Messages in this thread | | | Date | Tue, 4 Feb 2020 00:30:22 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH v3 10/12] mm/gup: /proc/vmstat: pin_user_pages (FOLL_PIN) reporting |
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On Mon, Feb 03, 2020 at 01:04:04PM -0800, John Hubbard wrote: > On 2/3/20 5:53 AM, Kirill A. Shutemov wrote: > > On Fri, Jan 31, 2020 at 07:40:27PM -0800, John Hubbard wrote: > >> diff --git a/mm/gup.c b/mm/gup.c > >> index c10d0d051c5b..9fe61d15fc0e 100644 > >> --- a/mm/gup.c > >> +++ b/mm/gup.c > >> @@ -29,6 +29,19 @@ struct follow_page_context { > >> unsigned int page_mask; > >> }; > >> > >> +#ifdef CONFIG_DEBUG_VM > > > > Why under CONFIG_DEBUG_VM? There's nothing about this in the cover letter. > > > > Early on, gup_benchmark showed a really significant slowdown from using these > counters. And I don't doubt that it's still the case. > > I'll re-measure and add a short summary and a few numbers to the patch commit > description, and to the v4 cover letter.
Looks like you'll show zeros for these counters if debug is off. It can be confusing to the user. I think these counters should go away if you don't count them.
-- Kirill A. Shutemov
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