--- old/src/share/vm/gc_implementation/g1/g1AllocRegion.cpp 2015-05-12 11:54:02.048744302 +0200 +++ /dev/null 2015-03-18 17:10:38.111854831 +0100 @@ -1,304 +0,0 @@ -/* - * Copyright (c) 2011, 2014, 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/g1/g1AllocRegion.inline.hpp" -#include "gc_implementation/g1/g1CollectedHeap.inline.hpp" -#include "runtime/orderAccess.inline.hpp" - -G1CollectedHeap* G1AllocRegion::_g1h = NULL; -HeapRegion* G1AllocRegion::_dummy_region = NULL; - -void G1AllocRegion::setup(G1CollectedHeap* g1h, HeapRegion* dummy_region) { - assert(_dummy_region == NULL, "should be set once"); - assert(dummy_region != NULL, "pre-condition"); - assert(dummy_region->free() == 0, "pre-condition"); - - // Make sure that any allocation attempt on this region will fail - // and will not trigger any asserts. - assert(allocate(dummy_region, 1, false) == NULL, "should fail"); - assert(par_allocate(dummy_region, 1, false) == NULL, "should fail"); - assert(allocate(dummy_region, 1, true) == NULL, "should fail"); - assert(par_allocate(dummy_region, 1, true) == NULL, "should fail"); - - _g1h = g1h; - _dummy_region = dummy_region; -} - -void G1AllocRegion::fill_up_remaining_space(HeapRegion* alloc_region, - bool bot_updates) { - assert(alloc_region != NULL && alloc_region != _dummy_region, - "pre-condition"); - - // Other threads might still be trying to allocate using a CAS out - // of the region we are trying to retire, as they can do so without - // holding the lock. So, we first have to make sure that noone else - // can allocate out of it by doing a maximal allocation. Even if our - // CAS attempt fails a few times, we'll succeed sooner or later - // given that failed CAS attempts mean that the region is getting - // closed to being full. - size_t free_word_size = alloc_region->free() / HeapWordSize; - - // This is the minimum free chunk we can turn into a dummy - // object. If the free space falls below this, then noone can - // allocate in this region anyway (all allocation requests will be - // of a size larger than this) so we won't have to perform the dummy - // allocation. - size_t min_word_size_to_fill = CollectedHeap::min_fill_size(); - - while (free_word_size >= min_word_size_to_fill) { - HeapWord* dummy = par_allocate(alloc_region, free_word_size, bot_updates); - if (dummy != NULL) { - // If the allocation was successful we should fill in the space. - CollectedHeap::fill_with_object(dummy, free_word_size); - alloc_region->set_pre_dummy_top(dummy); - break; - } - - free_word_size = alloc_region->free() / HeapWordSize; - // It's also possible that someone else beats us to the - // allocation and they fill up the region. In that case, we can - // just get out of the loop. - } - assert(alloc_region->free() / HeapWordSize < min_word_size_to_fill, - "post-condition"); -} - -void G1AllocRegion::retire(bool fill_up) { - assert(_alloc_region != NULL, ar_ext_msg(this, "not initialized properly")); - - trace("retiring"); - HeapRegion* alloc_region = _alloc_region; - if (alloc_region != _dummy_region) { - // We never have to check whether the active region is empty or not, - // and potentially free it if it is, given that it's guaranteed that - // it will never be empty. - assert(!alloc_region->is_empty(), - ar_ext_msg(this, "the alloc region should never be empty")); - - if (fill_up) { - fill_up_remaining_space(alloc_region, _bot_updates); - } - - assert(alloc_region->used() >= _used_bytes_before, - ar_ext_msg(this, "invariant")); - size_t allocated_bytes = alloc_region->used() - _used_bytes_before; - retire_region(alloc_region, allocated_bytes); - _used_bytes_before = 0; - _alloc_region = _dummy_region; - } - trace("retired"); -} - -HeapWord* G1AllocRegion::new_alloc_region_and_allocate(size_t word_size, - bool force) { - assert(_alloc_region == _dummy_region, ar_ext_msg(this, "pre-condition")); - assert(_used_bytes_before == 0, ar_ext_msg(this, "pre-condition")); - - trace("attempting region allocation"); - HeapRegion* new_alloc_region = allocate_new_region(word_size, force); - if (new_alloc_region != NULL) { - new_alloc_region->reset_pre_dummy_top(); - // Need to do this before the allocation - _used_bytes_before = new_alloc_region->used(); - HeapWord* result = allocate(new_alloc_region, word_size, _bot_updates); - assert(result != NULL, ar_ext_msg(this, "the allocation should succeeded")); - - OrderAccess::storestore(); - // Note that we first perform the allocation and then we store the - // region in _alloc_region. This is the reason why an active region - // can never be empty. - update_alloc_region(new_alloc_region); - trace("region allocation successful"); - return result; - } else { - trace("region allocation failed"); - return NULL; - } - ShouldNotReachHere(); -} - -void G1AllocRegion::fill_in_ext_msg(ar_ext_msg* msg, const char* message) { - msg->append("[%s] %s c: %u b: %s r: "PTR_FORMAT" u: "SIZE_FORMAT, - _name, message, _count, BOOL_TO_STR(_bot_updates), - p2i(_alloc_region), _used_bytes_before); -} - -void G1AllocRegion::init() { - trace("initializing"); - assert(_alloc_region == NULL && _used_bytes_before == 0, - ar_ext_msg(this, "pre-condition")); - assert(_dummy_region != NULL, ar_ext_msg(this, "should have been set")); - _alloc_region = _dummy_region; - _count = 0; - trace("initialized"); -} - -void G1AllocRegion::set(HeapRegion* alloc_region) { - trace("setting"); - // We explicitly check that the region is not empty to make sure we - // maintain the "the alloc region cannot be empty" invariant. - assert(alloc_region != NULL && !alloc_region->is_empty(), - ar_ext_msg(this, "pre-condition")); - assert(_alloc_region == _dummy_region && - _used_bytes_before == 0 && _count == 0, - ar_ext_msg(this, "pre-condition")); - - _used_bytes_before = alloc_region->used(); - _alloc_region = alloc_region; - _count += 1; - trace("set"); -} - -void G1AllocRegion::update_alloc_region(HeapRegion* alloc_region) { - trace("update"); - // We explicitly check that the region is not empty to make sure we - // maintain the "the alloc region cannot be empty" invariant. - assert(alloc_region != NULL && !alloc_region->is_empty(), - ar_ext_msg(this, "pre-condition")); - - _alloc_region = alloc_region; - _alloc_region->set_allocation_context(allocation_context()); - _count += 1; - trace("updated"); -} - -HeapRegion* G1AllocRegion::release() { - trace("releasing"); - HeapRegion* alloc_region = _alloc_region; - retire(false /* fill_up */); - assert(_alloc_region == _dummy_region, - ar_ext_msg(this, "post-condition of retire()")); - _alloc_region = NULL; - trace("released"); - return (alloc_region == _dummy_region) ? NULL : alloc_region; -} - -#if G1_ALLOC_REGION_TRACING -void G1AllocRegion::trace(const char* str, size_t word_size, HeapWord* result) { - // All the calls to trace that set either just the size or the size - // and the result are considered part of level 2 tracing and are - // skipped during level 1 tracing. - if ((word_size == 0 && result == NULL) || (G1_ALLOC_REGION_TRACING > 1)) { - const size_t buffer_length = 128; - char hr_buffer[buffer_length]; - char rest_buffer[buffer_length]; - - HeapRegion* alloc_region = _alloc_region; - if (alloc_region == NULL) { - jio_snprintf(hr_buffer, buffer_length, "NULL"); - } else if (alloc_region == _dummy_region) { - jio_snprintf(hr_buffer, buffer_length, "DUMMY"); - } else { - jio_snprintf(hr_buffer, buffer_length, - HR_FORMAT, HR_FORMAT_PARAMS(alloc_region)); - } - - if (G1_ALLOC_REGION_TRACING > 1) { - if (result != NULL) { - jio_snprintf(rest_buffer, buffer_length, SIZE_FORMAT" "PTR_FORMAT, - word_size, result); - } else if (word_size != 0) { - jio_snprintf(rest_buffer, buffer_length, SIZE_FORMAT, word_size); - } else { - jio_snprintf(rest_buffer, buffer_length, ""); - } - } else { - jio_snprintf(rest_buffer, buffer_length, ""); - } - - tty->print_cr("[%s] %u %s : %s %s", - _name, _count, hr_buffer, str, rest_buffer); - } -} -#endif // G1_ALLOC_REGION_TRACING - -G1AllocRegion::G1AllocRegion(const char* name, - bool bot_updates) - : _name(name), _bot_updates(bot_updates), - _alloc_region(NULL), _count(0), _used_bytes_before(0), - _allocation_context(AllocationContext::system()) { } - - -HeapRegion* MutatorAllocRegion::allocate_new_region(size_t word_size, - bool force) { - return _g1h->new_mutator_alloc_region(word_size, force); -} - -void MutatorAllocRegion::retire_region(HeapRegion* alloc_region, - size_t