--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/heapRegionManager.cpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,498 @@
+/*
+ * 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/g1/concurrentG1Refine.hpp"
+#include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/heapRegion.hpp"
+#include "gc/g1/heapRegionManager.inline.hpp"
+#include "gc/g1/heapRegionSet.inline.hpp"
+#include "memory/allocation.hpp"
+
+void HeapRegionManager::initialize(G1RegionToSpaceMapper* heap_storage,
+ G1RegionToSpaceMapper* prev_bitmap,
+ G1RegionToSpaceMapper* next_bitmap,
+ G1RegionToSpaceMapper* bot,
+ G1RegionToSpaceMapper* cardtable,
+ G1RegionToSpaceMapper* card_counts) {
+ _allocated_heapregions_length = 0;
+
+ _heap_mapper = heap_storage;
+
+ _prev_bitmap_mapper = prev_bitmap;
+ _next_bitmap_mapper = next_bitmap;
+
+ _bot_mapper = bot;
+ _cardtable_mapper = cardtable;
+
+ _card_counts_mapper = card_counts;
+
+ MemRegion reserved = heap_storage->reserved();
+ _regions.initialize(reserved.start(), reserved.end(), HeapRegion::GrainBytes);
+
+ _available_map.resize(_regions.length(), false);
+ _available_map.clear();
+}
+
+bool HeapRegionManager::is_available(uint region) const {
+ return _available_map.at(region);
+}
+
+#ifdef ASSERT
+bool HeapRegionManager::is_free(HeapRegion* hr) const {
+ return _free_list.contains(hr);
+}
+#endif
+
+HeapRegion* HeapRegionManager::new_heap_region(uint hrm_index) {
+ G1CollectedHeap* g1h = G1CollectedHeap::heap();
+ HeapWord* bottom = g1h->bottom_addr_for_region(hrm_index);
+ MemRegion mr(bottom, bottom + HeapRegion::GrainWords);
+ assert(reserved().contains(mr), "invariant");
+ return g1h->allocator()->new_heap_region(hrm_index, g1h->bot_shared(), mr);
+}
+
+void HeapRegionManager::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");
+
+ _num_committed += (uint)num_regions;
+
+ _heap_mapper->commit_regions(index, num_regions);
+
+ // Also commit auxiliary data
+ _prev_bitmap_mapper->commit_regions(index, num_regions);
+ _next_bitmap_mapper->commit_regions(index, num_regions);
+
+ _bot_mapper->commit_regions(index, num_regions);
+ _cardtable_mapper->commit_regions(index, num_regions);
+
+ _card_counts_mapper->commit_regions(index, num_regions);
+}
+
+void HeapRegionManager::uncommit_regions(uint start, size_t num_regions) {
+ guarantee(num_regions >= 1, err_msg("Need to specify at least one region to uncommit, tried to uncommit zero regions at %u", start));
+ 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());
+ }
+ }
+
+ _num_committed -= (uint)num_regions;
+
+ _available_map.par_clear_range(start, start + num_regions, BitMap::unknown_range);
+ _heap_mapper->uncommit_regions(start, num_regions);
+
+ // Also uncommit auxiliary data
+ _prev_bitmap_mapper->uncommit_regions(start, num_regions);
+ _next_bitmap_mapper->uncommit_regions(start, num_regions);
+
+ _bot_mapper->uncommit_regions(start, num_regions);
+ _cardtable_mapper->uncommit_regions(start, num_regions);
+
+ _card_counts_mapper->uncommit_regions(start, num_regions);
+}
+
+void HeapRegionManager::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);
+ }
+ }
+
+ _available_map.par_set_range(start, start + num_regions, BitMap::unknown_range);
+
+ 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));
+ }
+}
+
+MemoryUsage HeapRegionManager::get_auxiliary_data_memory_usage() const {
+ size_t used_sz =
+ _prev_bitmap_mapper->committed_size() +
+ _next_bitmap_mapper->committed_size() +
+ _bot_mapper->committed_size() +
+ _cardtable_mapper->committed_size() +
+ _card_counts_mapper->committed_size();
+
+ size_t committed_sz =
+ _prev_bitmap_mapper->reserved_size() +
+ _next_bitmap_mapper->reserved_size() +
+ _bot_mapper->reserved_size() +
+ _cardtable_mapper->reserved_size() +
+ _card_counts_mapper->reserved_size();
+
+ return MemoryUsage(0, used_sz, committed_sz, committed_sz);
+}
+
+uint HeapRegionManager::expand_by(uint num_regions) {
+ return expand_at(0, num_regions);
+}
+
+uint HeapRegionManager::expand_at(uint start, uint num_regions) {
+ if (num_regions == 0) {
+ return 0;
+ }
+
+ uint cur = start;
+ uint idx_last_found = 0;
+ uint num_last_found = 0;
+
+ uint expanded = 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;
+ }
+
+ verify_optional();
+ return expanded;
+}
+
+uint HeapRegionManager::find_contiguous(size_t num, bool empty_only) {
+ uint found = 0;
+ size_t length_found = 0;
+ uint cur = 0;
+
+ 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;
+ }
+ cur++;
+ }
+
+ 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_HRM_INDEX;
+ }
+}
+
+HeapRegion* HeapRegionManager::next_region_in_heap(const HeapRegion* r) const {
+ guarantee(r != NULL, "Start region must be a valid region");
+ guarantee(is_available(r->hrm_index()), err_msg("Trying to iterate starting from region %u which is not in the heap", r->hrm_index()));
+ for (uint i = r->hrm_index() + 1; i < _allocated_heapregions_length; i++) {
+ HeapRegion* hr = _regions.get_by_index(i);
+ if (is_available(i)) {
+ return hr;
+ }
+ }
+ return NULL;
+}
+
+void HeapRegionManager::iterate(HeapRegionClosure* blk) const {
+ uint len = max_length();
+
+ for (uint i = 0; i < len; i++) {
+ if (!is_available(i)) {
+ continue;
+ }
+ 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();
+ return;
+ }
+ }
+}
+
+uint HeapRegionManager::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;
+}
+
+void HeapRegionManager::par_iterate(HeapRegionClosure* blk, uint worker_id, HeapRegionClaimer* hrclaimer, bool concurrent) const {
+ const uint start_index = hrclaimer->start_region_for_worker(worker_id);
+
+ // 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.
