Thu, 21 Aug 2014 16:44:41 +0200
8055098: WB API should be extended to provide information about size and age of object.
Summary: Extend the WhiteBox API to provide information about the size and age of objects. Further add a mechanism to trigger a young GC.
Reviewed-by: tschatzl, sjohanss
Contributed-by: Leonid Mesnik <leonid.mesnik@oracle.com>
johnc@5078 | 1 | /* |
johnc@5078 | 2 | * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. |
johnc@5078 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
johnc@5078 | 4 | * |
johnc@5078 | 5 | * This code is free software; you can redistribute it and/or modify it |
johnc@5078 | 6 | * under the terms of the GNU General Public License version 2 only, as |
johnc@5078 | 7 | * published by the Free Software Foundation. |
johnc@5078 | 8 | * |
johnc@5078 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
johnc@5078 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
johnc@5078 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
johnc@5078 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
johnc@5078 | 13 | * accompanied this code). |
johnc@5078 | 14 | * |
johnc@5078 | 15 | * You should have received a copy of the GNU General Public License version |
johnc@5078 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
johnc@5078 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
johnc@5078 | 18 | * |
johnc@5078 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
johnc@5078 | 20 | * or visit www.oracle.com if you need additional information or have any |
johnc@5078 | 21 | * questions. |
johnc@5078 | 22 | * |
johnc@5078 | 23 | */ |
johnc@5078 | 24 | |
johnc@5078 | 25 | #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP |
johnc@5078 | 26 | #define SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP |
johnc@5078 | 27 | |
johnc@5078 | 28 | #include "gc_implementation/g1/g1_globals.hpp" |
johnc@5078 | 29 | #include "gc_implementation/g1/g1CardCounts.hpp" |
johnc@5078 | 30 | #include "memory/allocation.hpp" |
johnc@5078 | 31 | #include "runtime/safepoint.hpp" |
johnc@5078 | 32 | #include "runtime/thread.inline.hpp" |
johnc@5078 | 33 | #include "utilities/globalDefinitions.hpp" |
johnc@5078 | 34 | |
johnc@5078 | 35 | class DirtyCardQueue; |
johnc@5078 | 36 | class G1CollectedHeap; |
johnc@5078 | 37 | class G1RemSet; |
johnc@5078 | 38 | class HeapRegion; |
johnc@5078 | 39 | |
johnc@5078 | 40 | // An evicting cache of cards that have been logged by the G1 post |
johnc@5078 | 41 | // write barrier. Placing a card in the cache delays the refinement |
johnc@5078 | 42 | // of the card until the card is evicted, or the cache is drained |
johnc@5078 | 43 | // during the next evacuation pause. |
johnc@5078 | 44 | // |
johnc@5078 | 45 | // The first thing the G1 post write barrier does is to check whether |
johnc@5078 | 46 | // the card containing the updated pointer is already dirty and, if |
johnc@5078 | 47 | // so, skips the remaining code in the barrier. |
johnc@5078 | 48 | // |
johnc@5078 | 49 | // Delaying the refinement of a card will make the card fail the |
johnc@5078 | 50 | // first is_dirty check in the write barrier, skipping the remainder |
johnc@5078 | 51 | // of the write barrier. |
johnc@5078 | 52 | // |
johnc@5078 | 53 | // This can significantly reduce the overhead of the write barrier |
johnc@5078 | 54 | // code, increasing throughput. |
johnc@5078 | 55 | |