allocated_bytes) { - _g1h->retire_mutator_alloc_region(alloc_region, allocated_bytes); -} - -HeapRegion* SurvivorGCAllocRegion::allocate_new_region(size_t word_size, - bool force) { - assert(!force, "not supported for GC alloc regions"); - return _g1h->new_gc_alloc_region(word_size, count(), InCSetState::Young); -} - -void SurvivorGCAllocRegion::retire_region(HeapRegion* alloc_region, - size_t allocated_bytes) { - _g1h->retire_gc_alloc_region(alloc_region, allocated_bytes, InCSetState::Young); -} - -HeapRegion* OldGCAllocRegion::allocate_new_region(size_t word_size, - bool force) { - assert(!force, "not supported for GC alloc regions"); - return _g1h->new_gc_alloc_region(word_size, count(), InCSetState::Old); -} - -void OldGCAllocRegion::retire_region(HeapRegion* alloc_region, - size_t allocated_bytes) { - _g1h->retire_gc_alloc_region(alloc_region, allocated_bytes, InCSetState::Old); -} - -HeapRegion* OldGCAllocRegion::release() { - HeapRegion* cur = get(); - if (cur != NULL) { - // Determine how far we are from the next card boundary. If it is smaller than - // the minimum object size we can allocate into, expand into the next card. - HeapWord* top = cur->top(); - HeapWord* aligned_top = (HeapWord*)align_ptr_up(top, G1BlockOffsetSharedArray::N_bytes); - - size_t to_allocate_words = pointer_delta(aligned_top, top, HeapWordSize); - - if (to_allocate_words != 0) { - // We are not at a card boundary. Fill up, possibly into the next, taking the - // end of the region and the minimum object size into account. - to_allocate_words = MIN2(pointer_delta(cur->end(), cur->top(), HeapWordSize), - MAX2(to_allocate_words, G1CollectedHeap::min_fill_size())); - - // Skip allocation if there is not enough space to allocate even the smallest - // possible object. In this case this region will not be retained, so the - // original problem cannot occur. - if (to_allocate_words >= G1CollectedHeap::min_fill_size()) { - HeapWord* dummy = attempt_allocation(to_allocate_words, true /* bot_updates */); - CollectedHeap::fill_with_object(dummy, to_allocate_words); - } - } - } - return G1AllocRegion::release(); -} - - --- /dev/null 2015-03-18 17:10:38.111854831 +0100 +++ new/src/share/vm/gc/g1/g1AllocRegion.cpp 2015-05-12 11:54:01.870736861 +0200 @@ -0,0 +1,304 @@ +/* + * Copyright (c) 2011, 2015, 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/g1/g1AllocRegion.inline.hpp" +#include "gc/g1/g1CollectedHeap.inline.hpp" +#include "runtime/orderAccess.inline.hpp" + +G1CollectedHeap* G1AllocRegion::_g1h = NULL; +HeapRegion* G1AllocRegion::_dummy_region = NULL; + +void G1AllocRegion::setup(G1CollectedHeap* g1h, HeapRegion* dummy_region) { + assert(_dummy_region == NULL, "should be set once"); + assert(dummy_region != NULL, "pre-condition"); + assert(dummy_region->free() == 0, "pre-condition"); + + // Make sure that any allocation attempt on this region will fail + // and will not trigger any asserts. + assert(allocate(dummy_region, 1, false) == NULL, "should fail"); + assert(par_allocate(dummy_region, 1, false) == NULL, "should fail"); + assert(allocate(dummy_region, 1, true) == NULL, "should fail"); + assert(par_allocate(dummy_region, 1, true) == NULL, "should fail"); + + _g1h = g1h; + _dummy_region = dummy_region; +} + +void G1AllocRegion::fill_up_remaining_space(HeapRegion* alloc_region, + bool bot_updates) { + assert(alloc_region != NULL && alloc_region != _dummy_region, + "pre-condition"); + + // Other threads might still be trying to allocate using a CAS out + // of the region we are trying to retire, as they can do so without + // holding the lock. So, we first have to make sure that noone else + // can allocate out of it by doing a maximal allocation. Even if our + // CAS attempt fails a few times, we'll succeed sooner or later + // given that failed CAS attempts mean that the region is getting + // closed to being full. + size_t free_word_size = alloc_region->free() / HeapWordSize; + + // This is the minimum free chunk we can turn into a dummy + // object. If the free space falls below this, then noone can + // allocate in this region anyway (all allocation requests will be + // of a size larger than this) so we won't have to perform the dummy + // allocation. + size_t