From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933197Ab3AIVsV (ORCPT ); Wed, 9 Jan 2013 16:48:21 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:35342 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933059Ab3AIVsS (ORCPT ); Wed, 9 Jan 2013 16:48:18 -0500 Date: Wed, 9 Jan 2013 13:48:16 -0800 From: Andrew Morton To: Zlatko Calusic Cc: Mel Gorman , Hugh Dickins , Minchan Kim , linux-mm , Linux Kernel Mailing List Subject: Re: [PATCH] mm: wait for congestion to clear on all zones Message-Id: <20130109134816.db51a820.akpm@linux-foundation.org> In-Reply-To: <50EDE41C.7090107@iskon.hr> References: <50EDE41C.7090107@iskon.hr> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 09 Jan 2013 22:41:48 +0100 Zlatko Calusic wrote: > Currently we take a short nap (HZ/10) and wait for congestion to clear > before taking another pass with lower priority in balance_pgdat(). But > we do that only for the highest zone that we encounter is unbalanced > and congested. > > This patch changes that to wait on all congested zones in a single > pass in the hope that it will save us some scanning that way. Also we > take a nap as soon as congested zone is encountered and sc.priority < > DEF_PRIORITY - 2 (aka kswapd in trouble). > > ... > > The patch is against the mm tree. Make sure that > mm-avoid-calling-pgdat_balanced-needlessly.patch is applied first (not > yet in the mmotm tree). Tested on half a dozen systems with different > workloads for the last few days, working really well! But what are the user-observable effcets of this change? Less kernel CPU consumption, presumably? Did you quantify it?