From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mel Gorman Subject: Re: [PATCH 08/10] vmscan: isolated_lru_pages() stop neighbour search if neighbour cannot be isolated Date: Wed, 8 Sep 2010 12:12:30 +0100 Message-ID: <20100908111230.GC29263@csn.ul.ie> References: <1283770053-18833-1-git-send-email-mel@csn.ul.ie> <1283770053-18833-9-git-send-email-mel@csn.ul.ie> <20100907153708.GF4620@barrios-desktop> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Linux Kernel List , Rik van Riel , Johannes Weiner , Wu Fengguang , Andrea Arcangeli , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Dave Chinner , Chris Mason , Christoph Hellwig , Andrew Morton To: Minchan Kim Return-path: Content-Disposition: inline In-Reply-To: <20100907153708.GF4620@barrios-desktop> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Sep 08, 2010 at 12:37:08AM +0900, Minchan Kim wrote: > On Mon, Sep 06, 2010 at 11:47:31AM +0100, Mel Gorman wrote: > > From: KOSAKI Motohiro > > > > isolate_lru_pages() does not just isolate LRU tail pages, but also isolate > > neighbour pages of the eviction page. The neighbour search does not stop even > > if neighbours cannot be isolated which is excessive as the lumpy reclaim will > > no longer result in a successful higher order allocation. This patch stops > > the PFN neighbour pages if an isolation fails and moves on to the next block. > > > > Signed-off-by: KOSAKI Motohiro > > Signed-off-by: Mel Gorman > > --- > > mm/vmscan.c | 24 ++++++++++++++++-------- > > 1 files changed, 16 insertions(+), 8 deletions(-) > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index 64f9ca5..ff52b46 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -1047,14 +1047,18 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > > continue; > > > > /* Avoid holes within the zone. */ > > - if (unlikely(!pfn_valid_within(pfn))) > > + if (unlikely(!pfn_valid_within(pfn))) { > > + nr_lumpy_failed++; > > break; > > + } > > > > cursor_page = pfn_to_page(pfn); > > > > /* Check that we have not crossed a zone boundary. */ > > - if (unlikely(page_zone_id(cursor_page) != zone_id)) > > - continue; > > + if (unlikely(page_zone_id(cursor_page) != zone_id)) { > > + nr_lumpy_failed++; > > + break; > > + } > > > > /* > > * If we don't have enough swap space, reclaiming of > > @@ -1062,8 +1066,10 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > > * pointless. > > */ > > if (nr_swap_pages <= 0 && PageAnon(cursor_page) && > > - !PageSwapCache(cursor_page)) > > - continue; > > + !PageSwapCache(cursor_page)) { > > + nr_lumpy_failed++; > > + break; > > + } > > > > if (__isolate_lru_page(cursor_page, mode, file) == 0) { > > list_move(&cursor_page->lru, dst); > > @@ -1074,9 +1080,11 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, > > nr_lumpy_dirty++; > > scan++; > > } else { > > - if (mode == ISOLATE_BOTH && > > Why can we remove ISOLATION_BOTH check? Because this is lumpy reclaim and whether we are isolating inactive, active or both doesn't matter. The fact we failed to isolate the page and it has a reference count means that a contiguous allocation in that area will fail. > Is it a intentionall behavior change? > Yes. > > - page_count(cursor_page)) > > - nr_lumpy_failed++; > > + /* the page is freed already. */ > > + if (!page_count(cursor_page)) > > + continue; > > + nr_lumpy_failed++; > > + break; > > } > > } > > } -- 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