slab: infrastructure for bulk object allocation and freeing

Add the basic infrastructure for alloc/free operations on pointer arrays.
It includes a generic function in the common slab code that is used in
this infrastructure patch to create the unoptimized functionality for slab
bulk operations.

Allocators can then provide optimized allocation functions for situations
in which large numbers of objects are needed.  These optimization may
avoid taking locks repeatedly and bypass metadata creation if all objects
in slab pages can be used to provide the objects required.

Allocators can extend the skeletons provided and add their own code to the
bulk alloc and free functions.  They can keep the generic allocation and
freeing and just fall back to those if optimizations would not work (like
for example when debugging is on).

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/slab.h b/include/linux/slab.h
index a99f0e5243e1..7e37d448ed91 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -290,6 +290,16 @@ void *__kmalloc(size_t size, gfp_t flags);
 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags);
 void kmem_cache_free(struct kmem_cache *, void *);
 
+/*
+ * Bulk allocation and freeing operations. These are accellerated in an
+ * allocator specific way to avoid taking locks repeatedly or building
+ * metadata structures unnecessarily.
+ *
+ * Note that interrupts must be enabled when calling these functions.
+ */
+void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
+bool kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
+
 #ifdef CONFIG_NUMA
 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);