1 /*

     2  * Copyright 2005-2006 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  */

    24 # include "incls/_precompiled.incl"

    25 # include "incls/_vmGCOperations.cpp.incl"

    26 

    27 HS_DTRACE_PROBE_DECL1(hotspot, gc__begin, bool);

    28 HS_DTRACE_PROBE_DECL(hotspot, gc__end);

    29 

    30 // The same dtrace probe can't be inserted in two different files, so we

    31 // have to call it here, so it's only in one file.  Can't create new probes

    32 // for the other file anymore.   The dtrace probes have to remain stable.

    33 void VM_GC_Operation::notify_gc_begin(bool full) {

    34   HS_DTRACE_PROBE1(hotspot, gc__begin, full);

    35 }

    36 

    37 void VM_GC_Operation::notify_gc_end() {

    38   HS_DTRACE_PROBE(hotspot, gc__end);

    39 }

    40 

    41 void VM_GC_Operation::acquire_pending_list_lock() {

    42   // we may enter this with pending exception set

    43   instanceRefKlass::acquire_pending_list_lock(&_pending_list_basic_lock);

    44 }

    45 

    46 

    47 void VM_GC_Operation::release_and_notify_pending_list_lock() {

    48 

    49   instanceRefKlass::release_and_notify_pending_list_lock(&_pending_list_basic_lock);

    50 }

    51 

    52 // Allocations may fail in several threads at about the same time,

    53 // resulting in multiple gc requests.  We only want to do one of them.

    54 // In case a GC locker is active and the need for a GC is already signalled,

    55 // we want to skip this GC attempt altogether, without doing a futile

    56 // safepoint operation.

    57 bool VM_GC_Operation::skip_operation() const {

    58   bool skip = (_gc_count_before != Universe::heap()->total_collections());

    59   if (_full && skip) {

    60     skip = (_full_gc_count_before != Universe::heap()->total_full_collections());

    61   }

    62   if (!skip && GC_locker::is_active_and_needs_gc()) {

    63     skip = Universe::heap()->is_maximal_no_gc();

    64     assert(!(skip && (_gc_cause == GCCause::_gc_locker)),

    65            "GC_locker cannot be active when initiating GC");

    66   }

    67   return skip;

    68 }

    69 

    70 bool VM_GC_Operation::doit_prologue() {

    71   assert(Thread::current()->is_Java_thread(), "just checking");

    72 

    73   acquire_pending_list_lock();

    74   // If the GC count has changed someone beat us to the collection

    75   // Get the Heap_lock after the pending_list_lock.

    76   Heap_lock->lock();

    77   // Check invocations

    78   if (skip_operation()) {

    79     // skip collection

    80     Heap_lock->unlock();

    81     release_and_notify_pending_list_lock();

    82     _prologue_succeeded = false;

    83   } else {

    84     _prologue_succeeded = true;

    85   }

    86   return _prologue_succeeded;

    87 }

    88 

    89 

    90 void VM_GC_Operation::doit_epilogue() {

    91   assert(Thread::current()->is_Java_thread(), "just checking");

    92   // Release the Heap_lock first.

    93   Heap_lock->unlock();

    94   release_and_notify_pending_list_lock();

    95 }

    96 

    97 bool VM_GC_HeapInspection::doit_prologue() {

    98   if (Universe::heap()->supports_heap_inspection()) {

    99     return VM_GC_Operation::doit_prologue();

   100   } else {

   101     return false;

   102   }

   103 }

   104 

   105 bool VM_GC_HeapInspection::skip_operation() const {

   106   assert(Universe::heap()->supports_heap_inspection(), "huh?");

   107   return false;

   108 }

   109 

   110 void VM_GC_HeapInspection::doit() {

   111   HandleMark hm;

   112   CollectedHeap* ch = Universe::heap();

   113   if (_full_gc) {

   114     ch->collect_as_vm_thread(GCCause::_heap_inspection);

   115   } else {

   116     // make the heap parsable (no need to retire TLABs)

   117     ch->ensure_parsability(false);

   118   }

   119   HeapInspection::heap_inspection(_out);

   120 }

   121 

   122 

   123 void VM_GenCollectForAllocation::doit() {

   124   JvmtiGCForAllocationMarker jgcm;

   125   notify_gc_begin(false);

   126 

   127   GenCollectedHeap* gch = GenCollectedHeap::heap();

   128   GCCauseSetter gccs(gch, _gc_cause);

   129   _res = gch->satisfy_failed_allocation(_size, _tlab);

   130   assert(gch->is_in_reserved_or_null(_res), "result not in heap");

   131 

   132   if (_res == NULL && GC_locker::is_active_and_needs_gc()) {

   133     set_gc_locked();

   134   }

   135   notify_gc_end();

   136 }

   137 

   138 void VM_GenCollectFull::doit() {

   139   JvmtiGCFullMarker jgcm;

   140   notify_gc_begin(true);

   141 

   142   GenCollectedHeap* gch = GenCollectedHeap::heap();

   143   GCCauseSetter gccs(gch, _gc_cause);

   144   gch->do_full_collection(gch->must_clear_all_soft_refs(), _max_level);

   145   notify_gc_end();

   146 }