| /* |
| * Copyright (c) 2001, 2012, 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/adaptiveSizePolicy.hpp" |
| #include "gc_implementation/shared/gcPolicyCounters.hpp" |
| #include "gc_implementation/shared/vmGCOperations.hpp" |
| #include "memory/cardTableRS.hpp" |
| #include "memory/collectorPolicy.hpp" |
| #include "memory/gcLocker.inline.hpp" |
| #include "memory/genCollectedHeap.hpp" |
| #include "memory/generationSpec.hpp" |
| #include "memory/space.hpp" |
| #include "memory/universe.hpp" |
| #include "runtime/arguments.hpp" |
| #include "runtime/globals_extension.hpp" |
| #include "runtime/handles.inline.hpp" |
| #include "runtime/java.hpp" |
| #include "runtime/thread.inline.hpp" |
| #include "runtime/vmThread.hpp" |
| #ifndef SERIALGC |
| #include "gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.hpp" |
| #include "gc_implementation/concurrentMarkSweep/cmsGCAdaptivePolicyCounters.hpp" |
| #endif |
| |
| // CollectorPolicy methods. |
| |
| void CollectorPolicy::initialize_flags() { |
| if (MetaspaceSize > MaxMetaspaceSize) { |
| MaxMetaspaceSize = MetaspaceSize; |
| } |
| MetaspaceSize = MAX2(min_alignment(), align_size_down_(MetaspaceSize, min_alignment())); |
| // Don't increase Metaspace size limit above specified. |
| MaxMetaspaceSize = align_size_down(MaxMetaspaceSize, max_alignment()); |
| if (MetaspaceSize > MaxMetaspaceSize) { |
| MetaspaceSize = MaxMetaspaceSize; |
| } |
| |
| MinMetaspaceExpansion = MAX2(min_alignment(), align_size_down_(MinMetaspaceExpansion, min_alignment())); |
| MaxMetaspaceExpansion = MAX2(min_alignment(), align_size_down_(MaxMetaspaceExpansion, min_alignment())); |
| |
| MinHeapDeltaBytes = align_size_up(MinHeapDeltaBytes, min_alignment()); |
| |
| assert(MetaspaceSize % min_alignment() == 0, "metapace alignment"); |
| assert(MaxMetaspaceSize % max_alignment() == 0, "maximum metaspace alignment"); |
| if (MetaspaceSize < 256*K) { |
| vm_exit_during_initialization("Too small initial Metaspace size"); |
| } |
| } |
| |
| void CollectorPolicy::initialize_size_info() { |
| // User inputs from -mx and ms are aligned |
| set_initial_heap_byte_size(InitialHeapSize); |
| if (initial_heap_byte_size() == 0) { |
| set_initial_heap_byte_size(NewSize + OldSize); |
| } |
| set_initial_heap_byte_size(align_size_up(_initial_heap_byte_size, |
| min_alignment())); |
| |
| set_min_heap_byte_size(Arguments::min_heap_size()); |
| if (min_heap_byte_size() == 0) { |
| set_min_heap_byte_size(NewSize + OldSize); |
| } |
| set_min_heap_byte_size(align_size_up(_min_heap_byte_size, |
| min_alignment())); |
| |
| set_max_heap_byte_size(align_size_up(MaxHeapSize, max_alignment())); |
| |
| // Check heap parameter properties |
| if (initial_heap_byte_size() < M) { |
| vm_exit_during_initialization("Too small initial heap"); |
| } |
| // Check heap parameter properties |
| if (min_heap_byte_size() < M) { |
| vm_exit_during_initialization("Too small minimum heap"); |
| } |
| if (initial_heap_byte_size() <= NewSize) { |
| // make sure there is at least some room in old space |
| vm_exit_during_initialization("Too small initial heap for new size specified"); |
| } |
| if (max_heap_byte_size() < min_heap_byte_size()) { |
| vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified"); |
| } |
| if (initial_heap_byte_size() < min_heap_byte_size()) { |
| vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified"); |
| } |
| if (max_heap_byte_size() < initial_heap_byte_size()) { |
| vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified"); |
| } |
| |
| if (PrintGCDetails && Verbose) { |
| gclog_or_tty->print_cr("Minimum heap " SIZE_FORMAT " Initial heap " |
| SIZE_FORMAT " Maximum heap " SIZE_FORMAT, |
| min_heap_byte_size(), initial_heap_byte_size(), max_heap_byte_size()); |
| } |
| } |
| |
| bool CollectorPolicy::use_should_clear_all_soft_refs(bool v) { |
| bool result = _should_clear_all_soft_refs; |
| set_should_clear_all_soft_refs(false); |
| return result; |
| } |
| |
| GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap, |
| int max_covered_regions) { |
| switch (rem_set_name()) { |
| case GenRemSet::CardTable: { |
| CardTableRS* res = new CardTableRS(whole_heap, max_covered_regions); |
| return res; |
| } |
| default: |
| guarantee(false, "unrecognized GenRemSet::Name"); |
| return NULL; |
| } |
| } |
| |
| void CollectorPolicy::cleared_all_soft_refs() { |
| // If near gc overhear limit, continue to clear SoftRefs. SoftRefs may |
| // have been cleared in the last collection but if the gc overhear |
| // limit continues to be near, SoftRefs should still be cleared. |
| if (size_policy() != NULL) { |
| _should_clear_all_soft_refs = size_policy()->gc_overhead_limit_near(); |
| } |
| _all_soft_refs_clear = true; |
| } |
| |
| |
| // GenCollectorPolicy methods. |
| |
| size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) { |
| size_t x = base_size / (NewRatio+1); |
| size_t new_gen_size = x > min_alignment() ? |
| align_size_down(x, min_alignment()) : |
| min_alignment(); |
| return new_gen_size; |
| } |
| |
| size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size, |
| size_t maximum_size) { |
| size_t alignment = min_alignment(); |
| size_t max_minus = maximum_size - alignment; |
| return desired_size < max_minus ? desired_size : max_minus; |
| } |
| |
| |
| void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size, |
| size_t init_promo_size, |
| size_t init_survivor_size) { |
| const double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0; |
| _size_policy = new AdaptiveSizePolicy(init_eden_size, |
| init_promo_size, |
| init_survivor_size, |
| max_gc_minor_pause_sec, |
| GCTimeRatio); |
| } |
| |
| size_t GenCollectorPolicy::compute_max_alignment() { |
| // The card marking array and the offset arrays for old generations are |
| // committed in os pages as well. Make sure they are entirely full (to |
| // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1 |
| // byte entry and the os page size is 4096, the maximum heap size should |
| // be 512*4096 = 2MB aligned. |
| size_t alignment = GenRemSet::max_alignment_constraint(rem_set_name()); |
| |
| // Parallel GC does its own alignment of the generations to avoid requiring a |
| // large page (256M on some platforms) for the permanent generation. The |
| // other collectors should also be updated to do their own alignment and then |
| // this use of lcm() should be removed. |
| if (UseLargePages && !UseParallelGC) { |
| // in presence of large pages we have to make sure that our |
| // alignment is large page aware |
| alignment = lcm(os::large_page_size(), alignment); |
| } |
| |
| return alignment; |
| } |
| |
| void GenCollectorPolicy::initialize_flags() { |
| // All sizes must be multiples of the generation granularity. |
| set_min_alignment((uintx) Generation::GenGrain); |
| set_max_alignment(compute_max_alignment()); |
| assert(max_alignment() >= min_alignment() && |
| max_alignment() % min_alignment() == 0, |
| "invalid alignment constraints"); |
| |
| CollectorPolicy::initialize_flags(); |
| |
| // All generational heaps have a youngest gen; handle those flags here. |
| |
| // Adjust max size parameters |
| if (NewSize > MaxNewSize) { |
| MaxNewSize = NewSize; |
| } |
| NewSize = align_size_down(NewSize, min_alignment()); |
| MaxNewSize = align_size_down(MaxNewSize, min_alignment()); |
| |
| // Check validity of heap flags |
| assert(NewSize % min_alignment() == 0, "eden space alignment"); |
| assert(MaxNewSize % min_alignment() == 0, "survivor space alignment"); |
| |
| if (NewSize < 3*min_alignment()) { |
| // make sure there room for eden and two survivor spaces |
| vm_exit_during_initialization("Too small new size specified"); |
| } |
| if (SurvivorRatio < 1 || NewRatio < 1) { |
