From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932393Ab3GKLV6 (ORCPT ); Thu, 11 Jul 2013 07:21:58 -0400 Received: from merlin.infradead.org ([205.233.59.134]:41608 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932349Ab3GKLV5 (ORCPT ); Thu, 11 Jul 2013 07:21:57 -0400 Date: Thu, 11 Jul 2013 13:21:02 +0200 From: Peter Zijlstra To: Mel Gorman Cc: Srikar Dronamraju , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML Subject: Re: [PATCH 04/16] mm: numa: Do not migrate or account for hinting faults on the zero page Message-ID: <20130711112102.GF25631@dyad.programming.kicks-ass.net> References: <1373536020-2799-1-git-send-email-mgorman@suse.de> <1373536020-2799-5-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1373536020-2799-5-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 Thu, Jul 11, 2013 at 10:46:48AM +0100, Mel Gorman wrote: > +++ b/mm/memory.c > @@ -3560,8 +3560,13 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, > set_pte_at(mm, addr, ptep, pte); > update_mmu_cache(vma, addr, ptep); > > + /* > + * Do not account for faults against the huge zero page. The read-only s/huge // > + * data is likely to be read-cached on the local CPUs and it is less > + * useful to know about local versus remote hits on the zero page. > + */ > page = vm_normal_page(vma, addr, pte); > - if (!page) { > + if (!page || is_zero_pfn(page_to_pfn(page))) { > pte_unmap_unlock(ptep, ptl); > return 0; > } > -- > 1.8.1.4 >