Mercurial > hg > truffle
diff src/share/vm/gc_implementation/g1/heapRegionSeq.cpp @ 20336:6701abbc4441
8054818: Refactor HeapRegionSeq to manage heap region and auxiliary data
Summary: Let HeapRegionSeq manage the heap region and auxiliary data to decrease the amount of responsibilities of G1CollectedHeap, and encapsulate this work from other code.
Reviewed-by: jwilhelm, jmasa, mgerdin, brutisso
author | tschatzl |
---|---|
date | Tue, 19 Aug 2014 10:50:27 +0200 |
parents | eec72fa4b108 |
children | 1f1d373cd044 |
line wrap: on
line diff
--- a/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp Tue Aug 19 12:39:06 2014 +0200 +++ b/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp Tue Aug 19 10:50:27 2014 +0200 @@ -25,163 +25,189 @@ #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/heapRegionSet.inline.hpp" #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" +#include "gc_implementation/g1/concurrentG1Refine.hpp" #include "memory/allocation.hpp" -// Private +void HeapRegionSeq::initialize(ReservedSpace reserved) { + _reserved = reserved; + _storage.initialize(reserved, 0); + + _num_committed = 0; + + _allocated_heapregions_length = 0; + + _regions.initialize((HeapWord*)_storage.low_boundary(), (HeapWord*)_storage.high_boundary(), HeapRegion::GrainBytes); +} + +bool HeapRegionSeq::is_available(uint region) const { + return region < _num_committed; +} + +#ifdef ASSERT +bool HeapRegionSeq::is_free(HeapRegion* hr) const { + return _free_list.contains(hr); +} +#endif -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)); +HeapRegion* HeapRegionSeq::new_heap_region(uint hrs_index) { + HeapWord* bottom = G1CollectedHeap::heap()->bottom_addr_for_region(hrs_index); + MemRegion mr(bottom, bottom + HeapRegion::GrainWords); + assert(reserved().contains(mr), "invariant"); + return new HeapRegion(hrs_index, G1CollectedHeap::heap()->bot_shared(), mr); +} + +void HeapRegionSeq::update_committed_space(HeapWord* old_end, + HeapWord* new_end) { + assert(old_end != new_end, "don't call this otherwise"); + // We may not have officially committed the area. So construct and use a separate one. + MemRegion new_committed(heap_bottom(), new_end); + // Tell the card table about the update. + Universe::heap()->barrier_set()->resize_covered_region(new_committed); + // Tell the BOT about the update. + G1CollectedHeap::heap()->bot_shared()->resize(new_committed.word_size()); + // Tell the hot card cache about the update + G1CollectedHeap::heap()->concurrent_g1_refine()->hot_card_cache()->resize_card_counts(new_committed.byte_size()); +} + +void HeapRegionSeq::commit_regions(uint index, size_t num_regions) { + guarantee(num_regions > 0, "Must commit more than zero regions"); + guarantee(_num_committed + num_regions <= max_length(), "Cannot commit more than the maximum amount of regions"); - 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; + _storage.expand_by(num_regions * HeapRegion::GrainBytes); + update_committed_space(heap_top(), heap_top() + num_regions * HeapRegion::GrainWords); +} + +void HeapRegionSeq::uncommit_regions(uint start, size_t num_regions) { + guarantee(num_regions >= 1, "Need to specify at least one region to uncommit"); + guarantee(_num_committed >= num_regions, "pre-condition"); + + // Print before uncommitting. + if (G1CollectedHeap::heap()->hr_printer()->is_active()) { + for (uint i = start; i < start + num_regions; i++) { + HeapRegion* hr = at(i); + G1CollectedHeap::heap()->hr_printer()->uncommit(hr->bottom(), hr->end()); } - 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"); + + HeapWord* old_end = heap_top(); + _num_committed -= (uint)num_regions; + OrderAccess::fence(); + + _storage.shrink_by(num_regions * HeapRegion::GrainBytes); + update_committed_space(old_end, heap_top()); +} + +void HeapRegionSeq::make_regions_available(uint start, uint num_regions) { + guarantee(num_regions > 0, "No point in calling this for zero