--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,909 @@
+/*
+ * Copyright 2001-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_parallelScavengeHeap.cpp.incl"
+
+PSYoungGen* ParallelScavengeHeap::_young_gen = NULL;
+PSOldGen* ParallelScavengeHeap::_old_gen = NULL;
+PSPermGen* ParallelScavengeHeap::_perm_gen = NULL;
+PSAdaptiveSizePolicy* ParallelScavengeHeap::_size_policy = NULL;
+PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL;
+ParallelScavengeHeap* ParallelScavengeHeap::_psh = NULL;
+GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL;
+
+static void trace_gen_sizes(const char* const str,
+ size_t pg_min, size_t pg_max,
+ size_t og_min, size_t og_max,
+ size_t yg_min, size_t yg_max)
+{
+ if (TracePageSizes) {
+ tty->print_cr("%s: " SIZE_FORMAT "," SIZE_FORMAT " "
+ SIZE_FORMAT "," SIZE_FORMAT " "
+ SIZE_FORMAT "," SIZE_FORMAT " "
+ SIZE_FORMAT,
+ str, pg_min / K, pg_max / K,
+ og_min / K, og_max / K,
+ yg_min / K, yg_max / K,
+ (pg_max + og_max + yg_max) / K);
+ }
+}
+
+jint ParallelScavengeHeap::initialize() {
+ // Cannot be initialized until after the flags are parsed
+ GenerationSizer flag_parser;
+
+ size_t yg_min_size = flag_parser.min_young_gen_size();
+ size_t yg_max_size = flag_parser.max_young_gen_size();
+ size_t og_min_size = flag_parser.min_old_gen_size();
+ size_t og_max_size = flag_parser.max_old_gen_size();
+ // Why isn't there a min_perm_gen_size()?
+ size_t pg_min_size = flag_parser.perm_gen_size();
+ size_t pg_max_size = flag_parser.max_perm_gen_size();
+
+ trace_gen_sizes("ps heap raw",
+ pg_min_size, pg_max_size,
+ og_min_size, og_max_size,
+ yg_min_size, yg_max_size);
+
+ // The ReservedSpace ctor used below requires that the page size for the perm
+ // gen is <= the page size for the rest of the heap (young + old gens).
+ const size_t og_page_sz = os::page_size_for_region(yg_min_size + og_min_size,
+ yg_max_size + og_max_size,
+ 8);
+ const size_t pg_page_sz = MIN2(os::page_size_for_region(pg_min_size,
+ pg_max_size, 16),
+ og_page_sz);
+
+ const size_t pg_align = set_alignment(_perm_gen_alignment, pg_page_sz);
+ const size_t og_align = set_alignment(_old_gen_alignment, og_page_sz);
+ const size_t yg_align = set_alignment(_young_gen_alignment, og_page_sz);
+
+ // Update sizes to reflect the selected page size(s).
+ //
+ // NEEDS_CLEANUP. The default TwoGenerationCollectorPolicy uses NewRatio; it
+ // should check UseAdaptiveSizePolicy. Changes from generationSizer could
+ // move to the common code.
+ yg_min_size = align_size_up(yg_min_size, yg_align);
+ yg_max_size = align_size_up(yg_max_size, yg_align);
+ size_t yg_cur_size = align_size_up(flag_parser.young_gen_size(), yg_align);
+ yg_cur_size = MAX2(yg_cur_size, yg_min_size);
+
+ og_min_size = align_size_up(og_min_size, og_align);
+ og_max_size = align_size_up(og_max_size, og_align);
+ size_t og_cur_size = align_size_up(flag_parser.old_gen_size(), og_align);
+ og_cur_size = MAX2(og_cur_size, og_min_size);
+
+ pg_min_size = align_size_up(pg_min_size, pg_align);
+ pg_max_size = align_size_up(pg_max_size, pg_align);
+ size_t pg_cur_size = pg_min_size;
+
+ trace_gen_sizes("ps heap rnd",
+ pg_min_size, pg_max_size,
+ og_min_size, og_max_size,
+ yg_min_size, yg_max_size);
+
+ // The main part of the heap (old gen + young gen) can often use a larger page
+ // size than is needed or wanted for the perm gen. Use the "compound
+ // alignment" ReservedSpace ctor to avoid having to use the same page size for
+ // all gens.
+ ReservedSpace heap_rs(pg_max_size, pg_align, og_max_size + yg_max_size,
+ og_align);
+ os::trace_page_sizes("ps perm", pg_min_size, pg_max_size, pg_page_sz,
+ heap_rs.base(), pg_max_size);
+ os::trace_page_sizes("ps main", og_min_size + yg_min_size,
+ og_max_size + yg_max_size, og_page_sz,
+ heap_rs.base() + pg_max_size,
+ heap_rs.size() - pg_max_size);
+ if (!heap_rs.is_reserved()) {
+ vm_shutdown_during_initialization(
+ "Could not reserve enough space for object heap");
+ return JNI_ENOMEM;
+ }
+
+ _reserved = MemRegion((HeapWord*)heap_rs.base(),
+ (HeapWord*)(heap_rs.base() + heap_rs.size()));
+
+ CardTableExtension* const barrier_set = new CardTableExtension(_reserved, 3);
+ _barrier_set = barrier_set;
+ oopDesc::set_bs(_barrier_set);
+ if (_barrier_set == NULL) {
+ vm_shutdown_during_initialization(
+ "Could not reserve enough space for barrier set");
+ return JNI_ENOMEM;
+ }
+
+ // Initial young gen size is 4 Mb
+ //
+ // XXX - what about flag_parser.young_gen_size()?
+ const size_t init_young_size = align_size_up(4 * M, yg_align);
+ yg_cur_size = MAX2(MIN2(init_young_size, yg_max_size), yg_cur_size);
+
+ // Split the reserved space into perm gen and the main heap (everything else).
+ // The main heap uses a different alignment.
+ ReservedSpace perm_rs = heap_rs.first_part(pg_max_size);
+ ReservedSpace main_rs = heap_rs.last_part(pg_max_size, og_align);
+
+ // Make up the generations
+ // Calculate the maximum size that a generation can grow. This
+ // includes growth into the other generation. Note that the
+ // parameter _max_gen_size is kept as the maximum
+ // size of the generation as the boundaries currently stand.
+ // _max_gen_size is still used as that value.
+ double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
+ double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
+
+ _gens = new AdjoiningGenerations(main_rs,
+ og_cur_size,
+ og_min_size,
+ og_max_size,
+ yg_cur_size,
+ yg_min_size,
+ yg_max_size,
+ yg_align);
+
+ _old_gen = _gens->old_gen();
+ _young_gen = _gens->young_gen();
+
+ const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes();
+ const size_t old_capacity = _old_gen->capacity_in_bytes();
+ const size_t initial_promo_size = MIN2(eden_capacity, old_capacity);
+ _size_policy =
+ new PSAdaptiveSizePolicy(eden_capacity,
+ initial_promo_size,
+ young_gen()->to_space()->capacity_in_bytes(),
+ intra_generation_alignment(),
+ max_gc_pause_sec,
+ max_gc_minor_pause_sec,
+ GCTimeRatio
+ );
+
+ _perm_gen = new PSPermGen(perm_rs,
+ pg_align,
+ pg_cur_size,
+ pg_cur_size,
+ pg_max_size,
+ "perm", 2);
+
+ assert(!UseAdaptiveGCBoundary ||
+ (old_gen()->virtual_space()->high_boundary() ==
+ young_gen()->virtual_space()->low_boundary()),
+ "Boundaries must meet");
+ // initialize the policy counters - 2 collectors, 3 generations
+ _gc_policy_counters =
+ new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy);
+ _psh = this;
+
+ // Set up the GCTaskManager
+ _gc_task_manager = GCTaskManager::create(ParallelGCThreads);
+
+ if (UseParallelOldGC && !PSParallelCompact::initialize()) {
+ return JNI_ENOMEM;
+ }
+
+ return JNI_OK;
+}
+
+void ParallelScavengeHeap::post_initialize() {
+ // Need to init the tenuring threshold
+ PSScavenge::initialize();
+ if (UseParallelOldGC) {
+ PSParallelCompact::post_initialize();
+ if (VerifyParallelOldWithMarkSweep) {
+ // Will be used for verification of par old.
