Messages in this thread | | | Date | Fri, 2 Aug 2013 18:27:22 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH 1/4] mm, page_alloc: add likely macro to help compiler optimization |
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On Fri 02-08-13 11:07:56, Joonsoo Kim wrote: > We rarely allocate a page with ALLOC_NO_WATERMARKS and it is used > in slow path. For making fast path more faster, add likely macro to > help compiler optimization.
The code is different in mmotm tree (see mm: page_alloc: rearrange watermark checking in get_page_from_freelist)
Besides that, make sure you provide numbers which prove your claims about performance optimizations.
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index b100255..86ad44b 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1901,7 +1901,7 @@ zonelist_scan: > goto this_zone_full; > > BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK); > - if (!(alloc_flags & ALLOC_NO_WATERMARKS)) { > + if (likely(!(alloc_flags & ALLOC_NO_WATERMARKS))) { > unsigned long mark; > int ret; > > -- > 1.7.9.5 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
-- Michal Hocko SUSE Labs
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