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/*
* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "gc_implementation/shared/cSpaceCounters.hpp"
#include "gc_implementation/shared/vmGCOperations.hpp"
#include "gc_interface/collectedHeap.inline.hpp"
#include "memory/blockOffsetTable.inline.hpp"
#include "memory/compactPermGen.hpp"
#include "memory/gcLocker.hpp"
#include "memory/gcLocker.inline.hpp"
#include "memory/genCollectedHeap.hpp"
#include "memory/generation.inline.hpp"
#include "memory/permGen.hpp"
#include "memory/universe.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/java.hpp"
#include "runtime/vmThread.hpp"
HeapWord* PermGen::request_expand_and_allocate(Generation* gen, size_t size,
GCCause::Cause prev_cause) {
if (gen->capacity() < _capacity_expansion_limit ||
prev_cause != GCCause::_no_gc || UseG1GC) { // last disjunct is a temporary hack for G1
return gen->expand_and_allocate(size, false);
}
// We have reached the limit of capacity expansion where
// we will not expand further until a GC is done; request denied.
return NULL;
}
HeapWord* PermGen::mem_allocate_in_gen(size_t size, Generation* gen) {
GCCause::Cause next_cause = GCCause::_permanent_generation_full;
GCCause::Cause prev_cause = GCCause::_no_gc;
unsigned int gc_count_before, full_gc_count_before;
HeapWord* obj;
for (;;) {
{
MutexLocker ml(Heap_lock);
if ((obj = gen->allocate(size, false)) != NULL) {
return obj;
}
// Attempt to expand and allocate the requested space:
// specific subtypes may use specific policy to either expand
// or not. The default policy (see above) is to expand until
// _capacity_expansion_limit, and no further unless a GC is done.
// Concurrent collectors may decide to kick off a concurrent
// collection under appropriate conditions.
obj = request_expand_and_allocate(gen, size, prev_cause);
if (obj != NULL || prev_cause == GCCause::_last_ditch_collection) {
return obj;
}
if (GC_locker::is_active_and_needs_gc()) {
// If this thread is not in a jni critical section, we stall
// the requestor until the critical section has cleared and
// GC allowed. When the critical section clears, a GC is
// initiated by the last thread exiting the critical section; so
// we retry the allocation sequence from the beginning of the loop,
// rather than causing more, now probably unnecessary, GC attempts.
JavaThread* jthr = JavaThread::current();
if (!jthr->in_critical()) {
MutexUnlocker mul(Heap_lock);
// Wait for JNI critical section to be exited
GC_locker::stall_until_clear();
continue;
} else {
if (CheckJNICalls) {
fatal("Possible deadlock due to allocating while"
" in jni critical section");
}
return NULL;
}
}
// Read the GC count while holding the Heap_lock
gc_count_before = SharedHeap::heap()->total_collections();
full_gc_count_before = SharedHeap::heap()->total_full_collections();
}
// Give up heap lock above, VMThread::execute below gets it back
VM_GenCollectForPermanentAllocation op(size, gc_count_before, full_gc_count_before,
next_cause);
VMThread::execute(&op);
if (!op.prologue_succeeded() || op.gc_locked()) {
assert(op.result() == NULL, "must be NULL if gc_locked() is true");
continue; // retry and/or stall as necessary
}
obj = op.result();
assert(obj == NULL || SharedHeap::heap()->is_in_reserved(obj),
"result not in heap");
if (obj != NULL) {
return obj;
}
prev_cause = next_cause;
next_cause = GCCause::_last_ditch_collection;
}
}
CompactingPermGen::CompactingPermGen(ReservedSpace rs,
ReservedSpace shared_rs,
size_t initial_byte_size,
GenRemSet* remset,
PermanentGenerationSpec* perm_spec)
{
CompactingPermGenGen* g =
new CompactingPermGenGen(rs, shared_rs, initial_byte_size, -1, remset,
NULL, perm_spec);
if (g == NULL)
vm_exit_during_initialization("Could not allocate a CompactingPermGen");
_gen = g;
g->initialize_performance_counters();
_capacity_expansion_limit = g->capacity() + MaxPermHeapExpansion;
}
HeapWord* CompactingPermGen::mem_allocate(size_t size) {
return mem_allocate_in_gen(size, _gen);
}
void CompactingPermGen::compute_new_size() {
size_t desired_capacity = align_size_up(_gen->used(), MinPermHeapExpansion);
if (desired_capacity < PermSize) {
desired_capacity = PermSize;
}
if (_gen->capacity() > desired_capacity) {
_gen->shrink(_gen->capacity() - desired_capacity);
}
set_capacity_expansion_limit(_gen->capacity() + MaxPermHeapExpansion);
}
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