Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * 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

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  */

 #include "precompiled.hpp"

 #include "gc_implementation/g1/heapRegion.hpp"

 #include "gc_implementation/g1/heapRegionManager.inline.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"

 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) {

   HeapWord* bottom = G1CollectedHeap::heap()->bottom_addr_for_region(hrm_index);

   MemRegion mr(bottom, bottom + HeapRegion::GrainWords);

   assert(reserved().contains(mr), "invariant");

   return new HeapRegion(hrm_index, G1CollectedHeap::heap()->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));

   }

 }

 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;

 }

 uint HeapRegionManager::start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const {

   return num_regions * worker_i / num_workers;

 }

 void HeapRegionManager::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 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->startsHumongous()) {

       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