diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/gc/serial/tenuredGeneration.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/hotspot/share/gc/serial/tenuredGeneration.cpp Tue Sep 12 19:03:39 2017 +0200 @@ -0,0 +1,293 @@ +/* + * Copyright (c) 2001, 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/serial/genMarkSweep.hpp" +#include "gc/serial/tenuredGeneration.inline.hpp" +#include "gc/shared/blockOffsetTable.inline.hpp" +#include "gc/shared/cardGeneration.inline.hpp" +#include "gc/shared/collectorCounters.hpp" +#include "gc/shared/gcTimer.hpp" +#include "gc/shared/gcTrace.hpp" +#include "gc/shared/genOopClosures.inline.hpp" +#include "gc/shared/generationSpec.hpp" +#include "gc/shared/space.hpp" +#include "logging/log.hpp" +#include "memory/allocation.inline.hpp" +#include "oops/oop.inline.hpp" +#include "runtime/java.hpp" +#include "utilities/macros.hpp" +#if INCLUDE_ALL_GCS +#include "gc/cms/parOopClosures.hpp" +#endif + +TenuredGeneration::TenuredGeneration(ReservedSpace rs, + size_t initial_byte_size, + CardTableRS* remset) : + CardGeneration(rs, initial_byte_size, remset) +{ + 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"; + GenCollectorPolicy* gcp = GenCollectedHeap::heap()->gen_policy(); + // Generation Counters -- generation 1, 1 subspace + _gen_counters = new GenerationCounters(gen_name, 1, 1, + gcp->min_old_size(), gcp->max_old_size(), &_virtual_space); + + _gc_counters = new CollectorCounters("MSC", 1); + + _space_counters = new CSpaceCounters(gen_name, 0, + _virtual_space.reserved_size(), + _the_space, _gen_counters); +} + +void TenuredGeneration::gc_prologue(bool full) { + _capacity_at_prologue = capacity(); + _used_at_prologue = used(); +} + +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. + if (full) { + log_trace(gc)("TenuredGeneration::should_collect: because full"); + return true; + } + if (should_allocate(size, is_tlab)) { + log_trace(gc)("TenuredGeneration::should_collect: because should_allocate(" SIZE_FORMAT ")", size); + return true; + } + // If we don't have very much free space. + // XXX: 10000 should be a percentage of the capacity!!! + if (free() < 10000) { + log_trace(gc)("TenuredGeneration::should_collect: because free(): " SIZE_FORMAT, free()); + return true; + } + // If we had to expand to accommodate promotions from the young generation + if (_capacity_at_prologue < capacity()) { + log_trace(gc)("TenuredGeneration::should_collect: because_capacity_at_prologue: " SIZE_FORMAT " < capacity(): " SIZE_FORMAT, + _capacity_at_prologue, capacity()); + return true; + } + + return false; +} + +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(), + "used: " SIZE_FORMAT " used_after_gc: " SIZE_FORMAT + " capacity: " SIZE_FORMAT, used(), used_after_gc, capacity()); +} + +void TenuredGeneration::update_gc_stats(Generation* current_generation, + bool full) { + // If the young generation has been collected, gather any statistics + // that are of interest at this point. + bool current_is_young = GenCollectedHeap::heap()->is_young_gen(current_generation); + if (!full && current_is_young) { + // Calculate size of data promoted from the young generation + // before doing the collection. + size_t used_before_gc = used(); + + // If the young gen collection was 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(); + } +} + +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); + + log_trace(gc)("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; +} + +void TenuredGeneration::collect(bool full, + bool clear_all_soft_refs, + size_t size, + bool is_tlab) { + GenCollectedHeap* gch = GenCollectedHeap::heap(); + + // Temporarily expand the span of our ref processor, so + // refs discovery is over the entire heap, not just this generation + ReferenceProcessorSpanMutator + x(ref_processor(), gch->reserved_region()); + + STWGCTimer* gc_timer = GenMarkSweep::gc_timer(); + gc_timer->register_gc_start(); + + SerialOldTracer* gc_tracer = GenMarkSweep::gc_tracer(); + gc_tracer->report_gc_start(gch->gc_cause(), gc_timer->gc_start()); + + gch->pre_full_gc_dump(gc_timer); + + GenMarkSweep::invoke_at_safepoint(ref_processor(), clear_all_soft_refs); + + gch->post_full_gc_dump(gc_timer); + + gc_timer->register_gc_end(); + + gc_tracer->report_gc_end(gc_timer->gc_end(), gc_timer->time_partitions()); +} + +HeapWord* +TenuredGeneration::expand_and_allocate(size_t word_size, + bool is_tlab, + bool parallel) { + assert(!is_tlab, "TenuredGeneration does not support TLAB allocation"); + if (parallel) { + MutexLocker x(ParGCRareEvent_lock); + HeapWord* result = NULL; + size_t byte_size = word_size * HeapWordSize; + while (true) { + expand(byte_size, _min_heap_delta_bytes); + if (GCExpandToAllocateDelayMillis > 0) { + os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false); + } + result = _the_space->par_allocate(word_size); + if ( result != NULL) { + return result; + } else { + // If there's not enough expansion space available, give up. + if (_virtual_space.uncommitted_size() < byte_size) { + return NULL; + } + // else try again + } + } + } else { + expand(word_size*HeapWordSize, _min_heap_delta_bytes); + return _the_space->allocate(word_size); + } +} + +bool TenuredGeneration::expand(size_t bytes, size_t expand_bytes) { + GCMutexLocker x(ExpandHeap_lock); + return CardGeneration::expand(bytes, expand_bytes); +} + +size_t TenuredGeneration::unsafe_max_alloc_nogc() const { + return _the_space->free(); +} + +size_t TenuredGeneration::contiguous_available() const { + return _the_space->free() + _virtual_space.uncommitted_size(); +} + +void TenuredGeneration::assert_correct_size_change_locking() { + assert_locked_or_safepoint(ExpandHeap_lock); +} + +// Currently nothing to do. +void TenuredGeneration::prepare_for_verify() {} + +void TenuredGeneration::object_iterate(ObjectClosure* blk) { + _the_space->object_iterate(blk); +} + +void TenuredGeneration::save_marks() { + _the_space->set_saved_mark(); +} + +void TenuredGeneration::reset_saved_marks() { + _the_space->reset_saved_mark(); +} + +bool TenuredGeneration::no_allocs_since_save_marks() { + return _the_space->saved_mark_at_top(); +} + +#define TenuredGen_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ + \ +void TenuredGeneration:: \ +oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \ + blk->set_generation(this); \ + _the_space->oop_since_save_marks_iterate##nv_suffix(blk); \ + blk->reset_generation(); \ + save_marks(); \ +} + +ALL_SINCE_SAVE_MARKS_CLOSURES(TenuredGen_SINCE_SAVE_MARKS_ITERATE_DEFN) + +#undef TenuredGen_SINCE_SAVE_MARKS_ITERATE_DEFN + +void TenuredGeneration::gc_epilogue(bool full) { + // update the generation and space performance counters + update_counters(); + if (ZapUnusedHeapArea) { + _the_space->check_mangled_unused_area_complete(); + } +} + +void TenuredGeneration::record_spaces_top() { + assert(ZapUnusedHeapArea, "Not mangling unused space"); + _the_space->set_top_for_allocations(); +} + +void TenuredGeneration::verify() { + _the_space->verify(); +} + +void TenuredGeneration::print_on(outputStream* st) const { + Generation::print_on(st); + st->print(" the"); + _the_space->print_on(st); +}