(7/28/13 10:48 AM), SeungHun Lee wrote:
> "order >= MAX_ORDER" case is occur rarely.
>
> So I add unlikely for this check.
> ---
> mm/page_alloc.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index b8475ed..e644cf5 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2408,7 +2408,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
> * be using allocators in order of preference for an area that is
> * too large.
> */
> - if (order >= MAX_ORDER) {
> + if (unlikely(order >= MAX_ORDER)) {
> WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
> return NULL;
I don't think this improve any performance because here is a slowpath. However
I also don't find any issue to have this hint.
Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
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