Messages in this thread Patch in this message | | | From | Bernd Eckenfels <> | Subject | Re: [PATCH] kmem_find_general_cachep to static inline | Date | Wed, 05 Dec 2001 07:58:41 +0100 |
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In article <m16BKdv-000CgdC@Wasteland> you wrote: > First patch, please explain what I did wrong :)
Nothing, but can be improved further.
One can use that function in kmalloc() and then optimize the function using a binary search.
--- slab.c 2001/09/21 16:28:50 1.27 +++ slab.c 2001/12/05 07:51:58 @@ -1533,14 +1533,13 @@ */ void * kmalloc (size_t size, int flags) { - cache_sizes_t *csizep = cache_sizes; + kmem_cache_t *cp; + + cp = kmem_find_general_cachep(size, flags); + + if (cp) + return __kmem_cache_alloc(cp, flags); - for (; csizep->cs_size; csizep++) { - if (size > csizep->cs_size) - continue; - return __kmem_cache_alloc(flags & GFP_DMA ? - csizep->cs_dmacachep : csizep->cs_cachep, flags); - } return NULL; }
the patch for having the binary search will look something like:
From: Momchil Velikov <velco@fadata.bg>
@@ -1589,18 +1583,66 @@ void kfree (const void *objp)
kmem_cache_t * kmem_find_general_cachep (size_t size, int gfpflags) { - cache_sizes_t *csizep = cache_sizes; + int idx; - /* This function could be moved to the header file, and - * made inline so consumers can quickly determine what - * cache pointer they require. - */ - for ( ; csizep->cs_size; csizep++) { - if (size > csizep->cs_size) - continue; + switch (size) { +#if PAGE_SIZE == 4096 + case 0 ... 32: + idx = 0; + break; + case 33 ... 64: + idx = 1; + break; +#else + case 0 ... 64: + idx = 1; + break; +#endif + case 65 ... 128: + idx = 2; + break; + case 129 ... 256: + idx = 3; + break; + case 257 ...512: + idx = 4; + break; + case 513 ... 1024: + idx = 5; + break; + case 1025 ... 2048: + idx = 6; + break; + case 2049 ... 4096: + idx = 7; + break; + case 4097 ... 8192: + idx = 8; + break; + case 8193 ... 16384: + idx = 9; + break; + case 16385 ... 32768: + idx = 10; + break; + case 32769 ... 65536: + idx = 11; + break; + case 65537 ... 131072: + idx = 12; + break; + default: + idx = -1; break; } - return (gfpflags & GFP_DMA) ? csizep->cs_dmacachep : csizep->cs_cachep; + + if (idx == -1) + return NULL; + +#if PAGE_SIZE != 4096 + idx = idx - 1; +#endif + return (gfpflags & GFP_DMA) ? cache_sizes [idx].cs_dmacachep : cache_sizes [idx].cs_cachep; } #ifdef CONFIG_SMP
I have not tested yet if the "idx -1" is optimized good, or if it is better to have assigend idx the values depending on the #define. But otherwise it should work well.
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