From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756229Ab3GCSf5 (ORCPT ); Wed, 3 Jul 2013 14:35:57 -0400 Received: from merlin.infradead.org ([205.233.59.134]:45150 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755366Ab3GCSf4 (ORCPT ); Wed, 3 Jul 2013 14:35:56 -0400 Date: Wed, 3 Jul 2013 20:35:17 +0200 From: Peter Zijlstra To: Mel Gorman Cc: Srikar Dronamraju , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML Subject: Re: [PATCH 12/13] mm: numa: Scan pages with elevated page_mapcount Message-ID: <20130703183517.GC18898@dyad.programming.kicks-ass.net> References: <1372861300-9973-1-git-send-email-mgorman@suse.de> <1372861300-9973-13-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1372861300-9973-13-git-send-email-mgorman@suse.de> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 03, 2013 at 03:21:39PM +0100, Mel Gorman wrote: > Initial support for automatic NUMA balancing was unable to distinguish > between false shared versus private pages except by ignoring pages with an > elevated page_mapcount entirely. This patch kicks away the training wheels > as initial support for identifying shared/private pages is now in place. > Note that the patch still leaves shared, file-backed in VM_EXEC vmas in > place guessing that these are shared library pages. Migrating them are > likely to be of major benefit as generally the expectation would be that > these are read-shared between caches and that iTLB and iCache pressure is > generally low. This reminds me; there a clause in task_numa_work() that skips 'small' VMAs. I don't see the point of that. In fact; when using things like electric fence this might mean skipping most memory.