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From:   Shakeel Butt <shakeelb@google.com>
Date:   Sat, 9 May 2020 07:06:48 -0700
Message-ID: <CALvZod5DyMK0uGhPD5oYjds0Q8ew=1LTqjbHK4YLdsqrfYQqWg@mail.gmail.com>
Subject: Re: [PATCH 3/3] mm: swap: fix update_page_reclaim_stat for huge pages
To:     Johannes Weiner <hannes@cmpxchg.org>
Cc:     Mel Gorman <mgorman@suse.de>, Roman Gushchin <guro@fb.com>,
        Michal Hocko <mhocko@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Yafang Shao <laoar.shao@gmail.com>,
        Linux MM <linux-mm@kvack.org>,
        Cgroups <cgroups@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Fri, May 8, 2020 at 2:51 PM Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> On Fri, May 08, 2020 at 02:22:15PM -0700, Shakeel Butt wrote:
> > Currently update_page_reclaim_stat() updates the lruvec.reclaim_stats
> > just once for a page irrespective if a page is huge or not. Fix that by
> > passing the hpage_nr_pages(page) to it.
> >
> > Signed-off-by: Shakeel Butt <shakeelb@google.com>
>
> https://lore.kernel.org/patchwork/patch/685703/
>
> Laughs, then cries.
>

What happened to that patch? Fell through the cracks?

> > @@ -928,7 +928,7 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
> >       }
> >
> >       if (!PageUnevictable(page))
> > -             update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
> > +             update_page_reclaim_stat(lruvec, file, PageActive(page_tail), 1);
>
> The change to __pagevec_lru_add_fn() below makes sure the tail pages
> are already accounted. This would make them count twice.
>

Yes, you are right. I will just re-send your patch after rebase.


> >  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> >
> > @@ -973,7 +973,7 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
> >       if (page_evictable(page)) {
> >               lru = page_lru(page);
> >               update_page_reclaim_stat(lruvec, page_is_file_lru(page),
> > -                                      PageActive(page));
> > +                                      PageActive(page), nr_pages);
> >               if (was_unevictable)
> >                       __count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages);
> >       } else {