From: Christoph Lameter Date: Wed, 28 Nov 2012 16:23:16 +0000 (+0000) Subject: mm/sl[aou]b: Common alignment code X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=4590685546a3;p=linux-beck.git mm/sl[aou]b: Common alignment code Extract the code to do object alignment from the allocators. Do the alignment calculations in slab_common so that the __kmem_cache_create functions of the allocators do not have to deal with alignment. Signed-off-by: Christoph Lameter Signed-off-by: Pekka Enberg --- diff --git a/mm/slab.c b/mm/slab.c index e1790e56fd86..2c3a2e0394db 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2337,22 +2337,6 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) size &= ~(BYTES_PER_WORD - 1); } - /* calculate the final buffer alignment: */ - - /* 1) arch recommendation: can be overridden for debug */ - if (flags & SLAB_HWCACHE_ALIGN) { - /* - * Default alignment: as specified by the arch code. Except if - * an object is really small, then squeeze multiple objects into - * one cacheline. - */ - ralign = cache_line_size(); - while (size <= ralign / 2) - ralign /= 2; - } else { - ralign = BYTES_PER_WORD; - } - /* * Redzoning and user store require word alignment or possibly larger. * Note this will be overridden by architecture or caller mandated @@ -2369,10 +2353,6 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) size &= ~(REDZONE_ALIGN - 1); } - /* 2) arch mandated alignment */ - if (ralign < ARCH_SLAB_MINALIGN) { - ralign = ARCH_SLAB_MINALIGN; - } /* 3) caller mandated alignment */ if (ralign < cachep->align) { ralign = cachep->align; diff --git a/mm/slab.h b/mm/slab.h index 492eafa0b538..1cb9c9ee0e6f 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -32,6 +32,9 @@ extern struct list_head slab_caches; /* The slab cache that manages slab cache information */ extern struct kmem_cache *kmem_cache; +unsigned long calculate_alignment(unsigned long flags, + unsigned long align, unsigned long size); + /* Functions provided by the slab allocators */ extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags); diff --git a/mm/slab_common.c b/mm/slab_common.c index 497b45c25bae..a8e76d79ee65 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -72,6 +72,34 @@ static inline int kmem_cache_sanity_check(const char *name, size_t size) } #endif +/* + * Figure out what the alignment of the objects will be given a set of + * flags, a user specified alignment and the size of the objects. + */ +unsigned long calculate_alignment(unsigned long flags, + unsigned long align, unsigned long size) +{ + /* + * If the user wants hardware cache aligned objects then follow that + * suggestion if the object is sufficiently large. + * + * The hardware cache alignment cannot override the specified + * alignment though. If that is greater then use it. + */ + if (flags & SLAB_HWCACHE_ALIGN) { + unsigned long ralign = cache_line_size(); + while (size <= ralign / 2) + ralign /= 2; + align = max(align, ralign); + } + + if (align < ARCH_SLAB_MINALIGN) + align = ARCH_SLAB_MINALIGN; + + return ALIGN(align, sizeof(void *)); +} + + /* * kmem_cache_create - Create a cache. * @name: A string which is used in /proc/slabinfo to identify this cache. @@ -124,7 +152,7 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); if (s) { s->object_size = s->size = size; - s->align = align; + s->align = calculate_alignment(flags, align, size); s->ctor = ctor; s->name = kstrdup(name, GFP_KERNEL); if (!s->name) { @@ -211,7 +239,7 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t siz s->name = name; s->size = s->object_size = size; - s->align = ARCH_KMALLOC_MINALIGN; + s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size); err = __kmem_cache_create(s, flags); if (err) diff --git a/mm/slob.c b/mm/slob.c index 87e16c4d9143..795bab7d391d 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -123,7 +123,6 @@ static inline void clear_slob_page_free(struct page *sp) #define SLOB_UNIT sizeof(slob_t) #define SLOB_UNITS(size) (((size) + SLOB_UNIT - 1)/SLOB_UNIT) -#define SLOB_ALIGN L1_CACHE_BYTES /* * struct slob_rcu is inserted at the tail of allocated slob blocks, which @@ -527,20 +526,11 @@ EXPORT_SYMBOL(ksize); int __kmem_cache_create(struct kmem_cache *c, unsigned long flags) { - size_t align = c->size; - if (flags & SLAB_DESTROY_BY_RCU) { /* leave room for rcu footer at the end of object */ c->size += sizeof(struct slob_rcu); } c->flags = flags; - /* ignore alignment unless it's forced */ - c->align = (flags & SLAB_HWCACHE_ALIGN) ? SLOB_ALIGN : 0; - if (c->align < ARCH_SLAB_MINALIGN) - c->align = ARCH_SLAB_MINALIGN; - if (c->align < align) - c->align = align; - return 0; } diff --git a/mm/slub.c b/mm/slub.c index c82453ac812a..9640edd2cc78 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2760,32 +2760,6 @@ static inline int calculate_order(int size, int reserved) return -ENOSYS; } -/* - * Figure out what the alignment of the objects will be. - */ -static unsigned long calculate_alignment(unsigned long flags, - unsigned long align, unsigned long size) -{ - /* - * If the user wants hardware cache aligned objects then follow that - * suggestion if the object is sufficiently large. - * - * The hardware cache alignment cannot override the specified - * alignment though. If that is greater then use it. - */ - if (flags & SLAB_HWCACHE_ALIGN) { - unsigned long ralign = cache_line_size(); - while (size <= ralign / 2) - ralign /= 2; - align = max(align, ralign); - } - - if (align < ARCH_SLAB_MINALIGN) - align = ARCH_SLAB_MINALIGN; - - return ALIGN(align, sizeof(void *)); -} - static void init_kmem_cache_node(struct kmem_cache_node *n) { @@ -2919,7 +2893,6 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) { unsigned long flags = s->flags; unsigned long size = s->object_size; - unsigned long align = s->align; int order; /* @@ -2990,20 +2963,12 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) size += sizeof(void *); #endif - /* - * Determine the alignment based on various parameters that the - * user specified and the dynamic determination of cache line size - * on bootup. - */ - align = calculate_alignment(flags, align, s->object_size); - s->align = align; - /* * SLUB stores one object immediately after another beginning from * offset 0. In order to align the objects we have to simply size * each object to conform to the alignment. */ - size = ALIGN(size, align); + size = ALIGN(size, s->align); s->size = size; if (forced_order >= 0) order = forced_order; @@ -3032,7 +2997,6 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) s->max = s->oo; return !!oo_objects(s->oo); - } static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)