Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754474Ab0DFPLd (ORCPT ); Tue, 6 Apr 2010 11:11:33 -0400 Received: from gir.skynet.ie ([193.1.99.77]:50058 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752217Ab0DFPL1 (ORCPT ); Tue, 6 Apr 2010 11:11:27 -0400 Date: Tue, 6 Apr 2010 16:11:07 +0100 From: Mel Gorman To: Arve Hj?nnev?g Cc: KOSAKI Motohiro , TAO HU , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Ye Yuan.Bo-A22116" , Chang Qing-A21550 , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] mm: Check if any page in a pageblock is reserved before marking it MIGRATE_RESERVE Message-ID: <20100406151107.GH17882@csn.ul.ie> References: <20100405101424.GA21207@csn.ul.ie> <1270523356-1728-1-git-send-email-arve@android.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1270523356-1728-1-git-send-email-arve@android.com> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2528 Lines: 71 On Mon, Apr 05, 2010 at 08:09:16PM -0700, Arve Hj?nnev?g wrote: > This fixes a problem where the first pageblock got marked MIGRATE_RESERVE even > though it only had a few free pages. This in turn caused no contiguous memory > to be reserved and frequent kswapd wakeups that emptied the caches to get more > contiguous memory. > > Signed-off-by: Arve Hj?nnev?g I would have used pageblock_reserve_suitable because what you are really checking is "is this page block suitable for use by MIGRATE_RESERVE?". The definition was "is the first page PageReserved" and you are changing it to "does the page block have any memory holes or PageReserved pages?" No biggie though. Change it if you like before upstreaming. Either way. Acked-by: Mel Gorman Thanks > --- > mm/page_alloc.c | 16 +++++++++++++++- > 1 files changed, 15 insertions(+), 1 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index fb7df1d..46ade16 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2860,6 +2860,20 @@ static inline unsigned long wait_table_bits(unsigned long size) > #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1)) > > /* > + * Check if a pageblock contains reserved pages > + */ > +static int pageblock_is_reserved(unsigned long start_pfn) > +{ > + unsigned long end_pfn = start_pfn + pageblock_nr_pages; > + unsigned long pfn; > + > + for (pfn = start_pfn; pfn < end_pfn; pfn++) > + if (!pfn_valid_within(pfn) || PageReserved(pfn_to_page(pfn))) > + return 1; > + return 0; > +} > + > +/* > * Mark a number of pageblocks as MIGRATE_RESERVE. The number > * of blocks reserved is based on min_wmark_pages(zone). The memory within > * the reserve will tend to store contiguous free pages. Setting min_free_kbytes > @@ -2898,7 +2912,7 @@ static void setup_zone_migrate_reserve(struct zone *zone) > continue; > > /* Blocks with reserved pages will never free, skip them. */ > - if (PageReserved(page)) > + if (pageblock_is_reserved(pfn)) > continue; > > block_migratetype = get_pageblock_migratetype(page); > -- > 1.6.5.1 > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/