+ PSMarkSweep::initialize();
+ }
+ } else {
+ PSMarkSweep::initialize();
+ }
+ PSPromotionManager::initialize();
+}
+
+void ParallelScavengeHeap::update_counters() {
+ young_gen()->update_counters();
+ old_gen()->update_counters();
+ perm_gen()->update_counters();
+}
+
+size_t ParallelScavengeHeap::capacity() const {
+ size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes();
+ return value;
+}
+
+size_t ParallelScavengeHeap::used() const {
+ size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes();
+ return value;
+}
+
+bool ParallelScavengeHeap::is_maximal_no_gc() const {
+ return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc();
+}
+
+
+size_t ParallelScavengeHeap::permanent_capacity() const {
+ return perm_gen()->capacity_in_bytes();
+}
+
+size_t ParallelScavengeHeap::permanent_used() const {
+ return perm_gen()->used_in_bytes();
+}
+
+size_t ParallelScavengeHeap::max_capacity() const {
+ size_t estimated = reserved_region().byte_size();
+ estimated -= perm_gen()->reserved().byte_size();
+ if (UseAdaptiveSizePolicy) {
+ estimated -= _size_policy->max_survivor_size(young_gen()->max_size());
+ } else {
+ estimated -= young_gen()->to_space()->capacity_in_bytes();
+ }
+ return MAX2(estimated, capacity());
+}
+
+bool ParallelScavengeHeap::is_in(const void* p) const {
+ if (young_gen()->is_in(p)) {
+ return true;
+ }
+
+ if (old_gen()->is_in(p)) {
+ return true;
+ }
+
+ if (perm_gen()->is_in(p)) {
+ return true;
+ }
+
+ return false;
+}
+
+bool ParallelScavengeHeap::is_in_reserved(const void* p) const {
+ if (young_gen()->is_in_reserved(p)) {
+ return true;
+ }
+
+ if (old_gen()->is_in_reserved(p)) {
+ return true;
+ }
+
+ if (perm_gen()->is_in_reserved(p)) {
+ return true;
+ }
+
+ return false;
+}
+
+// Static method
+bool ParallelScavengeHeap::is_in_young(oop* p) {
+ ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+ assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
+ "Must be ParallelScavengeHeap");
+
+ PSYoungGen* young_gen = heap->young_gen();
+
+ if (young_gen->is_in_reserved(p)) {
+ return true;
+ }
+
+ return false;
+}
+
+// Static method
+bool ParallelScavengeHeap::is_in_old_or_perm(oop* p) {
+ ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+ assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
+ "Must be ParallelScavengeHeap");
+
+ PSOldGen* old_gen = heap->old_gen();
+ PSPermGen* perm_gen = heap->perm_gen();
+
+ if (old_gen->is_in_reserved(p)) {
+ return true;
+ }
+
+ if (perm_gen->is_in_reserved(p)) {
+ return true;
+ }
+
+ return false;
+}
+
+// There are two levels of allocation policy here.
+//
+// When an allocation request fails, the requesting thread must invoke a VM
+// operation, transfer control to the VM thread, and await the results of a
+// garbage collection. That is quite expensive, and we should avoid doing it
+// multiple times if possible.
+//
+// To accomplish this, we have a basic allocation policy, and also a
+// failed allocation policy.
+//
+// The basic allocation policy controls how you allocate memory without
+// attempting garbage collection. It is okay to grab locks and
+// expand the heap, if that can be done without coming to a safepoint.
+// It is likely that the basic allocation policy will not be very
+// aggressive.
+//
+// The failed allocation policy is invoked from the VM thread after
+// the basic allocation policy is unable to satisfy a mem_allocate
+// request. This policy needs to cover the entire range of collection,
+// heap expansion, and out-of-memory conditions. It should make every
+// attempt to allocate the requested memory.
