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view src/share/vm/adlc/arena.cpp @ 3979:4dfb2df418f2
6484982: G1: process references during evacuation pauses
Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate.
Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp
author | johnc |
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date | Thu, 22 Sep 2011 10:57:37 -0700 |
parents | f95d63e2154a |
children | 9758d9f36299 |
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/* * Copyright (c) 1998, 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. * */ #include "adlc.hpp" void* Chunk::operator new(size_t requested_size, size_t length) { return CHeapObj::operator new(requested_size + length); } void Chunk::operator delete(void* p, size_t length) { CHeapObj::operator delete(p); } Chunk::Chunk(size_t length) { _next = NULL; // Chain on the linked list _len = length; // Save actual size } //------------------------------chop------------------------------------------- void Chunk::chop() { Chunk *k = this; while( k ) { Chunk *tmp = k->_next; // clear out this chunk (to detect allocation bugs) memset(k, 0xBAADBABE, k->_len); free(k); // Free chunk (was malloc'd) k = tmp; } } void Chunk::next_chop() { _next->chop(); _next = NULL; } //------------------------------Arena------------------------------------------ Arena::Arena( size_t init_size ) { init_size = (init_size+3) & ~3; _first = _chunk = new (init_size) Chunk(init_size); _hwm = _chunk->bottom(); // Save the cached hwm, max _max = _chunk->top(); set_size_in_bytes(init_size); } Arena::Arena() { _first = _chunk = new (Chunk::init_size) Chunk(Chunk::init_size); _hwm = _chunk->bottom(); // Save the cached hwm, max _max = _chunk->top(); set_size_in_bytes(Chunk::init_size); } Arena::Arena( Arena *a ) : _chunk(a->_chunk), _hwm(a->_hwm), _max(a->_max), _first(a->_first) { set_size_in_bytes(a->size_in_bytes()); } //------------------------------used------------------------------------------- // Total of all Chunks in arena size_t Arena::used() const { size_t sum = _chunk->_len - (_max-_hwm); // Size leftover in this Chunk register Chunk *k = _first; while( k != _chunk) { // Whilst have Chunks in a row sum += k->_len; // Total size of this Chunk k = k->_next; // Bump along to next Chunk } return sum; // Return total consumed space. } //------------------------------grow------------------------------------------- // Grow a new Chunk void* Arena::grow( size_t x ) { // Get minimal required size. Either real big, or even bigger for giant objs size_t len = max(x, Chunk::size); register Chunk *k = _chunk; // Get filled-up chunk address _chunk = new (len) Chunk(len); if( k ) k->_next = _chunk; // Append new chunk to end of linked list else _first = _chunk; _hwm = _chunk->bottom(); // Save the cached hwm, max _max = _chunk->top(); set_size_in_bytes(size_in_bytes() + len); void* result = _hwm; _hwm += x; return result; } //------------------------------calloc----------------------------------------- // Allocate zeroed storage in Arena void *Arena::Acalloc( size_t items, size_t x ) { size_t z = items*x; // Total size needed void *ptr = Amalloc(z); // Get space memset( ptr, 0, z ); // Zap space return ptr; // Return space } //------------------------------realloc---------------------------------------- // Reallocate storage in Arena. void *Arena::Arealloc( void *old_ptr, size_t old_size, size_t new_size ) { char *c_old = (char*)old_ptr; // Handy name // Stupid fast special case if( new_size <= old_size ) { // Shrink in-place if( c_old+old_size == _hwm) // Attempt to free the excess bytes _hwm = c_old+new_size; // Adjust hwm return c_old; } // See if we can resize in-place if( (c_old+old_size == _hwm) && // Adjusting recent thing (c_old+new_size <= _max) ) { // Still fits where it sits _hwm = c_old+new_size; // Adjust hwm return c_old; // Return old pointer } // Oops, got to relocate guts void *new_ptr = Amalloc(new_size); memcpy( new_ptr, c_old, old_size ); Afree(c_old,old_size); // Mostly done to keep stats accurate return new_ptr; } //------------------------------reset------------------------------------------ // Reset this Arena to empty, and return this Arenas guts in a new Arena. Arena *Arena::reset(void) { Arena *a = new Arena(this); // New empty arena _first = _chunk = NULL; // Normal, new-arena initialization _hwm = _max = NULL; return a; // Return Arena with guts } //------------------------------contains--------------------------------------- // Determine if pointer belongs to this Arena or not. bool Arena::contains( const void *ptr ) const { if( (void*)_chunk->bottom() <= ptr && ptr < (void*)_hwm ) return true; // Check for in this chunk for( Chunk *c = _first; c; c = c->_next ) if( (void*)c->bottom() <= ptr && ptr < (void*)c->top()) return true; // Check for every chunk in Arena return false; // Not in any Chunk, so not in Arena } //----------------------------------------------------------------------------- // CHeapObj void* CHeapObj::operator new(size_t size){ return (void *) malloc(size); } void CHeapObj::operator delete(void* p){ free(p); }