Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756937Ab1FVKr4 (ORCPT ); Wed, 22 Jun 2011 06:47:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46187 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755128Ab1FVKrx (ORCPT ); Wed, 22 Jun 2011 06:47:53 -0400 Message-ID: <4E01C80F.8070605@redhat.com> Date: Wed, 22 Jun 2011 18:46:39 +0800 From: Cong Wang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc14 Thunderbird/3.1.10 MIME-Version: 1.0 To: Mel Gorman CC: Mel Gorman , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Andrea Arcangeli , Benjamin Herrenschmidt , Rik van Riel , Johannes Weiner , KAMEZAWA Hiroyuki , linux-mm@kvack.org Subject: Re: [PATCH 2/3] mm: make the threshold of enabling THP configurable References: <1308587683-2555-1-git-send-email-amwang@redhat.com> <1308587683-2555-2-git-send-email-amwang@redhat.com> <20110620165955.GB9396@suse.de> <4DFF8050.9070201@redhat.com> <20110621093640.GD9396@suse.de> <4E015672.2020407@redhat.com> <20110622091611.GB7585@csn.ul.ie> In-Reply-To: <20110622091611.GB7585@csn.ul.ie> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1024 Lines: 25 于 2011年06月22日 17:16, Mel Gorman 写道: > > What I meant was that there is a rational reason why 512M is the > default for enabling THP by default. Tuning it lower than that by any > means makes very little sense. Tuning it higher might make some sense > but it is more likely that THP would simply be disabled via sysctl. I > see very little advantage to introducing this Kconfig option other > than as a source of confusion when running make oldconfig. > The tunable range is (512, 8192), so 512M is the minimum. Sure, I knew it can be disabled via /sys, actually we can do even more in user-space, that is totally move the 512M check out of kernel, why we didn't? In short, I think we should either remove the 512M from kernel, or make 512M to be tunable. Thanks. -- 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/