+
+// Basic allocation policy. Should never be called at a safepoint, or
+// from the VM thread.
+//
+// This method must handle cases where many mem_allocate requests fail
+// simultaneously. When that happens, only one VM operation will succeed,
+// and the rest will not be executed. For that reason, this method loops
+// during failed allocation attempts. If the java heap becomes exhausted,
+// we rely on the size_policy object to force a bail out.
+HeapWord* ParallelScavengeHeap::mem_allocate(
+ size_t size,
+ bool is_noref,
+ bool is_tlab,
+ bool* gc_overhead_limit_was_exceeded) {
+ assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
+ assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
+ assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
+
+ HeapWord* result = young_gen()->allocate(size, is_tlab);
+
+ uint loop_count = 0;
+ uint gc_count = 0;
+
+ while (result == NULL) {
+ // We don't want to have multiple collections for a single filled generation.
+ // To prevent this, each thread tracks the total_collections() value, and if
+ // the count has changed, does not do a new collection.
+ //
+ // The collection count must be read only while holding the heap lock. VM
+ // operations also hold the heap lock during collections. There is a lock
+ // contention case where thread A blocks waiting on the Heap_lock, while
+ // thread B is holding it doing a collection. When thread A gets the lock,
+ // the collection count has already changed. To prevent duplicate collections,
+ // The policy MUST attempt allocations during the same period it reads the
+ // total_collections() value!
+ {
+ MutexLocker ml(Heap_lock);
+ gc_count = Universe::heap()->total_collections();
+
+ result = young_gen()->allocate(size, is_tlab);
+
+ // (1) If the requested object is too large to easily fit in the
+ // young_gen, or
+ // (2) If GC is locked out via GCLocker, young gen is full and
+ // the need for a GC already signalled to GCLocker (done
+ // at a safepoint),
+ // ... then, rather than force a safepoint and (a potentially futile)
+ // collection (attempt) for each allocation, try allocation directly
+ // in old_gen. For case (2) above, we may in the future allow
+ // TLAB allocation directly in the old gen.
+ if (result != NULL) {
+ return result;
+ }
+ if (!is_tlab &&
+ size >= (young_gen()->eden_space()->capacity_in_words() / 2)) {
+ result = old_gen()->allocate(size, is_tlab);
+ if (result != NULL) {
+ return result;
+ }
+ }
+ if (GC_locker::is_active_and_needs_gc()) {
+ // GC is locked out. If this is a TLAB allocation,
+ // return NULL; the requestor will retry allocation
+ // of an idividual object at a time.
+ if (is_tlab) {
+ return NULL;
+ }
+
+ // 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);
+ GC_locker::stall_until_clear();
+ continue;
+ } else {
+ if (CheckJNICalls) {
+ fatal("Possible deadlock due to allocating while"
+ " in jni critical section");
+ }
+ return NULL;
+ }
+ }
+ }
+
+ if (result == NULL) {
+
+ // Exit the loop if if the gc time limit has been exceeded.
+ // The allocation must have failed above (result must be NULL),
+ // and the most recent collection must have exceeded the
+ // gc time limit. Exit the loop so that an out-of-memory
+ // will be thrown (returning a NULL will do that), but
+ // clear gc_time_limit_exceeded so that the next collection
+ // will succeeded if the applications decides to handle the
+ // out-of-memory and tries to go on.
+ *gc_overhead_limit_was_exceeded = size_policy()->gc_time_limit_exceeded();
+ if (size_policy()->gc_time_limit_exceeded()) {
+ size_policy()->set_gc_time_limit_exceeded(false);
+ if (PrintGCDetails && Verbose) {
+ gclog_or_tty->print_cr("ParallelScavengeHeap::mem_allocate: "
+ "return NULL because gc_time_limit_exceeded is set");
+ }
+ return NULL;
+ }
+
+ // Generate a VM operation
+ VM_ParallelGCFailedAllocation op(size, is_tlab, gc_count);
+ VMThread::execute(&op);
+
+ // Did the VM operation execute? If so, return the result directly.
