Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755275Ab1BJNjB (ORCPT ); Thu, 10 Feb 2011 08:39:01 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:33249 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751179Ab1BJNjA convert rfc822-to-8bit (ORCPT ); Thu, 10 Feb 2011 08:39:00 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=C0SYFKfo24uEncvi8vMF1LcmhvuybTMM5VD7+M8blqmIQTzNzS3Ggxr/DhnqYmRUTN OVqEWKgREm+5XhWvaYG1vmN0PO7dGk8X10F75hsIXC0VvLgsgiM0oJMzIBVrZg3GWIZc 1XN22oLkvP3MSTYMJfNVn0233lUhpUot7Ze88= 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 To: Namhyung Kim Cc: Andrew Morton , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1277 Lines: 38 On Thu, Feb 10, 2011 at 10:18 PM, Namhyung Kim wrote: > 2011-02-10 (목), 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. -- Kind regards, Minchan Kim -- 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/