# HG changeset patch # User brutisso # Date 1376636556 -7200 # Node ID 5a62937e55b3c61acc1e16c952896e0400a14c96 # Parent 33d39b75663ffcfd65ab5fab4a4b41cb3e284185# Parent 56b94e55267ac4f11d91f8f66bd27f3fd1885ee5 Merge diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp --- a/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Fri Aug 16 09:02:36 2013 +0200 @@ -50,6 +50,7 @@ #include "memory/genMarkSweep.hpp" #include "memory/genOopClosures.inline.hpp" #include "memory/iterator.hpp" +#include "memory/padded.hpp" #include "memory/referencePolicy.hpp" #include "memory/resourceArea.hpp" #include "memory/tenuredGeneration.hpp" diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/gc_implementation/parNew/parNewGeneration.cpp --- a/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Fri Aug 16 09:02:36 2013 +0200 @@ -927,11 +927,9 @@ workers->active_workers(), Threads::number_of_non_daemon_threads()); workers->set_active_workers(active_workers); - _next_gen = gch->next_gen(this); - assert(_next_gen != NULL, - "This must be the youngest gen, and not the only gen"); assert(gch->n_gens() == 2, "Par collection currently only works with single older gen."); + _next_gen = gch->next_gen(this); // Do we have to avoid promotion_undo? if (gch->collector_policy()->is_concurrent_mark_sweep_policy()) { set_avoid_promotion_undo(true); diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/gc_implementation/parNew/parNewGeneration.hpp --- a/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2001, 2013, 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 @@ -29,6 +29,7 @@ #include "gc_implementation/shared/parGCAllocBuffer.hpp" #include "gc_implementation/shared/copyFailedInfo.hpp" #include "memory/defNewGeneration.hpp" +#include "memory/padded.hpp" #include "utilities/taskqueue.hpp" class ChunkArray; diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/gc_implementation/parNew/parOopClosures.hpp --- a/src/share/vm/gc_implementation/parNew/parOopClosures.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/gc_implementation/parNew/parOopClosures.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2007, 2013, 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 @@ -26,6 +26,7 @@ #define SHARE_VM_GC_IMPLEMENTATION_PARNEW_PAROOPCLOSURES_HPP #include "memory/genOopClosures.hpp" +#include "memory/padded.hpp" // Closures for ParNewGeneration diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp --- a/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp Fri Aug 16 09:02:36 2013 +0200 @@ -29,14 +29,16 @@ #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp" #include "gc_implementation/shared/gcTrace.hpp" #include "gc_implementation/shared/mutableSpace.hpp" +#include "memory/allocation.inline.hpp" #include "memory/memRegion.hpp" +#include "memory/padded.inline.hpp" #include "oops/oop.inline.hpp" #include "oops/oop.psgc.inline.hpp" -PSPromotionManager** PSPromotionManager::_manager_array = NULL; -OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL; -PSOldGen* PSPromotionManager::_old_gen = NULL; -MutableSpace* PSPromotionManager::_young_space = NULL; +PaddedEnd* PSPromotionManager::_manager_array = NULL; +OopStarTaskQueueSet* PSPromotionManager::_stack_array_depth = NULL; +PSOldGen* PSPromotionManager::_old_gen = NULL; +MutableSpace* PSPromotionManager::_young_space = NULL; void PSPromotionManager::initialize() { ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); @@ -45,8 +47,10 @@ _old_gen = heap->old_gen(); _young_space = heap->young_gen()->to_space(); + // To prevent false sharing, we pad the PSPromotionManagers + // and make sure that the first instance starts at a cache line. assert(_manager_array == NULL, "Attempt to initialize twice"); - _manager_array = NEW_C_HEAP_ARRAY(PSPromotionManager*, ParallelGCThreads+1, mtGC); + _manager_array = PaddedArray::create_unfreeable(ParallelGCThreads + 1); guarantee(_manager_array != NULL, "Could not initialize promotion manager"); _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads); @@ -54,26 +58,21 @@ // Create and register the PSPromotionManager(s) for the worker threads. for(uint i=0; iregister_queue(i, _manager_array[i]->claimed_stack_depth()); + stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth()); } - // The VMThread gets its own PSPromotionManager, which is not available // for work stealing. - _manager_array[ParallelGCThreads] = new PSPromotionManager(); - guarantee(_manager_array[ParallelGCThreads] != NULL, "Could not create PSPromotionManager"); } PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(int index) { assert(index >= 0 && index < (int)ParallelGCThreads, "index out of range"); assert(_manager_array != NULL, "Sanity"); - return _manager_array[index]; + return &_manager_array[index]; } PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() { assert(_manager_array != NULL, "Sanity"); - return _manager_array[ParallelGCThreads]; + return &_manager_array[ParallelGCThreads]; } void PSPromotionManager::pre_scavenge() { diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.hpp --- a/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -29,6 +29,8 @@ #include "gc_implementation/shared/gcTrace.hpp" #include "gc_implementation/shared/copyFailedInfo.hpp" #include "memory/allocation.hpp" +#include "memory/padded.hpp" +#include "utilities/globalDefinitions.hpp" #include "utilities/taskqueue.hpp" // @@ -51,14 +53,14 @@ class PSOldGen; class ParCompactionManager; -class PSPromotionManager : public CHeapObj { +class PSPromotionManager VALUE_OBJ_CLASS_SPEC { friend class PSScavenge; friend class PSRefProcTaskExecutor; private: - static PSPromotionManager** _manager_array; - static OopStarTaskQueueSet* _stack_array_depth; - static PSOldGen* _old_gen; - static MutableSpace* _young_space; + static PaddedEnd* _manager_array; + static OopStarTaskQueueSet* _stack_array_depth; + static PSOldGen* _old_gen; + static MutableSpace* _young_space; #if TASKQUEUE_STATS size_t _masked_pushes; diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp --- a/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -32,7 +32,7 @@ inline PSPromotionManager* PSPromotionManager::manager_array(int index) { assert(_manager_array != NULL, "access of NULL manager_array"); assert(index >= 0 && index <= (int)ParallelGCThreads, "out of range manager_array access"); - return _manager_array[index]; + return &_manager_array[index]; } template diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/gc_implementation/shared/objectCountEventSender.cpp --- a/src/share/vm/gc_implementation/shared/objectCountEventSender.cpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/gc_implementation/shared/objectCountEventSender.cpp Fri Aug 16 09:02:36 2013 +0200 @@ -32,6 +32,7 @@ #if INCLUDE_SERVICES void ObjectCountEventSender::send(const KlassInfoEntry* entry, GCId gc_id, jlong timestamp) { +#if INCLUDE_TRACE assert(Tracing::is_event_enabled(EventObjectCountAfterGC::eventId), "Only call this method if the event is enabled"); @@ -42,6 +43,7 @@ event.set_totalSize(entry->words() * BytesPerWord); event.set_endtime(timestamp); event.commit(); +#endif // INCLUDE_TRACE } bool ObjectCountEventSender::should_send_event() { diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/memory/cardTableRS.cpp --- a/src/share/vm/memory/cardTableRS.cpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/memory/cardTableRS.cpp Fri Aug 16 09:02:36 2013 +0200 @@ -310,46 +310,31 @@ _ct_bs->non_clean_card_iterate_possibly_parallel(sp, urasm, cl, this); } -void CardTableRS::clear_into_younger(Generation* gen) { - GenCollectedHeap* gch = GenCollectedHeap::heap(); - // Generations younger than gen have been evacuated. We can clear - // card table entries for gen (we know that it has no pointers - // to younger gens) and for those below. The card tables for - // the youngest gen need never be cleared. +void CardTableRS::clear_into_younger(Generation* old_gen) { + assert(old_gen->level() == 1, "Should only be called for the old generation"); + // The card tables for the youngest gen need never be cleared. // There's a bit of subtlety in the clear() and invalidate() // methods that we exploit here and in invalidate_or_clear() // below to avoid missing cards at the fringes. If clear() or // invalidate() are changed in the future, this code should // be revisited. 