johnc@5078 | 56 | class G1HotCardCache: public CHeapObj<mtGC> { |
johnc@5078 | 57 | G1CollectedHeap* _g1h; |
johnc@5078 | 58 | |
johnc@5078 | 59 | // The card cache table |
johnc@5078 | 60 | jbyte** _hot_cache; |
johnc@5078 | 61 | |
johnc@5078 | 62 | int _hot_cache_size; |
johnc@5078 | 63 | int _n_hot; |
johnc@5078 | 64 | int _hot_cache_idx; |
johnc@5078 | 65 | |
johnc@5078 | 66 | int _hot_cache_par_chunk_size; |
johnc@5078 | 67 | volatile int _hot_cache_par_claimed_idx; |
johnc@5078 | 68 | |
johnc@5078 | 69 | bool _use_cache; |
johnc@5078 | 70 | |
johnc@5078 | 71 | G1CardCounts _card_counts; |
johnc@5078 | 72 | |
johnc@5078 | 73 | bool default_use_cache() const { |
johnc@5078 | 74 | return (G1ConcRSLogCacheSize > 0); |
johnc@5078 | 75 | } |
johnc@5078 | 76 | |
johnc@5078 | 77 | public: |
johnc@5078 | 78 | G1HotCardCache(G1CollectedHeap* g1h); |
johnc@5078 | 79 | ~G1HotCardCache(); |
johnc@5078 | 80 | |
tschatzl@7051 | 81 | void initialize(G1RegionToSpaceMapper* card_counts_storage); |
johnc@5078 | 82 | |
johnc@5078 | 83 | bool use_cache() { return _use_cache; } |
johnc@5078 | 84 | |
johnc@5078 | 85 | void set_use_cache(bool b) { |
johnc@5078 | 86 | _use_cache = (b ? default_use_cache() : false); |
johnc@5078 | 87 | } |
johnc@5078 | 88 | |
johnc@5078 | 89 | // Returns the card to be refined or NULL. |
johnc@5078 | 90 | // |
johnc@5078 | 91 | // Increments the count for given the card. if the card is not 'hot', |
johnc@5078 | 92 | // it is returned for immediate refining. Otherwise the card is |
johnc@5078 | 93 | // added to the hot card cache. |
johnc@5078 | 94 | // If there is enough room in the hot card cache for the card we're |
johnc@5078 | 95 | // adding, NULL is returned and no further action in needed. |
johnc@5078 | 96 | // If we evict a card from the cache to make room for the new card, |
johnc@5078 | 97 | // the evicted card is then returned for refinement. |
johnc@5078 | 98 | jbyte* insert(jbyte* card_ptr); |
johnc@5078 | 99 | |
johnc@5078 | 100 | // Refine the cards that have delayed as a result of |
johnc@5078 | 101 | // being in the cache. |
vkempik@6552 | 102 | void drain(uint worker_i, G1RemSet* g1rs, DirtyCardQueue* into_cset_dcq); |
johnc@5078 | 103 | |
johnc@5078 | 104 | // Set up for parallel processing of the cards in the hot cache |
johnc@5078 | 105 | void reset_hot_cache_claimed_index() { |
johnc@5078 | 106 | _hot_cache_par_claimed_idx = 0; |
johnc@5078 | 107 | } |
johnc@5078 | 108 | |
johnc@5078 | 109 | // Resets the hot card cache and discards the entries. |
johnc@5078 | 110 | void reset_hot_cache() { |
johnc@5078 | 111 | assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint"); |
johnc@5078 | 112 | assert(Thread::current()->is_VM_thread(), "Current thread should be the VMthread"); |
johnc@5078 | 113 | _hot_cache_idx = 0; _n_hot = 0; |
johnc@5078 | 114 | } |
johnc@5078 | 115 | |
johnc@5078 | 116 | bool hot_cache_is_empty() { return _n_hot == 0; } |
johnc@5078 | 117 | |
johnc@5078 | 118 | // Zeros the values in the card counts table for entire committed heap |
johnc@5078 | 119 | void reset_card_counts(); |
johnc@5078 | 120 | |
johnc@5078 | 121 | // Zeros the values in the card counts table for the given region |
johnc@5078 | 122 | void reset_card_counts(HeapRegion* hr); |
johnc@5078 | 123 | }; |
johnc@5078 | 124 | |
johnc@5078 | 125 | #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP |