Mercurial > hg > graal-compiler
view src/share/vm/interpreter/oopMapCache.hpp @ 2149:7e37af9d69ef
7011379: G1: overly long concurrent marking cycles
Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads.
Reviewed-by: johnc, ysr
author | tonyp |
---|---|
date | Wed, 19 Jan 2011 09:35:17 -0500 |
parents | c760f78e0a53 |
children | d2a62e0f25eb |
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/* * Copyright (c) 1997, 2010, 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. * */ #ifndef SHARE_VM_INTERPRETER_OOPMAPCACHE_HPP #define SHARE_VM_INTERPRETER_OOPMAPCACHE_HPP #include "oops/generateOopMap.hpp" #include "runtime/mutex.hpp" // A Cache for storing (method, bci) -> oopMap. // The memory management system uses the cache when locating object // references in an interpreted frame. // // OopMapCache's are allocated lazily per instanceKlass. // The oopMap (InterpreterOopMap) is stored as a bit mask. If the // bit_mask can fit into two words it is stored in // the _bit_mask array, otherwise it is allocated on the heap. // For OopMapCacheEntry the bit_mask is allocated in the C heap // because these entries persist between garbage collections. // For InterpreterOopMap the bit_mask is allocated in // a resource area for better performance. InterpreterOopMap // should only be created and deleted during same garbage collection. // // If ENABBLE_ZAP_DEAD_LOCALS is defined, two bits are used // per entry instead of one. In all cases, // the first bit is set to indicate oops as opposed to other // values. If the second bit is available, // it is set for dead values. We get the following encoding: // // 00 live value // 01 live oop // 10 dead value // 11 <unused> (we cannot distinguish between dead oops or values with the current oop map generator) class OffsetClosure { public: virtual void offset_do(int offset) = 0; }; class InterpreterOopMap: ResourceObj { friend class OopMapCache; public: enum { N = 2, // the number of words reserved // for inlined mask storage small_mask_limit = N * BitsPerWord, // the maximum number of bits // available for small masks, // small_mask_limit can be set to 0 // for testing bit_mask allocation #ifdef ENABLE_ZAP_DEAD_LOCALS bits_per_entry = 2, dead_bit_number = 1, #else bits_per_entry = 1, #endif oop_bit_number = 0 }; private: methodOop _method; // the method for which the mask is valid unsigned short _bci; // the bci for which the mask is valid int _mask_size; // the mask size in bits int _expression_stack_size; // the size of the expression stack in slots protected: intptr_t _bit_mask[N]; // the bit mask if // mask_size <= small_mask_limit, // ptr to bit mask otherwise // "protected" so that sub classes can // access it without using trickery in // methd bit_mask(). #ifdef ASSERT bool _resource_allocate_bit_mask; #endif // access methods methodOop method() const { return _method; } void set_method(methodOop v) { _method = v; } int bci() const { return _bci; } void set_bci(int v) { _bci = v; } int mask_size() const { return _mask_size; } void set_mask_size(int v) { _mask_size = v; } int number_of_entries() const { return mask_size() / bits_per_entry; } // Test bit mask size and return either the in-line bit mask or allocated // bit mask. uintptr_t* bit_mask() { return (uintptr_t*)(mask_size() <= small_mask_limit ? (intptr_t)_bit_mask : _bit_mask[0]); } // return the word size of_bit_mask. mask_size() <= 4 * MAX_USHORT size_t mask_word_size() { return (mask_size() + BitsPerWord - 1) / BitsPerWord; } uintptr_t entry_at(int offset) { int i = offset * bits_per_entry; return bit_mask()[i / BitsPerWord] >> (i % BitsPerWord); } void set_expression_stack_size(int sz) { _expression_stack_size = sz; } #ifdef ENABLE_ZAP_DEAD_LOCALS bool is_dead(int offset) { return (entry_at(offset) & (1 << dead_bit_number)) != 0; } #endif // Lookup bool match(methodHandle method, int bci) { return _method == method() && _bci == bci; } bool is_empty(); // Initialization void initialize(); public: InterpreterOopMap(); ~InterpreterOopMap(); // Copy the OopMapCacheEntry in parameter "from" into this // InterpreterOopMap. If the _bit_mask[0] in "from" points to // allocated space (i.e., the bit mask was to large to hold // in-line), allocate the space from a Resource area. void resource_copy(OopMapCacheEntry* from); void iterate_oop(OffsetClosure* oop_closure); void oop_iterate(OopClosure * blk); void oop_iterate(OopClosure * blk, MemRegion mr); void verify(); void print(); bool is_oop (int offset) { return (entry_at(offset) & (1 << oop_bit_number )) != 0; } int expression_stack_size() { return _expression_stack_size; } #ifdef ENABLE_ZAP_DEAD_LOCALS void iterate_all(OffsetClosure* oop_closure, OffsetClosure* value_closure, OffsetClosure* dead_closure); #endif }; class OopMapCache : public CHeapObj { private: enum { _size = 32, // Use fixed size for now _probe_depth = 3 // probe depth in case of collisions }; OopMapCacheEntry* _array; unsigned int hash_value_for(methodHandle method, int bci); OopMapCacheEntry* entry_at(int i) const; Mutex _mut; void flush(); public: OopMapCache(); ~OopMapCache(); // free up memory // flush cache entry is occupied by an obsolete method void flush_obsolete_entries(); // Returns the oopMap for (method, bci) in parameter "entry". // Returns false if an oop map was not found. void lookup(methodHandle method, int bci, InterpreterOopMap* entry); // Compute an oop map without updating the cache or grabbing any locks (for debugging) static void compute_one_oop_map(methodHandle method, int bci, InterpreterOopMap* entry); // Helpers // Iterate over the entries in the cached OopMapCacheEntry's void oop_iterate(OopClosure *blk); void oop_iterate(OopClosure *blk, MemRegion mr); void verify(); // Returns total no. of bytes allocated as part of OopMapCache's static long memory_usage() PRODUCT_RETURN0; }; #endif // SHARE_VM_INTERPRETER_OOPMAPCACHE_HPP