diff -r 000000000000 -r f90c822e73f8 src/share/vm/memory/tenuredGeneration.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/tenuredGeneration.cpp Wed Apr 27 01:25:04 2016 +0800 @@ -0,0 +1,301 @@ +/* + * 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 + * 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/collectorCounters.hpp" +#include "gc_implementation/shared/parGCAllocBuffer.hpp" +#include "memory/allocation.inline.hpp" +#include "memory/blockOffsetTable.inline.hpp" +#include "memory/generation.inline.hpp" +#include "memory/generationSpec.hpp" +#include "memory/space.hpp" +#include "memory/tenuredGeneration.hpp" +#include "oops/oop.inline.hpp" +#include "runtime/java.hpp" +#include "utilities/macros.hpp" + +TenuredGeneration::TenuredGeneration(ReservedSpace rs, + size_t initial_byte_size, int level, + GenRemSet* remset) : + OneContigSpaceCardGeneration(rs, initial_byte_size, + level, remset, NULL) +{ + HeapWord* bottom = (HeapWord*) _virtual_space.low(); + HeapWord* end = (HeapWord*) _virtual_space.high(); + _the_space = new TenuredSpace(_bts, MemRegion(bottom, end)); + _the_space->reset_saved_mark(); + _shrink_factor = 0; + _capacity_at_prologue = 0; + + _gc_stats = new GCStats(); + + // initialize performance counters + + const char* gen_name = "old"; + + // Generation Counters -- generation 1, 1 subspace + _gen_counters = new GenerationCounters(gen_name, 1, 1, &_virtual_space); + + _gc_counters = new CollectorCounters("MSC", 1); + + _space_counters = new CSpaceCounters(gen_name, 0, + _virtual_space.reserved_size(), + _the_space, _gen_counters); +#if INCLUDE_ALL_GCS + if (UseParNewGC) { + typedef ParGCAllocBufferWithBOT* ParGCAllocBufferWithBOTPtr; + _alloc_buffers = NEW_C_HEAP_ARRAY(ParGCAllocBufferWithBOTPtr, + ParallelGCThreads, mtGC); + if (_alloc_buffers == NULL) + vm_exit_during_initialization("Could not allocate alloc_buffers"); + for (uint i = 0; i < ParallelGCThreads; i++) { + _alloc_buffers[i] = + new ParGCAllocBufferWithBOT(OldPLABSize, _bts); + if (_alloc_buffers[i] == NULL) + vm_exit_during_initialization("Could not allocate alloc_buffers"); + } + } else { + _alloc_buffers = NULL; + } +#endif // INCLUDE_ALL_GCS +} + + +const char* TenuredGeneration::name() const { + return "tenured generation"; +} + +void TenuredGeneration::gc_prologue(bool full) { + _capacity_at_prologue = capacity(); + _used_at_prologue = used(); + if (VerifyBeforeGC) { + verify_alloc_buffers_clean(); + } +} + +void TenuredGeneration::gc_epilogue(bool full) { + if (VerifyAfterGC) { + verify_alloc_buffers_clean(); + } + OneContigSpaceCardGeneration::gc_epilogue(full); +} + + +bool TenuredGeneration::should_collect(bool full, + size_t size, + bool is_tlab) { + // This should be one big conditional or (||), but I want to be able to tell + // why it returns what it returns (without re-evaluating the conditionals + // in case they aren't idempotent), so I'm doing it this way. + // DeMorgan says it's okay. + bool result = false; + if (!result && full) { + result = true; + if (PrintGC && Verbose) { + gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" + " full"); + } + } + if (!result && should_allocate(size, is_tlab)) { + result = true; + if (PrintGC && Verbose) { + gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" + " should_allocate(" SIZE_FORMAT ")", + size); + } + } + // If we don't have very much free space. + // XXX: 10000 should be a percentage of the capacity!!! + if (!result && free() < 10000) { + result = true; + if (PrintGC && Verbose) { + gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" + " free(): " SIZE_FORMAT, + free()); + } + } + // If we had to expand to accomodate promotions from younger generations + if (!result && _capacity_at_prologue < capacity()) { + result = true; + if (PrintGC && Verbose) { + gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" + "_capacity_at_prologue: " SIZE_FORMAT " < capacity(): " SIZE_FORMAT, + _capacity_at_prologue, capacity()); + } + } + return result; +} + +void TenuredGeneration::collect(bool full, + bool clear_all_soft_refs, + size_t size, + bool is_tlab) { + retire_alloc_buffers_before_full_gc(); + OneContigSpaceCardGeneration::collect(full, clear_all_soft_refs, + size, is_tlab); +} + +void TenuredGeneration::compute_new_size() { + assert_locked_or_safepoint(Heap_lock); + + // Compute some numbers about the state of the heap. + const size_t used_after_gc = used(); + const size_t capacity_after_gc = capacity(); + + CardGeneration::compute_new_size(); + + assert(used() == used_after_gc && used_after_gc <= capacity(), + err_msg("used: " SIZE_FORMAT " used_after_gc: " SIZE_FORMAT + " capacity: " SIZE_FORMAT, used(), used_after_gc, capacity())); +} +void TenuredGeneration::update_gc_stats(int current_level, + bool full) { + // If the next lower level(s) has been collected, gather any statistics + // that are of interest at this point. + if (!full && (current_level + 1) == level()) { + // Calculate size of data promoted from the younger generations + // before doing the collection. + size_t used_before_gc = used(); + + // If the younger gen collections were skipped, then the + // number of promoted bytes will be 0 and adding it to the + // average will incorrectly lessen the average. It is, however, + // also possible that no promotion was needed. + if (used_before_gc >= _used_at_prologue) { + size_t promoted_in_bytes = used_before_gc - _used_at_prologue; + gc_stats()->avg_promoted()->sample(promoted_in_bytes); + } + } +} + +void TenuredGeneration::update_counters() { + if (UsePerfData) { + _space_counters->update_all(); + _gen_counters->update_all(); + } +} + + +#if INCLUDE_ALL_GCS +oop TenuredGeneration::par_promote(int thread_num, + oop old, markOop m, size_t word_sz) { + + ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num]; + HeapWord* obj_ptr = buf->allocate(word_sz); + bool is_lab = true; + if (obj_ptr == NULL) { +#ifndef PRODUCT + if (Universe::heap()->promotion_should_fail()) { + return NULL; + } +#endif // #ifndef PRODUCT + + // Slow path: + if (word_sz * 100 < ParallelGCBufferWastePct * buf->word_sz()) { + // Is small enough; abandon this buffer and start a new one. + size_t buf_size = buf->word_sz(); + HeapWord* buf_space = + TenuredGeneration::par_allocate(buf_size, false); + if (buf_space == NULL) { + buf_space = expand_and_allocate(buf_size, false, true /* parallel*/); + } + if (buf_space != NULL) { + buf->retire(false, false); + buf->set_buf(buf_space); + obj_ptr = buf->allocate(word_sz); + assert(obj_ptr != NULL, "Buffer was definitely big enough..."); + } + }; + // Otherwise, buffer allocation failed; try allocating object + // individually. + if (obj_ptr == NULL) { + obj_ptr = TenuredGeneration::par_allocate(word_sz, false); + if (obj_ptr == NULL) { + obj_ptr = expand_and_allocate(word_sz, false, true /* parallel */); + } + } + if (obj_ptr == NULL) return NULL; + } + assert(obj_ptr != NULL, "program logic"); + Copy::aligned_disjoint_words((HeapWord*)old, obj_ptr, word_sz); + oop obj = oop(obj_ptr); + // Restore the mark word copied above. + obj->set_mark(m); + return obj; +} + +void TenuredGeneration::par_promote_alloc_undo(int thread_num, + HeapWord* obj, + size_t word_sz) { + ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num]; + if (buf->contains(obj)) { + guarantee(buf->contains(obj + word_sz - 1), + "should contain whole object"); + buf->undo_allocation(obj, word_sz); + } else { + CollectedHeap::fill_with_object(obj, word_sz); + } +} + +void TenuredGeneration::par_promote_alloc_done(int thread_num) { + ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num]; + buf->retire(true, ParallelGCRetainPLAB); +} + +void TenuredGeneration::retire_alloc_buffers_before_full_gc() { + if (UseParNewGC) { + for (uint i = 0; i < ParallelGCThreads; i++) { + _alloc_buffers[i]->retire(true /*end_of_gc*/, false /*retain*/); + } + } +} + +// Verify that any retained parallel allocation buffers do not +// intersect with dirty cards. +void TenuredGeneration::verify_alloc_buffers_clean() { + if (UseParNewGC) { + for (uint i = 0; i < ParallelGCThreads; i++) { + _rs->verify_aligned_region_empty(_alloc_buffers[i]->range()); + } + } +} + +#else // INCLUDE_ALL_GCS +void TenuredGeneration::retire_alloc_buffers_before_full_gc() {} +void TenuredGeneration::verify_alloc_buffers_clean() {} +#endif // INCLUDE_ALL_GCS + +bool TenuredGeneration::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const { + size_t available = max_contiguous_available(); + size_t av_promo = (size_t)gc_stats()->avg_promoted()->padded_average(); + bool res = (available >= av_promo) || (available >= max_promotion_in_bytes); + if (PrintGC && Verbose) { + gclog_or_tty->print_cr( + "Tenured: promo attempt is%s safe: available("SIZE_FORMAT") %s av_promo("SIZE_FORMAT")," + "max_promo("SIZE_FORMAT")", + res? "":" not", available, res? ">=":"<", + av_promo, max_promotion_in_bytes); + } + return res; +}