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authorChristoph Lameter <clameter@sgi.com>2007-05-06 14:49:38 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-07 12:12:53 -0700
commit614410d5892af5f86d0ec14e28f9f6d5f4ac9e9b (patch)
tree616c8437f45590a0ca6e2efdc2a5dfb61799d0ec
parent47bfdc0d5a18a4b760ffb6a332932aaa5c0859e0 (diff)
downloadop-kernel-dev-614410d5892af5f86d0ec14e28f9f6d5f4ac9e9b.zip
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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: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/slub_def.h8
-rw-r--r--mm/slub.c2
2 files changed, 7 insertions, 3 deletions
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 30b154c..f8e0c86 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -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)
diff --git a/mm/slub.c b/mm/slub.c
index 4a8585b..9d52cce 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -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? */
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