regions"); + commit_regions(start, num_regions); + for (uint i = start; i < start + num_regions; i++) { + if (_regions.get_by_index(i) == NULL) { + HeapRegion* new_hr = new_heap_region(i); + _regions.set_by_index(i, new_hr); + _allocated_heapregions_length = MAX2(_allocated_heapregions_length, i + 1); } - return first; - } else { - // we failed to find enough space for the humongous object - return G1_NULL_HRS_INDEX; + } + + _num_committed += (size_t)num_regions; + + OrderAccess::fence(); + + for (uint i = start; i < start + num_regions; i++) { + assert(is_available(i), err_msg("Just made region %u available but is apparently not.", i)); + HeapRegion* hr = at(i); + if (G1CollectedHeap::heap()->hr_printer()->is_active()) { + G1CollectedHeap::heap()->hr_printer()->commit(hr->bottom(), hr->end()); + } + HeapWord* bottom = G1CollectedHeap::heap()->bottom_addr_for_region(i); + MemRegion mr(bottom, bottom + HeapRegion::GrainWords); + + hr->initialize(mr); + insert_into_free_list(at(i)); } } -// Public +uint HeapRegionSeq::expand_by(uint num_regions) { + // Only ever expand from the end of the heap. + return expand_at(_num_committed, num_regions); +} + +uint HeapRegionSeq::expand_at(uint start, uint num_regions) { + if (num_regions == 0) { + return 0; + } -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"); + uint cur = start; + uint idx_last_found = 0; + uint num_last_found = 0; + + uint expanded = 0; - _next_search_index = 0; - _allocated_length = 0; + while (expanded < num_regions && + (num_last_found = find_unavailable_from_idx(cur, &idx_last_found)) > 0) { + uint to_expand = MIN2(num_regions - expanded, num_last_found); + make_regions_available(idx_last_found, to_expand); + expanded += to_expand; + cur = idx_last_found + num_last_found + 1; + } - _regions.initialize(bottom, end, HeapRegion::GrainBytes); + verify_optional(); + return expanded; } -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"); - } +uint HeapRegionSeq::find_contiguous(size_t num, bool empty_only) { + uint found = 0; + size_t length_found = 0; + uint cur = 0; - 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(); + while (length_found < num && cur < max_length()) { + HeapRegion* hr = _regions.get_by_index(cur); + if ((!empty_only && !is_available(cur)) || (is_available(cur) && hr != NULL && hr->is_empty())) { + // This region is a potential candidate for allocation into. + length_found++; + } else { + // This region is not a candidate. The next region is the next possible one. + found = cur + 1; + length_found = 0; } - // 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); + cur++; + } - next_bottom = hr->end(); + if (length_found == num) { + for (uint i = found; i < (found + num); i++) { + HeapRegion* hr = _regions.get_by_index(i); + // sanity check + guarantee((!empty_only && !is_available(i)) || (is_available(i) && hr != NULL && hr->is_empty()), + err_msg("Found region sequence starting at " UINT32_FORMAT ", length " SIZE_FORMAT + " that is not empty at " UINT32_FORMAT ". Hr is " PTR_FORMAT, found, num, i, p2i(hr))); + } + return found; + } else { + return G1_NO_HRS_INDEX; } - 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; +HeapRegion* HeapRegionSeq::next_region_in_heap(const HeapRegion* r) const { + guarantee(r != NULL, "Start region must be a valid region"); + guarantee(is_available(r->hrs_index()), err_msg("Trying to iterate starting from region %u which is not in the heap", r->hrs_index())); + for (uint i = r->hrs_index() + 1; i < _allocated_heapregions_length; i++) { + HeapRegion* hr = _regions.get_by_index(i); + if (is_available(i)) { + return hr; } - 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; + return NULL; } 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 = max_length(); - 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 < len; i++) { + if (!is_available(i)) { + continue; } - } - for (uint i = 0; i < hr_index; i += 1) { + guarantee(at(i) != NULL, err_msg("Tried to access