Mercurial > hg > truffle
view src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp @ 20543:e7d0505c8a30
8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso
author | tschatzl |
---|---|
date | Fri, 10 Oct 2014 15:51:58 +0200 |
parents | 1f1d373cd044 |
children | 7848fc12602b |
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/* * 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/g1/g1CollectedHeap.inline.hpp" #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp" #include "gc_implementation/g1/heapRegion.hpp" #include "gc_implementation/g1/satbQueue.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/orderAccess.inline.hpp" #include "runtime/thread.inline.hpp" G1SATBCardTableModRefBS::G1SATBCardTableModRefBS(MemRegion whole_heap, int max_covered_regions) : CardTableModRefBSForCTRS(whole_heap, max_covered_regions) { _kind = G1SATBCT; } void G1SATBCardTableModRefBS::enqueue(oop pre_val) { // Nulls should have been already filtered. assert(pre_val->is_oop(true), "Error"); if (!JavaThread::satb_mark_queue_set().is_active()) return; Thread* thr = Thread::current(); if (thr->is_Java_thread()) { JavaThread* jt = (JavaThread*)thr; jt->satb_mark_queue().enqueue(pre_val); } else { MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag); JavaThread::satb_mark_queue_set().shared_satb_queue()->enqueue(pre_val); } } template <class T> void G1SATBCardTableModRefBS::write_ref_array_pre_work(T* dst, int count) { if (!JavaThread::satb_mark_queue_set().is_active()) return; T* elem_ptr = dst; for (int i = 0; i < count; i++, elem_ptr++) { T heap_oop = oopDesc::load_heap_oop(elem_ptr); if (!oopDesc::is_null(heap_oop)) { enqueue(oopDesc::decode_heap_oop_not_null(heap_oop)); } } } void G1SATBCardTableModRefBS::write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) { if (!dest_uninitialized) { write_ref_array_pre_work(dst, count); } } void G1SATBCardTableModRefBS::write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) { if (!dest_uninitialized) { write_ref_array_pre_work(dst, count); } } bool G1SATBCardTableModRefBS::mark_card_deferred(size_t card_index) { jbyte val = _byte_map[card_index]; // It's already processed if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) { return false; } if (val == g1_young_gen) { // the card is for a young gen region. We don't need to keep track of all pointers into young return false; } // Cached bit can be installed either on a clean card or on a claimed card. jbyte new_val = val; if (val == clean_card_val()) { new_val = (jbyte)deferred_card_val(); } else { if (val & claimed_card_val()) { new_val = val | (jbyte)deferred_card_val(); } } if (new_val != val) { Atomic::cmpxchg(new_val, &_byte_map[card_index], val); } return true; } void G1SATBCardTableModRefBS::g1_mark_as_young(const MemRegion& mr) { jbyte *const first = byte_for(mr.start()); jbyte *const last = byte_after(mr.last()); // Below we may use an explicit loop instead of memset() because on // certain platforms memset() can give concurrent readers phantom zeros. if (UseMemSetInBOT) { memset(first, g1_young_gen, last - first); } else { for (jbyte* i = first; i < last; i++) { *i = g1_young_gen; } } } #ifndef PRODUCT void G1SATBCardTableModRefBS::verify_g1_young_region(MemRegion mr) { verify_region(mr, g1_young_gen, true); } #endif void G1SATBCardTableLoggingModRefBSChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) { // Default value for a clean card on the card table is -1. So we cannot take advantage of the zero_filled parameter. MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords); _card_table->clear(mr); } G1SATBCardTableLoggingModRefBS:: G1SATBCardTableLoggingModRefBS(MemRegion whole_heap, int max_covered_regions) : G1SATBCardTableModRefBS(whole_heap, max_covered_regions), _dcqs(JavaThread::dirty_card_queue_set()), _listener() { _kind = G1SATBCTLogging; _listener.set_card_table(this); } void G1SATBCardTableLoggingModRefBS::initialize(G1RegionToSpaceMapper* mapper) { mapper->set_mapping_changed_listener(&_listener); _byte_map_size = mapper->reserved().byte_size(); _guard_index = cards_required(_whole_heap.word_size()) - 1; _last_valid_index = _guard_index - 1; HeapWord* low_bound = _whole_heap.start(); HeapWord* high_bound = _whole_heap.end(); _cur_covered_regions = 1; _covered[0] = _whole_heap; _byte_map = (jbyte*) mapper->reserved().start(); byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift); assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map"); assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map"); if (TraceCardTableModRefBS) { gclog_or_tty->print_cr("G1SATBCardTableModRefBS::G1SATBCardTableModRefBS: "); gclog_or_tty->print_cr(" " " &_byte_map[0]: " INTPTR_FORMAT " &_byte_map[_last_valid_index]: " INTPTR_FORMAT, p2i(&_byte_map[0]), p2i(&_byte_map[_last_valid_index])); gclog_or_tty->print_cr(" " " byte_map_base: " INTPTR_FORMAT, p2i(byte_map_base)); } } void G1SATBCardTableLoggingModRefBS::write_ref_field_work(void* field, oop new_val, bool release) { volatile jbyte* byte = byte_for(field); if (*byte == g1_young_gen) { return; } OrderAccess::storeload(); if (*byte != dirty_card) { *byte = dirty_card; Thread* thr = Thread::current(); if (thr->is_Java_thread()) { JavaThread* jt = (JavaThread*)thr; jt->dirty_card_queue().enqueue(byte); } else { MutexLockerEx x(Shared_DirtyCardQ_lock, Mutex::_no_safepoint_check_flag); _dcqs.shared_dirty_card_queue()->enqueue(byte); } } } void G1SATBCardTableLoggingModRefBS::write_ref_field_static(void* field, oop new_val) { uintptr_t field_uint = (uintptr_t)field; uintptr_t new_val_uint = cast_from_oop<uintptr_t>(new_val); uintptr_t comb = field_uint ^ new_val_uint; comb = comb >> HeapRegion::LogOfHRGrainBytes; if (comb == 0) return; if (new_val == NULL) return; // Otherwise, log it. G1SATBCardTableLoggingModRefBS* g1_bs = (G1SATBCardTableLoggingModRefBS*)Universe::heap()->barrier_set(); g1_bs->write_ref_field_work(field, new_val); } void G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr, bool whole_heap) { volatile jbyte* byte = byte_for(mr.start()); jbyte* last_byte = byte_for(mr.last()); Thread* thr = Thread::current(); if (whole_heap) { while (byte <= last_byte) { *byte = dirty_card; byte++; } } else { // skip all consecutive young cards for (; byte <= last_byte && *byte == g1_young_gen; byte++); if (byte <= last_byte) { OrderAccess::storeload(); // Enqueue if necessary. if (thr->is_Java_thread()) { JavaThread* jt = (JavaThread*)thr; for (; byte <= last_byte; byte++) { if (*byte == g1_young_gen) { continue; } if (*byte != dirty_card) { *byte = dirty_card; jt->dirty_card_queue().enqueue(byte); } } } else { MutexLockerEx x(Shared_DirtyCardQ_lock, Mutex::_no_safepoint_check_flag); for (; byte <= last_byte; byte++) { if (*byte == g1_young_gen) { continue; } if (*byte != dirty_card) { *byte = dirty_card; _dcqs.shared_dirty_card_queue()->enqueue(byte); } } } } } }