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Remove linear search for blocks when allocating

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cozis
2024-05-08 20:25:37 +02:00
parent b552dd4d11
commit 237a2afd91
2 changed files with 53 additions and 36 deletions
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buddy.h
+12 -7
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@@ -29,20 +29,20 @@
/*
* This is the minimum and maximum block size. The allocator uses free
* lists to keep track of unused blocks, so a block must be at least
* the size of a pointer. We assume a pointer is 8 bytes long, so the
* minimum value must be greater or equal to 3 (log2(8) = 3).
* This is the minimum and maximum block size. The allocator uses doubly
* linked free lists to keep track of unused blocks, so a block must be
* at least the size of two pointers. We assume a pointer is 8 bytes long,
* so the minimum value must be greater or equal to 4 (log2(2*8) = 4).
*
* For the maximum value there is really no downside in making it big,
* except for the fact that the pool provided by the user should at
* least be that big.
*/
#define BUDDY_ALLOC_MAX_BLOCK_LOG2 13
#define BUDDY_ALLOC_MIN_BLOCK_LOG2 3
#define BUDDY_ALLOC_MIN_BLOCK_LOG2 4
_Static_assert(BUDDY_ALLOC_MIN_BLOCK_LOG2 <= BUDDY_ALLOC_MAX_BLOCK_LOG2);
_Static_assert(BUDDY_ALLOC_MIN_BLOCK_LOG2 > 2);
_Static_assert(BUDDY_ALLOC_MIN_BLOCK_LOG2 > 3);
#define BUDDY_ALLOC_NUM_LISTS (BUDDY_ALLOC_MAX_BLOCK_LOG2 - BUDDY_ALLOC_MIN_BLOCK_LOG2 + 1)
#define BUDDY_ALLOC_MAX_BLOCK_SIZE (1U << BUDDY_ALLOC_MAX_BLOCK_LOG2)
@@ -67,10 +67,15 @@ struct page_info {
uint32_t bits[BUDDY_ALLOC_WORDS_PER_PAGE];
};
struct buddy_page {
struct buddy_page *prev;
struct buddy_page *next;
};
struct buddy_alloc {
void *base;
size_t size;
void *lists[BUDDY_ALLOC_NUM_LISTS];
struct buddy_page *lists[BUDDY_ALLOC_NUM_LISTS];
struct page_info *info;
int num_info;
};