src/share/vm/runtime/perfMemory.cpp

Fri, 21 Nov 2008 08:09:11 -0800

author
coleenp
date
Fri, 21 Nov 2008 08:09:11 -0800
changeset 882
2b42b31e7928
parent 435
a61af66fc99e
child 869
de78b80cedec
permissions
-rw-r--r--

6676175: BigApps crash JVM Client VM (build 10.0-b22, mixed mode, sharing) with SIGSEGV (0xb)
Summary: Add test for biased locking epoch before walking own thread stack in case of rare race
Reviewed-by: phh, never

     1 /*
     2  * Copyright 2001-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
    21  * have any questions.
    22  *
    23  */
    25 # include "incls/_precompiled.incl"
    26 # include "incls/_perfMemory.cpp.incl"
    28 char*                    PerfMemory::_start = NULL;
    29 char*                    PerfMemory::_end = NULL;
    30 char*                    PerfMemory::_top = NULL;
    31 size_t                   PerfMemory::_capacity = 0;
    32 jint                     PerfMemory::_initialized = false;
    33 PerfDataPrologue*        PerfMemory::_prologue = NULL;
    35 void perfMemory_init() {
    37   if (!UsePerfData) return;
    39   PerfMemory::initialize();
    40 }
    42 void perfMemory_exit() {
    44   if (!UsePerfData) return;
    45   if (!PerfMemory::is_initialized()) return;
    47   // if the StatSampler is active, then we don't want to remove
    48   // resources it may be dependent on. Typically, the StatSampler
    49   // is disengaged from the watcher thread when this method is called,
    50   // but it is not disengaged if this method is invoked during a
    51   // VM abort.
    52   //
    53   if (!StatSampler::is_active())
    54     PerfDataManager::destroy();
    56   // remove the persistent external resources, if any. this method
    57   // does not unmap or invalidate any virtual memory allocated during
    58   // initialization.
    59   //
    60   PerfMemory::destroy();
    61 }
    63 void PerfMemory::initialize() {
    65   if (_prologue != NULL)
    66     // initialization already performed
    67     return;
    69   size_t capacity = align_size_up(PerfDataMemorySize,
    70                                   os::vm_allocation_granularity());
    72   if (PerfTraceMemOps) {
    73     tty->print("PerfDataMemorySize = " SIZE_FORMAT ","
    74                " os::vm_allocation_granularity = " SIZE_FORMAT ","
    75                " adjusted size = " SIZE_FORMAT "\n",
    76                PerfDataMemorySize,
    77                os::vm_allocation_granularity(),
    78                capacity);
    79   }
    81   // allocate PerfData memory region
    82   create_memory_region(capacity);
    84   if (_start == NULL) {
    86     // the PerfMemory region could not be created as desired. Rather
    87     // than terminating the JVM, we revert to creating the instrumentation
    88     // on the C heap. When running in this mode, external monitoring
    89     // clients cannot attach to and monitor this JVM.
    90     //
    91     // the warning is issued only in debug mode in order to avoid
    92     // additional output to the stdout or stderr output streams.
    93     //
    94     if (PrintMiscellaneous && Verbose) {
    95       warning("Could not create PerfData Memory region, reverting to malloc");
    96     }
    98     _prologue = NEW_C_HEAP_OBJ(PerfDataPrologue);
    99   }
   100   else {
   102     // the PerfMemory region was created as expected.
   104     if (PerfTraceMemOps) {
   105       tty->print("PerfMemory created: address = " INTPTR_FORMAT ","
   106                  " size = " SIZE_FORMAT "\n",
   107                  (void*)_start,
   108                  _capacity);
   109     }
   111     _prologue = (PerfDataPrologue *)_start;
   112     _end = _start + _capacity;
   113     _top = _start + sizeof(PerfDataPrologue);
   114   }
   116   assert(_prologue != NULL, "prologue pointer must be initialized");
   118 #ifdef VM_LITTLE_ENDIAN
   119   _prologue->magic = (jint)0xc0c0feca;
   120   _prologue->byte_order = PERFDATA_LITTLE_ENDIAN;
   121 #else
   122   _prologue->magic = (jint)0xcafec0c0;
   123   _prologue->byte_order = PERFDATA_BIG_ENDIAN;
   124 #endif
   126   _prologue->major_version = PERFDATA_MAJOR_VERSION;
   127   _prologue->minor_version = PERFDATA_MINOR_VERSION;
   128   _prologue->accessible = 0;
   130   _prologue->entry_offset = sizeof(PerfDataPrologue);
