On Fri, Jan 23, 2015 at 03:37:28PM -0600, Christoph Lameter wrote: > This patch adds the basic infrastructure for alloc / free operations > on pointer arrays. It includes a fallback function that can perform > the array operations using the single alloc and free that every > slab allocator performs. > > Allocators must define _HAVE_SLAB_ALLOCATOR_OPERATIONS in their > header files in order to implement their own fast version for > these array operations. > > Array operations allow a reduction of the processing overhead > during allocation and therefore speed up acquisition of larger > amounts of objects. > > Signed-off-by: Christoph Lameter <cl@xxxxxxxxx> > > Index: linux/include/linux/slab.h > =================================================================== > --- linux.orig/include/linux/slab.h > +++ linux/include/linux/slab.h > @@ -123,6 +123,7 @@ struct kmem_cache *memcg_create_kmem_cac > void kmem_cache_destroy(struct kmem_cache *); > int kmem_cache_shrink(struct kmem_cache *); > void kmem_cache_free(struct kmem_cache *, void *); > +void kmem_cache_free_array(struct kmem_cache *, size_t, void **); > > /* > * Please use this macro to create slab caches. Simply specify the > @@ -290,6 +291,39 @@ static __always_inline int kmalloc_index > void *__kmalloc(size_t size, gfp_t flags); > void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags); > > +/* > + * Additional flags that may be specified in kmem_cache_alloc_array()'s > + * gfp flags. > + * > + * If no flags are specified then kmem_cache_alloc_array() will first exhaust > + * the partial slab page lists of the local node, then allocate new pages from > + * the page allocator as long as more than objects per page objects are wanted > + * and fill up the rest from local cached objects. If that is not enough then > + * the remaining objects will be allocated via kmem_cache_alloc() > + */ > + > +/* Use objects cached for the processor */ > +#define GFP_SLAB_ARRAY_LOCAL ((__force gfp_t)0x40000000) > + > +/* Use slabs from this node that have objects available */ > +#define GFP_SLAB_ARRAY_PARTIAL ((__force gfp_t)0x20000000) > + > +/* Allocate new slab pages from page allocator */ > +#define GFP_SLAB_ARRAY_NEW ((__force gfp_t)0x10000000) Hello, Christoph. Please correct my e-mail address next time. :) iamjoonsoo.kim@xxxxxxx or js1304@xxxxxxxxx IMHO, exposing these options is not a good idea. It's really implementation specific. And, this flag won't show consistent performance according to specific slab implementation. For example, to get best performance, if SLAB is used, GFP_SLAB_ARRAY_LOCAL would be the best option, but, for the same purpose, if SLUB is used, GFP_SLAB_ARRAY_NEW would be the best option. And, performance could also depend on number of objects and size. And, overriding gfp flag isn't a good idea. Someday gfp could use these values and they can't notice that these are used in slab subsystem with different meaning. Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>