Mercurial > hg > truffle
view src/share/vm/prims/jvmtiTagMap.hpp @ 452:00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery.
Reviewed-by: apetrusenko, jcoomes
author | ysr |
---|---|
date | Thu, 20 Nov 2008 12:27:41 -0800 |
parents | a61af66fc99e |
children | c18cbe5936b8 |
line wrap: on
line source
/* * Copyright 2003-2005 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. * */ // JvmtiTagMap #ifndef _JAVA_JVMTI_TAG_MAP_H_ #define _JAVA_JVMTI_TAG_MAP_H_ // forward references class JvmtiTagHashmap; class JvmtiTagHashmapEntry; class JvmtiTagHashmapEntryClosure; class JvmtiTagMap : public CHeapObj { private: enum{ n_hashmaps = 2, // encapsulates 2 hashmaps max_free_entries = 4096 // maximum number of free entries per env }; // memory region for young generation static MemRegion _young_gen; static void get_young_generation(); JvmtiEnv* _env; // the jvmti environment Mutex _lock; // lock for this tag map JvmtiTagHashmap* _hashmap[n_hashmaps]; // the hashmaps JvmtiTagHashmapEntry* _free_entries; // free list for this environment int _free_entries_count; // number of entries on the free list // create a tag map JvmtiTagMap(JvmtiEnv* env); // accessors inline Mutex* lock() { return &_lock; } inline JvmtiEnv* env() const { return _env; } // rehash tags maps for generation start to end void rehash(int start, int end); // indicates if the object is in the young generation static bool is_in_young(oop o); // iterate over all entries in this tag map void entry_iterate(JvmtiTagHashmapEntryClosure* closure); public: // indicates if this tag map is locked bool is_locked() { return lock()->is_locked(); } // return the appropriate hashmap for a given object JvmtiTagHashmap* hashmap_for(oop o); // create/destroy entries JvmtiTagHashmapEntry* create_entry(jweak ref, jlong tag); void destroy_entry(JvmtiTagHashmapEntry* entry); // returns true if the hashmaps are empty bool is_empty(); // return tag for the given environment static JvmtiTagMap* tag_map_for(JvmtiEnv* env); // destroy tag map ~JvmtiTagMap(); // set/get tag void set_tag(jobject obj, jlong tag); jlong get_tag(jobject obj); // deprecated heap iteration functions void iterate_over_heap(jvmtiHeapObjectFilter object_filter, KlassHandle klass, jvmtiHeapObjectCallback heap_object_callback, const void* user_data); void iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback, jvmtiStackReferenceCallback stack_ref_callback, jvmtiObjectReferenceCallback object_ref_callback, const void* user_data); void iterate_over_objects_reachable_from_object(jobject object, jvmtiObjectReferenceCallback object_reference_callback, const void* user_data); // advanced (JVMTI 1.1) heap iteration functions void iterate_through_heap(jint heap_filter, KlassHandle klass, const jvmtiHeapCallbacks* callbacks, const void* user_data); void follow_references(jint heap_filter, KlassHandle klass, jobject initial_object, const jvmtiHeapCallbacks* callbacks, const void* user_data); // get tagged objects jvmtiError get_objects_with_tags(const jlong* tags, jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr); // call post-GC to rehash the tag maps. static void gc_epilogue(bool full); // call after referencing processing has completed (CMS) static void cms_ref_processing_epilogue(); }; #endif /* _JAVA_JVMTI_TAG_MAP_H_ */