Extract the optimized lookup functions from slub and put them into slab_common.c. Then make slab use these functions as well. Joonsoo notes that this fixes some issues with constant folding which also reduces the code size for slub. https://lkml.org/lkml/2012/10/20/82 Signed-off-by: Christoph Lameter <cl@xxxxxxxxx> Index: linux/mm/slab.c =================================================================== --- linux.orig/mm/slab.c 2013-01-10 09:55:50.169745534 -0600 +++ linux/mm/slab.c 2013-01-10 09:55:55.401828014 -0600 @@ -656,40 +656,6 @@ static inline struct array_cache *cpu_ca return cachep->array[smp_processor_id()]; } -static inline struct kmem_cache *__find_general_cachep(size_t size, - gfp_t gfpflags) -{ - int i; - -#if DEBUG - /* This happens if someone tries to call - * kmem_cache_create(), or __kmalloc(), before - * the generic caches are initialized. - */ - BUG_ON(kmalloc_caches[INDEX_AC] == NULL); -#endif - if (!size) - return ZERO_SIZE_PTR; - - i = kmalloc_index(size); - - /* - * Really subtle: The last entry with cs->cs_size==ULONG_MAX - * has cs_{dma,}cachep==NULL. Thus no special case - * for large kmalloc calls required. - */ -#ifdef CONFIG_ZONE_DMA - if (unlikely(gfpflags & GFP_DMA)) - return kmalloc_dma_caches[i]; -#endif - return kmalloc_caches[i]; -} - -static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags) -{ - return __find_general_cachep(size, gfpflags); -} - static size_t slab_mgmt_size(size_t nr_objs, size_t align) { return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align); @@ -2426,7 +2392,7 @@ __kmem_cache_create (struct kmem_cache * cachep->reciprocal_buffer_size = reciprocal_value(size); if (flags & CFLGS_OFF_SLAB) { - cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u); + cachep->slabp_cache = kmalloc_slab(slab_size, 0u); /* * This is a possibility for one of the malloc_sizes caches. * But since we go off slab only for object size greater than @@ -3729,7 +3695,7 @@ __do_kmalloc_node(size_t size, gfp_t fla { struct kmem_cache *cachep; - cachep = kmem_find_general_cachep(size, flags); + cachep = kmalloc_slab(size, flags); if (unlikely(ZERO_OR_NULL_PTR(cachep))) return cachep; return kmem_cache_alloc_node_trace(cachep, flags, node, size); @@ -3774,7 +3740,7 @@ static __always_inline void *__do_kmallo * Then kmalloc uses the uninlined functions instead of the inline * functions. */ - cachep = __find_general_cachep(size, flags); + cachep = kmalloc_slab(size, flags); if (unlikely(ZERO_OR_NULL_PTR(cachep))) return cachep; ret = slab_alloc(cachep, flags, caller); Index: linux/mm/slab.h =================================================================== --- linux.orig/mm/slab.h 2013-01-10 09:55:50.169745534 -0600 +++ linux/mm/slab.h 2013-01-10 09:55:55.401828014 -0600 @@ -38,6 +38,9 @@ unsigned long calculate_alignment(unsign #ifndef CONFIG_SLOB /* Kmalloc array related functions */ void create_kmalloc_caches(unsigned long); + +/* Find the kmalloc slab corresponding for a certain size */ +struct kmem_cache *kmalloc_slab(size_t, gfp_t); #endif Index: linux/mm/slab_common.c =================================================================== --- linux.orig/mm/slab_common.c 2013-01-10 09:55:50.169745534 -0600 +++ linux/mm/slab_common.c 2013-01-10 09:55:55.401828014 -0600 @@ -328,6 +328,68 @@ EXPORT_SYMBOL(kmalloc_dma_caches); #endif /* + * Conversion table for small slabs sizes / 8 to the index in the + * kmalloc array. This is necessary for slabs < 192 since we have non power + * of two cache sizes there. The size of larger slabs can be determined using + * fls. + */ +static s8 size_index[24] = { + 3, /* 8 */ + 4, /* 16 */ + 5, /* 24 */ + 5, /* 32 */ + 6, /* 40 */ + 6, /* 48 */ + 6, /* 56 */ + 6, /* 64 */ + 1, /* 72 */ + 1, /* 80 */ + 1, /* 88 */ + 1, /* 96 */ + 7, /* 104 */ + 7, /* 112 */ + 7, /* 120 */ + 7, /* 128 */ + 2, /* 136 */ + 2, /* 144 */ + 2, /* 152 */ + 2, /* 160 */ + 2, /* 168 */ + 2, /* 176 */ + 2, /* 184 */ + 2 /* 192 */ +}; + +static inline int size_index_elem(size_t bytes) +{ + return (bytes - 1) / 8; +} + +/* + * Find the kmem_cache structure that serves a given size of + * allocation + */ +struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) +{ + int index; + + if (size <= 192) { + if (!size) + return ZERO_SIZE_PTR; + + index = size_index[size_index_elem(size)]; + } else + index = fls(size - 1); + +#ifdef CONFIG_ZONE_DMA + if (unlikely((flags & SLAB_CACHE_DMA))) + return kmalloc_dma_caches[index]; + +#endif + return kmalloc_caches[index]; +} + +/* * Create the kmalloc array. Some of the regular kmalloc arrays * may already have been created because they were needed to * enable allocations for slab creation. @@ -336,6 +398,47 @@ void __init create_kmalloc_caches(unsign { int i; + /* + * Patch up the size_index table if we have strange large alignment + * requirements for the kmalloc array. This is only the case for + * MIPS it seems. The standard arches will not generate any code here. + * + * Largest permitted alignment is 256 bytes due to the way we + * handle the index determination for the smaller caches. + * + * Make sure that nothing crazy happens if someone starts tinkering + * around with ARCH_KMALLOC_MINALIGN + */ + BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || + (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); + + for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { + int elem = size_index_elem(i); + + if (elem >= ARRAY_SIZE(size_index)) + break; + size_index[elem] = KMALLOC_SHIFT_LOW; + } + + if (KMALLOC_MIN_SIZE >= 64) { + /* + * The 96 byte size cache is not used if the alignment + * is 64 byte. + */ + for (i = 64 + 8; i <= 96; i += 8) + size_index[size_index_elem(i)] = 7; + + } + + if (KMALLOC_MIN_SIZE >= 128) { + /* + * The 192 byte sized cache is not used if the alignment + * is 128 byte. Redirect kmalloc to use the 256 byte cache + * instead. + */ + for (i = 128 + 8; i <= 192; i += 8) + size_index[size_index_elem(i)] = 8; + } /* Caches that are not of the two-to-the-power-of size */ if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1]) kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags); @@ -379,8 +482,6 @@ void __init create_kmalloc_caches(unsign } #endif } - - #endif /* !CONFIG_SLOB */ Index: linux/mm/slub.c =================================================================== --- linux.orig/mm/slub.c 2013-01-10 09:55:50.173745560 -0600 +++ linux/mm/slub.c 2013-01-10 09:55:55.405828073 -0600 @@ -2982,7 +2982,7 @@ static int calculate_sizes(struct kmem_c s->allocflags |= __GFP_COMP; if (s->flags & SLAB_CACHE_DMA) - s->allocflags |= SLUB_DMA; + s->allocflags |= GFP_DMA; if (s->flags & SLAB_RECLAIM_ACCOUNT) s->allocflags |= __GFP_RECLAIMABLE; @@ -3210,64 +3210,6 @@ static int __init setup_slub_nomerge(cha __setup("slub_nomerge", setup_slub_nomerge); -/* - * Conversion table for small slabs sizes / 8 to the index in the - * kmalloc array. This is necessary for slabs < 192 since we have non power - * of two cache sizes there. The size of larger slabs can be determined using - * fls. - */ -static s8 size_index[24] = { - 3, /* 8 */ - 4, /* 16 */ - 5, /* 24 */ - 5, /* 32 */ - 6, /* 40 */ - 6, /* 48 */ - 6, /* 56 */ - 6, /* 64 */ - 1, /* 72 */ - 1, /* 80 */ - 1, /* 88 */ - 1, /* 96 */ - 7, /* 104 */ - 7, /* 112 */ - 7, /* 120 */ - 7, /* 128 */ - 2, /* 136 */ - 2, /* 144 */ - 2, /* 152 */ - 2, /* 160 */ - 2, /* 168 */ - 2, /* 176 */ - 2, /* 184 */ - 2 /* 192 */ -}; - -static inline int size_index_elem(size_t bytes) -{ - return (bytes - 1) / 8; -} - -static struct kmem_cache *get_slab(size_t size, gfp_t flags) -{ - int index; - - if (size <= 192) { - if (!size) - return ZERO_SIZE_PTR; - - index = size_index[size_index_elem(size)]; - } else - index = fls(size - 1); - -#ifdef CONFIG_ZONE_DMA - if (unlikely((flags & SLUB_DMA))) - return kmalloc_dma_caches[index]; - -#endif - return kmalloc_caches[index]; -} - void *__kmalloc(size_t size, gfp_t flags) { struct kmem_cache *s; @@ -3276,7 +3218,7 @@ void *__kmalloc(size_t size, gfp_t flags if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) return kmalloc_large(size, flags); - s = get_slab(size, flags); + s = kmalloc_slab(size, flags); if (unlikely(ZERO_OR_NULL_PTR(s))) return s; @@ -3319,7 +3261,7 @@ void *__kmalloc_node(size_t size, gfp_t return ret; } - s = get_slab(size, flags); + s = kmalloc_slab(size, flags); if (unlikely(ZERO_OR_NULL_PTR(s))) return