From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id A124E8D0039 for ; Thu, 10 Feb 2011 08:39:01 -0500 (EST) Received: by iwc10 with SMTP id 10so1314100iwc.14 for ; Thu, 10 Feb 2011 05:38:59 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1297343929.1449.3.camel@leonhard> References: <1297338408-3590-1-git-send-email-namhyung@gmail.com> <1297343929.1449.3.camel@leonhard> Date: Thu, 10 Feb 2011 22:38:59 +0900 Message-ID: Subject: Re: [RFC PATCH] mm: handle simple case in free_pcppages_bulk() From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Namhyung Kim Cc: Andrew Morton , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, Feb 10, 2011 at 10:18 PM, Namhyung Kim wrote: > 2011-02-10 (=EB=AA=A9), 22:10 +0900, Minchan Kim: >> Hello Namhyung, >> > > Hi Minchan, > > >> On Thu, Feb 10, 2011 at 8:46 PM, Namhyung Kim wrote= : >> > Now I'm seeing that there are some cases to free all pages in a >> > pcp lists. In that case, just frees all pages in the lists instead >> > of being bothered with round-robin lists traversal. >> >> I though about that but I didn't send the patch. >> That's because many cases which calls free_pcppages_bulk(, >> pcp->count,..) are slow path so it adds comparison overhead on fast >> path while it loses the effectiveness in slow path. >> > > Hmm.. How about adding unlikely() then? Doesn't it help much here? Yes. It would help but I am not sure how much it is. AFAIR, when Mel submit the patch, he tried to prove the effectiveness with some experiment and profiler. I think if you want it really, we might need some number. I am not sure it's worth. --=20 Kind regards, Minchan Kim -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org