Messages in this thread | | | Date | Mon, 16 Sep 2013 17:11:50 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH 07/50] mm: Account for a THP NUMA hinting update as one PTE update |
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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 <mgorman@suse.de> > > >> --- > > >> 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
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