From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx149.postini.com [74.125.245.149]) by kanga.kvack.org (Postfix) with SMTP id D2A656B0034 for ; Sun, 16 Jun 2013 14:04:53 -0400 (EDT) Received: by mail-pb0-f53.google.com with SMTP id xb12so2056639pbc.12 for ; Sun, 16 Jun 2013 11:04:53 -0700 (PDT) Date: Sun, 16 Jun 2013 11:04:50 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH] mm: Add unlikely for current_order test In-Reply-To: <51BC4A83.50302@gmail.com> Message-ID: References: <51BC4A83.50302@gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Zhang Yanfei Cc: Andrew Morton , Linux MM , "linux-kernel@vger.kernel.org" On Sat, 15 Jun 2013, Zhang Yanfei wrote: > From: Zhang Yanfei > > Since we have an unlikely for the "current_order >= pageblock_order / 2" > test above, adding an unlikely for this "current_order >= pageblock_order" > test seems more appropriate. > I don't understand the justification at all, current_order being unlikely greater than or equal to pageblock_order / 2 doesn't imply at all that it's unlikely that current_order is greater than or equal to pageblock_order. > Signed-off-by: Zhang Yanfei > --- > 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 c3edb62..1b6d7de 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1071,7 +1071,7 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype) > rmv_page_order(page); > > /* Take ownership for orders >= pageblock_order */ > - if (current_order >= pageblock_order && > + if (unlikely(current_order >= pageblock_order) && > !is_migrate_cma(migratetype)) > change_pageblock_range(page, current_order, > start_migratetype); -- 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: email@kvack.org