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8fb8e3f636
Instead of searching all memory blocks for available space to fulfill a memory request, only search the head block. If the head block does not have space, assume that previous block would most likely not be able to fulfill request either. This could potentially lead to more memory fragmentation, but also avoids searching memory blocks that probably will not be able to fulfill request. This pattern will benefit consumers that are able to generate a good estimate for how much memory will be needed, or if they are performing fixed sized allocations, so that once a block is exhausted it will never be able to fulfill a future request. Signed-off-by: Jameson Miller <jamill@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
56 lines
1.2 KiB
C
56 lines
1.2 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 mp_block *mem_pool_alloc_block(struct mem_pool *mem_pool, size_t block_alloc)
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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_block = mem_pool->mp_block;
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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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mem_pool->mp_block = p;
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return p;
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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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mem_pool->pool_alloc += len;
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return xmalloc(len);
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}
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p = mem_pool_alloc_block(mem_pool, mem_pool->block_alloc);
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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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