Mercurial > hg > graal-jvmci-8
view src/share/vm/gc_implementation/parallelScavenge/psScavenge.hpp @ 453:c96030fff130
6684579: SoftReference processing can be made more efficient
Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa
author | ysr |
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date | Thu, 20 Nov 2008 16:56:09 -0800 |
parents | d1605aabd0a1 |
children | c18cbe5936b8 |
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/* * Copyright 2002-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ class GCTaskManager; class GCTaskQueue; class OopStack; class ReferenceProcessor; class ParallelScavengeHeap; class PSIsAliveClosure; class PSRefProcTaskExecutor; class PSScavenge: AllStatic { friend class PSIsAliveClosure; friend class PSKeepAliveClosure; friend class PSPromotionManager; enum ScavengeSkippedCause { not_skipped = 0, to_space_not_empty, promoted_too_large, full_follows_scavenge }; // Saved value of to_space->top(), used to prevent objects in to_space from // being rescanned. static HeapWord* _to_space_top_before_gc; // Number of consecutive attempts to scavenge that were skipped static int _consecutive_skipped_scavenges; protected: // Flags/counters static ReferenceProcessor* _ref_processor; // Reference processor for scavenging. static PSIsAliveClosure _is_alive_closure; // Closure used for reference processing static CardTableExtension* _card_table; // We cache the card table for fast access. static bool _survivor_overflow; // Overflow this collection static int _tenuring_threshold; // tenuring threshold for next scavenge static elapsedTimer _accumulated_time; // total time spent on scavenge static HeapWord* _young_generation_boundary; // The lowest address possible for the young_gen. // This is used to decide if an oop should be scavenged, // cards should be marked, etc. static GrowableArray<markOop>* _preserved_mark_stack; // List of marks to be restored after failed promotion static GrowableArray<oop>* _preserved_oop_stack; // List of oops that need their mark restored. static CollectorCounters* _counters; // collector performance counters static void clean_up_failed_promotion(); static bool should_attempt_scavenge(); static HeapWord* to_space_top_before_gc() { return _to_space_top_before_gc; } static inline void save_to_space_top_before_gc(); // Private accessors static CardTableExtension* const card_table() { assert(_card_table != NULL, "Sanity"); return _card_table; } public: // Accessors static int tenuring_threshold() { return _tenuring_threshold; } static elapsedTimer* accumulated_time() { return &_accumulated_time; } static bool promotion_failed() { return _preserved_mark_stack != NULL; } static int consecutive_skipped_scavenges() { return _consecutive_skipped_scavenges; } // Performance Counters static CollectorCounters* counters() { return _counters; } // Used by scavenge_contents && psMarkSweep static ReferenceProcessor* const reference_processor() { assert(_ref_processor != NULL, "Sanity"); return _ref_processor; } // Used to add tasks static GCTaskManager* const gc_task_manager(); // The promotion managers tell us if they encountered overflow static void set_survivor_overflow(bool state) { _survivor_overflow = state; } // Adaptive size policy support. When the young generation/old generation // boundary moves, _young_generation_boundary must be reset static void set_young_generation_boundary(HeapWord* v) { _young_generation_boundary = v; } // Called by parallelScavengeHeap to init the tenuring threshold static void initialize(); // Scavenge entry point static void invoke(); // Return true is a collection was done. Return // false if the collection was skipped. static bool invoke_no_policy(); // If an attempt to promote fails, this method is invoked static void oop_promotion_failed(oop obj, markOop obj_mark); template <class T> static inline bool should_scavenge(T* p); // These call should_scavenge() above and, if it returns true, also check that // the object was not newly copied into to_space. The version with the bool // argument is a convenience wrapper that fetches the to_space pointer from // the heap and calls the other version (if the arg is true). template <class T> static inline bool should_scavenge(T* p, MutableSpace* to_space); template <class T> static inline bool should_scavenge(T* p, bool check_to_space); template <class T> inline static void copy_and_push_safe_barrier(PSPromotionManager* pm, T* p); // Is an object in the young generation // This assumes that the HeapWord argument is in the heap, // so it only checks one side of the complete predicate. inline static bool is_obj_in_young(HeapWord* o) { const bool result = (o >= _young_generation_boundary); return result; } };