+ // This prevents us from looping until time out on requests that can
+ // not be satisfied.
+ if (op.prologue_succeeded()) {
+ assert(Universe::heap()->is_in_or_null(op.result()),
+ "result not in heap");
+
+ // If GC was locked out during VM operation then retry allocation
+ // and/or stall as necessary.
+ if (op.gc_locked()) {
+ assert(op.result() == NULL, "must be NULL if gc_locked() is true");
+ continue; // retry and/or stall as necessary
+ }
+ // If a NULL result is being returned, an out-of-memory
+ // will be thrown now. Clear the gc_time_limit_exceeded
+ // flag to avoid the following situation.
+ // gc_time_limit_exceeded is set during a collection
+ // the collection fails to return enough space and an OOM is thrown
+ // the next GC is skipped because the gc_time_limit_exceeded
+ // flag is set and another OOM is thrown
+ if (op.result() == NULL) {
+ size_policy()->set_gc_time_limit_exceeded(false);
+ }
+ return op.result();
+ }
+ }
+
+ // The policy object will prevent us from looping forever. If the
+ // time spent in gc crosses a threshold, we will bail out.
+ loop_count++;
+ if ((result == NULL) && (QueuedAllocationWarningCount > 0) &&
+ (loop_count % QueuedAllocationWarningCount == 0)) {
+ warning("ParallelScavengeHeap::mem_allocate retries %d times \n\t"
+ " size=%d %s", loop_count, size, is_tlab ? "(TLAB)" : "");
+ }
+ }
+
+ return result;
+}
+
+// Failed allocation policy. Must be called from the VM thread, and
+// only at a safepoint! Note that this method has policy for allocation
+// flow, and NOT collection policy. So we do not check for gc collection
+// time over limit here, that is the responsibility of the heap specific
+// collection methods. This method decides where to attempt allocations,
+// and when to attempt collections, but no collection specific policy.
+HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size, bool is_tlab) {
+ assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
+ assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
+ assert(!Universe::heap()->is_gc_active(), "not reentrant");
+ assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
+
+ size_t mark_sweep_invocation_count = total_invocations();
+
+ // We assume (and assert!) that an allocation at this point will fail
+ // unless we collect.
+
+ // First level allocation failure, scavenge and allocate in young gen.
+ GCCauseSetter gccs(this, GCCause::_allocation_failure);
+ PSScavenge::invoke();
+ HeapWord* result = young_gen()->allocate(size, is_tlab);
+
+ // Second level allocation failure.
+ // Mark sweep and allocate in young generation.
+ if (result == NULL) {
+ // There is some chance the scavenge method decided to invoke mark_sweep.
+ // Don't mark sweep twice if so.
+ if (mark_sweep_invocation_count == total_invocations()) {
+ invoke_full_gc(false);
+ result = young_gen()->allocate(size, is_tlab);
+ }
+ }
+
+ // Third level allocation failure.
+ // After mark sweep and young generation allocation failure,
+ // allocate in old generation.
+ if (result == NULL && !is_tlab) {
+ result = old_gen()->allocate(size, is_tlab);
+ }
+
+ // Fourth level allocation failure. We're running out of memory.
+ // More complete mark sweep and allocate in young generation.
+ if (result == NULL) {
+ invoke_full_gc(true);
+ result = young_gen()->allocate(size, is_tlab);
+ }
+
+ // Fifth level allocation failure.
+ // After more complete mark sweep, allocate in old generation.
+ if (result == NULL && !is_tlab) {
+ result = old_gen()->allocate(size, is_tlab);
+ }
+
+ return result;
+}
+
+//
+// This is the policy loop for allocating in the permanent generation.
+// If the initial allocation fails, we create a vm operation which will
+// cause a collection.
+HeapWord* ParallelScavengeHeap::permanent_mem_allocate(size_t size) {
+ assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
+ assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
+ assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
+
+ HeapWord* result;
+
+ uint loop_count = 0;
+ uint gc_count = 0;
+ uint full_gc_count = 0;
+
+ do {
+ // We don't want to have multiple collections for a single filled generation.
+ // To prevent this, each thread tracks the total_collections() value, and if
+ // the count has changed, does not do a new collection.
+ //
+ // The collection count must be read only while holding the heap lock. VM
+ // operations also hold the heap lock during collections. There is a lock
+ // contention case where thread A blocks waiting on the Heap_lock, while
+ // thread B is holding it doing a collection. When thread A gets the lock,
+ // the collection count has already changed. To prevent duplicate collections,
+ // The policy MUST attempt allocations during the same period it reads the
+ // total_collections() value!
+ {
+ MutexLocker ml(Heap_lock);
+ gc_count = Universe::heap()->total_collections();
+ full_gc_count = Universe::heap()->total_full_collections();
+
+ result = perm_gen()->allocate_permanent(size);
+ }
+
+ if (result == NULL) {
+
+ // Exit the loop if the gc time limit has been exceeded.
+ // The allocation must have failed above (result must be NULL),
+ // and the most recent collection must have exceeded the
+ // gc time limit. Exit the loop so that an out-of-memory
+ // will be thrown (returning a NULL will do that), but
+ // clear gc_time_limit_exceeded so that the next collection
+ // will succeeded if the applications decides to handle the
+ // out-of-memory and tries to go on.
+ if (size_policy()->gc_time_limit_exceeded()) {
+ size_policy()->set_gc_time_limit_exceeded(false);
+ if (PrintGCDetails && Verbose) {
+ gclog_or_tty->print_cr("ParallelScavengeHeap::permanent_mem_allocate: "
+ "return NULL because gc_time_limit_exceeded is set");
+ }
+ assert(result == NULL, "Allocation did not fail");
+ return NULL;
+ }
+
+ // Generate a VM operation
+ VM_ParallelGCFailedPermanentAllocation op(size, gc_count, full_gc_count);
+ VMThread::execute(&op);
+
+ // Did the VM operation execute? If so, return the result directly.
+ // This prevents us from looping until time out on requests that can
+ // not be satisfied.
+ if (op.prologue_succeeded()) {
+ assert(Universe::heap()->is_in_permanent_or_null(op.result()),
+ "result not in heap");
+ // If a NULL results is being returned, an out-of-memory
+ // will be thrown now. Clear the gc_time_limit_exceeded
+ // flag to avoid the following situation.
+ // gc_time_limit_exceeded is set during a collection
+ // the collection fails to return enough space and an OOM is thrown
+ // the next GC is skipped because the gc_time_limit_exceeded
+ // flag is set and another OOM is thrown
+ if (op.result() == NULL) {
+ size_policy()->set_gc_time_limit_exceeded(false);
+ }
+ return op.result();
+ }
+ }
+
+ // The policy object will prevent us from looping forever. If the
+ // time spent in gc crosses a threshold, we will bail out.
+ loop_count++;
+ if ((QueuedAllocationWarningCount > 0) &&
+ (loop_count % QueuedAllocationWarningCount == 0)) {
+ warning("ParallelScavengeHeap::permanent_mem_allocate retries %d times \n\t"
+ " size=%d", loop_count, size);
+ }
+ } while (result == NULL);
+
+ return result;
+}
+
+//
+// This is the policy code for permanent allocations which have failed
+// and require a collection. Note that just as in failed_mem_allocate,
+// we do not set collection policy, only where & when to allocate and
+// collect.
+HeapWord* ParallelScavengeHeap::failed_permanent_mem_allocate(size_t size) {
+ assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
+ assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
+ assert(!Universe::heap()->is_gc_active(), "not reentrant");
+ assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
+ assert(size > perm_gen()->free_in_words(), "Allocation should fail");
+
+ // We assume (and assert!) that an allocation at this point will fail
+ // unless we collect.
+
+ // First level allocation failure. Mark-sweep and allocate in perm gen.
+ GCCauseSetter gccs(this, GCCause::_allocation_failure);
+ invoke_full_gc(false);
+ HeapWord* result = perm_gen()->allocate_permanent(size);
+
+ // Second level allocation failure. We're running out of memory.
+ if (result == NULL) {
+ invoke_full_gc(true);
+ result = perm_gen()->allocate_permanent(size);
+ }
+
+ return result;
+}
+
+void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) {
+ CollectedHeap::ensure_parsability(retire_tlabs);
+ young_gen()->eden_space()->ensure_parsability();
+}
+
+size_t ParallelScavengeHeap::unsafe_max_alloc() {
+ return young_gen()->eden_space()->free_in_bytes();
+}
+
+size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const {
+ return young_gen()->eden_space()->tlab_capacity(thr);
+}
+
+size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const {
+ return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
+}
+
+HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
+ return young_gen()->allocate(size, true);
+}
+
+void ParallelScavengeHeap::fill_all_tlabs(bool retire) {
+ CollectedHeap::fill_all_tlabs(retire);
+}
+
+void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
+ CollectedHeap::accumulate_statistics_all_tlabs();
+}
+
+void ParallelScavengeHeap::resize_all_tlabs() {
+ CollectedHeap::resize_all_tlabs();
+}
+
+// This method is used by System.gc() and JVMTI.
+void ParallelScavengeHeap::collect(GCCause::Cause cause) {
+ assert(!Heap_lock->owned_by_self(),
+ "this thread should not own the Heap_lock");
+
+ unsigned int gc_count = 0;
+ unsigned int full_gc_count = 0;
+ {
+ MutexLocker ml(Heap_lock);
+ // This value is guarded by the Heap_lock
+ gc_count = Universe::heap()->total_collections();
+ full_gc_count = Universe::heap()->total_full_collections();
+ }
+
+ VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause);
+ VMThread::execute(&op);
+}
+
+// This interface assumes that it's being called by the
+// vm thread. It collects the heap assuming that the
+// heap lock is already held and that we are executing in
+// the context of the vm thread.
+void ParallelScavengeHeap::collect_as_vm_thread(GCCause::Cause cause) {
+ assert(Thread::current()->is_VM_thread(), "Precondition#1");
+ assert(Heap_lock->is_locked(), "Precondition#2");
+ GCCauseSetter gcs(this, cause);
+ switch (cause) {
+ case GCCause::_heap_inspection:
+ case GCCause::_heap_dump: {
+ HandleMark hm;
+ invoke_full_gc(false);
+ break;
+ }
+ default: // XXX FIX ME
+ ShouldNotReachHere();
+ }
+}
+
+
+void ParallelScavengeHeap::oop_iterate(OopClosure* cl) {
+ Unimplemented();
+}
+
+void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) {
+ young_gen()->object_iterate(cl);
+ old_gen()->object_iterate(cl);
+ perm_gen()->object_iterate(cl);
+}
+
+void ParallelScavengeHeap::permanent_oop_iterate(OopClosure* cl) {
+ Unimplemented();
+}
+
+void ParallelScavengeHeap::permanent_object_iterate(ObjectClosure* cl) {
+ perm_gen()->object_iterate(cl);
+}
+
+HeapWord* ParallelScavengeHeap::block_start(const void* addr) const {
+ if (young_gen()->is_in_reserved(addr)) {
+ assert(young_gen()->is_in(addr),
+ "addr should be in allocated part of young gen");
+ Unimplemented();
+ } else if (old_gen()->is_in_reserved(addr)) {
+ assert(old_gen()->is_in(addr),
+ "addr should be in allocated part of old gen");
+ return old_gen()->start_array()->object_start((HeapWord*)addr);
+ } else if (perm_gen()->is_in_reserved(addr)) {
+ assert(perm_gen()->is_in(addr),
+ "addr should be in allocated part of perm gen");
+ return perm_gen()->start_array()->object_start((HeapWord*)addr);
+ }
+ return 0;
+}
+
+size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const {
+ return oop(addr)->size();
+}
+
+bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const {
+ return block_start(addr) == addr;
+}
+
+jlong ParallelScavengeHeap::millis_since_last_gc() {
+ return UseParallelOldGC ?