min_word_size_to_fill = CollectedHeap::min_fill_size(); + + while (free_word_size >= min_word_size_to_fill) { + HeapWord* dummy = par_allocate(alloc_region, free_word_size, bot_updates); + if (dummy != NULL) { + // If the allocation was successful we should fill in the space. + CollectedHeap::fill_with_object(dummy, free_word_size); + alloc_region->set_pre_dummy_top(dummy); + break; + } + + free_word_size = alloc_region->free() / HeapWordSize; + // It's also possible that someone else beats us to the + // allocation and they fill up the region. In that case, we can + // just get out of the loop. + } + assert(alloc_region->free() / HeapWordSize < min_word_size_to_fill, + "post-condition"); +} + +void G1AllocRegion::retire(bool fill_up) { + assert(_alloc_region != NULL, ar_ext_msg(this, "not initialized properly")); + + trace("retiring"); + HeapRegion* alloc_region = _alloc_region; + if (alloc_region != _dummy_region) { + // We never have to check whether the active region is empty or not, + // and potentially free it if it is, given that it's guaranteed that + // it will never be empty. + assert(!alloc_region->is_empty(), + ar_ext_msg(this, "the alloc region should never be empty")); + + if (fill_up) { + fill_up_remaining_space(alloc_region, _bot_updates); + } + + assert(alloc_region->used() >= _used_bytes_before, + ar_ext_msg(this, "invariant")); + size_t allocated_bytes = alloc_region->used() - _used_bytes_before; + retire_region(alloc_region, allocated_bytes); + _used_bytes_before = 0; + _alloc_region = _dummy_region; + } + trace("retired"); +} + +HeapWord* G1AllocRegion::new_alloc_region_and_allocate(size_t word_size, + bool force) { + assert(_alloc_region == _dummy_region, ar_ext_msg(this, "pre-condition")); + assert(_used_bytes_before == 0, ar_ext_msg(this, "pre-condition")); + + trace("attempting region allocation"); + HeapRegion* new_alloc_region = allocate_new_region(word_size, force); + if (new_alloc_region != NULL) { + new_alloc_region->reset_pre_dummy_top(); + // Need to do this before the allocation + _used_bytes_before = new_alloc_region->used(); + HeapWord* result = allocate(new_alloc_region, word_size, _bot_updates); + assert(result != NULL, ar_ext_msg(this, "the allocation should succeeded")); + + OrderAccess::storestore(); + // Note that we first perform the allocation and then we store the + // region in _alloc_region. This is the reason why an active region + // can never be empty. + update_alloc_region(new_alloc_region); + trace("region allocation successful"); + return result; + } else { + trace("region allocation failed"); + return NULL; + } + ShouldNotReachHere(); +} + +void G1AllocRegion::fill_in_ext_msg(ar_ext_msg* msg, const char* message) { + msg->append("[%s] %s c: %u b: %s r: "PTR_FORMAT" u: "SIZE_FORMAT, + _name, message, _count, BOOL_TO_STR(_bot_updates), + p2i(_alloc_region), _used_bytes_before); +} + +void G1AllocRegion::init() { + trace("initializing"); + assert(_alloc_region == NULL && _used_bytes_before == 0, + ar_ext_msg(this, "pre-condition")); + assert(_dummy_region != NULL, ar_ext_msg(this, "should have been set")); + _alloc_region = _dummy_region; + _count = 0; + trace("initialized"); +} + +void G1AllocRegion::set(HeapRegion* alloc_region) { + trace("setting"); + // We explicitly check that the region is not empty to make sure we + // maintain the "the alloc region cannot be empty" invariant. + assert(alloc_region != NULL && !alloc_region->is_empty(), + ar_ext_msg(this, "pre-condition")); + assert(_alloc_region == _dummy_region && + _used_bytes_before == 0 && _count == 0, + ar_ext_msg(this, "pre-condition")); + + _used_bytes_before = alloc_region->used(); + _alloc_region = alloc_region; + _count += 1; + trace("set"); +} + +void G1AllocRegion::update_alloc_region(HeapRegion* alloc_region) { + trace("update"); + // We explicitly check that the region is not empty to make sure we + // maintain the "the alloc region cannot be empty" invariant. + assert(alloc_region != NULL && !alloc_region->is_empty(), + ar_ext_msg(this, "pre-condition")); + + _alloc_region = alloc_region; + _alloc_region->set_allocation_context(allocation_context()); + _count += 