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    SubjectRe: [patch 1/5] mm: page_alloc: increase __GFP_BITS_SHIFT to include __GFP_OTHER_NODE
    On Mon 25-07-11 22:19:15, Johannes Weiner wrote:
    > From: Johannes Weiner <hannes@cmpxchg.org>
    >
    > __GFP_OTHER_NODE is used for NUMA allocations on behalf of other
    > nodes. It's supposed to be passed through from the page allocator to
    > zone_statistics(), but it never gets there as gfp_allowed_mask is not
    > wide enough and masks out the flag early in the allocation path.
    >
    > The result is an accounting glitch where successful NUMA allocations
    > by-agent are not properly attributed as local.
    >
    > Increase __GFP_BITS_SHIFT so that it includes __GFP_OTHER_NODE.
    >
    > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

    Reviewed-by: Michal Hocko <mhocko@suse.cz>

    > ---
    > include/linux/gfp.h | 2 +-
    > 1 files changed, 1 insertions(+), 1 deletions(-)
    >
    > diff --git a/include/linux/gfp.h b/include/linux/gfp.h
    > index cb40892..3a76faf 100644
    > --- a/include/linux/gfp.h
    > +++ b/include/linux/gfp.h
    > @@ -92,7 +92,7 @@ struct vm_area_struct;
    > */
    > #define __GFP_NOTRACK_FALSE_POSITIVE (__GFP_NOTRACK)
    >
    > -#define __GFP_BITS_SHIFT 23 /* Room for 23 __GFP_FOO bits */
    > +#define __GFP_BITS_SHIFT 24 /* Room for N __GFP_FOO bits */
    > #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
    >
    > /* This equals 0, but use constants in case they ever change */
    > --
    > 1.7.6

    --
    Michal Hocko
    SUSE Labs
    SUSE LINUX s.r.o.
    Lihovarska 1060/12
    190 00 Praha 9
    Czech Republic


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