region %u that has a NULL HeapRegion*", i)); bool res = blk->doHeapRegion(at(i)); if (res) { blk->incomplete(); @@ -190,71 +216,219 @@ } } +uint HeapRegionSeq::find_unavailable_from_idx(uint start_idx, uint* res_idx) const { + guarantee(res_idx != NULL, "checking"); + guarantee(start_idx <= (max_length() + 1), "checking"); + + uint num_regions = 0; + + uint cur = start_idx; + while (cur < max_length() && is_available(cur)) { + cur++; + } + if (cur == max_length()) { + return num_regions; + } + *res_idx = cur; + while (cur < max_length() && !is_available(cur)) { + cur++; + } + num_regions = cur - *res_idx; +#ifdef ASSERT + for (uint i = *res_idx; i < (*res_idx + num_regions); i++) { + assert(!is_available(i), "just checking"); + } + assert(cur == max_length() || num_regions == 0 || is_available(cur), + err_msg("The region at the current position %u must be available or at the end of the heap.", cur)); +#endif + return num_regions; +} + +uint HeapRegionSeq::start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const { + return num_regions * worker_i / num_workers; +} + +void HeapRegionSeq::par_iterate(HeapRegionClosure* blk, uint worker_id, uint num_workers, jint claim_value) const { + const uint start_index = start_region_for_worker(worker_id, num_workers, _allocated_heapregions_length); + + // Every worker will actually look at all regions, skipping over regions that + // are currently not committed. + // This also (potentially) iterates over regions newly allocated during GC. This + // is no problem except for some extra work. + for (uint count = 0; count < _allocated_heapregions_length; count++) { + const uint index = (start_index + count) % _allocated_heapregions_length; + assert(0 <= index && index < _allocated_heapregions_length, "sanity"); + // Skip over unavailable regions + if (!is_available(index)) { + continue; + } + HeapRegion* r = _regions.get_by_index(index); + // We'll ignore "continues humongous" regions (we'll process them + // when we come across their corresponding "start humongous" + // region) and regions already claimed. + if (r->claim_value() == claim_value || r->continuesHumongous()) { + continue; + } + // OK, try to claim it + if (!r->claimHeapRegion(claim_value)) { + continue; + } + // Success! + if (r->startsHumongous()) { + // If the region is "starts humongous" we'll iterate over its + // "continues humongous" first; in fact we'll do them + // first. The order is important. In one case, calling the + // closure on the "starts humongous" region might de-allocate + // and clear all its "continues humongous" regions and, as a + // result, we might end up processing them twice. So, we'll do + // them first (note: most closures will ignore them anyway) and + // then we'll do the "starts humongous" region. + for (uint ch_index = index + 1; ch_index < index + r->region_num(); ch_index++) { + HeapRegion* chr = _regions.get_by_index(ch_index); + + assert(chr->continuesHumongous(), "Must be humongous region"); + assert(chr->humongous_start_region() == r, + err_msg("Must work on humongous continuation of the original start region " + PTR_FORMAT ", but is " PTR_FORMAT, p2i(r), p2i(chr))); + assert(chr->claim_value() != claim_value, + "Must not have been claimed yet because claiming of humongous continuation first claims the start region"); + + bool claim_result = chr->claimHeapRegion(claim_value); + // We should always be able to claim it; no one else should + // be trying to claim this region. + guarantee(claim_result, "We should always be able to claim the continuesHumongous part of the humongous object"); + + bool res2 = blk->doHeapRegion(chr); + if (res2) { + return; + } + + // Right now, this holds (i.e., no closure that actually + // does something with "continues humongous" regions + // clears them). We might have to weaken it in the future, + // but let's leave these two asserts here for extra safety. + assert(chr->continuesHumongous(), "should