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- First attempt to improve memory manager during realloc()'s

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This commit is contained in:
Andi Gutmans 2002-12-09 08:14:00 +00:00
parent 8f6d5dc775
commit 671c6bb4c3
2 changed files with 37 additions and 5 deletions
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41
Zend/zend_mm.c
View File

@ -57,6 +57,7 @@
#define ZEND_MM_ALIGNED_FREE_HEADER_SIZE ZEND_MM_ALIGNED_SIZE(sizeof(zend_mm_free_block))
#define ZEND_MM_ALIGNED_SEGMENT_SIZE ZEND_MM_ALIGNED_SIZE(sizeof(zend_mm_segment))
#define ZEND_MM_ALIGNED_MAX_HEADER_SIZE MAX(ZEND_MM_ALIGNED_HEADER_SIZE, ZEND_MM_ALIGNED_FREE_HEADER_SIZE)
/* Memory calculations */
#define ZEND_MM_BLOCK_AT(blk, offset) ((zend_mm_block *) (((char *) (blk))+(offset)))
@ -152,14 +153,15 @@ zend_bool zend_mm_add_memory_block(zend_mm_heap *heap, size_t block_size)
block_size -= ZEND_MM_ALIGNED_SEGMENT_SIZE;
mm_block = (zend_mm_free_block *) ((char *) segment + ZEND_MM_ALIGNED_SEGMENT_SIZE);
mm_block->size = block_size - ZEND_MM_ALIGNED_FREE_HEADER_SIZE; /* keep one guard block in the end */
mm_block->size = block_size - ZEND_MM_ALIGNED_HEADER_SIZE; /* keep one guard block in the end */
mm_block->type = ZEND_MM_FREE_BLOCK;
mm_block->prev_size = 0; /* Size is always at least ZEND_MM_ALIGNED_HEADER_SIZE big (>0) so 0 is OK */
/* setup guard block */
guard_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
guard_block->type = ZEND_MM_USED_BLOCK;
guard_block->size = ZEND_MM_ALIGNED_FREE_HEADER_SIZE;
guard_block->size = ZEND_MM_ALIGNED_HEADER_SIZE;
guard_block->guard_block = 1;
guard_block->prev_size = mm_block->size;
ZEND_MM_DEBUG(("Setup guard block at 0x%0.8X\n", guard_block));
@ -231,9 +233,9 @@ void *zend_mm_alloc(zend_mm_heap *heap, size_t size)
zend_mm_finished_searching_for_block:
if (!best_fit) {
if (true_size > (heap->block_size - ZEND_MM_ALIGNED_SEGMENT_SIZE - ZEND_MM_ALIGNED_FREE_HEADER_SIZE)) {
if (true_size > (heap->block_size - ZEND_MM_ALIGNED_SEGMENT_SIZE - ZEND_MM_ALIGNED_HEADER_SIZE)) {
/* Make sure we add a memory block which is big enough */
zend_mm_add_memory_block(heap, true_size + ZEND_MM_ALIGNED_SEGMENT_SIZE + ZEND_MM_ALIGNED_FREE_HEADER_SIZE);
zend_mm_add_memory_block(heap, true_size + ZEND_MM_ALIGNED_SEGMENT_SIZE + ZEND_MM_ALIGNED_HEADER_SIZE);
} else {
zend_mm_add_memory_block(heap, heap->block_size);
}
@ -242,6 +244,7 @@ zend_mm_finished_searching_for_block:
/* mark as used */
best_fit->type = ZEND_MM_USED_BLOCK;
((zend_mm_block *) best_fit)->guard_block = 0;
/* remove from free list */
zend_mm_remove_from_free_list(heap, best_fit);
@ -257,7 +260,7 @@ void zend_mm_free(zend_mm_heap *heap, void *p)
zend_mm_block *mm_block = ZEND_MM_HEADER_OF(p);
zend_mm_block *prev_block, *next_block;
if (mm_block->type!=ZEND_MM_USED_BLOCK) {
if (mm_block->type != ZEND_MM_USED_BLOCK) {
/* error */
return;
}
@ -300,6 +303,34 @@ void *zend_mm_realloc(zend_mm_heap *heap, void *p, size_t size)
next_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
if ((mm_block->prev_size == 0) && (next_block->type == ZEND_MM_USED_BLOCK) &&
(next_block->guard_block)) {
zend_mm_segment *segment = (zend_mm_segment *) ((char *)mm_block - ZEND_MM_ALIGNED_SEGMENT_SIZE);
zend_mm_segment *segment_copy = segment;
zend_mm_block *guard_block;
size_t realloc_to_size;
/* segment size, size of block and size of guard block */
realloc_to_size = ZEND_MM_ALIGNED_SEGMENT_SIZE+true_size+ZEND_MM_ALIGNED_HEADER_SIZE;
segment = realloc(segment, realloc_to_size);
if (segment != segment_copy) {
/* The segment moved. Fix the segment list */
fprintf(stderr, "Segment moved! This is not handled right now\n");
exit(1);
}
mm_block->size = true_size;
/* setup guard block */
guard_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
guard_block->type = ZEND_MM_USED_BLOCK;
guard_block->size = ZEND_MM_ALIGNED_HEADER_SIZE;
guard_block->guard_block = 1;
guard_block->prev_size = mm_block->size;
return ZEND_MM_DATA_OF(mm_block);
}
if (next_block->type != ZEND_MM_FREE_BLOCK || (mm_block->size + next_block->size < true_size)) {
void *ptr;

1
Zend/zend_mm.h
View File

@ -32,6 +32,7 @@ typedef struct _zend_mm_block {
unsigned int size : 31;
unsigned int type : 1;
size_t prev_size;
unsigned int guard_block : 1;
} zend_mm_block;
typedef struct _zend_mm_free_block {