s; @@ -3632,7 +3574,6 @@ void __init kmem_cache_init(void) { static __initdata struct kmem_cache boot_kmem_cache, boot_kmem_cache_node; - int i; if (debug_guardpage_minorder()) slub_max_order = 0; @@ -3663,45 +3604,6 @@ void __init kmem_cache_init(void) kmem_cache_node = bootstrap(&boot_kmem_cache_node); /* Now we can use the kmem_cache to allocate kmalloc slabs */ - - /* - * Patch up the size_index table if we have strange large alignment - * requirements for the kmalloc array. This is only the case for - * MIPS it seems. The standard arches will not generate any code here. - * - * Largest permitted alignment is 256 bytes due to the way we - * handle the index determination for the smaller caches. - * - * Make sure that nothing crazy happens if someone starts tinkering - * around with ARCH_KMALLOC_MINALIGN - */ - BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || - (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); - - for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { - int elem = size_index_elem(i); - if (elem >= ARRAY_SIZE(size_index)) - break; - size_index[elem] = KMALLOC_SHIFT_LOW; - } - - if (KMALLOC_MIN_SIZE == 64) { - /* - * The 96 byte size cache is not used if the alignment - * is 64 byte. - */ - for (i = 64 + 8; i <= 96; i += 8) - size_index[size_index_elem(i)] = 7; - } else if (KMALLOC_MIN_SIZE == 128) { - /* - * The 192 byte sized cache is not used if the alignment - * is 128 byte. Redirect kmalloc to use the 256 byte cache - * instead. - */ - for (i = 128 + 8; i <= 192; i += 8) - size_index[size_index_elem(i)] = 8; - } - create_kmalloc_caches(0); #ifdef CONFIG_SMP @@ -3877,7 +3779,7 @@ void *__kmalloc_track_caller(size_t size if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) return kmalloc_large(size, gfpflags); - s = get_slab(size, gfpflags); + s = kmalloc_slab(size, gfpflags); if (unlikely(ZERO_OR_NULL_PTR(s))) return s; @@ -3907,7 +3809,7 @@ void *__kmalloc_node_track_caller(size_t return ret; } - s = get_slab(size, gfpflags); + s = kmalloc_slab(size, gfpflags); if (unlikely(ZERO_OR_NULL_PTR(s))) return s; Index: linux/include/linux/slub_def.h =================================================================== --- linux.orig/include/linux/slub_def.h 2013-01-10 09:55:49.489734859 -0600 +++ linux/include/linux/slub_def.h 2013-01-10 09:55:55.405828073 -0600 @@ -115,29 +115,6 @@ struct kmem_cache { struct kmem_cache_node *node[MAX_NUMNODES]; }; -#ifdef CONFIG_ZONE_DMA -#define SLUB_DMA __GFP_DMA -#else -/* Disable DMA functionality */ -#define SLUB_DMA (__force gfp_t)0 -#endif - -/* - * Find the slab cache for a given combination of allocation flags and size. - * - * This ought to end up with a global pointer to the right cache - * in kmalloc_caches. - */ -static __always_inline struct kmem_cache *kmalloc_slab(size_t size) -{ - int index = kmalloc_index(size); - - if (index == 0) - return NULL; - - return kmalloc_caches[index]; -} - void *kmem_cache_alloc(struct kmem_cache *, gfp_t); void *__kmalloc(size_t size, gfp_t flags); @@ -195,13 +172,14 @@ static __always_inline void *kmalloc(siz if (size > KMALLOC_MAX_CACHE_SIZE) return kmalloc_large(size, flags); - if (!(flags & SLUB_DMA)) { - struct kmem_cache *s = kmalloc_slab(size); + if (!(flags & GFP_DMA)) { + int index = kmalloc_index(size); - if (!s) + if (!index) return ZERO_SIZE_PTR; - return kmem_cache_alloc_trace(s, flags, size); + return kmem_cache_alloc_trace(kmalloc_caches[index], + flags, size); } } return __kmalloc(size, flags); @@ -228,13 +206,14 @@ kmem_cache_alloc_node_trace(struct kmem_ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node) { if (__builtin_constant_p(size) && - size <= KMALLOC_MAX_CACHE_SIZE && !(flags & SLUB_DMA)) { - struct kmem_cache *s = kmalloc_slab(size); + size <= KMALLOC_MAX_CACHE_SIZE && !(flags & GFP_DMA)) { + int index = kmalloc_index(size); - if (!s) + if (!index) return ZERO_SIZE_PTR; - return kmem_cache_alloc_node_trace(s, flags, node, size); + return kmem_cache_alloc_node_trace(kmalloc_caches[index], + flags, node, size); } return __kmalloc_node(size, flags, node); } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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