1; + trace("updated"); +} + +HeapRegion* G1AllocRegion::release() { + trace("releasing"); + HeapRegion* alloc_region = _alloc_region; + retire(false /* fill_up */); + assert(_alloc_region == _dummy_region, + ar_ext_msg(this, "post-condition of retire()")); + _alloc_region = NULL; + trace("released"); + return (alloc_region == _dummy_region) ? NULL : alloc_region; +} + +#if G1_ALLOC_REGION_TRACING +void G1AllocRegion::trace(const char* str, size_t word_size, HeapWord* result) { + // All the calls to trace that set either just the size or the size + // and the result are considered part of level 2 tracing and are + // skipped during level 1 tracing. + if ((word_size == 0 && result == NULL) || (G1_ALLOC_REGION_TRACING > 1)) { + const size_t buffer_length = 128; + char hr_buffer[buffer_length]; + char rest_buffer[buffer_length]; + + HeapRegion* alloc_region = _alloc_region; + if (alloc_region == NULL) { + jio_snprintf(hr_buffer, buffer_length, "NULL"); + } else if (alloc_region == _dummy_region) { + jio_snprintf(hr_buffer, buffer_length, "DUMMY"); + } else { + jio_snprintf(hr_buffer, buffer_length, + HR_FORMAT, HR_FORMAT_PARAMS(alloc_region)); + } + + if (G1_ALLOC_REGION_TRACING > 1) { + if (result != NULL) { + jio_snprintf(rest_buffer, buffer_length, SIZE_FORMAT" "PTR_FORMAT, + word_size, result); + } else if (word_size != 0) { + jio_snprintf(rest_buffer, buffer_length, SIZE_FORMAT, word_size); + } else { + jio_snprintf(rest_buffer, buffer_length, ""); + } + } else { + jio_snprintf(rest_buffer, buffer_length, ""); + } + + tty->print_cr("[%s] %u %s : %s %s", + _name, _count, hr_buffer, str, rest_buffer); + } +} +#endif // G1_ALLOC_REGION_TRACING + +G1AllocRegion::G1AllocRegion(const char* name, + bool bot_updates) + : _name(name), _bot_updates(bot_updates), + _alloc_region(NULL), _count(0), _used_bytes_before(0), + _allocation_context(AllocationContext::system()) { } + + +HeapRegion* MutatorAllocRegion::allocate_new_region(size_t word_size, + bool force) { + return _g1h->new_mutator_alloc_region(word_size, force); +} + +void MutatorAllocRegion::retire_region(HeapRegion* alloc_region, + size_t allocated_bytes) { + _g1h->retire_mutator_alloc_region(alloc_region, allocated_bytes); +} + +HeapRegion* SurvivorGCAllocRegion::allocate_new_region(size_t word_size, + bool force) { + assert(!force, "not supported for GC alloc regions"); + return _g1h->new_gc_alloc_region(word_size, count(), InCSetState::Young); +} + +void SurvivorGCAllocRegion::retire_region(HeapRegion* alloc_region, + size_t allocated_bytes) { + _g1h->retire_gc_alloc_region(alloc_region, allocated_bytes, InCSetState::Young); +} + +HeapRegion* OldGCAllocRegion::allocate_new_region(size_t word_size, + bool force) { + assert(!force, "not supported for GC alloc regions"); + return _g1h->new_gc_alloc_region(word_size, count(), InCSetState::Old); +} + +void OldGCAllocRegion::retire_region(HeapRegion* alloc_region, + size_t allocated_bytes) { + _g1h->retire_gc_alloc_region(alloc_region, allocated_bytes, InCSetState::Old); +} + +HeapRegion* OldGCAllocRegion::release() { + HeapRegion* cur = get(); + if (cur != NULL) { + // Determine how far we are from the next card boundary. If it is smaller than + // the minimum object size we can allocate into, expand into the next card. + HeapWord* top = cur->top(); + HeapWord* aligned_top = (HeapWord*)align_ptr_up(top, G1BlockOffsetSharedArray::N_bytes); + + size_t to_allocate_words = pointer_delta(aligned_top, top, HeapWordSize); + + if (to_allocate_words != 0) { + // We are not at a card boundary. Fill up, possibly into the next, taking the + // end of the region and the minimum object size into account. + to_allocate_words = MIN2(pointer_delta(cur->end(), cur->top(), HeapWordSize), + MAX2(to_allocate_words, G1CollectedHeap::min_fill_size())); + + // Skip allocation if there is not enough space to allocate even the smallest + // possible object. In this case this region will not be retained, so the + // original problem cannot occur. + if (to_allocate_words >= G1CollectedHeap::min_fill_size()) { + HeapWord* dummy = attempt_allocation(to_allocate_words, true /* bot_updates */); + CollectedHeap::fill_with_object(dummy, to_allocate_words); + } + } + } + return G1AllocRegion::release(); +} + +