From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx186.postini.com [74.125.245.186]) by kanga.kvack.org (Postfix) with SMTP id 4B1FA6B004D for ; Sat, 17 Nov 2012 13:20:27 -0500 (EST) Received: by mail-ee0-f41.google.com with SMTP id d41so2695306eek.14 for ; Sat, 17 Nov 2012 10:20:25 -0800 (PST) Message-ID: <50A7D524.2060809@gmail.com> Date: Sat, 17 Nov 2012 19:19:16 +0100 From: Francesco Lavra MIME-Version: 1.0 Subject: Re: [Linaro-mm-sig] [PATCH] mm: skip watermarks check for already isolated blocks in split_free_page() References: <1352357944-14830-1-git-send-email-m.szyprowski@samsung.com> In-Reply-To: <1352357944-14830-1-git-send-email-m.szyprowski@samsung.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Marek Szyprowski Cc: linux-mm@kvack.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, Arnd Bergmann , Bartlomiej Zolnierkiewicz , Mel Gorman , Michal Nazarewicz , Minchan Kim , Kyungmin Park , Andrew Morton Hi, On 11/08/2012 07:59 AM, Marek Szyprowski wrote: > Since commit 2139cbe627b8 ("cma: fix counting of isolated pages") free > pages in isolated pageblocks are not accounted to NR_FREE_PAGES counters, > so watermarks check is not required if one operates on a free page in > isolated pageblock. > > Signed-off-by: Marek Szyprowski > --- > mm/page_alloc.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index fd154fe..43ab09f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1394,10 +1394,12 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype) > zone = page_zone(page); > order = page_order(page); > > - /* Obey watermarks as if the page was being allocated */ > - watermark = low_wmark_pages(zone) + (1 << order); > - if (!zone_watermark_ok(zone, 0, watermark, 0, 0)) > - return 0; > + if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE) { get_pageblock_migratetype(page) is also called later on in this function and assigned to the mt variable: maybe the assignment should be moved before (or inside) the above line? -- Francesco -- 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