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108 lines
2.5 KiB
108 lines
2.5 KiB
2 months ago
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/*
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* UCW Library -- Fast Allocator for Fixed-Size Elements
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*
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* (c) 2007 Martin Mares <mj@ucw.cz>
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*
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* This software may be freely distributed and used according to the terms
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* of the GNU Lesser General Public License.
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*/
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/*
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* This allocator is optimized for intensive allocation and freeing of small
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* blocks of identical sizes. System memory is allocated by multiples of the
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* page size and it is returned back only when the whole eltpool is deleted.
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*
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* In the future, we can add returning of memory to the system and also cache
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* coloring like in the SLAB allocator used in the Linux kernel.
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*/
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#undef LOCAL_DEBUG
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#include <ucw/lib.h>
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#include <ucw/eltpool.h>
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struct eltpool *
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ep_new(uint elt_size, uint elts_per_chunk)
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{
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struct eltpool *pool = xmalloc_zero(sizeof(*pool));
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pool->elt_size = ALIGN_TO(MAX(elt_size, sizeof(struct eltpool_free)), CPU_STRUCT_ALIGN);
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pool->chunk_size = CPU_PAGE_SIZE;
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while (pool->elt_size * elts_per_chunk + sizeof(struct eltpool_chunk) > pool->chunk_size)
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pool->chunk_size *= 2;
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pool->elts_per_chunk = (pool->chunk_size - sizeof(struct eltpool_chunk)) / pool->elt_size;
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DBG("ep_new(): got elt_size=%d, epc=%d; used chunk_size=%d, epc=%d", elt_size, elts_per_chunk, pool->chunk_size, pool->elts_per_chunk);
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return pool;
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}
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void
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ep_delete(struct eltpool *pool)
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{
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struct eltpool_chunk *ch;
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while (ch = pool->first_chunk)
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{
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pool->first_chunk = ch->next;
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page_free(ch, pool->chunk_size);
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}
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xfree(pool);
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}
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void *
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ep_alloc_slow(struct eltpool *pool)
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{
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struct eltpool_chunk *ch = page_alloc(pool->chunk_size);
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void *p = (void *)(ch+1);
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for (uint i=1; i<pool->elts_per_chunk; i++)
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{
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struct eltpool_free *f = p;
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f->next = pool->first_free;
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pool->first_free = f;
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p += pool->elt_size;
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}
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ch->next = pool->first_chunk;
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pool->first_chunk = ch;
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pool->num_chunks++;
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return p;
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}
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u64
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ep_total_size(struct eltpool *pool)
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{
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return (u64)pool->num_chunks * pool->chunk_size + sizeof(*pool);
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}
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#ifdef TEST
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#include <stdio.h>
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#include <ucw/clists.h>
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struct argh {
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cnode n;
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byte x[1];
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} PACKED;
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int main(void)
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{
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struct eltpool *ep = ep_new(sizeof(struct argh), 64);
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clist l;
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clist_init(&l);
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for (uint i=0; i<65536; i++)
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{
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struct argh *a = ep_alloc(ep);
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if (i % 3)
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clist_add_tail(&l, &a->n);
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else
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clist_add_head(&l, &a->n);
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if (!(i % 5))
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{
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a = clist_head(&l);
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clist_remove(&a->n);
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ep_free(ep, a);
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}
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}
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ep_delete(ep);
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puts("OK");
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return 0;
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}
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#endif
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