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

 /*

  * Copyright (c) 2013, 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/dirtyCardQueue.hpp"

 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"

 #include "gc_implementation/g1/g1HotCardCache.hpp"

 #include "gc_implementation/g1/g1RemSet.hpp"

 #include "runtime/atomic.hpp"

 G1HotCardCache::G1HotCardCache(G1CollectedHeap *g1h):

   _g1h(g1h), _hot_cache(NULL), _use_cache(false), _card_counts(g1h) {}

 void G1HotCardCache::initialize(G1RegionToSpaceMapper* card_counts_storage) {

   if (default_use_cache()) {

     _use_cache = true;

     _hot_cache_size = (1 << G1ConcRSLogCacheSize);

     _hot_cache = NEW_C_HEAP_ARRAY(jbyte*, _hot_cache_size, mtGC);

     _n_hot = 0;

     _hot_cache_idx = 0;

     // For refining the cards in the hot cache in parallel

     uint n_workers = (ParallelGCThreads > 0 ?

                         _g1h->workers()->total_workers() : 1);

     _hot_cache_par_chunk_size = MAX2(1, _hot_cache_size / (int)n_workers);

     _hot_cache_par_claimed_idx = 0;

     _card_counts.initialize(card_counts_storage);

   }

 }

 G1HotCardCache::~G1HotCardCache() {

   if (default_use_cache()) {

     assert(_hot_cache != NULL, "Logic");

     FREE_C_HEAP_ARRAY(jbyte*, _hot_cache, mtGC);

   }

 }

 jbyte* G1HotCardCache::insert(jbyte* card_ptr) {

   uint count = _card_counts.add_card_count(card_ptr);

   if (!_card_counts.is_hot(count)) {

     // The card is not hot so do not store it in the cache;

     // return it for immediate refining.

     return card_ptr;

   }

   // Otherwise, the card is hot.

   jbyte* res = NULL;

   MutexLockerEx x(HotCardCache_lock, Mutex::_no_safepoint_check_flag);

   if (_n_hot == _hot_cache_size) {

     res = _hot_cache[_hot_cache_idx];

     _n_hot--;

   }

   // Now _n_hot < _hot_cache_size, and we can insert at _hot_cache_idx.

   _hot_cache[_hot_cache_idx] = card_ptr;

   _hot_cache_idx++;

   if (_hot_cache_idx == _hot_cache_size) {

     // Wrap around

     _hot_cache_idx = 0;

   }

   _n_hot++;

   return res;

 }

 void G1HotCardCache::drain(uint worker_i,

                            G1RemSet* g1rs,

                            DirtyCardQueue* into_cset_dcq) {

   if (!default_use_cache()) {

     assert(_hot_cache == NULL, "Logic");

     return;

   }

   assert(_hot_cache != NULL, "Logic");

   assert(!use_cache(), "cache should be disabled");

   int start_idx;

   while ((start_idx = _hot_cache_par_claimed_idx) < _n_hot) { // read once

     int end_idx = start_idx + _hot_cache_par_chunk_size;

     if (start_idx ==

         Atomic::cmpxchg(end_idx, &_hot_cache_par_claimed_idx, start_idx)) {

       // The current worker has successfully claimed the chunk [start_idx..end_idx)

       end_idx = MIN2(end_idx, _n_hot);

       for (int i = start_idx; i < end_idx; i++) {

         jbyte* card_ptr = _hot_cache[i];

         if (card_ptr != NULL) {

           if (g1rs->refine_card(card_ptr, worker_i, true)) {

             // The part of the heap spanned by the card contains references

             // that point into the current collection set.

             // We need to record the card pointer in the DirtyCardQueueSet

             // that we use for such cards.

             //

             // The only time we care about recording cards that contain

             // references that point into the collection set is during

             // RSet updating while within an evacuation pause.

             // In this case worker_i should be the id of a GC worker thread

             assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint");

             assert(worker_i < (ParallelGCThreads == 0 ? 1 : ParallelGCThreads),

                    err_msg("incorrect worker id: "UINT32_FORMAT, worker_i));

             into_cset_dcq->enqueue(card_ptr);

           }

         }

       }

     }

   }

   // The existing entries in the hot card cache, which were just refined

   // above, are discarded prior to re-enabling the cache near the end of the GC.

 }

 void G1HotCardCache::reset_card_counts(HeapRegion* hr) {

   _card_counts.clear_region(hr);

 }

 void G1HotCardCache::reset_card_counts() {

   _card_counts.clear_all();

 }