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Commit 614410d5 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
Browse files

SLUB: allocate smallest object size if the user asks for 0 bytes 



Makes SLUB behave like SLAB in this area to avoid issues....

Throw a stack dump to alert people.

At some point the behavior should be switched back.  NULL is no memory as
far as I can tell and if the use asked for 0 bytes then he need to get no
memory.

Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 47bfdc0d

include/linux/slub_def.h

+6 −2
Original line number Diff line number Diff line
@@ -80,8 +80,12 @@ extern struct kmem_cache kmalloc_caches[KMALLOC_SHIFT_HIGH + 1]; 
 */

static inline int kmalloc_index(int size)

{

	if (size == 0)

		return 0;

	/*

	 * We should return 0 if size == 0 but we use the smallest object

	 * here for SLAB legacy reasons.

	 */

	WARN_ON_ONCE(size == 0);



	if (size > 64 && size <= 96)

		return 1;

	if (size > 128 && size <= 192)

mm/slub.c

+1 −1
Original line number Diff line number Diff line
@@ -1979,7 +1979,7 @@ static struct kmem_cache *get_slab(size_t size, gfp_t flags) 
{

	int index = kmalloc_index(size);



	if (!size)

	if (!index)

		return NULL;



	/* Allocation too large? */