Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751002Ab3IPQNE (ORCPT ); Mon, 16 Sep 2013 12:13:04 -0400 Received: from cantor2.suse.de ([195.135.220.15]:47214 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750741Ab3IPQND (ORCPT ); Mon, 16 Sep 2013 12:13:03 -0400 Date: Mon, 16 Sep 2013 17:11:50 +0100 From: Mel Gorman To: Peter Zijlstra Cc: Rik van Riel , 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: <20130916161150.GF22421@suse.de> 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> <20130916145438.GT21832@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20130916145438.GT21832@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2094 Lines: 56 On Mon, Sep 16, 2013 at 04:54:38PM +0200, Peter Zijlstra wrote: > 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? > It's really the number of ptes that are updated. > > 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(). well, it's still a THP page. Is it worth renaming? -- Mel Gorman SUSE Labs -- 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/