From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932193Ab2EKIie (ORCPT ); Fri, 11 May 2012 04:38:34 -0400 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:42499 "EHLO LGEMRELSE7Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757871Ab2EKIi0 (ORCPT ); Fri, 11 May 2012 04:38:26 -0400 X-AuditID: 9c930197-b7be2ae000000ebb-53-4faccfffd675 Message-ID: <4FACD00D.4060003@kernel.org> Date: Fri, 11 May 2012 17:38:37 +0900 From: Minchan Kim User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120410 Thunderbird/11.0.1 MIME-Version: 1.0 Newsgroups: gmane.linux.kernel.mm,gmane.linux.kernel To: Sasha Levin CC: Hugh Dickins , Linus Torvalds , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: raise MemFree by reverting percpu_pagelist_fraction to 0 References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/11/2012 05:30 PM, Sasha Levin wrote: > On Fri, May 11, 2012 at 10:00 AM, Hugh Dickins wrote: >> Commit 93278814d359 "mm: fix division by 0 in percpu_pagelist_fraction()" >> mistakenly initialized percpu_pagelist_fraction to the sysctl's minimum 8, >> which leaves 1/8th of memory on percpu lists (on each cpu??); but most of >> us expect it to be left unset at 0 (and it's not then used as a divisor). > > I'm a bit confused about this, does it mean that once you set > percpu_pagelist_fraction to a value above the minimum, you can no > longer set it back to being 0? Unfortunately, Yes. :( It's rather awkward and need fix. -- Kind regards, Minchan Kim