Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757031Ab3IPNqF (ORCPT ); Mon, 16 Sep 2013 09:46:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:30417 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756942Ab3IPNqB (ORCPT ); Mon, 16 Sep 2013 09:46:01 -0400 Message-ID: <52370A2F.90006@redhat.com> Date: Mon, 16 Sep 2013 09:39:59 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Peter Zijlstra CC: Mel Gorman , Srikar Dronamraju , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML Subject: Re: [PATCH 07/50] mm: Account for a THP NUMA hinting update as one PTE update References: <1378805550-29949-1-git-send-email-mgorman@suse.de> <1378805550-29949-8-git-send-email-mgorman@suse.de> <20130916123645.GD9326@twins.programming.kicks-ass.net> In-Reply-To: <20130916123645.GD9326@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1547 Lines: 41 On 09/16/2013 08:36 AM, Peter Zijlstra wrote: > On Tue, Sep 10, 2013 at 10:31:47AM +0100, Mel Gorman wrote: >> A THP PMD update is accounted for as 512 pages updated in vmstat. This is >> large difference when estimating the cost of automatic NUMA balancing and >> can be misleading when comparing results that had collapsed versus split >> THP. This patch addresses the accounting issue. >> >> Signed-off-by: Mel Gorman >> --- >> mm/mprotect.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/mm/mprotect.c b/mm/mprotect.c >> index 94722a4..2bbb648 100644 >> --- a/mm/mprotect.c >> +++ b/mm/mprotect.c >> @@ -145,7 +145,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, >> split_huge_page_pmd(vma, addr, pmd); >> else if (change_huge_pmd(vma, pmd, addr, newprot, >> prot_numa)) { >> - pages += HPAGE_PMD_NR; >> + pages++; > > But now you're not counting pages anymore.. The migrate statistics still count pages. That makes sense, since the amount of work scales with the amount of memory moved. It is just the "number of faults" counters that actually count the number of faults again, instead of the number of pages represented by each fault. IMHO this change makes sense. -- All rights reversed -- 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/