfs(p, size); 6186 } 6187 } 6188 } 6189 6190 // Case 2 6191 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6192 test_log("size align req_addr result"); 6193 6194 for (int i = 0; i < num_sizes; i++) { 6195 const size_t size = sizes[i]; 6196 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6197 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 6198 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6199 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6200 size, alignment, p2i(req_addr), p2i(p), 6201 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6202 if (p != NULL) { 6203 assert(p == req_addr, "must be"); 6204 small_page_write(p, size); 6205 os::Linux::release_memory_special_huge_tlbfs(p, size); 6206 } 6207 } 6208 } 6209 6210 // Case 3 6211 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6212 test_log("size align req_addr result"); 6213 6214 for (int i = 0; i < num_sizes; i++) { 6215 const size_t size = sizes[i]; 6216 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6217 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6218 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6219 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6220 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6221 // as the area around req_addr contains already existing mappings, the API should always 6222 // return NULL (as per contract, it cannot return another address) 6223 assert(p == NULL, "must be"); 6224 } 6225 } 6226 6227 ::munmap(mapping2, mapping_size); 6228 6229 } 6230 6231 static void test_reserve_memory_special_huge_tlbfs() { 6232 if (!UseHugeTLBFS) { 6233 return; 6234 } 6235 6236 test_reserve_memory_special_huge_tlbfs_only(); 6237 test_reserve_memory_special_huge_tlbfs_mixed(); 6238 } 6239 6240 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6241 if (!UseSHM) { 6242 return; 6243 } 6244 6245 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6246 6247 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6248 6249 if (addr != NULL) { 6250 assert(is_ptr_aligned(addr, alignment), "Check"); 6251 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6252 6253 small_page_write(addr, size); 6254 6255 os::Linux::release_memory_special_shm(addr, size); 6256 } 6257 } 6258 6259 static void test_reserve_memory_special_shm() { 6260 size_t lp = os::large_page_size(); 6261 size_t ag = os::vm_allocation_granularity(); 6262 6263 for (size_t size = ag; size < lp * 3; size += ag) { 6264 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6265 test_reserve_memory_special_shm(size, alignment); 6266 } 6267 } 6268 } 6269 6270 static void test() { 6271 test_reserve_memory_special_huge_tlbfs(); 6272 test_reserve_memory_special_shm(); 6273 } 6274 }; 6275 6276 void TestReserveMemorySpecial_test() { 6277 TestReserveMemorySpecial::test(); 6278 } 6279 6280 #endif