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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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