From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id CA89F9000BD for ; Mon, 20 Jun 2011 13:19:09 -0400 (EDT) Message-ID: <4DFF8106.8090702@redhat.com> Date: Tue, 21 Jun 2011 01:19:02 +0800 From: Cong Wang MIME-Version: 1.0 Subject: Re: [PATCH 1/3] mm: completely disable THP by transparent_hugepage=never References: <1308587683-2555-1-git-send-email-amwang@redhat.com> <20110620165844.GA9396@suse.de> <4DFF7E3B.1040404@redhat.com> <4DFF7F0A.8090604@redhat.com> In-Reply-To: <4DFF7F0A.8090604@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: Mel Gorman , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Andrea Arcangeli , Johannes Weiner , KAMEZAWA Hiroyuki , linux-mm@kvack.org ao? 2011a1'06ae??21ae?JPY 01:10, Rik van Riel a??e??: > On 06/20/2011 01:07 PM, Cong Wang wrote: >> ao? 2011a1'06ae??21ae?JPY 00:58, Mel Gorman a??e??: >>> 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. >>>> >>> >>> I don't get why it's broken. Why would the user be prevented from >>> enabling it at runtime? >>> >> >> We need to a way to totally disable it, right? Otherwise, when I configure >> THP in .config, I always have THP initialized even when I pass "=never". >> >> For me, if you don't provide such way to disable it, it is not flexible. >> >> I meet this problem when I try to disable THP in kdump kernel, there is >> no user of THP in kdump kernel, THP is a waste for kdump kernel. This is >> why I need to find a way to totally disable it. > > What you have not explained yet is why having THP > halfway initialized (but not used, and without a > khugepaged thread) is a problem at all. > > Why is it a problem for you? It occupies some memory, memory is valuable in kdump kernel (usually only 128M). :) Since I am sure no one will use it, why do I still need to initialize it at all? Thanks. -- 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