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src/share/vm/gc_implementation/g1/g1HotCardCache.hpp@710a3c8b516e (annotated)

src/share/vm/gc_implementation/g1/g1HotCardCache.hpp

Tue, 08 Aug 2017 15:57:29 +0800

author

aoqi

date

Tue, 08 Aug 2017 15:57:29 +0800

changeset 6876

710a3c8b516e

parent 6552

8847586c9037

parent 0

f90c822e73f8

child 7535

7ae4e26cb1e0

permissions

-rw-r--r--

merge

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation.
aoqi@0	8	*
aoqi@0	9	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	12	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	13	* accompanied this code).
aoqi@0	14	*
aoqi@0	15	* You should have received a copy of the GNU General Public License version
aoqi@0	16	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	18	*
aoqi@0	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	20	* or visit www.oracle.com if you need additional information or have any
aoqi@0	21	* questions.
aoqi@0	22	*
aoqi@0	23	*/
aoqi@0	24
aoqi@0	25	#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP
aoqi@0	26	#define SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP
aoqi@0	27
aoqi@0	28	#include "gc_implementation/g1/g1_globals.hpp"
aoqi@0	29	#include "gc_implementation/g1/g1CardCounts.hpp"
aoqi@0	30	#include "memory/allocation.hpp"
aoqi@0	31	#include "runtime/safepoint.hpp"
aoqi@0	32	#include "runtime/thread.inline.hpp"
aoqi@0	33	#include "utilities/globalDefinitions.hpp"
aoqi@0	34
aoqi@0	35	class DirtyCardQueue;
aoqi@0	36	class G1CollectedHeap;
aoqi@0	37	class G1RemSet;
aoqi@0	38	class HeapRegion;
aoqi@0	39
aoqi@0	40	// An evicting cache of cards that have been logged by the G1 post
aoqi@0	41	// write barrier. Placing a card in the cache delays the refinement
aoqi@0	42	// of the card until the card is evicted, or the cache is drained
aoqi@0	43	// during the next evacuation pause.
aoqi@0	44	//
aoqi@0	45	// The first thing the G1 post write barrier does is to check whether
aoqi@0	46	// the card containing the updated pointer is already dirty and, if
aoqi@0	47	// so, skips the remaining code in the barrier.
aoqi@0	48	//
aoqi@0	49	// Delaying the refinement of a card will make the card fail the
aoqi@0	50	// first is_dirty check in the write barrier, skipping the remainder
aoqi@0	51	// of the write barrier.
aoqi@0	52	//
aoqi@0	53	// This can significantly reduce the overhead of the write barrier
aoqi@0	54	// code, increasing throughput.
aoqi@0	55
aoqi@0	56	class G1HotCardCache: public CHeapObj<mtGC> {
aoqi@0	57	G1CollectedHeap* _g1h;
aoqi@0	58
aoqi@0	59	// The card cache table
aoqi@0	60	jbyte** _hot_cache;
aoqi@0	61
aoqi@0	62	int _hot_cache_size;
aoqi@0	63	int _n_hot;
aoqi@0	64	int _hot_cache_idx;
aoqi@0	65
aoqi@0	66	int _hot_cache_par_chunk_size;
aoqi@0	67	volatile int _hot_cache_par_claimed_idx;
aoqi@0	68
aoqi@0	69	bool _use_cache;
aoqi@0	70
aoqi@0	71	G1CardCounts _card_counts;
aoqi@0	72
aoqi@0	73	bool default_use_cache() const {
aoqi@0	74	return (G1ConcRSLogCacheSize > 0);
aoqi@0	75	}
aoqi@0	76
aoqi@0	77	public:
aoqi@0	78	G1HotCardCache(G1CollectedHeap* g1h);
aoqi@0	79	~G1HotCardCache();
aoqi@0	80
aoqi@0	81	void initialize();
aoqi@0	82
aoqi@0	83	bool use_cache() { return _use_cache; }
aoqi@0	84
aoqi@0	85	void set_use_cache(bool b) {
aoqi@0	86	_use_cache = (b ? default_use_cache() : false);
aoqi@0	87	}
aoqi@0	88
aoqi@0	89	// Returns the card to be refined or NULL.
aoqi@0	90	//
aoqi@0	91	// Increments the count for given the card. if the card is not 'hot',
aoqi@0	92	// it is returned for immediate refining. Otherwise the card is
aoqi@0	93	// added to the hot card cache.
aoqi@0	94	// If there is enough room in the hot card cache for the card we're
aoqi@0	95	// adding, NULL is returned and no further action in needed.
aoqi@0	96	// If we evict a card from the cache to make room for the new card,
aoqi@0	97	// the evicted card is then returned for refinement.
aoqi@0	98	jbyte* insert(jbyte* card_ptr);
aoqi@0	99
aoqi@0	100	// Refine the cards that have delayed as a result of
aoqi@0	101	// being in the cache.
aoqi@0	102	void drain(uint worker_i, G1RemSet* g1rs, DirtyCardQueue* into_cset_dcq);
aoqi@0	103
aoqi@0	104	// Set up for parallel processing of the cards in the hot cache
aoqi@0	105	void reset_hot_cache_claimed_index() {
aoqi@0	106	_hot_cache_par_claimed_idx = 0;
aoqi@0	107	}
aoqi@0	108
aoqi@0	109	// Resets the hot card cache and discards the entries.
aoqi@0	110	void reset_hot_cache() {
aoqi@0	111	assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint");
aoqi@0	112	assert(Thread::current()->is_VM_thread(), "Current thread should be the VMthread");
aoqi@0	113	_hot_cache_idx = 0; _n_hot = 0;
aoqi@0	114	}
aoqi@0	115
aoqi@0	116	bool hot_cache_is_empty() { return _n_hot == 0; }
aoqi@0	117
aoqi@0	118	// Resizes the card counts table to match the given capacity
aoqi@0	119	void resize_card_counts(size_t heap_capacity);
aoqi@0	120
aoqi@0	121	// Zeros the values in the card counts table for entire committed heap
aoqi@0	122	void reset_card_counts();
aoqi@0	123
aoqi@0	124	// Zeros the values in the card counts table for the given region
aoqi@0	125	void reset_card_counts(HeapRegion* hr);
aoqi@0	126	};
aoqi@0	127
aoqi@0	128	#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP