Mercurial > hg > graal-compiler
view src/share/vm/gc_implementation/g1/heapRegionSeq.cpp @ 20295:3f2894c5052e
8048112: G1 Full GC needs to support the case when the very first region is not available
Summary: Refactor preparation for compaction during Full GC so that it lazily initializes the first compaction point. This also avoids problems later when the first region may not be committed. Also reviewed by K. Barrett.
Reviewed-by: brutisso
author | tschatzl |
---|---|
date | Mon, 21 Jul 2014 10:00:31 +0200 |
parents | 78bbf4d43a14 |
children | 52b4284cb496 eec72fa4b108 |
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/* * Copyright (c) 2001, 2014, 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/heapRegion.hpp" #include "gc_implementation/g1/heapRegionSeq.inline.hpp" #include "gc_implementation/g1/heapRegionSet.hpp" #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" #include "memory/allocation.hpp" // Private uint HeapRegionSeq::find_contiguous_from(uint from, uint num) { uint len = length(); assert(num > 1, "use this only for sequences of length 2 or greater"); assert(from <= len, err_msg("from: %u should be valid and <= than %u", from, len)); uint curr = from; uint first = G1_NULL_HRS_INDEX; uint num_so_far = 0; while (curr < len && num_so_far < num) { if (at(curr)->is_empty()) { if (first == G1_NULL_HRS_INDEX) { first = curr; num_so_far = 1; } else { num_so_far += 1; } } else { first = G1_NULL_HRS_INDEX; num_so_far = 0; } curr += 1; } assert(num_so_far <= num, "post-condition"); if (num_so_far == num) { // we found enough space for the humongous object assert(from <= first && first < len, "post-condition"); assert(first < curr && (curr - first) == num, "post-condition"); for (uint i = first; i < first + num; ++i) { assert(at(i)->is_empty(), "post-condition"); } return first; } else { // we failed to find enough space for the humongous object return G1_NULL_HRS_INDEX; } } // Public void HeapRegionSeq::initialize(HeapWord* bottom, HeapWord* end) { assert((uintptr_t) bottom % HeapRegion::GrainBytes == 0, "bottom should be heap region aligned"); assert((uintptr_t) end % HeapRegion::GrainBytes == 0, "end should be heap region aligned"); _next_search_index = 0; _allocated_length = 0; _regions.initialize(bottom, end, HeapRegion::GrainBytes); } MemRegion HeapRegionSeq::expand_by(HeapWord* old_end, HeapWord* new_end, FreeRegionList* list) { assert(old_end < new_end, "don't call it otherwise"); G1CollectedHeap* g1h = G1CollectedHeap::heap(); HeapWord* next_bottom = old_end; assert(heap_bottom() <= next_bottom, "invariant"); while (next_bottom < new_end) { assert(next_bottom < heap_end(), "invariant"); uint index = length(); assert(index < max_length(), "otherwise we cannot expand further"); if (index == 0) { // We have not allocated any regions so far assert(next_bottom == heap_bottom(), "invariant"); } else { // next_bottom should match the end of the last/previous region assert(next_bottom == at(index - 1)->end(), "invariant"); } if (index == _allocated_length) { // We have to allocate a new HeapRegion. HeapRegion* new_hr = g1h->new_heap_region(index, next_bottom); if (new_hr == NULL) { // allocation failed, we bail out and return what we have done so far return MemRegion(old_end, next_bottom); } assert(_regions.get_by_index(index) == NULL, "invariant"); _regions.set_by_index(index, new_hr); increment_allocated_length(); } // Have to increment the length first, otherwise we will get an // assert failure at(index) below. increment_length(); HeapRegion* hr = at(index); list->add_as_tail(hr); next_bottom = hr->end(); } assert(next_bottom == new_end, "post-condition"); return MemRegion(old_end, next_bottom); } uint HeapRegionSeq::free_suffix() { uint res = 0; uint index = length(); while (index > 0) { index -= 1; if (!at(index)->is_empty()) { break; } res += 1; } return res; } uint HeapRegionSeq::find_contiguous(uint num) { assert(num > 1, "use this only for sequences of length 2 or greater"); assert(_next_search_index <= length(), err_msg("_next_search_index: %u should be valid and <= than %u", _next_search_index, length())); uint start = _next_search_index; uint res = find_contiguous_from(start, num); if (res == G1_NULL_HRS_INDEX && start > 0) { // Try starting from the beginning. If _next_search_index was 0, // no point in doing this again. res = find_contiguous_from(0, num); } if (res != G1_NULL_HRS_INDEX) { assert(res < length(), err_msg("res: %u should be valid", res)); _next_search_index = res + num; assert(_next_search_index <= length(), err_msg("_next_search_index: %u should be valid and <= than %u", _next_search_index, length())); } return res; } void HeapRegionSeq::iterate(HeapRegionClosure* blk) const { iterate_from((HeapRegion*) NULL, blk); } void HeapRegionSeq::iterate_from(HeapRegion* hr, HeapRegionClosure* blk) const { uint hr_index = 0; if (hr != NULL) { hr_index = hr->hrs_index(); } uint len = length(); for (uint i = hr_index; i < len; i += 1) { bool res = blk->doHeapRegion(at(i)); if (res) { blk->incomplete(); return; } } for (uint i = 0; i < hr_index; i += 1) { bool res = blk->doHeapRegion(at(i)); if (res) { blk->incomplete(); return; } } } uint HeapRegionSeq::shrink_by(uint num_regions_to_remove) { // Reset this in case it's currently pointing into the regions that // we just removed. _next_search_index = 0; assert(length() > 0, "the region sequence should not be empty"); assert(length() <= _allocated_length, "invariant"); assert(_allocated_length > 0, "we should have at least one region committed"); assert(num_regions_to_remove < length(), "We should never remove all regions"); uint i = 0; for (; i < num_regions_to_remove; i++) { HeapRegion* cur = at(length() - 1); if (!cur->is_empty()) { // We have to give up if the region can not be moved break; } assert(!cur->isHumongous(), "Humongous regions should not be empty"); decrement_length(); } return i; } #ifndef PRODUCT void HeapRegionSeq::verify_optional() { guarantee(length() <= _allocated_length, err_msg("invariant: _length: %u _allocated_length: %u", length(), _allocated_length)); guarantee(_allocated_length <= max_length(), err_msg("invariant: _allocated_length: %u _max_length: %u", _allocated_length, max_length())); guarantee(_next_search_index <= length(), err_msg("invariant: _next_search_index: %u _length: %u", _next_search_index, length())); HeapWord* prev_end = heap_bottom(); for (uint i = 0; i < _allocated_length; i += 1) { HeapRegion* hr = _regions.get_by_index(i); guarantee(hr != NULL, err_msg("invariant: i: %u", i)); guarantee(hr->bottom() == prev_end, err_msg("invariant i: %u "HR_FORMAT" prev_end: "PTR_FORMAT, i, HR_FORMAT_PARAMS(hr), p2i(prev_end))); guarantee(hr->hrs_index() == i, err_msg("invariant: i: %u hrs_index(): %u", i, hr->hrs_index())); if (i < length()) { // Asserts will fire if i is >= _length HeapWord* addr = hr->bottom(); guarantee(addr_to_region(addr) == hr, "sanity"); guarantee(addr_to_region_unsafe(addr) == hr, "sanity"); } else { guarantee(hr->is_empty(), "sanity"); guarantee(!hr->isHumongous(), "sanity"); // using assert instead of guarantee here since containing_set() // is only available in non-product builds. assert(hr->containing_set() == NULL, "sanity"); } if (hr->startsHumongous()) { prev_end = hr->orig_end(); } else { prev_end = hr->end(); } } for (uint i = _allocated_length; i < max_length(); i += 1) { guarantee(_regions.get_by_index(i) == NULL, err_msg("invariant i: %u", i)); } } #endif // PRODUCT