--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp Mon Aug 18 15:41:57 2014 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp Mon Aug 18 16:10:44 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
+