   131   _prologue->num_entries = 0;
   132   _prologue->used = 0;
   133   _prologue->overflow = 0;
   134   _prologue->mod_time_stamp = 0;
   136   OrderAccess::release_store(&_initialized, 1);
   137 }
   139 void PerfMemory::destroy() {
   141   assert(_prologue != NULL, "prologue pointer must be initialized");
   143   if (_start != NULL && _prologue->overflow != 0) {
   145     // This state indicates that the contiguous memory region exists and
   146     // that it wasn't large enough to hold all the counters. In this case,
   147     // we output a warning message to the user on exit if the -XX:+Verbose
   148     // flag is set (a debug only flag). External monitoring tools can detect
   149     // this condition by monitoring the _prologue->overflow word.
   150     //
   151     // There are two tunables that can help resolve this issue:
   152     //   - increase the size of the PerfMemory with -XX:PerfDataMemorySize=<n>
   153     //   - decrease the maximum string constant length with
   154     //     -XX:PerfMaxStringConstLength=<n>
   155     //
   156     if (PrintMiscellaneous && Verbose) {
   157       warning("PerfMemory Overflow Occurred.\n"
   158               "\tCapacity = " SIZE_FORMAT " bytes"
   159               "  Used = " SIZE_FORMAT " bytes"
   160               "  Overflow = " INT32_FORMAT " bytes"
   161               "\n\tUse -XX:PerfDataMemorySize=<size> to specify larger size.",
   162               PerfMemory::capacity(),
   163               PerfMemory::used(),
   164               _prologue->overflow);
   165     }
   166   }
   168   if (_start != NULL) {
   170     // this state indicates that the contiguous memory region was successfully
   171     // and that persistent resources may need to be cleaned up. This is
   172     // expected to be the typical condition.
   173     //
   174     delete_memory_region();
   175   }
   177   _start = NULL;
   178   _end = NULL;
   179   _top = NULL;
   180   _prologue = NULL;
   181   _capacity = 0;
   182 }
   184 // allocate an aligned block of memory from the PerfData memory
   185 // region. This method assumes that the PerfData memory region
   186 // was aligned on a double word boundary when created.
   187 //
   188 char* PerfMemory::alloc(size_t size) {
   190   if (!UsePerfData) return NULL;
   192   MutexLocker ml(PerfDataMemAlloc_lock);
   194   assert(_prologue != NULL, "called before initialization");
   196   // check that there is enough memory for this request
   197   if ((_top + size) >= _end) {
   199     _prologue->overflow += (jint)size;
   201     return NULL;
   202   }
   204   char* result = _top;
   206   _top += size;
   208   assert(contains(result), "PerfData memory pointer out of range");
   210   _prologue->used = (jint)used();
   211   _prologue->num_entries = _prologue->num_entries + 1;
   213   return result;
   214 }
   216 void PerfMemory::mark_updated() {
   217   if (!UsePerfData) return;
   219   _prologue->mod_time_stamp = os::elapsed_counter();
   220 }
   222 // Returns the complete path including the file name of performance data file.
   223 // Caller is expected to release the allocated memory.
   224 char* PerfMemory::get_perfdata_file_path() {
   225   char* dest_file = NULL;
   227   if (PerfDataSaveFile != NULL) {
   228     // dest_file_name stores the validated file name if file_name
   229     // contains %p which will be replaced by pid.
   230     dest_file = NEW_C_HEAP_ARRAY(char, JVM_MAXPATHLEN);
   231     if(!Arguments::copy_expand_pid(PerfDataSaveFile, strlen(PerfDataSaveFile),
   232                                    dest_file, JVM_MAXPATHLEN)) {
   233       FREE_C_HEAP_ARRAY(char, dest_file);
   234       if (PrintMiscellaneous && Verbose) {
   235         warning("Invalid performance data file path name specified, "\
   236                 "fall back to a default name");
   237       }
   238     } else {
   239       return dest_file;
   240     }
   241   }
   242   // create the name of the file for retaining the instrumentation memory.
   243   dest_file = NEW_C_HEAP_ARRAY(char, PERFDATA_FILENAME_LEN);
   244   jio_snprintf(dest_file, PERFDATA_FILENAME_LEN,
   245                "%s_%d", PERFDATA_NAME, os::current_process_id());
   247   return dest_file;
   248 }

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