Mercurial > hg > graal-jvmci-8
view src/share/vm/gc_implementation/g1/collectionSetChooser.cpp @ 5986:500023bd0818
7143511: G1: Another instance of high GC Worker Other time (50ms)
Summary: Tiered compilation has increased the number of nmethods in the code cache. This has, in turn, significantly increased the number of marked nmethods processed during the StrongRootsScope destructor. Create a specialized version of CodeBlobToOopClosure for G1 which places only those nmethods that contain pointers into the collection set on to the marked nmethods list.
Reviewed-by: iveresov, tonyp
author | johnc |
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date | Tue, 13 Mar 2012 11:05:32 -0700 |
parents | 21595f05bc93 |
children | 720b6a76dd9d |
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/* * 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/g1/collectionSetChooser.hpp" #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" #include "gc_implementation/g1/g1CollectorPolicy.hpp" #include "gc_implementation/g1/g1ErgoVerbose.hpp" #include "memory/space.inline.hpp" CSetChooserCache::CSetChooserCache() { for (int i = 0; i < CacheLength; ++i) _cache[i] = NULL; clear(); } void CSetChooserCache::clear() { _occupancy = 0; _first = 0; for (int i = 0; i < CacheLength; ++i) { HeapRegion *hr = _cache[i]; if (hr != NULL) hr->set_sort_index(-1); _cache[i] = NULL; } } #ifndef PRODUCT bool CSetChooserCache::verify() { guarantee(false, "CSetChooserCache::verify(): don't call this any more"); int index = _first; HeapRegion *prev = NULL; for (int i = 0; i < _occupancy; ++i) { guarantee(_cache[index] != NULL, "cache entry should not be empty"); HeapRegion *hr = _cache[index]; guarantee(!hr->is_young(), "should not be young!"); if (prev != NULL) { guarantee(prev->gc_efficiency() >= hr->gc_efficiency(), "cache should be correctly ordered"); } guarantee(hr->sort_index() == get_sort_index(index), "sort index should be correct"); index = trim_index(index + 1); prev = hr; } for (int i = 0; i < (CacheLength - _occupancy); ++i) { guarantee(_cache[index] == NULL, "cache entry should be empty"); index = trim_index(index + 1); } guarantee(index == _first, "we should have reached where we started from"); return true; } #endif // PRODUCT void CSetChooserCache::insert(HeapRegion *hr) { guarantee(false, "CSetChooserCache::insert(): don't call this any more"); assert(!is_full(), "cache should not be empty"); hr->calc_gc_efficiency(); int empty_index; if (_occupancy == 0) { empty_index = _first; } else { empty_index = trim_index(_first + _occupancy); assert(_cache[empty_index] == NULL, "last slot should be empty"); int last_index = trim_index(empty_index - 1); HeapRegion *last = _cache[last_index]; assert(last != NULL,"as the cache is not empty, last should not be empty"); while (empty_index != _first && last->gc_efficiency() < hr->gc_efficiency()) { _cache[empty_index] = last; last->set_sort_index(get_sort_index(empty_index)); empty_index = last_index; last_index = trim_index(last_index - 1); last = _cache[last_index]; } } _cache[empty_index] = hr; hr->set_sort_index(get_sort_index(empty_index)); ++_occupancy; assert(verify(), "cache should be consistent"); } HeapRegion *CSetChooserCache::remove_first() { guarantee(false, "CSetChooserCache::remove_first(): " "don't call this any more"); if (_occupancy > 0) { assert(_cache[_first] != NULL, "cache should have at least one region"); HeapRegion *ret = _cache[_first]; _cache[_first] = NULL; ret->set_sort_index(-1); --_occupancy; _first = trim_index(_first + 1); assert(verify(), "cache should be consistent"); return ret; } else { return NULL; } } // Even though we don't use the GC efficiency in our heuristics as // much as we used to, we still order according to GC efficiency. This // will cause regions with a lot of live objects and large RSets to // end up at the end of the array. Given that we might skip collecting // the last few old regions, if after a few mixed GCs the remaining // have reclaimable bytes under a certain threshold, the hope is that // the ones we'll skip are ones with both large RSets and a lot of // live objects, not the ones with just a lot of live objects if we // ordered according to the amount of reclaimable bytes per region. static int orderRegions(HeapRegion* hr1, HeapRegion* hr2) { if (hr1 == NULL) { if (hr2 == NULL) { return 0; } else { return 1; } } else