From: Yang Shi <shy828301@gmail.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Roman Gushchin <guro@fb.com>, Kirill Tkhai <ktkhai@virtuozzo.com>,
Shakeel Butt <shakeelb@google.com>,
Dave Chinner <david@fromorbit.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [v5 PATCH 08/11] mm: vmscan: use per memcg nr_deferred of shrinker
Date: Fri, 29 Jan 2021 09:33:54 -0800 [thread overview]
Message-ID: <CAHbLzkq-U3PO+V0a0BRkcT2xd3A7U5Gz_5n7ff8gRcFHTaw3yg@mail.gmail.com> (raw)
In-Reply-To: <f205b9b8-5fdd-1c76-25ed-d96ed608c14c@suse.cz>
On Fri, Jan 29, 2021 at 7:13 AM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> On 1/28/21 12:33 AM, Yang Shi wrote:
> > Use per memcg's nr_deferred for memcg aware shrinkers. The shrinker's nr_deferred
> > will be used in the following cases:
> > 1. Non memcg aware shrinkers
> > 2. !CONFIG_MEMCG
> > 3. memcg is disabled by boot parameter
> >
> > Signed-off-by: Yang Shi <shy828301@gmail.com>
> > ---
> > mm/vmscan.c | 87 ++++++++++++++++++++++++++++++++++++++++++++---------
> > 1 file changed, 73 insertions(+), 14 deletions(-)
> >
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 20be0db291fe..e1f8960f5cf6 100644
>
> ...
>
> > @@ -653,14 +717,9 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
> > next_deferred = 0;
> > /*
> > * move the unused scan count back into the shrinker in a
> > - * manner that handles concurrent updates. If we exhausted the
> > - * scan, there is no need to do an update.
> > + * manner that handles concurrent updates.
> > */
> > - if (next_deferred > 0)
> > - new_nr = atomic_long_add_return(next_deferred,
> > - &shrinker->nr_deferred[nid]);
> > - else
> > - new_nr = atomic_long_read(&shrinker->nr_deferred[nid]);
>
> Why not keep this write avoidance if next_deferred == 0 in the new helper?
Because IMHO the write avoidance may not make too much difference
since nr_deferred was updated for the most cases per my tracing
result. So I thought this would make the code more clean.
>
> > + new_nr = set_nr_deferred(next_deferred, shrinker, shrinkctl);
> >
> > trace_mm_shrink_slab_end(shrinker, shrinkctl->nid, freed, nr, new_nr, total_scan);
> > return freed;
> >
>
next prev parent reply other threads:[~2021-01-29 17:34 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-27 23:33 [v5 PATCH 0/11] Make shrinker's nr_deferred memcg aware Yang Shi
2021-01-27 23:33 ` [v5 PATCH 01/11] mm: vmscan: use nid from shrink_control for tracepoint Yang Shi
2021-01-28 16:02 ` Vlastimil Babka
2021-01-27 23:33 ` [v5 PATCH 02/11] mm: vmscan: consolidate shrinker_maps handling code Yang Shi
2021-01-28 16:10 ` Vlastimil Babka
2021-01-28 21:16 ` Yang Shi
2021-01-29 14:33 ` Kirill Tkhai
2021-01-29 17:11 ` Yang Shi
2021-01-27 23:33 ` [v5 PATCH 03/11] mm: vmscan: use shrinker_rwsem to protect shrinker_maps allocation Yang Shi
2021-01-28 16:19 ` Vlastimil Babka
2021-01-27 23:33 ` [v5 PATCH 04/11] mm: vmscan: remove memcg_shrinker_map_size Yang Shi
2021-01-28 16:53 ` Vlastimil Babka
2021-01-28 21:22 ` Yang Shi
2021-01-29 11:22 ` Vlastimil Babka
2021-01-29 17:05 ` Yang Shi
2021-01-27 23:33 ` [v5 PATCH 05/11] mm: memcontrol: rename shrinker_map to shrinker_info Yang Shi
2021-01-28 17:38 ` Vlastimil Babka
2021-01-28 22:05 ` Yang Shi
2021-01-27 23:33 ` [v5 PATCH 06/11] mm: vmscan: use a new flag to indicate shrinker is registered Yang Shi
2021-01-28 17:56 ` Vlastimil Babka
2021-01-28 23:47 ` Yang Shi
2021-01-27 23:33 ` [v5 PATCH 07/11] mm: vmscan: add per memcg shrinker nr_deferred Yang Shi
2021-01-29 13:00 ` Vlastimil Babka
2021-01-29 14:46 ` Kirill Tkhai
2021-01-29 17:20 ` Yang Shi
2021-01-29 18:04 ` Yang Shi
2021-02-01 15:17 ` Vlastimil Babka
2021-02-01 17:09 ` Yang Shi
2021-01-27 23:33 ` [v5 PATCH 08/11] mm: vmscan: use per memcg nr_deferred of shrinker Yang Shi
2021-01-29 14:55 ` Kirill Tkhai
2021-01-29 14:59 ` Kirill Tkhai
2021-01-29 17:22 ` Yang Shi
2021-01-29 15:13 ` Vlastimil Babka
2021-01-29 17:33 ` Yang Shi [this message]
2021-01-27 23:33 ` [v5 PATCH 09/11] mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers Yang Shi
2021-01-29 15:40 ` Vlastimil Babka
2021-01-29 17:34 ` Yang Shi
2021-01-27 23:33 ` [v5 PATCH 10/11] mm: memcontrol: reparent nr_deferred when memcg offline Yang Shi
2021-01-29 15:52 ` Vlastimil Babka
2021-01-29 17:38 ` Yang Shi
2021-01-27 23:33 ` [v5 PATCH 11/11] mm: vmscan: shrink deferred objects proportional to priority Yang Shi
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