+ const uint n_regions = hrclaimer->n_regions();
+ for (uint count = 0; count < n_regions; count++) {
+ const uint index = (start_index + count) % n_regions;
+ assert(index < n_regions, "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.
+ // However, if the iteration is specified as concurrent, the values for
+ // is_starts_humongous and is_continues_humongous can not be trusted,
+ // and we should just blindly iterate over regions regardless of their
+ // humongous status.
+ if (hrclaimer->is_region_claimed(index) || (!concurrent && r->is_continues_humongous())) {
+ continue;
+ }
+ // OK, try to claim it
+ if (!hrclaimer->claim_region(index)) {
+ continue;
+ }
+ // Success!
+ // As mentioned above, special treatment of humongous regions can only be
+ // done if we are iterating non-concurrently.
+ if (!concurrent && r->is_starts_humongous()) {
+ // 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->is_continues_humongous(), "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(!hrclaimer->is_region_claimed(ch_index),
+ "Must not have been claimed yet because claiming of humongous continuation first claims the start region");
+
+ // Claim the region so no other worker tries to process the region. When a worker processes a
+ // starts_humongous region it may also process the associated continues_humongous regions.
+ // The continues_humongous regions can be changed to free regions. Unless this worker claims
+ // all of these regions, other workers might try claim and process these newly free regions.
+ bool claim_result = hrclaimer->claim_region(ch_index);
+ 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->is_continues_humongous(), "should still be the case");
+ assert(chr->humongous_start_region() == r, "sanity");
+ }
+ }
+
+ bool res = blk->doHeapRegion(r);
+ if (res) {
+ return;
+ }
+ }
+}
+
+uint HeapRegionManager::shrink_by(uint num_regions_to_remove) {
+ assert(length() > 0, "the region sequence should not be empty");
+ 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");
+
+ 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;
+
+ while ((removed < num_regions_to_remove) &&
+ (num_last_found = find_empty_from_idx_reverse(cur, &idx_last_found)) > 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;
+ }
+
+ verify_optional();
+
+ return removed;
+}
+
+uint HeapRegionManager::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 HeapRegionManager::verify() {
+ guarantee(length() <= _allocated_heapregions_length,
+ err_msg("invariant: _length: %u _allocated_length: %u",
+ length(), _allocated_heapregions_length));
+ guarantee(_allocated_heapregions_length <= max_length(),
+ err_msg("invariant: _allocated_length: %u _max_length: %u",
+ _allocated_heapregions_length, max_length()));
+
+ bool prev_committed = true;
+ uint num_committed = 0;
+ HeapWord* prev_end = heap_bottom();
+ 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(!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->hrm_index() == i,
+ err_msg("invariant: i: %u hrm_index(): %u", i, hr->hrm_index()));
+ // 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->is_starts_humongous()) {
+ prev_end = hr->orig_end();
+ } else {
+ prev_end = hr->end();
+ }
+ }
+ 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 HeapRegionManager::verify_optional() {
+ verify();
+}
+#endif // PRODUCT
+
+HeapRegionClaimer::HeapRegionClaimer(uint n_workers) :
+ _n_workers(n_workers), _n_regions(G1CollectedHeap::heap()->_hrm._allocated_heapregions_length), _claims(NULL) {
+ assert(n_workers > 0, "Need at least one worker.");
+ _claims = NEW_C_HEAP_ARRAY(uint, _n_regions, mtGC);
+ memset(_claims, Unclaimed, sizeof(*_claims) * _n_regions);
+}
+
+HeapRegionClaimer::~HeapRegionClaimer() {
+ if (_claims != NULL) {
+ FREE_C_HEAP_ARRAY(uint, _claims);
+ }
+}
+
+uint HeapRegionClaimer::start_region_for_worker(uint worker_id) const {
+ assert(worker_id < _n_workers, "Invalid worker_id.");
+ return _n_regions * worker_id / _n_workers;
+}
+
+bool HeapRegionClaimer::is_region_claimed(uint region_index) const {
+ assert(region_index < _n_regions, "Invalid index.");
+ return _claims[region_index] == Claimed;
+}
+
+bool HeapRegionClaimer::claim_region(uint region_index) {
+ assert(region_index < _n_regions, "Invalid index.");
+ uint old_val = Atomic::cmpxchg(Claimed, &_claims[region_index], Unclaimed);
+ return old_val == Unclaimed;
+}