if (hr2 == NULL) { return -1; } double gc_eff1 = hr1->gc_efficiency(); double gc_eff2 = hr2->gc_efficiency(); if (gc_eff1 > gc_eff2) { return -1; } if (gc_eff1 < gc_eff2) { return 1; } else { return 0; } } static int orderRegions(HeapRegion** hr1p, HeapRegion** hr2p) { return orderRegions(*hr1p, *hr2p); } CollectionSetChooser::CollectionSetChooser() : // The line below is the worst bit of C++ hackery I've ever written // (Detlefs, 11/23). You should think of it as equivalent to // "_regions(100, true)": initialize the growable array and inform it // that it should allocate its elem array(s) on the C heap. // // The first argument, however, is actually a comma expression // (set_allocation_type(this, C_HEAP), 100). The purpose of the // set_allocation_type() call is to replace the default allocation // type for embedded objects STACK_OR_EMBEDDED with C_HEAP. It will // allow to pass the assert in GenericGrowableArray() which checks // that a growable array object must be on C heap if elements are. // // Note: containing object is allocated on C heap since it is CHeapObj. // _markedRegions((ResourceObj::set_allocation_type((address)&_markedRegions, ResourceObj::C_HEAP), 100), true /* C_Heap */), _curr_index(0), _length(0), _regionLiveThresholdBytes(0), _remainingReclaimableBytes(0), _first_par_unreserved_idx(0) { _regionLiveThresholdBytes = HeapRegion::GrainBytes * (size_t) G1OldCSetRegionLiveThresholdPercent / 100; } #ifndef PRODUCT bool CollectionSetChooser::verify() { guarantee(_length >= 0, err_msg("_length: %d", _length)); guarantee(0 <= _curr_index && _curr_index <= _length, err_msg("_curr_index: %d _length: %d", _curr_index, _length)); int index = 0; size_t sum_of_reclaimable_bytes = 0; while (index < _curr_index) { guarantee(_markedRegions.at(index) == NULL, "all entries before _curr_index should be NULL"); index += 1; } HeapRegion *prev = NULL; while (index < _length) { HeapRegion *curr = _markedRegions.at(index++); guarantee(curr != NULL, "Regions in _markedRegions array cannot be NULL"); int si = curr->sort_index(); guarantee(!curr->is_young(), "should not be young!"); guarantee(!curr->isHumongous(), "should not be humongous!"); guarantee(si > -1 && si == (index-1), "sort index invariant"); if (prev != NULL) { guarantee(orderRegions(prev, curr) != 1, err_msg("GC eff prev: %1.4f GC eff curr: %1.4f", prev->gc_efficiency(), curr->gc_efficiency())); } sum_of_reclaimable_bytes += curr->reclaimable_bytes(); prev = curr; } guarantee(sum_of_reclaimable_bytes == _remainingReclaimableBytes, err_msg("reclaimable bytes inconsistent, " "remaining: "SIZE_FORMAT" sum: "SIZE_FORMAT, _remainingReclaimableBytes, sum_of_reclaimable_bytes)); return true; } #endif void CollectionSetChooser::fillCache() { guarantee(false, "fillCache: don't call this any more"); while (!_cache.is_full() && (_curr_index < _length)) { HeapRegion* hr = _markedRegions.at(_curr_index); assert(hr != NULL, err_msg("Unexpected NULL hr in _markedRegions at index %d", _curr_index)); _curr_index += 1; assert(!hr->is_young(), "should not be young!"); assert(hr->sort_index() == _curr_index-1, "sort_index invariant"); _markedRegions.at_put(hr->sort_index(), NULL); _cache.insert(hr); assert(!_cache.is_empty(), "cache should not be empty"); } assert(verify(), "cache should be consistent"); } void CollectionSetChooser::sortMarkedHeapRegions() { // First trim any unused portion of the top in the parallel case. if (_first_par_unreserved_idx > 0) { if (G1PrintParCleanupStats) { gclog_or_tty->print(" Truncating _markedRegions from %d to %d.\n", _markedRegions.length(), _first_par_unreserved_idx); } assert(_first_par_unreserved_idx <= _markedRegions.length(), "Or we didn't reserved enough length"); _markedRegions.trunc_to(_first_par_unreserved_idx); } _markedRegions.sort(orderRegions); assert(_length <= _markedRegions.length(), "Requirement"); assert(_length == 0 || _markedRegions.at(_length - 1) != NULL, "Testing _length"); assert(_length == _markedRegions.length() || _markedRegions.at(_length) == NULL, "Testing _length"); if (G1PrintParCleanupStats) { gclog_or_tty->print_cr(" Sorted %d marked regions.", _length); } for (int i = 0; i < _length; i++) { assert(_markedRegions.at(i) != NULL, "Should be true by sorting!"); _markedRegions.at(i)->set_sort_index(i); } if (G1PrintRegionLivenessInfo) { G1PrintRegionLivenessInfoClosure cl(gclog_or_tty, "Post-Sorting"); for (int i = 0; i < _length; ++i) { HeapRegion* r = _markedRegions.at(i); cl.doHeapRegion(r); } } assert(verify(), "CSet chooser verification"); } size_t CollectionSetChooser::calcMinOldCSetLength() { // The min old CSet region bound is based on the maximum desired // number of mixed GCs after a cycle. I.e., even if some old regions // look expensive, we should add them to the CSet anyway to make // sure we go through the available old regions in no more than the // maximum desired number of mixed GCs. // // The calculation is based on the number of marked regions we added // to the CSet chooser in the first place, not how many remain, so // that the result is the same during all mixed GCs that follow a cycle. const size_t region_num = (size_t) _length; const size_t gc_num = (size_t) G1MixedGCCountTarget; size_t result = region_num / gc_num; // emulate ceiling if (result * gc_num < region_num) { result += 1; } return result; } size_t CollectionSetChooser::calcMaxOldCSetLength() { // The max old CSet region bound is based on the threshold expressed // as a percentage of the heap size. I.e., it should bound the // number of old regions added to the CSet irrespective of how many // of them are available. G1CollectedHeap* g1h = G1CollectedHeap::heap(); const size_t region_num = g1h->n_regions(); const size_t perc = (size_t) G1OldCSetRegionThresholdPercent; size_t result = region_num * perc / 100; // emulate ceiling if (100 * result < region_num * perc) { result += 1; } return result; } void CollectionSetChooser::addMarkedHeapRegion(HeapRegion* hr) { assert(!hr->isHumongous(), "Humongous regions shouldn't be added to the collection set"); assert(!hr->is_young(), "should not be young!"); _markedRegions.append(hr); _length++; _remainingReclaimableBytes += hr->reclaimable_bytes(); hr->calc_gc_efficiency(); } void CollectionSetChooser::prepareForAddMarkedHeapRegionsPar(size_t n_regions, size_t chunkSize) { _first_par_unreserved_idx = 0; int n_threads = ParallelGCThreads; if (UseDynamicNumberOfGCThreads) { assert(G1CollectedHeap::heap()->workers()->active_workers() > 0, "Should have been set earlier"); // This is defensive code. As the assertion above says, the number // of active threads should be > 0, but in case there is some path // or some improperly initialized variable with leads to no // active threads, protect against that in a product build. n_threads = MAX2(G1CollectedHeap::heap()->workers()->active_workers(), 1U); } size_t max_waste = n_threads * chunkSize; // it should be aligned with respect to chunkSize size_t aligned_n_regions = (n_regions + (chunkSize - 1)) / chunkSize * chunkSize; assert( aligned_n_regions % chunkSize == 0, "should be aligned" ); _markedRegions.at_put_grow((int)(aligned_n_regions + max_waste - 1), NULL); } jint CollectionSetChooser::getParMarkedHeapRegionChunk(jint n_regions) { // Don't do this assert because this can be called at a point // where the loop up stream will not execute again but might // try to claim more chunks (loop test has not been done yet). // assert(_markedRegions.length() > _first_par_unreserved_idx, // "Striding beyond the marked regions"); jint res = Atomic::add(n_regions, &_first_par_unreserved_idx); assert(_markedRegions.length() > res + n_regions - 1, "Should already have been expanded"); return res - n_regions; } void CollectionSetChooser::setMarkedHeapRegion(jint index, HeapRegion* hr) { assert(_markedRegions.at(index) == NULL, "precondition"); assert(!hr->is_young(), "should not be young!"); _markedRegions.at_put(index, hr); hr->calc_gc_efficiency(); } void CollectionSetChooser::updateTotals(jint region_num, size_t reclaimable_bytes) { // Only take the lock if we actually need to update the totals. if (region_num > 0) { assert(reclaimable_bytes > 0, "invariant"); // We could have just used atomics instead of taking the // lock. However, we currently don't have an atomic add for size_t. MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); _length += (int) region_num; _remainingReclaimableBytes += reclaimable_bytes; } else { assert(reclaimable_bytes == 0, "invariant"); } } void CollectionSetChooser::clearMarkedHeapRegions() { for (int i = 0; i < _markedRegions.length(); i++) { HeapRegion* r = _markedRegions.at(i); if (r != NULL) { r->set_sort_index(-1); } } _markedRegions.clear(); _curr_index = 0; _length = 0; _remainingReclaimableBytes = 0; };