| vm_exit_during_initialization("Invalid heap ratio specified"); |
| } |
| } |
| |
| void TwoGenerationCollectorPolicy::initialize_flags() { |
| GenCollectorPolicy::initialize_flags(); |
| |
| OldSize = align_size_down(OldSize, min_alignment()); |
| if (NewSize + OldSize > MaxHeapSize) { |
| MaxHeapSize = NewSize + OldSize; |
| } |
| MaxHeapSize = align_size_up(MaxHeapSize, max_alignment()); |
| |
| always_do_update_barrier = UseConcMarkSweepGC; |
| |
| // Check validity of heap flags |
| assert(OldSize % min_alignment() == 0, "old space alignment"); |
| assert(MaxHeapSize % max_alignment() == 0, "maximum heap alignment"); |
| } |
| |
| // Values set on the command line win over any ergonomically |
| // set command line parameters. |
| // Ergonomic choice of parameters are done before this |
| // method is called. Values for command line parameters such as NewSize |
| // and MaxNewSize feed those ergonomic choices into this method. |
| // This method makes the final generation sizings consistent with |
| // themselves and with overall heap sizings. |
| // In the absence of explicitly set command line flags, policies |
| // such as the use of NewRatio are used to size the generation. |
| void GenCollectorPolicy::initialize_size_info() { |
| CollectorPolicy::initialize_size_info(); |
| |
| // min_alignment() is used for alignment within a generation. |
| // There is additional alignment done down stream for some |
| // collectors that sometimes causes unwanted rounding up of |
| // generations sizes. |
| |
| // Determine maximum size of gen0 |
| |
| size_t max_new_size = 0; |
| if (FLAG_IS_CMDLINE(MaxNewSize) || FLAG_IS_ERGO(MaxNewSize)) { |
| if (MaxNewSize < min_alignment()) { |
| max_new_size = min_alignment(); |
| } |
| if (MaxNewSize >= max_heap_byte_size()) { |
| max_new_size = align_size_down(max_heap_byte_size() - min_alignment(), |
| min_alignment()); |
| warning("MaxNewSize (" SIZE_FORMAT "k) is equal to or " |
| "greater than the entire heap (" SIZE_FORMAT "k). A " |
| "new generation size of " SIZE_FORMAT "k will be used.", |
| MaxNewSize/K, max_heap_byte_size()/K, max_new_size/K); |
| } else { |
| max_new_size = align_size_down(MaxNewSize, min_alignment()); |
| } |
| |
| // The case for FLAG_IS_ERGO(MaxNewSize) could be treated |
| // specially at this point to just use an ergonomically set |
| // MaxNewSize to set max_new_size. For cases with small |
| // heaps such a policy often did not work because the MaxNewSize |
| // was larger than the entire heap. The interpretation given |
| // to ergonomically set flags is that the flags are set |
| // by different collectors for their own special needs but |
| // are not allowed to badly shape the heap. This allows the |
| // different collectors to decide what's best for themselves |
| // without having to factor in the overall heap shape. It |
| // can be the case in the future that the collectors would |
| // only make "wise" ergonomics choices and this policy could |
| // just accept those choices. The choices currently made are |
| // not always "wise". |
| } else { |
| max_new_size = scale_by_NewRatio_aligned(max_heap_byte_size()); |
| // Bound the maximum size by NewSize below (since it historically |
| // would have been NewSize and because the NewRatio calculation could |
| // yield a size that is too small) and bound it by MaxNewSize above. |
| // Ergonomics plays here by previously calculating the desired |
| // NewSize and MaxNewSize. |
| max_new_size = MIN2(MAX2(max_new_size, NewSize), MaxNewSize); |
| } |
| assert(max_new_size > 0, "All paths should set max_new_size"); |
| |
| // Given the maximum gen0 size, determine the initial and |
| // minimum gen0 sizes. |
| |
| if (max_heap_byte_size() == min_heap_byte_size()) { |
| // The maximum and minimum heap sizes are the same so |
| // the generations minimum and initial must be the |
| // same as its maximum. |
