Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755871Ab3IPOyz (ORCPT ); Mon, 16 Sep 2013 10:54:55 -0400 Received: from merlin.infradead.org ([205.233.59.134]:53005 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753907Ab3IPOyy (ORCPT ); Mon, 16 Sep 2013 10:54:54 -0400 Date: Mon, 16 Sep 2013 16:54:38 +0200 From: Peter Zijlstra To: Rik van Riel 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 Message-ID: <20130916145438.GT21832@twins.programming.kicks-ass.net> 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> <52370A2F.90006@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52370A2F.90006@redhat.com> 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 Content-Length: 1819 Lines: 46 On Mon, Sep 16, 2013 at 09:39:59AM -0400, Rik van Riel wrote: > 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. Right. > 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. So you're suggesting s/pages/faults/ or somesuch? > IMHO this change makes sense. I never said the change didn't make sense as such. Just that we're no longer counting pages in change_*_range(). -- 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/