diff options
Diffstat (limited to 'mysys')
| -rw-r--r-- | mysys/my_alloc.c | 37 |
1 files changed, 32 insertions, 5 deletions
diff --git a/mysys/my_alloc.c b/mysys/my_alloc.c index c9784ddc9a0..f0bc62b10a0 100644 --- a/mysys/my_alloc.c +++ b/mysys/my_alloc.c @@ -22,6 +22,27 @@ #undef EXTRA_DEBUG #define EXTRA_DEBUG + +/* + Initialize memory root + + SYNOPSIS + init_alloc_root() + mem_root - memory root to initialize + block_size - size of chunks (blocks) used for memory allocation + (It is external size of chunk i.e. it should include + memory required for internal structures, thus it + should be no less than ALLOC_ROOT_MIN_BLOCK_SIZE) + pre_alloc_size - if non-0, then size of block that should be + pre-allocated during memory root initialization. + + DESCRIPTION + This function prepares memory root for further use, sets initial size of + chunk for memory allocation and pre-allocates first block if specified. + Altough error can happen during execution of this function if pre_alloc_size + is non-0 it won't be reported. Instead it will be reported as error in first + alloc_root() on this memory root. +*/ void init_alloc_root(MEM_ROOT *mem_root, uint block_size, uint pre_alloc_size __attribute__((unused))) { @@ -29,7 +50,7 @@ void init_alloc_root(MEM_ROOT *mem_root, uint block_size, DBUG_PRINT("enter",("root: 0x%lx", mem_root)); mem_root->free= mem_root->used= mem_root->pre_alloc= 0; mem_root->min_malloc= 32; - mem_root->block_size= block_size-MALLOC_OVERHEAD-sizeof(USED_MEM)-8; + mem_root->block_size= block_size - ALLOC_ROOT_MIN_BLOCK_SIZE; mem_root->error_handler= 0; mem_root->block_num= 4; /* We shift this with >>2 */ mem_root->first_block_usage= 0; @@ -54,9 +75,9 @@ void init_alloc_root(MEM_ROOT *mem_root, uint block_size, SYNOPSIS reset_root_defaults() mem_root memory root to change defaults of - block_size new value of block size. Must be - greater than ~68 bytes (the exact value depends on - platform and compilation flags) + block_size new value of block size. Must be greater or equal + than ALLOC_ROOT_MIN_BLOCK_SIZE (this value is about + 68 bytes and depends on platform and compilation flags) pre_alloc_size new size of preallocated block. If not zero, must be equal to or greater than block size, otherwise means 'no prealloc'. @@ -70,7 +91,9 @@ void init_alloc_root(MEM_ROOT *mem_root, uint block_size, void reset_root_defaults(MEM_ROOT *mem_root, uint block_size, uint pre_alloc_size __attribute__((unused))) { - mem_root->block_size= block_size-MALLOC_OVERHEAD-sizeof(USED_MEM)-8; + DBUG_ASSERT(alloc_root_inited(mem_root)); + + mem_root->block_size= block_size - ALLOC_ROOT_MIN_BLOCK_SIZE; #if !(defined(HAVE_purify) && defined(EXTRA_DEBUG)) if (pre_alloc_size) { @@ -123,6 +146,8 @@ gptr alloc_root(MEM_ROOT *mem_root,unsigned int Size) DBUG_ENTER("alloc_root"); DBUG_PRINT("enter",("root: 0x%lx", mem_root)); + DBUG_ASSERT(alloc_root_inited(mem_root)); + Size+=ALIGN_SIZE(sizeof(USED_MEM)); if (!(next = (USED_MEM*) my_malloc(Size,MYF(MY_WME)))) { @@ -140,6 +165,8 @@ gptr alloc_root(MEM_ROOT *mem_root,unsigned int Size) reg1 USED_MEM *next= 0; reg2 USED_MEM **prev; + DBUG_ASSERT(alloc_root_inited(mem_root)); + Size= ALIGN_SIZE(Size); if ((*(prev= &mem_root->free)) != NULL) { |