| set_min_gen0_size(max_new_size); |
| set_initial_gen0_size(max_new_size); |
| set_max_gen0_size(max_new_size); |
| } else { |
| size_t desired_new_size = 0; |
| if (!FLAG_IS_DEFAULT(NewSize)) { |
| // If NewSize is set ergonomically (for example by cms), it |
| // would make sense to use it. If it is used, also use it |
| // to set the initial size. Although there is no reason |
| // the minimum size and the initial size have to be the same, |
| // the current implementation gets into trouble during the calculation |
| // of the tenured generation sizes if they are different. |
| // Note that this makes the initial size and the minimum size |
| // generally small compared to the NewRatio calculation. |
| _min_gen0_size = NewSize; |
| desired_new_size = NewSize; |
| max_new_size = MAX2(max_new_size, NewSize); |
| } else { |
| // For the case where NewSize is the default, use NewRatio |
| // to size the minimum and initial generation sizes. |
| // Use the default NewSize as the floor for these values. If |
| // NewRatio is overly large, the resulting sizes can be too |
| // small. |
| _min_gen0_size = MAX2(scale_by_NewRatio_aligned(min_heap_byte_size()), |
| NewSize); |
| desired_new_size = |
| MAX2(scale_by_NewRatio_aligned(initial_heap_byte_size()), |
| NewSize); |
| } |
| |
| assert(_min_gen0_size > 0, "Sanity check"); |
| set_initial_gen0_size(desired_new_size); |
| set_max_gen0_size(max_new_size); |
| |
| // At this point the desirable initial and minimum sizes have been |
| // determined without regard to the maximum sizes. |
| |
| // Bound the sizes by the corresponding overall heap sizes. |
| set_min_gen0_size( |
| bound_minus_alignment(_min_gen0_size, min_heap_byte_size())); |
| set_initial_gen0_size( |
| bound_minus_alignment(_initial_gen0_size, initial_heap_byte_size())); |
| set_max_gen0_size( |
| bound_minus_alignment(_max_gen0_size, max_heap_byte_size())); |
| |
| // At this point all three sizes have been checked against the |
| // maximum sizes but have not been checked for consistency |
| // among the three. |
| |
| // Final check min <= initial <= max |
| set_min_gen0_size(MIN2(_min_gen0_size, _max_gen0_size)); |
| set_initial_gen0_size( |
| MAX2(MIN2(_initial_gen0_size, _max_gen0_size), _min_gen0_size)); |
| set_min_gen0_size(MIN2(_min_gen0_size, _initial_gen0_size)); |
| } |
| |
| if (PrintGCDetails && Verbose) { |
| gclog_or_tty->print_cr("1: Minimum gen0 " SIZE_FORMAT " Initial gen0 " |
| SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT, |
| min_gen0_size(), initial_gen0_size(), max_gen0_size()); |
| } |
| } |
| |
| // Call this method during the sizing of the gen1 to make |
| // adjustments to gen0 because of gen1 sizing policy. gen0 initially has |
| // the most freedom in sizing because it is done before the |
| // policy for gen1 is applied. Once gen1 policies have been applied, |
| // there may be conflicts in the shape of the heap and this method |
| // is used to make the needed adjustments. The application of the |
| // policies could be more sophisticated (iterative for example) but |
| // keeping it simple also seems a worthwhile goal. |
| bool TwoGenerationCollectorPolicy::adjust_gen0_sizes(size_t* gen0_size_ptr, |
| size_t* gen1_size_ptr, |
| size_t heap_size, |
| size_t min_gen0_size) { |
| bool result = false; |
| if ((*gen1_size_ptr + *gen0_size_ptr) > heap_size) { |
| if (((*gen0_size_ptr + OldSize) > heap_size) && |
| (heap_size - min_gen0_size) >= min_alignment()) { |
| // Adjust gen0 down to accomodate OldSize |
| *gen0_size_ptr = heap_size - min_gen0_size; |
| *gen0_size_ptr = |
| MAX2((uintx)align_size_down(*gen0_size_ptr, min_alignment()), |
| min_alignment()); |
| assert(*gen0_size_ptr > 0, "Min gen0 is too large"); |
| result = true; |
| } else { |
| *gen1_size_ptr = heap_size - *gen0_size_ptr; |
| *gen1_size_ptr = |
| MAX2((uintx)align_size_down(*gen1_size_ptr, min_alignment()), |
| min_alignment()); |
| } |
| } |
| return result; |
| } |
| |
| // Minimum sizes of the generations may be different than |
| // the initial sizes. An inconsistently is permitted here |
| // in the total size that can be specified explicitly by |
| // command line specification of OldSize and NewSize and |
| // also a command line specification of -Xms. Issue a warning |
| // but allow the values to pass. |
| |
| void TwoGenerationCollectorPolicy::initialize_size_info() { |
| GenCollectorPolicy::initialize_size_info(); |
| |
| // At this point the minimum, initial and maximum sizes |
| // of the overall heap and of gen0 have been determined. |
| // The maximum gen1 size can be determined from the maximum gen0 |
| // and maximum heap size since no explicit flags exits |
| // for setting the gen1 maximum. |
| _max_gen1_size = max_heap_byte_size() - _max_gen0_size; |
| _max_gen1_size = |
| MAX2((uintx)align_size_down(_max_gen1_size, min_alignment()), |
| min_alignment()); |
| // If no explicit command line flag has been set for the |
| // gen1 size, use what is left for gen1. |
| if (FLAG_IS_DEFAULT(OldSize) || FLAG_IS_ERGO(OldSize)) { |
| // The user has not specified any value or ergonomics |
| // has chosen a value (which may or may not be consistent |
| // with the overall heap size). In either case make |
| // the minimum, maximum and initial sizes consistent |
| // with the gen0 sizes and the overall heap sizes. |
| assert(min_heap_byte_size() > _min_gen0_size, |
| "gen0 has an unexpected minimum size"); |
| set_min_gen1_size(min_heap_byte_size() - min_gen0_size()); |
| set_min_gen1_size( |
| MAX2((uintx)align_size_down(_min_gen1_size, min_alignment()), |
| min_alignment())); |
| set_initial_gen1_size(initial_heap_byte_size() - initial_gen0_size()); |
| set_initial_gen1_size( |
| MAX2((uintx)align_size_down(_initial_gen1_size, min_alignment()), |
| min_alignment())); |
| |
| } else { |
| // It's been explicitly set on the command line. Use the |
| // OldSize and then determine the consequences. |
| set_min_gen1_size(OldSize); |
| set_initial_gen1_size(OldSize); |
| |
| // If the user has explicitly set an OldSize that is inconsistent |
| // with other command line flags, issue a warning. |
| // The generation minimums and the overall heap mimimum should |
| // be within one heap alignment. |
| if ((_min_gen1_size + _min_gen0_size + min_alignment()) < |
| min_heap_byte_size()) { |
| warning("Inconsistency between minimum heap size and minimum " |
| "generation sizes: using minimum heap = " SIZE_FORMAT, |
| min_heap_byte_size()); |
| } |
| if ((OldSize > _max_gen1_size)) { |
| warning("Inconsistency between maximum heap size and maximum " |
| "generation sizes: using maximum heap = " SIZE_FORMAT |
| " -XX:OldSize flag is being ignored", |
| max_heap_byte_size()); |
| } |
| // If there is an inconsistency between the OldSize and the minimum and/or |
| // initial size of gen0, since OldSize was explicitly set, OldSize wins. |
| if (adjust_gen0_sizes(&_min_gen0_size, &_min_gen1_size, |
| min_heap_byte_size(), OldSize)) { |
| if (PrintGCDetails && Verbose) { |
| gclog_or_tty->print_cr("2: Minimum gen0 " SIZE_FORMAT " Initial gen0 " |
| SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT, |
| min_gen0_size(), initial_gen0_size(), max_gen0_size()); |
| } |
| } |
| // Initial size |
| if (adjust_gen0_sizes(&_initial_gen0_size, &_initial_gen1_size, |
| initial_heap_byte_size(), OldSize)) { |
| if (PrintGCDetails && Verbose) { |
| gclog_or_tty->print_cr("3: Minimum gen0 " SIZE_FORMAT " Initial gen0 " |
| SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT, |
| min_gen0_size(), initial_gen0_size(), max_gen0_size()); |
| } |
| } |
| } |
| // Enforce the maximum gen1 size. |
| set_min_gen1_size(MIN2(_min_gen1_size, _max_gen1_size)); |
| |
| // Check that min gen1 <= initial gen1 <= max gen1 |
| set_initial_gen1_size(MAX2(_initial_gen1_size, _min_gen1_size)); |
| set_initial_gen1_size(MIN2(_initial_gen1_size, _max_gen1_size)); |
| |
| if (PrintGCDetails && Verbose) { |
| gclog_or_tty->print_cr("Minimum gen1 " SIZE_FORMAT " Initial gen1 " |
| SIZE_FORMAT " Maximum gen1 " SIZE_FORMAT, |
| min_gen1_size(), initial_gen1_size(), max_gen1_size()); |
| } |
| } |
| |
| HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size, |
| bool is_tlab, |
| bool* gc_overhead_limit_was_exceeded) { |
| GenCollectedHeap *gch = GenCollectedHeap::heap(); |
| |
| debug_only(gch->check_for_valid_allocation_state()); |
| assert(gch->no_gc_in_progress(), "Allocation during gc not allowed"); |
| |
| // In general gc_overhead_limit_was_exceeded should be false so |
| // set it so here and reset it to true only if the gc time |
| // limit is being exceeded as checked below. |
| *gc_overhead_limit_was_exceeded = false; |
| |
| HeapWord* result = NULL; |
| |
| // Loop until the allocation is satisified, |
| // or unsatisfied after GC. |
| for (int try_count = 1; /* return or throw */; try_count += 1) { |
| HandleMark hm; // discard any handles allocated in each iteration |
| |
| // First allocation attempt is lock-free. |
| Generation *gen0 = gch->get_gen(0); |
| assert(gen0->supports_inline_contig_alloc(), |
| "Otherwise, must do alloc within heap lock"); |
| if (gen0->should_allocate(size, is_tlab)) { |
| result = gen0->par_allocate(size, is_tlab); |
| if (result != NULL) { |
| assert(gch->is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| } |
| unsigned int gc_count_before; // read inside the Heap_lock locked region |
| { |
| MutexLocker ml(Heap_lock); |
| if (PrintGC && Verbose) { |
| gclog_or_tty->print_cr("TwoGenerationCollectorPolicy::mem_allocate_work:" |
| " attempting locked slow path allocation"); |
| } |
| // Note that only large objects get a shot at being |
| // allocated in later generations. |
| bool first_only = ! should_try_older_generation_allocation(size); |
| |
| result = gch->attempt_allocation(size, is_tlab, first_only); |
| if (result != NULL) { |
| assert(gch->is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| |
| if (GC_locker::is_active_and_needs_gc()) { |
| if (is_tlab) { |
| return NULL; // Caller will retry allocating individual object |
| } |
| if (!gch->is_maximal_no_gc()) { |
| // Try and expand heap to satisfy request |
| result = expand_heap_and_allocate(size, is_tlab); |
| // result could be null if we are out of space |
| if (result != NULL) { |
| return result; |
| } |
| } |
| |
| // 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 the heap lock is held. |
| gc_count_before = Universe::heap()->total_collections(); |
| } |
| |
| VM_GenCollectForAllocation op(size, |
| is_tlab, |
| gc_count_before); |
| VMThread::execute(&op); |
| if (op.prologue_succeeded()) { |
| result = op.result(); |
| if (op.gc_locked()) { |
| assert(result == NULL, "must be NULL if gc_locked() is true"); |
| continue; // retry and/or stall as necessary |
| } |
| |
| // Allocation has failed and a collection |
| // has been done. If the gc time limit was exceeded the |
| // this time, return NULL so that an out-of-memory |
| // will be thrown. Clear gc_overhead_limit_exceeded |
| // so that the overhead exceeded does not persist. |
| |
| const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded(); |
| const bool softrefs_clear = all_soft_refs_clear(); |
| assert(!limit_exceeded || softrefs_clear, "Should have been cleared"); |
| if (limit_exceeded && softrefs_clear) { |
| *gc_overhead_limit_was_exceeded = true; |
| size_policy()->set_gc_overhead_limit_exceeded(false); |
| if (op.result() != NULL) { |
| CollectedHeap::fill_with_object(op.result(), size); |
| } |
| return NULL; |
| } |
| assert(result == NULL || gch->is_in_reserved(result), |
| "result not in heap"); |
| return result; |
| } |
| |
