From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx130.postini.com [74.125.245.130]) by kanga.kvack.org (Postfix) with SMTP id 595166B00C5 for ; Tue, 11 Sep 2012 07:23:16 -0400 (EDT) Received: by wibhm6 with SMTP id hm6so2815562wib.8 for ; Tue, 11 Sep 2012 04:23:14 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1347324112-14134-1-git-send-email-minchan@kernel.org> Date: Tue, 11 Sep 2012 20:23:14 +0900 Message-ID: Subject: Re: [PATCH] mm: cma: Discard clean pages during contiguous allocation instead of migration From: Kyungmin Park Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Michal Nazarewicz Cc: Minchan Kim , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Marek Szyprowski , Rik van Riel , Mel Gorman On 9/11/12, Michal Nazarewicz wrote: > > On Tue, Sep 11 2012, Minchan Kim wrote: >> This patch drops clean cache pages instead of migration during >> alloc_contig_range() to minimise allocation latency by reducing the >> amount >> of migration is necessary. It's useful for CMA because latency of >> migration >> is more important than evicting the background processes working set. >> In addition, as pages are reclaimed then fewer free pages for migration >> targets are required so it avoids memory reclaiming to get free pages, >> which is a contributory factor to increased latency. >> >> * from v1 >> * drop migrate_mode_t >> * add reclaim_clean_pages_from_list instad of MIGRATE_DISCARD support = - >> Mel >> >> I measured elapsed time of __alloc_contig_migrate_range which migrates >> 10M in 40M movable zone in QEMU machine. >> >> Before - 146ms, After - 7ms >> >> Cc: Marek Szyprowski >> Cc: Michal Nazarewicz > > Acked-by: Michal Nazarewicz Tested-by: Kyungmin Park > > Thanks! > > -- > Best regards, _ _ > .o. | Liege of Serenely Enlightened Majesty of o' \,=3D./ `o > ..o | Computer Science, Micha=C5=82 =E2=80=9Cmina86=E2=80=9D Nazarewicz = (o o) > ooo +------------------ooO--(_)--Ooo-- -- 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