From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id 25DF36B003D for ; Tue, 21 Apr 2009 12:12:10 -0400 (EDT) Date: Tue, 21 Apr 2009 17:12:16 +0100 From: Mel Gorman Subject: Re: [PATCH 17/25] Do not call get_pageblock_migratetype() more than necessary Message-ID: <20090421161215.GD29083@csn.ul.ie> References: <1240266011-11140-1-git-send-email-mel@csn.ul.ie> <1240266011-11140-18-git-send-email-mel@csn.ul.ie> <20090421200154.F174.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20090421200154.F174.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Linux Memory Management List , Christoph Lameter , Nick Piggin , Linux Kernel Mailing List , Lin Ming , Zhang Yanmin , Peter Zijlstra , Pekka Enberg , Andrew Morton List-ID: On Tue, Apr 21, 2009 at 08:03:10PM +0900, KOSAKI Motohiro wrote: > > get_pageblock_migratetype() is potentially called twice for every page > > free. Once, when being freed to the pcp lists and once when being freed > > back to buddy. When freeing from the pcp lists, it is known what the > > pageblock type was at the time of free so use it rather than rechecking. > > In low memory situations under memory pressure, this might skew > > anti-fragmentation slightly but the interference is minimal and > > decisions that are fragmenting memory are being made anyway. > > > > Signed-off-by: Mel Gorman > > Reviewed-by: Christoph Lameter > > --- > > mm/page_alloc.c | 16 ++++++++++------ > > 1 files changed, 10 insertions(+), 6 deletions(-) > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index c57c602..a1ca038 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -456,16 +456,18 @@ static inline int page_is_buddy(struct page *page, struct page *buddy, > > */ > > > > static inline void __free_one_page(struct page *page, > > - struct zone *zone, unsigned int order) > > + struct zone *zone, unsigned int order, > > + int migratetype) > > { > > unsigned long page_idx; > > int order_size = 1 << order; > > - int migratetype = get_pageblock_migratetype(page); > > > > if (unlikely(PageCompound(page))) > > if (unlikely(destroy_compound_page(page, order))) > > return; > > > > + VM_BUG_ON(migratetype == -1); > > + > > page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1); > > > > VM_BUG_ON(page_idx & (order_size - 1)); > > @@ -534,17 +536,18 @@ static void free_pages_bulk(struct zone *zone, int count, > > page = list_entry(list->prev, struct page, lru); > > /* have to delete it as __free_one_page list manipulates */ > > list_del(&page->lru); > > - __free_one_page(page, zone, order); > > + __free_one_page(page, zone, order, page_private(page)); > > } > > spin_unlock(&zone->lock); > > looks good. > Reviewed-by: KOSAKI Motohiro > > > btw, I can't review rest patch today. I plan to do that tommorow, sorry. > No problem. Thanks a million for the work you've done so far. It was a big help and you caught a fair few problems in there. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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