still be the case"); + assert(chr->humongous_start_region() == r, "sanity"); + } + } + + bool res = blk->doHeapRegion(r); + if (res) { + 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(length() <= _allocated_heapregions_length, "invariant"); + assert(_allocated_heapregions_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 (num_regions_to_remove == 0) { + return 0; + } + + uint removed = 0; + uint cur = _allocated_heapregions_length - 1; + uint idx_last_found = 0; + uint num_last_found = 0; - if (!cur->is_empty()) { - // We have to give up if the region can not be moved - break; + if ((num_last_found = find_empty_from_idx_reverse(cur, &idx_last_found)) > 0) { + // Only allow uncommit from the end of the heap. + if ((idx_last_found + num_last_found) != _allocated_heapregions_length) { + return 0; + } + uint to_remove = MIN2(num_regions_to_remove - removed, num_last_found); + + uncommit_regions(idx_last_found + num_last_found - to_remove, to_remove); + + cur -= num_last_found; + removed += to_remove; } - assert(!cur->isHumongous(), "Humongous regions should not be empty"); - decrement_length(); - } - return i; + verify_optional(); + + return removed; } -#ifndef PRODUCT -void HeapRegionSeq::verify_optional() { - guarantee(length() <= _allocated_length, +uint HeapRegionSeq::find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const { + guarantee(start_idx < _allocated_heapregions_length, "checking"); + guarantee(res_idx != NULL, "checking"); + + uint num_regions_found = 0; + + jlong cur = start_idx; + while (cur != -1 && !(is_available(cur) && at(cur)->is_empty())) { + cur--; + } + if (cur == -1) { + return num_regions_found; + } + jlong old_cur = cur; + // cur indexes the first empty region + while (cur != -1 && is_available(cur) && at(cur)->is_empty()) { + cur--; + } + *res_idx = cur + 1; + num_regions_found = old_cur - cur; + +#ifdef ASSERT + for (uint i = *res_idx; i < (*res_idx + num_regions_found); i++) { + assert(at(i)->is_empty(), "just checking"); + } +#endif + return num_regions_found; +} + +void HeapRegionSeq::verify() { + guarantee(length() <= _allocated_heapregions_length, err_msg("invariant: _length: %u _allocated_length: %u", - length(), _allocated_length)); - guarantee(_allocated_length <= max_length(), + length(), _allocated_heapregions_length)); + guarantee(_allocated_heapregions_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())); + _allocated_heapregions_length, max_length())); + bool prev_committed = true; + uint num_committed = 0; HeapWord* prev_end = heap_bottom(); - for (uint i = 0; i < _allocated_length; i += 1) { + for (uint i = 0; i < _allocated_heapregions_length; i++) { + if (!is_available(i)) { + prev_committed = false; + continue; + } + num_committed++; HeapRegion* hr = _regions.get_by_index(i); guarantee(hr != NULL, err_msg("invariant: i: %u", i)); - guarantee(hr->bottom() == prev_end, + guarantee(!prev_committed || 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"); - } 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"); - } + // Asserts will fire if i is >= _length + HeapWord* addr = hr->bottom(); + guarantee(addr_to_region(addr) == hr, "sanity"); + // We cannot check whether the region is part of a particular set: at the time + // this method may be called, we have only completed allocation of the regions, + // but not put into a region set. + prev_committed = true; if (hr->startsHumongous()) { prev_end = hr->orig_end(); } else { prev_end = hr->end(); } } - for (uint i = _allocated_length; i < max_length(); i += 1) { + for (uint i = _allocated_heapregions_length; i < max_length(); i++) { guarantee(_regions.get_by_index(i) == NULL, err_msg("invariant i: %u", i)); } + + guarantee(num_committed == _num_committed, err_msg("Found %u committed regions, but should be %u", num_committed, _num_committed)); + _free_list.verify(); +} + +#ifndef PRODUCT +void HeapRegionSeq::verify_optional() { + verify(); } #endif // PRODUCT +