20040107.ysr - Generation* g = gen; - for(Generation* prev_gen = gch->prev_gen(g); - prev_gen != NULL; - g = prev_gen, prev_gen = gch->prev_gen(g)) { - MemRegion to_be_cleared_mr = g->prev_used_region(); - clear(to_be_cleared_mr); - } + clear(old_gen->prev_used_region()); } -void CardTableRS::invalidate_or_clear(Generation* gen, bool younger) { - GenCollectedHeap* gch = GenCollectedHeap::heap(); - // For each generation gen (and younger) - // invalidate the cards for the currently occupied part - // of that generation and clear the cards for the +void CardTableRS::invalidate_or_clear(Generation* old_gen) { + assert(old_gen->level() == 1, "Should only be called for the old generation"); + // Invalidate the cards for the currently occupied part of + // the old generation and clear the cards for the // unoccupied part of the generation (if any, making use // of that generation's prev_used_region to determine that // region). No need to do anything for the youngest // generation. Also see note#20040107.ysr above. - Generation* g = gen; - for(Generation* prev_gen = gch->prev_gen(g); prev_gen != NULL; - g = prev_gen, prev_gen = gch->prev_gen(g)) { - MemRegion used_mr = g->used_region(); - MemRegion to_be_cleared_mr = g->prev_used_region().minus(used_mr); - if (!to_be_cleared_mr.is_empty()) { - clear(to_be_cleared_mr); - } - invalidate(used_mr); - if (!younger) break; + MemRegion used_mr = old_gen->used_region(); + MemRegion to_be_cleared_mr = old_gen->prev_used_region().minus(used_mr); + if (!to_be_cleared_mr.is_empty()) { + clear(to_be_cleared_mr); } + invalidate(used_mr); } diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/memory/cardTableRS.hpp --- a/src/share/vm/memory/cardTableRS.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/memory/cardTableRS.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -142,12 +142,12 @@ void verify_aligned_region_empty(MemRegion mr); void clear(MemRegion mr) { _ct_bs->clear(mr); } - void clear_into_younger(Generation* gen); + void clear_into_younger(Generation* old_gen); void invalidate(MemRegion mr, bool whole_heap = false) { _ct_bs->invalidate(mr, whole_heap); } - void invalidate_or_clear(Generation* gen, bool younger); + void invalidate_or_clear(Generation* old_gen); static uintx ct_max_alignment_constraint() { return CardTableModRefBS::ct_max_alignment_constraint(); diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/memory/defNewGeneration.cpp --- a/src/share/vm/memory/defNewGeneration.cpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/memory/defNewGeneration.cpp Fri Aug 16 09:02:36 2013 +0200 @@ -567,8 +567,6 @@ gc_tracer.report_gc_start(gch->gc_cause(), _gc_timer->gc_start()); _next_gen = gch->next_gen(this); - assert(_next_gen != NULL, - "This must be the youngest gen, and not the only gen"); // If the next generation is too full to accommodate promotion // from this generation, pass on collection; let the next generation @@ -901,8 +899,6 @@ if (_next_gen == NULL) { GenCollectedHeap* gch = GenCollectedHeap::heap(); _next_gen = gch->next_gen(this); - assert(_next_gen != NULL, - "This must be the youngest gen, and not the only gen"); } return _next_gen->promotion_attempt_is_safe(used()); } diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/memory/genCollectedHeap.cpp --- a/src/share/vm/memory/genCollectedHeap.cpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/memory/genCollectedHeap.cpp Fri Aug 16 09:02:36 2013 +0200 @@ -1070,13 +1070,13 @@ void GenCollectedHeap::prepare_for_compaction() { - Generation* scanning_gen = _gens[_n_gens-1]; + guarantee(_n_gens = 2, "Wrong number of generations"); + Generation* old_gen = _gens[1]; // Start by compacting into same gen. - CompactPoint cp(scanning_gen, NULL, NULL); - while (scanning_gen != NULL) { - scanning_gen->prepare_for_compaction(&cp); - scanning_gen = prev_gen(scanning_gen); - } + CompactPoint cp(old_gen, NULL, NULL); + old_gen->prepare_for_compaction(&cp); + Generation* young_gen = _gens[0]; + young_gen->prepare_for_compaction(&cp); } GCStats* GenCollectedHeap::gc_stats(int level) const { @@ -1245,27 +1245,14 @@ generation_iterate(&ep_cl, false); } -oop GenCollectedHeap::handle_failed_promotion(Generation* gen, +oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen, oop obj, size_t obj_size) { + guarantee(old_gen->level() == 1, "We only get here with an old generation"); assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); HeapWord* result = NULL; - // First give each higher generation a chance to allocate the promoted object. - Generation* allocator = next_gen(gen); - if (allocator != NULL) { - do { - result = allocator->allocate(obj_size, false); - } while (result == NULL && (allocator = next_gen(allocator)) != NULL); - } - - if (result == NULL) { - // Then give gen and higher generations a chance to expand and allocate the - // object. - do { - result = gen->expand_and_allocate(obj_size, false); - } while (result == NULL && (gen = next_gen(gen)) != NULL); - } + result = old_gen->expand_and_allocate(obj_size, false); if (result != NULL) { Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/memory/genCollectedHeap.hpp --- a/src/share/vm/memory/genCollectedHeap.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/memory/genCollectedHeap.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -368,25 +368,23 @@ // collection. virtual bool is_maximal_no_gc() const; - // Return the generation before "gen", or else NULL. + // Return the generation before "gen". Generation* prev_gen(Generation* gen) const { int l = gen->level(); - if (l == 0) return NULL; - else return _gens[l-1]; + guarantee(l > 0, "Out of bounds"); + return _gens[l-1]; } - // Return the generation after "gen", or else NULL. + // Return the generation after "gen". Generation* next_gen(Generation* gen) const { int l = gen->level() + 1; - if (l == _n_gens) return NULL; - else return _gens[l]; + guarantee(l < _n_gens, "Out of bounds"); + return _gens[l]; } Generation* get_gen(int i) const { - if (i >= 0 && i < _n_gens) - return _gens[i]; - else - return NULL; + guarantee(i >= 0 && i < _n_gens, "Out of bounds"); + return _gens[i]; } int n_gens() const { @@ -485,9 +483,9 @@ // Promotion of obj into gen failed. Try to promote obj to higher // gens in ascending order; return the new location of obj if successful. - // Otherwise, try expand-and-allocate for obj in each generation starting at - // gen; return the new location of obj if successful. Otherwise, return NULL. - oop handle_failed_promotion(Generation* gen, + // Otherwise, try expand-and-allocate for obj in both the young and old + // generation; return the new location of obj if successful. Otherwise, return NULL. + oop handle_failed_promotion(Generation* old_gen, oop obj, size_t obj_size); diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/memory/genMarkSweep.cpp --- a/src/share/vm/memory/genMarkSweep.cpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/memory/genMarkSweep.cpp Fri Aug 16 09:02:36 2013 +0200 @@ -52,8 +52,8 @@ #include "utilities/copy.hpp" #include "utilities/events.hpp" -void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp, - bool clear_all_softrefs) { +void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp, bool clear_all_softrefs) { + guarantee(level == 1, "We always collect both old and young."); assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); GenCollectedHeap* gch = GenCollectedHeap::heap(); @@ -84,11 +84,6 @@ // Capture heap size before collection for printing. size_t gch_prev_used = gch->used(); - // Some of the card table updates below assume that the perm gen is - // also being collected. - assert(level == gch->n_gens() - 1, - "All generations are being collected, ergo perm gen too."); - // Capture used regions for each generation that will be // subject to collection, so that card table adjustments can // be made intelligently (see clear / invalidate further below). @@ -126,17 +121,15 @@ all_empty = all_empty && gch->get_gen(i)->used() == 0; } GenRemSet* rs = gch->rem_set(); + Generation* old_gen = gch->get_gen(level); // Clear/invalidate below make use of the "prev_used_regions" saved earlier. if (all_empty) { // We've evacuated all generations below us. - Generation* g = gch->get_gen(level); - rs->clear_into_younger(g); + rs->clear_into_younger(old_gen); } else { // Invalidate the cards corresponding to the currently used - // region and clear those corresponding to the evacuated region - // of all generations just collected (i.e. level and younger). - rs->invalidate_or_clear(gch->get_gen(level), - true /* younger */); + // region and clear those corresponding to the evacuated region. + rs->invalidate_or_clear(old_gen); } Threads::gc_epilogue(); diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/memory/genRemSet.hpp --- a/src/share/vm/memory/genRemSet.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/memory/genRemSet.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -135,7 +135,7 @@ // younger than gen from generations gen and older. // The parameter clear_perm indicates if the perm_gen's // remembered set should also be processed/cleared. - virtual void clear_into_younger(Generation* gen) = 0; + virtual void clear_into_younger(Generation* old_gen) = 0; // Informs the RS that refs in the given "mr" may have changed // arbitrarily, and therefore may contain old-to-young pointers. @@ -146,11 +146,8 @@ // Informs the RS that refs in this generation // may have changed arbitrarily, and therefore may contain - // old-to-young pointers in arbitrary locations. The parameter - // younger indicates if the same should be done for younger generations - // as well. The parameter perm indicates if the same should be done for - // perm gen as well. - virtual void invalidate_or_clear(Generation* gen, bool younger) = 0; + // old-to-young pointers in arbitrary locations. + virtual void invalidate_or_clear(Generation* old_gen) = 0; }; #endif // SHARE_VM_MEMORY_GENREMSET_HPP diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/memory/padded.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/padded.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -0,0 +1,93 @@ +/* + * Copyright (c) 2013, 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. + * + */ + +#ifndef SHARE_VM_MEMORY_PADDED_HPP +#define SHARE_VM_MEMORY_PADDED_HPP + +#include "memory/allocation.hpp" +#include "utilities/globalDefinitions.hpp" + +// Bytes needed to pad type to avoid cache-line sharing; alignment should be the +// expected cache line size (a power of two). The first addend avoids sharing +// when the start address is not a multiple of alignment; the second maintains +// alignment of starting addresses that happen to be a multiple. +#define PADDING_SIZE(type, alignment) \ + ((alignment) + align_size_up_(sizeof(type), alignment)) + +// Templates to create a subclass padded to avoid cache line sharing. These are +// effective only when applied to derived-most (leaf) classes. + +// When no args are passed to the base ctor. +template +class Padded : public T { + private: + char _pad_buf_[PADDING_SIZE(T, alignment)]; +}; + +// When either 0 or 1 args may be passed to the base ctor. +template +class Padded01 : public T { + public: + Padded01(): T() { } + Padded01(Arg1T arg1): T(arg1) { } + private: + char _pad_buf_[PADDING_SIZE(T, alignment)]; +}; + +// Super class of PaddedEnd when pad_size != 0. +template +class PaddedEndImpl : public T { + private: + char _pad_buf[pad_size]; +}; + +// Super class of PaddedEnd when pad_size == 0. +template +class PaddedEndImpl : public T { + // No padding. +}; + +#define PADDED_END_SIZE(type, alignment) (align_size_up_(sizeof(type), alignment) - sizeof(type)) + +// More memory conservative implementation of Padded. The subclass adds the +// minimal amount of padding needed to make the size of the objects be aligned. +// This will help reducing false sharing, +// if the start address is a multiple of alignment. +template +class PaddedEnd : public PaddedEndImpl { + // C++ don't allow zero-length arrays. The padding is put in a + // super class that is specialized for the pad_size == 0 case. +}; + +// Helper class to create an array of PaddedEnd objects. All elements will +// start at a multiple of alignment and the size will be aligned to alignment. +template +class PaddedArray { + public: + // Creates an aligned padded array. + // The memory can't be deleted since the raw memory chunk is not returned. + static PaddedEnd* create_unfreeable(uint length); +}; + +#endif // SHARE_VM_MEMORY_PADDED_HPP diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/memory/padded.inline.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/padded.inline.