зеркало из https://github.com/microsoft/git.git
151 строка
3.5 KiB
C
151 строка
3.5 KiB
C
/*
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* Memory Pool implementation logic.
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*/
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#include "cache.h"
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#include "mem-pool.h"
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static struct trace_key trace_mem_pool = TRACE_KEY_INIT(MEMPOOL);
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#define BLOCK_GROWTH_SIZE 1024*1024 - sizeof(struct mp_block);
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/*
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* Allocate a new mp_block and insert it after the block specified in
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* `insert_after`. If `insert_after` is NULL, then insert block at the
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* head of the linked list.
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*/
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static struct mp_block *mem_pool_alloc_block(struct mem_pool *mem_pool, size_t block_alloc, struct mp_block *insert_after)
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{
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struct mp_block *p;
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mem_pool->pool_alloc += sizeof(struct mp_block) + block_alloc;
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p = xmalloc(st_add(sizeof(struct mp_block), block_alloc));
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p->next_free = (char *)p->space;
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p->end = p->next_free + block_alloc;
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if (insert_after) {
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p->next_block = insert_after->next_block;
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insert_after->next_block = p;
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} else {
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p->next_block = mem_pool->mp_block;
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mem_pool->mp_block = p;
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}
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return p;
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}
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void mem_pool_init(struct mem_pool **mem_pool, size_t initial_size)
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{
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struct mem_pool *pool;
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if (*mem_pool)
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return;
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pool = xcalloc(1, sizeof(*pool));
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pool->block_alloc = BLOCK_GROWTH_SIZE;
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if (initial_size > 0)
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mem_pool_alloc_block(pool, initial_size, NULL);
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*mem_pool = pool;
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trace_printf_key(&trace_mem_pool, "mem_pool (%p): init (%"PRIuMAX") initial size\n",
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pool, (uintmax_t)initial_size);
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}
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void mem_pool_discard(struct mem_pool *mem_pool, int invalidate_memory)
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{
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struct mp_block *block, *block_to_free;
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trace_printf_key(&trace_mem_pool, "mem_pool (%p): discard (%"PRIuMAX") unused\n",
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mem_pool, (uintmax_t)(mem_pool->mp_block->end - mem_pool->mp_block->next_free));
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block = mem_pool->mp_block;
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while (block)
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{
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block_to_free = block;
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block = block->next_block;
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if (invalidate_memory)
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memset(block_to_free->space, 0xDD, ((char *)block_to_free->end) - ((char *)block_to_free->space));
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free(block_to_free);
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}
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free(mem_pool);
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}
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void *mem_pool_alloc(struct mem_pool *mem_pool, size_t len)
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{
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struct mp_block *p = NULL;
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void *r;
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/* round up to a 'uintmax_t' alignment */
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if (len & (sizeof(uintmax_t) - 1))
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len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
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if (mem_pool->mp_block &&
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mem_pool->mp_block->end - mem_pool->mp_block->next_free >= len)
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p = mem_pool->mp_block;
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if (!p) {
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if (len >= (mem_pool->block_alloc / 2))
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return mem_pool_alloc_block(mem_pool, len, mem_pool->mp_block);
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p = mem_pool_alloc_block(mem_pool, mem_pool->block_alloc, NULL);
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}
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r = p->next_free;
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p->next_free += len;
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return r;
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}
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void *mem_pool_calloc(struct mem_pool *mem_pool, size_t count, size_t size)
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{
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size_t len = st_mult(count, size);
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void *r = mem_pool_alloc(mem_pool, len);
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memset(r, 0, len);
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return r;
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}
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int mem_pool_contains(struct mem_pool *mem_pool, void *mem)
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{
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struct mp_block *p;
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/* Check if memory is allocated in a block */
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for (p = mem_pool->mp_block; p; p = p->next_block)
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if ((mem >= ((void *)p->space)) &&
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(mem < ((void *)p->end)))
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return 1;
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return 0;
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}
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void mem_pool_combine(struct mem_pool *dst, struct mem_pool *src)
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{
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struct mp_block *p;
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/* Append the blocks from src to dst */
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if (dst->mp_block && src->mp_block) {
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/*
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* src and dst have blocks, append
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* blocks from src to dst.
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*/
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p = dst->mp_block;
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while (p->next_block)
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p = p->next_block;
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p->next_block = src->mp_block;
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} else if (src->mp_block) {
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/*
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* src has blocks, dst is empty.
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*/
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dst->mp_block = src->mp_block;
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} else {
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/* src is empty, nothing to do. */
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}
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dst->pool_alloc += src->pool_alloc;
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src->pool_alloc = 0;
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src->mp_block = NULL;
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}
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