| /* |
| * 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/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" |
| |
| TenuredGeneration::TenuredGeneration(ReservedSpace rs, |
| size_t initial_byte_size, int level, |
| GenRemSet* remset) : |
| OneContigSpaceCardGeneration(rs, initial_byte_size, |
| MinHeapDeltaBytes, 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); |
| #ifndef SERIALGC |
| if (UseParNewGC && ParallelGCThreads > 0) { |
| 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 // SERIALGC |
| } |
| |
| |
| const char* TenuredGeneration::name() const { |
| return "tenured generation"; |
| } |
| |
| void TenuredGeneration::compute_new_size() { |
| assert(_shrink_factor <= 100, "invalid shrink factor"); |
| size_t current_shrink_factor = _shrink_factor; |
| _shrink_factor = 0; |
| |
| // We don't have floating point command-line arguments |
| // Note: argument processing ensures that MinHeapFreeRatio < 100. |
| const double minimum_free_percentage = MinHeapFreeRatio / 100.0; |
| const double maximum_used_percentage = 1.0 - minimum_free_percentage; |
| |
| // Compute some numbers about the state of the heap. |
| const size_t used_after_gc = used(); |
| const size_t capacity_after_gc = capacity(); |
| |
| const double min_tmp = used_after_gc / maximum_used_percentage; |
| size_t minimum_desired_capacity = (size_t)MIN2(min_tmp, double(max_uintx)); |
| // Don't shrink less than the initial generation size |
| minimum_desired_capacity = MAX2(minimum_desired_capacity, |
| spec()->init_size()); |
| assert(used_after_gc <= minimum_desired_capacity, "sanity check"); |
| |
| if (PrintGC && Verbose) { |
| const size_t free_after_gc = free(); |
| const double free_percentage = ((double)free_after_gc) / capacity_after_gc; |
| gclog_or_tty->print_cr("TenuredGeneration::compute_new_size: "); |
| gclog_or_tty->print_cr(" " |
| " minimum_free_percentage: %6.2f" |
| " maximum_used_percentage: %6.2f", |
| minimum_free_percentage, |
| maximum_used_percentage); |
| gclog_or_tty->print_cr(" " |
| " free_after_gc : %6.1fK" |
| " used_after_gc : %6.1fK" |
| " capacity_after_gc : %6.1fK", |
| free_after_gc / (double) K, |
| used_after_gc / (double) K, |
| capacity_after_gc / (double) K); |
| gclog_or_tty->print_cr(" " |
| " free_percentage: %6.2f", |
| free_percentage); |
| } |
| |
| if (capacity_after_gc < minimum_desired_capacity) { |
| // If we have less free space than we want then expand |
| size_t expand_bytes = minimum_desired_capacity - capacity_after_gc; |
| // Don't expand unless it's significant |
| if (expand_bytes >= _min_heap_delta_bytes) { |
| expand(expand_bytes, 0); // safe if expansion fails |
| } |
| if (PrintGC && Verbose) { |
| gclog_or_tty->print_cr(" expanding:" |
| " minimum_desired_capacity: %6.1fK" |
| " expand_bytes: %6.1fK" |
| " _min_heap_delta_bytes: %6.1fK", |
| minimum_desired_capacity / (double) K, |
| expand_bytes / (double) K, |
| _min_heap_delta_bytes / (double) K); |
| } |
| return; |
| } |
| |
| // No expansion, now see if we want to shrink |
| size_t shrink_bytes = 0; |
| // We would never want to shrink more than this |
| size_t max_shrink_bytes = capacity_after_gc - minimum_desired_capacity; |
| |
| if (MaxHeapFreeRatio < 100) { |
| const double maximum_free_percentage = MaxHeapFreeRatio / 100.0; |
| const double minimum_used_percentage = 1.0 - maximum_free_percentage; |
| const double max_tmp = used_after_gc / minimum_used_percentage; |
| size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(max_uintx)); |
| maximum_desired_capacity = MAX2(maximum_desired_capacity, |
| spec()->init_size()); |
| if (PrintGC && Verbose) { |