| // Give a warning if we seem to be looping forever. |
| if ((QueuedAllocationWarningCount > 0) && |
| (try_count % QueuedAllocationWarningCount == 0)) { |
| warning("TwoGenerationCollectorPolicy::mem_allocate_work retries %d times \n\t" |
| " size=%d %s", try_count, size, is_tlab ? "(TLAB)" : ""); |
| } |
| } |
| } |
| |
| HeapWord* GenCollectorPolicy::expand_heap_and_allocate(size_t size, |
| bool is_tlab) { |
| GenCollectedHeap *gch = GenCollectedHeap::heap(); |
| HeapWord* result = NULL; |
| for (int i = number_of_generations() - 1; i >= 0 && result == NULL; i--) { |
| Generation *gen = gch->get_gen(i); |
| if (gen->should_allocate(size, is_tlab)) { |
| result = gen->expand_and_allocate(size, is_tlab); |
| } |
| } |
| assert(result == NULL || gch->is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| |
| HeapWord* GenCollectorPolicy::satisfy_failed_allocation(size_t size, |
| bool is_tlab) { |
| GenCollectedHeap *gch = GenCollectedHeap::heap(); |
| GCCauseSetter x(gch, GCCause::_allocation_failure); |
| HeapWord* result = NULL; |
| |
| assert(size != 0, "Precondition violated"); |
| if (GC_locker::is_active_and_needs_gc()) { |
| // GC locker is active; instead of a collection we will attempt |
| // to expand the heap, if there's room for expansion. |
| if (!gch->is_maximal_no_gc()) { |
| result = expand_heap_and_allocate(size, is_tlab); |
| } |
| return result; // could be null if we are out of space |
| } else if (!gch->incremental_collection_will_fail(false /* don't consult_young */)) { |
| // Do an incremental collection. |
| gch->do_collection(false /* full */, |
| false /* clear_all_soft_refs */, |
| size /* size */, |
| is_tlab /* is_tlab */, |
| number_of_generations() - 1 /* max_level */); |
| } else { |
| if (Verbose && PrintGCDetails) { |
| gclog_or_tty->print(" :: Trying full because partial may fail :: "); |
| } |
| // Try a full collection; see delta for bug id 6266275 |
| // for the original code and why this has been simplified |
| // with from-space allocation criteria modified and |
| // such allocation moved out of the safepoint path. |
| gch->do_collection(true /* full */, |
| false /* clear_all_soft_refs */, |
| size /* size */, |
| is_tlab /* is_tlab */, |
| number_of_generations() - 1 /* max_level */); |
| } |
| |
| result = gch->attempt_allocation(size, is_tlab, false /*first_only*/); |
| |
| if (result != NULL) { |
| assert(gch->is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| |
| // OK, collection failed, try expansion. |
| result = expand_heap_and_allocate(size, is_tlab); |
| if (result != NULL) { |
| return result; |
| } |
| |
| // If we reach this point, we're really out of memory. Try every trick |
| // we can to reclaim memory. Force collection of soft references. Force |
| // a complete compaction of the heap. Any additional methods for finding |
| // free memory should be here, especially if they are expensive. If this |
| // attempt fails, an OOM exception will be thrown. |
| { |
| IntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted |
| |
| gch->do_collection(true /* full */, |
| true /* clear_all_soft_refs */, |
| size /* size */, |
| is_tlab /* is_tlab */, |
| number_of_generations() - 1 /* max_level */); |
| } |
| |
| result = gch->attempt_allocation(size, is_tlab, false /* first_only */); |
| if (result != NULL) { |
| assert(gch->is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| |
| assert(!should_clear_all_soft_refs(), |
| "Flag should have been handled and cleared prior to this point"); |
| |
| // What else? We might try synchronous finalization later. If the total |
| // space available is large enough for the allocation, then a more |
| // complete compaction phase than we've tried so far might be |
| // appropriate. |
| return NULL; |
| } |
| |
| MetaWord* CollectorPolicy::satisfy_failed_metadata_allocation( |
| ClassLoaderData* loader_data, |
| size_t word_size, |
| Metaspace::MetadataType mdtype) { |
| uint loop_count = 0; |
| uint gc_count = 0; |
| uint full_gc_count = 0; |
| |
| assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock"); |
| |
| do { |
| MetaWord* result = NULL; |
| if (GC_locker::is_active_and_needs_gc()) { |
| // If the GC_locker is active, just expand and allocate. |
| // If that does not succeed, wait if this thread is not |
| // in a critical section itself. |
| result = |
| loader_data->metaspace_non_null()->expand_and_allocate(word_size, |
| mdtype); |
| if (result != NULL) { |
| return result; |
| } |
| JavaThread* jthr = JavaThread::current(); |
| if (!jthr->in_critical()) { |
| // Wait for JNI critical section to be exited |
| GC_locker::stall_until_clear(); |
| // The GC invoked by the last thread leaving the critical |
| // section will be a young collection and a full collection |
| // is (currently) needed for unloading classes so continue |
| // to the next iteration to get a full GC. |
| continue; |
| } else { |
| if (CheckJNICalls) { |
| fatal("Possible deadlock due to allocating while" |
| " in jni critical section"); |
| } |
| return NULL; |
| } |
| } |
| |
| { // Need lock to get self consistent gc_count's |
| MutexLocker ml(Heap_lock); |
| gc_count = Universe::heap()->total_collections(); |
| full_gc_count = Universe::heap()->total_full_collections(); |
| } |
| |
| // Generate a VM operation |
| VM_CollectForMetadataAllocation op(loader_data, |
| word_size, |
| mdtype, |
| gc_count, |
| full_gc_count, |
| GCCause::_metadata_GC_threshold); |
| VMThread::execute(&op); |
| if (op.prologue_succeeded()) { |
| return op.result(); |
| } |
| loop_count++; |
| if ((QueuedAllocationWarningCount > 0) && |
| (loop_count % QueuedAllocationWarningCount == 0)) { |
| warning("satisfy_failed_metadata_allocation() retries %d times \n\t" |
| " size=%d", loop_count, word_size); |
| } |
| } while (true); // Until a GC is done |
| } |
| |
| // Return true if any of the following is true: |
| // . the allocation won't fit into the current young gen heap |
| // . gc locker is occupied (jni critical section) |
| // . heap memory is tight -- the most recent previous collection |
| // was a full collection because a partial collection (would |
| // have) failed and is likely to fail again |
| bool GenCollectorPolicy::should_try_older_generation_allocation( |
| size_t word_size) const { |
| GenCollectedHeap* gch = GenCollectedHeap::heap(); |
| size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc(); |
| return (word_size > heap_word_size(gen0_capacity)) |
| || GC_locker::is_active_and_needs_gc() |
| || gch->incremental_collection_failed(); |
| } |
| |
| |
| // |
| // MarkSweepPolicy methods |
| // |
| |
| MarkSweepPolicy::MarkSweepPolicy() { |
| initialize_all(); |
| } |
| |
| void MarkSweepPolicy::initialize_generations() { |
| _generations = new GenerationSpecPtr[number_of_generations()]; |
| if (_generations == NULL) |
| vm_exit_during_initialization("Unable to allocate gen spec"); |
| |
| if (UseParNewGC && ParallelGCThreads > 0) { |
| _generations[0] = new GenerationSpec(Generation::ParNew, _initial_gen0_size, _max_gen0_size); |
| } else { |
| _generations[0] = new GenerationSpec(Generation::DefNew, _initial_gen0_size, _max_gen0_size); |
| } |
| _generations[1] = new GenerationSpec(Generation::MarkSweepCompact, _initial_gen1_size, _max_gen1_size); |
| |
| if (_generations[0] == NULL || _generations[1] == NULL) |
| vm_exit_during_initialization("Unable to allocate gen spec"); |
| } |
| |
| void MarkSweepPolicy::initialize_gc_policy_counters() { |
| // initialize the policy counters - 2 collectors, 3 generations |
| if (UseParNewGC && ParallelGCThreads > 0) { |
| _gc_policy_counters = new GCPolicyCounters("ParNew:MSC", 2, 3); |
| } |
| else { |
| _gc_policy_counters = new GCPolicyCounters("Copy:MSC", 2, 3); |
| } |
| } |