+ PSParallelCompact::millis_since_last_gc() :
+ PSMarkSweep::millis_since_last_gc();
+}
+
+void ParallelScavengeHeap::prepare_for_verify() {
+ ensure_parsability(false); // no need to retire TLABs for verification
+}
+
+void ParallelScavengeHeap::print() const { print_on(tty); }
+
+void ParallelScavengeHeap::print_on(outputStream* st) const {
+ young_gen()->print_on(st);
+ old_gen()->print_on(st);
+ perm_gen()->print_on(st);
+}
+
+void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const {
+ PSScavenge::gc_task_manager()->threads_do(tc);
+}
+
+void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const {
+ PSScavenge::gc_task_manager()->print_threads_on(st);
+}
+
+void ParallelScavengeHeap::print_tracing_info() const {
+ if (TraceGen0Time) {
+ double time = PSScavenge::accumulated_time()->seconds();
+ tty->print_cr("[Accumulated GC generation 0 time %3.7f secs]", time);
+ }
+ if (TraceGen1Time) {
+ double time = PSMarkSweep::accumulated_time()->seconds();
+ tty->print_cr("[Accumulated GC generation 1 time %3.7f secs]", time);
+ }
+}
+
+
+void ParallelScavengeHeap::verify(bool allow_dirty, bool silent) {
+ // Why do we need the total_collections()-filter below?
+ if (total_collections() > 0) {
+ if (!silent) {
+ gclog_or_tty->print("permanent ");
+ }
+ perm_gen()->verify(allow_dirty);
+
+ if (!silent) {
+ gclog_or_tty->print("tenured ");
+ }
+ old_gen()->verify(allow_dirty);
+
+ if (!silent) {
+ gclog_or_tty->print("eden ");
+ }
+ young_gen()->verify(allow_dirty);
+ }
+ if (!silent) {
+ gclog_or_tty->print("ref_proc ");
+ }
+ ReferenceProcessor::verify();
+}
+
+void ParallelScavengeHeap::print_heap_change(size_t prev_used) {
+ if (PrintGCDetails && Verbose) {
+ gclog_or_tty->print(" " SIZE_FORMAT
+ "->" SIZE_FORMAT
+ "(" SIZE_FORMAT ")",
+ prev_used, used(), capacity());
+ } else {
+ gclog_or_tty->print(" " SIZE_FORMAT "K"
+ "->" SIZE_FORMAT "K"
+ "(" SIZE_FORMAT "K)",
+ prev_used / K, used() / K, capacity() / K);
+ }
+}
+
+ParallelScavengeHeap* ParallelScavengeHeap::heap() {
+ assert(_psh != NULL, "Uninitialized access to ParallelScavengeHeap::heap()");
+ assert(_psh->kind() == CollectedHeap::ParallelScavengeHeap, "not a parallel scavenge heap");
+ return _psh;
+}
+
+// Before delegating the resize to the young generation,
+// the reserved space for the young and old generations
+// may be changed to accomodate the desired resize.
+void ParallelScavengeHeap::resize_young_gen(size_t eden_size,
+ size_t survivor_size) {
+ if (UseAdaptiveGCBoundary) {
+ if (size_policy()->bytes_absorbed_from_eden() != 0) {
+ size_policy()->reset_bytes_absorbed_from_eden();
+ return; // The generation changed size already.
+ }
+ gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size);
+ }
+
+ // Delegate the resize to the generation.
+ _young_gen->resize(eden_size, survivor_size);
+}
+
+// Before delegating the resize to the old generation,
+// the reserved space for the young and old generations
+// may be changed to accomodate the desired resize.
+void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
+ if (UseAdaptiveGCBoundary) {
+ if (size_policy()->bytes_absorbed_from_eden() != 0) {
+ size_policy()->reset_bytes_absorbed_from_eden();
+ return; // The generation changed size already.
+ }
+ gens()->adjust_boundary_for_old_gen_needs(desired_free_space);
+ }
+
+ // Delegate the resize to the generation.
+ _old_gen->resize(desired_free_space);
+}