| gclog_or_tty->print_cr(" " |
| " maximum_free_percentage: %6.2f" |
| " minimum_used_percentage: %6.2f", |
| maximum_free_percentage, |
| minimum_used_percentage); |
| gclog_or_tty->print_cr(" " |
| " _capacity_at_prologue: %6.1fK" |
| " minimum_desired_capacity: %6.1fK" |
| " maximum_desired_capacity: %6.1fK", |
| _capacity_at_prologue / (double) K, |
| minimum_desired_capacity / (double) K, |
| maximum_desired_capacity / (double) K); |
| } |
| assert(minimum_desired_capacity <= maximum_desired_capacity, |
| "sanity check"); |
| |
| if (capacity_after_gc > maximum_desired_capacity) { |
| // Capacity too large, compute shrinking size |
| shrink_bytes = capacity_after_gc - maximum_desired_capacity; |
| // We don't want shrink all the way back to initSize if people call |
| // System.gc(), because some programs do that between "phases" and then |
| // we'd just have to grow the heap up again for the next phase. So we |
| // damp the shrinking: 0% on the first call, 10% on the second call, 40% |
| // on the third call, and 100% by the fourth call. But if we recompute |
| // size without shrinking, it goes back to 0%. |
| shrink_bytes = shrink_bytes / 100 * current_shrink_factor; |
| assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size"); |
| if (current_shrink_factor == 0) { |
| _shrink_factor = 10; |
| } else { |
| _shrink_factor = MIN2(current_shrink_factor * 4, (size_t) 100); |
| } |
| if (PrintGC && Verbose) { |
| gclog_or_tty->print_cr(" " |
| " shrinking:" |
| " initSize: %.1fK" |
| " maximum_desired_capacity: %.1fK", |
| spec()->init_size() / (double) K, |
| maximum_desired_capacity / (double) K); |
| gclog_or_tty->print_cr(" " |
| " shrink_bytes: %.1fK" |
| " current_shrink_factor: %d" |
| " new shrink factor: %d" |
| " _min_heap_delta_bytes: %.1fK", |
| shrink_bytes / (double) K, |
| current_shrink_factor, |
| _shrink_factor, |
| _min_heap_delta_bytes / (double) K); |
| } |
| } |
| } |
| |
| if (capacity_after_gc > _capacity_at_prologue) { |
| // We might have expanded for promotions, in which case we might want to |
| // take back that expansion if there's room after GC. That keeps us from |
| // stretching the heap with promotions when there's plenty of room. |
| size_t expansion_for_promotion = capacity_after_gc - _capacity_at_prologue; |
| expansion_for_promotion = MIN2(expansion_for_promotion, max_shrink_bytes); |
| // We have two shrinking computations, take the largest |
| shrink_bytes = MAX2(shrink_bytes, expansion_for_promotion); |
| assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size"); |
| if (PrintGC && Verbose) { |
| gclog_or_tty->print_cr(" " |
| " aggressive shrinking:" |
| " _capacity_at_prologue: %.1fK" |
| " capacity_after_gc: %.1fK" |
| " expansion_for_promotion: %.1fK" |
| " shrink_bytes: %.1fK", |
| capacity_after_gc / (double) K, |
| _capacity_at_prologue / (double) K, |
| expansion_for_promotion / (double) K, |
| shrink_bytes / (double) K); |
| } |
| } |
| // Don't shrink unless it's significant |
| if (shrink_bytes >= _min_heap_delta_bytes) { |
| shrink(shrink_bytes); |
| } |
| assert(used() == used_after_gc && used_after_gc <= capacity(), |
| "sanity check"); |
| } |
| |
| 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::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(); |
| } |
| } |
| |
| |
| #ifndef SERIALGC |
| 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 // SERIALGC |
| void TenuredGeneration::retire_alloc_buffers_before_full_gc() {} |
| void TenuredGeneration::verify_alloc_buffers_clean() {} |
| #endif // SERIALGC |
| |
| 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; |
| } |
