Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755326Ab1FTQ42 (ORCPT ); Mon, 20 Jun 2011 12:56:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23562 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751507Ab1FTQ41 (ORCPT ); Mon, 20 Jun 2011 12:56:27 -0400 Message-ID: <4DFF7B99.2060909@redhat.com> Date: Mon, 20 Jun 2011 12:55:53 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.7) Gecko/20100720 Fedora/3.1.1-1.fc13 Lightning/1.0b2pre Thunderbird/3.1.1 MIME-Version: 1.0 To: Andrea Arcangeli CC: Amerigo Wang , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Johannes Weiner , KAMEZAWA Hiroyuki , linux-mm@kvack.org Subject: Re: [PATCH 1/3] mm: completely disable THP by transparent_hugepage=never References: <1308587683-2555-1-git-send-email-amwang@redhat.com> <20110620165035.GE20843@redhat.com> In-Reply-To: <20110620165035.GE20843@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1141 Lines: 25 On 06/20/2011 12:50 PM, Andrea Arcangeli wrote: > On Tue, Jun 21, 2011 at 12:34:28AM +0800, Amerigo Wang wrote: >> transparent_hugepage=never should mean to disable THP completely, >> otherwise we don't have a way to disable THP completely. >> The design is broken. > > We want to allow people to boot with transparent_hugepage=never but to > still allow people to enable it later at runtime. Not sure why you > find it broken... Your patch is just crippling down the feature with > no gain. There is absolutely no gain to disallow root to enable THP > later at runtime with sysfs, root can enable it anyway by writing into > /dev/mem. > > Unless you're root and you enable it, it's completely disabled, so I > don't see what you mean it's not completely disabled. Not even > khugepaged is started, try to grep of khugepaged... Agreed, I don't really see the reason for these patches. Amerigo? -- 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/