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9f2adffcca
savepoint support was added a year ago as get_last_memroot_block() and free_all_new_blocks(), but it didn't work and was disabled. * fix it to work * instead of freeing the memory, only mark blocks free - this feature is supposed to be used inside a loop (otherwise there is no need to free anything, end of statement will do it anyway). And freeing blocks inside a loop is a bad idea, as they'll be all malloc-ed on the next iteration again. So, don't. * fix a bug in mark_blocks_free() - it doesn't change the number of blocks
75 lines
2.2 KiB
C
75 lines
2.2 KiB
C
/* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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/*
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Data structures for mysys/my_alloc.c (root memory allocator)
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*/
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#ifndef _my_alloc_h
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#define _my_alloc_h
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#include "mysql/psi/psi_base.h"
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#define ALLOC_MAX_BLOCK_TO_DROP 4096
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#define ALLOC_MAX_BLOCK_USAGE_BEFORE_DROP 10
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#define ROOT_FLAG_READ_ONLY 4
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct st_used_mem
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{ /* struct for once_alloc (block) */
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struct st_used_mem *next; /* Next block in use */
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size_t left; /* memory left in block */
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size_t size; /* size of block */
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} USED_MEM;
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typedef struct st_mem_root
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{
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USED_MEM *free; /* blocks with free memory in it */
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USED_MEM *used; /* blocks almost without free memory */
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USED_MEM *pre_alloc; /* preallocated block */
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/* if block have less memory it will be put in 'used' list */
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size_t min_malloc;
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size_t block_size; /* initial block size */
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unsigned int block_num; /* allocated blocks counter */
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/*
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first free block in queue test counter (if it exceed
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MAX_BLOCK_USAGE_BEFORE_DROP block will be dropped in 'used' list)
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*/
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unsigned short first_block_usage;
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unsigned short flags;
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void (*error_handler)(void);
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PSI_memory_key psi_key;
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} MEM_ROOT;
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typedef struct st_mem_root_savepoint
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{
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MEM_ROOT *root;
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USED_MEM *free;
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USED_MEM *used;
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unsigned short first_block_usage;
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} MEM_ROOT_SAVEPOINT;
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#ifdef __cplusplus
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}
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#endif
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#endif
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