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -0,0 +1,49 @@ +/* + * Copyright (c) 2013, 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 "memory/allocation.inline.hpp" +#include "memory/padded.hpp" +#include "utilities/debug.hpp" +#include "utilities/globalDefinitions.hpp" + +// Creates an aligned padded array. +// The memory can't be deleted since the raw memory chunk is not returned. +template +PaddedEnd* PaddedArray::create_unfreeable(uint length) { + // Check that the PaddedEnd class works as intended. + STATIC_ASSERT(is_size_aligned_(sizeof(PaddedEnd), alignment)); + + // Allocate a chunk of memory large enough to allow for some alignment. + void* chunk = AllocateHeap(length * sizeof(PaddedEnd) + alignment, flags); + + // Make the initial alignment. + PaddedEnd* aligned_padded_array = (PaddedEnd*)align_pointer_up(chunk, alignment); + + // Call the default constructor for each element. + for (uint i = 0; i < length; i++) { + ::new (&aligned_padded_array[i]) T(); + } + + return aligned_padded_array; +} diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/utilities/debug.hpp --- a/src/share/vm/utilities/debug.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/utilities/debug.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -225,6 +225,22 @@ void warning(const char* format, ...); +#ifdef ASSERT +// Compile-time asserts. +template struct StaticAssert; +template <> struct StaticAssert {}; + +// Only StaticAssert is defined, so if cond evaluates to false we get +// a compile time exception when trying to use StaticAssert. +#define STATIC_ASSERT(cond) \ + do { \ + StaticAssert<(cond)> DUMMY_STATIC_ASSERT; \ + (void)DUMMY_STATIC_ASSERT; /* ignore */ \ + } while (false) +#else +#define STATIC_ASSERT(cond) +#endif + // out of shared space reporting enum SharedSpaceType { SharedPermGen, diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/utilities/exceptions.hpp --- a/src/share/vm/utilities/exceptions.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/utilities/exceptions.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -306,6 +306,6 @@ // which preserves pre-existing exceptions and does not allow new // exceptions. -#define EXCEPTION_MARK Thread* THREAD; ExceptionMark __em(THREAD); +#define EXCEPTION_MARK Thread* THREAD = NULL; ExceptionMark __em(THREAD); #endif // SHARE_VM_UTILITIES_EXCEPTIONS_HPP diff -r 56b94e55267a -r 5a62937e55b3 src/share/vm/utilities/globalDefinitions.hpp --- a/src/share/vm/utilities/globalDefinitions.hpp Thu Aug 15 15:26:16 2013 +0200 +++ b/src/share/vm/utilities/globalDefinitions.hpp Fri Aug 16 09:02:36 2013 +0200 @@ -410,6 +410,8 @@ return align_size_down_(size, alignment); } +#define is_size_aligned_(size, alignment) ((size) == (align_size_up_(size, alignment))) + // Align objects by rounding up their size, in HeapWord units. #define align_object_size_(size) align_size_up_(size, MinObjAlignment) @@ -428,6 +430,10 @@ return align_size_up(offset, HeapWordsPerLong); } +inline void* align_pointer_up(const void* addr, size_t size) { + return (void*) align_size_up_((uintptr_t)addr, size); +} + // Clamp an address to be within a specific page // 1. If addr is on the page it is returned as is // 2. If addr is above the page_address the start of the *next* page will be returned @@ -449,32 +455,6 @@ // The expected size in bytes of a cache line, used to pad data structures. #define DEFAULT_CACHE_LINE_SIZE 64 -// Bytes needed to pad type to avoid cache-line sharing; alignment should be the -// expected cache line size (a power of two). The first addend avoids sharing -// when the start address is not a multiple of alignment; the second maintains -// alignment of starting addresses that happen to be a multiple. -#define PADDING_SIZE(type, alignment) \ - ((alignment) + align_size_up_(sizeof(type), alignment)) - -// Templates to create a subclass padded to avoid cache line sharing. These are -// effective only when applied to derived-most (leaf) classes. - -// When no args are passed to the base ctor. -template -class Padded: public T { -private: - char _pad_buf_[PADDING_SIZE(T, alignment)]; -}; - -// When either 0 or 1 args may be passed to the base ctor. -template -class Padded01: public T { -public: - Padded01(): T() { } - Padded01(Arg1T arg1): T(arg1) { } -private: - char _pad_buf_[PADDING_SIZE(T, alignment)]; -}; //---------------------------------------------------------------------------------------------------- // Utility macros for compilers