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Subject[PATCH] SLUB: Fix __GFP_ZERO unlikely() annotation
Date
The unlikely() annotation in slab_alloc() covers too much of the expression.
It's actually very likely that the object is not NULL so use unlikely() only
for the __GFP_ZERO expression like SLAB does.

The patch reduces kernel text by 29 bytes on x86-64:

text data bss dec hex filename
24185 8560 176 32921 8099 mm/slub.o.orig
24156 8560 176 32892 807c mm/slub.o

Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---
mm/slub.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 4996fc7..0956396 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1735,7 +1735,7 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
}
local_irq_restore(flags);

- if (unlikely((gfpflags & __GFP_ZERO) && object))
+ if (unlikely(gfpflags & __GFP_ZERO) && object)
memset(object, 0, objsize);

kmemcheck_slab_alloc(s, gfpflags, object, c->objsize);
--
1.6.3.3


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