1 /*

     2  * Copyright 2001-2007 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 

    25 # include "incls/_precompiled.incl"

    26 # include "incls/_collectedHeap.cpp.incl"

    27 

    28 

    29 #ifdef ASSERT

    30 int CollectedHeap::_fire_out_of_memory_count = 0;

    31 #endif

    32 

    33 // Memory state functions.

    34 

    35 CollectedHeap::CollectedHeap() :

    36   _reserved(), _barrier_set(NULL), _is_gc_active(false),

    37   _total_collections(0), _total_full_collections(0),

    38   _max_heap_capacity(0),

    39   _gc_cause(GCCause::_no_gc), _gc_lastcause(GCCause::_no_gc) {

    40   NOT_PRODUCT(_promotion_failure_alot_count = 0;)

    41   NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)

    42 

    43   if (UsePerfData) {

    44     EXCEPTION_MARK;

    45 

    46     // create the gc cause jvmstat counters

    47     _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",

    48                              80, GCCause::to_string(_gc_cause), CHECK);

    49 

    50     _perf_gc_lastcause =

    51                 PerfDataManager::create_string_variable(SUN_GC, "lastCause",

    52                              80, GCCause::to_string(_gc_lastcause), CHECK);

    53   }

    54 }

    55 

    56 

    57 #ifndef PRODUCT

    58 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {

    59   if (CheckMemoryInitialization && ZapUnusedHeapArea) {

    60     for (size_t slot = 0; slot < size; slot += 1) {

    61       assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),

    62              "Found badHeapWordValue in post-allocation check");

    63     }

    64   }

    65 }

    66 

    67 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size)

    68  {

    69   if (CheckMemoryInitialization && ZapUnusedHeapArea) {

    70     for (size_t slot = 0; slot < size; slot += 1) {

    71       assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),

    72              "Found non badHeapWordValue in pre-allocation check");

    73     }

    74   }

    75 }

    76 #endif // PRODUCT

    77 

    78 #ifdef ASSERT

    79 void CollectedHeap::check_for_valid_allocation_state() {

    80   Thread *thread = Thread::current();

    81   // How to choose between a pending exception and a potential

    82   // OutOfMemoryError?  Don't allow pending exceptions.

    83   // This is a VM policy failure, so how do we exhaustively test it?

    84   assert(!thread->has_pending_exception(),

    85          "shouldn't be allocating with pending exception");

    86   if (StrictSafepointChecks) {

    87     assert(thread->allow_allocation(),

    88            "Allocation done by thread for which allocation is blocked "

    89            "by No_Allocation_Verifier!");

    90     // Allocation of an oop can always invoke a safepoint,

    91     // hence, the true argument

    92     thread->check_for_valid_safepoint_state(true);

    93   }

    94 }

    95 #endif

    96 

    97 HeapWord* CollectedHeap::allocate_from_tlab_slow(Thread* thread, size_t size) {

    98 

    99   // Retain tlab and allocate object in shared space if

   100   // the amount free in the tlab is too large to discard.

   101   if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {

   102     thread->tlab().record_slow_allocation(size);

   103     return NULL;

   104   }

   105 

   106   // Discard tlab and allocate a new one.

   107   // To minimize fragmentation, the last TLAB may be smaller than the rest.

   108   size_t new_tlab_size = thread->tlab().compute_size(size);

   109 

   110   thread->tlab().clear_before_allocation();

   111 

   112   if (new_tlab_size == 0) {

   113     return NULL;

   114   }

   115 

   116   // Allocate a new TLAB...

   117   HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);

   118   if (obj == NULL) {

   119     return NULL;

   120   }

   121   if (ZeroTLAB) {

   122     // ..and clear it.

   123     Copy::zero_to_words(obj, new_tlab_size);

   124   } else {

   125     // ...and clear just the allocated object.

   126     Copy::zero_to_words(obj, size);

   127   }

   128   thread->tlab().fill(obj, obj + size, new_tlab_size);

   129   return obj;

   130 }

   131 

   132 oop CollectedHeap::new_store_barrier(oop new_obj) {

   133   // %%% This needs refactoring.  (It was imported from the server compiler.)

   134   guarantee(can_elide_tlab_store_barriers(), "store barrier elision not supported");

   135   BarrierSet* bs = this->barrier_set();

   136   assert(bs->has_write_region_opt(), "Barrier set does not have write_region");

   137   int new_size = new_obj->size();

   138   bs->write_region(MemRegion((HeapWord*)new_obj, new_size));

   139   return new_obj;

   140 }

   141 

   142 bool CollectedHeap::can_elide_permanent_oop_store_barriers() const {

   143   // %%% This needs refactoring.  (It was gating logic from the server compiler.)

   144   guarantee(kind() < CollectedHeap::G1CollectedHeap, "");

   145   return !UseConcMarkSweepGC;

   146 }

   147 

   148 

   149 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {

   150   guarantee(false, "thread-local allocation buffers not supported");

   151   return NULL;

   152 }

   153 

   154 void CollectedHeap::fill_all_tlabs(bool retire) {

   155   assert(UseTLAB, "should not reach here");

   156   // See note in ensure_parsability() below.

   157   assert(SafepointSynchronize::is_at_safepoint() ||

   158          !is_init_completed(),

   159          "should only fill tlabs at safepoint");

   160   // The main thread starts allocating via a TLAB even before it

   161   // has added itself to the threads list at vm boot-up.

   162   assert(Threads::first() != NULL,

   163          "Attempt to fill tlabs before main thread has been added"

   164          " to threads list is doomed to failure!");

   165   for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {

   166      thread->tlab().make_parsable(retire);

   167   }

   168 }

   169 

   170 void CollectedHeap::ensure_parsability(bool retire_tlabs) {

   171   // The second disjunct in the assertion below makes a concession

   172   // for the start-up verification done while the VM is being

   173   // created. Callers be careful that you know that mutators

   174   // aren't going to interfere -- for instance, this is permissible

   175   // if we are still single-threaded and have either not yet

   176   // started allocating (nothing much to verify) or we have

   177   // started allocating but are now a full-fledged JavaThread

   178   // (and have thus made our TLAB's) available for filling.

   179   assert(SafepointSynchronize::is_at_safepoint() ||

   180          !is_init_completed(),

   181          "Should only be called at a safepoint or at start-up"

   182          " otherwise concurrent mutator activity may make heap "

   183          " unparsable again");

   184   if (UseTLAB) {

   185     fill_all_tlabs(retire_tlabs);

   186   }

   187 }

   188 

   189 void CollectedHeap::accumulate_statistics_all_tlabs() {

   190   if (UseTLAB) {

   191     assert(SafepointSynchronize::is_at_safepoint() ||

   192          !is_init_completed(),

   193          "should only accumulate statistics on tlabs at safepoint");

   194 

   195     ThreadLocalAllocBuffer::accumulate_statistics_before_gc();

   196   }

   197 }

   198 

   199 void CollectedHeap::resize_all_tlabs() {

   200   if (UseTLAB) {

   201     assert(SafepointSynchronize::is_at_safepoint() ||

   202          !is_init_completed(),

   203          "should only resize tlabs at safepoint");

   204 

   205     ThreadLocalAllocBuffer::resize_all_tlabs();

   206   }

   207 }