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