From: Johannes Weiner <hannes@cmpxchg.org>
To: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <andi@firstfloor.org>, Michal Hocko <mhocko@suse.cz>,
Tim Chen <tim.c.chen@linux.intel.com>,
kernel-team@fb.com
Subject: Re: [PATCH 05/10] mm: remove LRU balancing effect of temporary page isolation
Date: Tue, 7 Jun 2016 09:57:26 -0400 [thread overview]
Message-ID: <20160607135726.GA9978@cmpxchg.org> (raw)
In-Reply-To: <1465261878.16365.149.camel@redhat.com>
On Mon, Jun 06, 2016 at 09:11:18PM -0400, Rik van Riel wrote:
> On Mon, 2016-06-06 at 18:15 -0400, Johannes Weiner wrote:
> > On Mon, Jun 06, 2016 at 05:56:09PM -0400, Rik van Riel wrote:
> > >
> > > On Mon, 2016-06-06 at 15:48 -0400, Johannes Weiner wrote:
> > > >
> > > >
> > > > +void lru_cache_putback(struct page *page)
> > > > +{
> > > > + struct pagevec *pvec = &get_cpu_var(lru_putback_pvec);
> > > > +
> > > > + get_page(page);
> > > > + if (!pagevec_space(pvec))
> > > > + __pagevec_lru_add(pvec, false);
> > > > + pagevec_add(pvec, page);
> > > > + put_cpu_var(lru_putback_pvec);
> > > > +}
> > > >
> > > Wait a moment.
> > >
> > > So now we have a putback_lru_page, which does adjust
> > > the statistics, and an lru_cache_putback which does
> > > not?
> > >
> > > This function could use a name that is not as similar
> > > to its counterpart :)
> > lru_cache_add() and lru_cache_putback() are the two sibling
> > functions,
> > where the first influences the LRU balance and the second one
> > doesn't.
> >
> > The last hunk in the patch (obscured by showing the label instead of
> > the function name as context) updates putback_lru_page() from using
> > lru_cache_add() to using lru_cache_putback().
> >
> > Does that make sense?
>
> That means the page reclaim does not update the
> "rotated" statistics. That seems undesirable,
> no? Am I overlooking something?
Oh, reclaim doesn't use putback_lru_page(), except for the stray
unevictable corner case. It does open-coded putback in batch, and
those functions continue to update the reclaim statistics. See the
recent_scanned/recent_rotated manipulations in putback_inactive_pages(),
shrink_inactive_list(), and shrink_active_list().
putback_lru_page() is mainly used by page migration, cgroup migration,
mlock etc. - all operations which muck with the LRU for purposes other
than reclaim or aging, and so shouldn't affect the anon/file balance.
This patch only changes those LRU users, not page reclaim.
next prev parent reply other threads:[~2016-06-07 13:57 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-06 19:48 [PATCH 00/10] mm: balance LRU lists based on relative thrashing Johannes Weiner
2016-06-06 19:48 ` [PATCH 01/10] mm: allow swappiness that prefers anon over file Johannes Weiner
2016-06-07 0:25 ` Minchan Kim
2016-06-07 14:18 ` Johannes Weiner
2016-06-08 0:06 ` Minchan Kim
2016-06-08 15:58 ` Johannes Weiner
2016-06-09 1:01 ` Minchan Kim
2016-06-09 13:32 ` Johannes Weiner
2016-06-06 19:48 ` [PATCH 02/10] mm: swap: unexport __pagevec_lru_add() Johannes Weiner
2016-06-06 21:32 ` Rik van Riel
2016-06-07 9:07 ` Michal Hocko
2016-06-08 7:14 ` Minchan Kim
2016-06-06 19:48 ` [PATCH 03/10] mm: fold and remove lru_cache_add_anon() and lru_cache_add_file() Johannes Weiner
2016-06-06 21:33 ` Rik van Riel
2016-06-07 9:12 ` Michal Hocko
2016-06-08 7:24 ` Minchan Kim
2016-06-06 19:48 ` [PATCH 04/10] mm: fix LRU balancing effect of new transparent huge pages Johannes Weiner
2016-06-06 21:36 ` Rik van Riel
2016-06-07 9:19 ` Michal Hocko
2016-06-08 7:28 ` Minchan Kim
2016-06-06 19:48 ` [PATCH 05/10] mm: remove LRU balancing effect of temporary page isolation Johannes Weiner
2016-06-06 21:56 ` Rik van Riel
2016-06-06 22:15 ` Johannes Weiner
2016-06-07 1:11 ` Rik van Riel
2016-06-07 13:57 ` Johannes Weiner [this message]
2016-06-07 9:26 ` Michal Hocko
2016-06-07 14:06 ` Johannes Weiner
2016-06-07 9:49 ` Michal Hocko
2016-06-08 7:39 ` Minchan Kim
2016-06-08 16:02 ` Johannes Weiner
2016-06-06 19:48 ` [PATCH 06/10] mm: remove unnecessary use-once cache bias from LRU balancing Johannes Weiner
2016-06-07 2:20 ` Rik van Riel
2016-06-07 14:11 ` Johannes Weiner
2016-06-08 8:03 ` Minchan Kim
2016-06-08 12:31 ` Michal Hocko
2016-06-06 19:48 ` [PATCH 07/10] mm: base LRU balancing on an explicit cost model Johannes Weiner
2016-06-06 19:13 ` kbuild test robot
2016-06-07 2:34 ` Rik van Riel
2016-06-07 14:12 ` Johannes Weiner
2016-06-08 8:14 ` Minchan Kim
2016-06-08 16:06 ` Johannes Weiner
2016-06-08 12:51 ` Michal Hocko
2016-06-08 16:16 ` Johannes Weiner
2016-06-09 12:18 ` Michal Hocko
2016-06-09 13:33 ` Johannes Weiner
2016-06-06 19:48 ` [PATCH 08/10] mm: deactivations shouldn't bias the LRU balance Johannes Weiner
2016-06-08 8:15 ` Minchan Kim
2016-06-08 12:57 ` Michal Hocko
2016-06-06 19:48 ` [PATCH 09/10] mm: only count actual rotations as LRU reclaim cost Johannes Weiner
2016-06-08 8:19 ` Minchan Kim
2016-06-08 13:18 ` Michal Hocko
2016-06-06 19:48 ` [PATCH 10/10] mm: balance LRU lists based on relative thrashing Johannes Weiner
2016-06-06 19:22 ` kbuild test robot
2016-06-06 23:50 ` Tim Chen
2016-06-07 16:23 ` Johannes Weiner
2016-06-07 19:56 ` Tim Chen
2016-06-08 13:58 ` Michal Hocko
2016-06-10 2:19 ` Minchan Kim
2016-06-13 15:52 ` Johannes Weiner
2016-06-15 2:23 ` Minchan Kim
2016-06-16 15:12 ` Johannes Weiner
2016-06-17 7:49 ` Minchan Kim
2016-06-17 17:01 ` Johannes Weiner
2016-06-20 7:42 ` Minchan Kim
2016-06-22 21:56 ` Johannes Weiner
2016-06-24 6:22 ` Minchan Kim
2016-06-07 9:51 ` [PATCH 00/10] " Michal Hocko
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