Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751344AbZIHPc5 (ORCPT ); Tue, 8 Sep 2009 11:32:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750847AbZIHPc5 (ORCPT ); Tue, 8 Sep 2009 11:32:57 -0400 Received: from smtp2.ultrahosting.com ([74.213.174.253]:39142 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750777AbZIHPc4 (ORCPT ); Tue, 8 Sep 2009 11:32:56 -0400 Date: Tue, 8 Sep 2009 11:32:02 -0400 (EDT) From: Christoph Lameter X-X-Sender: cl@V090114053VZO-1 To: Peter Zijlstra cc: KOSAKI Motohiro , Mike Galbraith , Ingo Molnar , linux-mm , Oleg Nesterov , lkml Subject: Re: [rfc] lru_add_drain_all() vs isolation In-Reply-To: Message-ID: References: <20090908190148.0CC9.A69D9226@jp.fujitsu.com> <1252405209.7746.38.camel@twins> <20090908193712.0CCF.A69D9226@jp.fujitsu.com> <1252411520.7746.68.camel@twins> <1252419602.7746.73.camel@twins> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 867 Lines: 24 The usefulness of a scheme like this requires: 1. There are cpus that continually execute user space code without system interaction. 2. There are repeated VM activities that require page isolation / migration. The first page isolation activity will then clear the lru caches of the processes doing number crunching in user space (and therefore the first isolation will still interrupt). The second and following isolation will then no longer interrupt the processes. 2. is rare. So the question is if the additional code in the LRU handling can be justified. If lru handling is not time sensitive then yes. -- 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/