From: Dave Chinner <david@fromorbit.com>
To: Yang Shi <shy828301@gmail.com>
Cc: Roman Gushchin <guro@fb.com>, Kirill Tkhai <ktkhai@virtuozzo.com>,
Shakeel Butt <shakeelb@google.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: [v2 PATCH 7/9] mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers
Date: Fri, 18 Dec 2020 12:09:28 +1100 [thread overview]
Message-ID: <20201218010928.GB1199812@dread.disaster.area> (raw)
In-Reply-To: <CAHbLzkoWco5gq8tuxbTsfpTF3GPUQLn9uNUTy1nUNwKGVPonmg@mail.gmail.com>
On Thu, Dec 17, 2020 at 04:56:48PM -0800, Yang Shi wrote:
> On Tue, Dec 15, 2020 at 3:07 PM Yang Shi <shy828301@gmail.com> wrote:
> > > This guarantees that only the shrinker instances taht have a
> > > correctly set up memcg attached to them will have the
> > > SHRINKER_MEMCG_AWARE flag set. Hence in all the rest of the shrinker
> > > code, we only ever need to check for SHRINKER_MEMCG_AWARE to
> > > determine what we should do....
> >
> > Thanks. I see your point. We could move the memcg specific details
> > into prealloc_memcg_shrinker().
> >
> > It seems we have to acquire shrinker_rwsem before we check and modify
> > SHIRNKER_MEMCG_AWARE bit if we may clear it.
>
> Hi Dave,
>
> Is it possible that shrinker register races with shrinker unregister?
> It seems impossible to me by a quick visual code inspection. But I'm
> not a VFS expert so I'm not quite sure.
Uh, if you have a shrinker racing to register and unregister, you've
got a major bug in your object initialisation/teardown code. i.e.
calling reagister/unregister at the same time for the same shrinker
is a bug, pure and simple.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2020-12-18 1:10 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-14 22:37 [RFC v2 PATCH 0/9] Make shrinker's nr_deferred memcg aware Yang Shi
2020-12-14 22:37 ` [v2 PATCH 1/9] mm: vmscan: use nid from shrink_control for tracepoint Yang Shi
2020-12-14 22:37 ` [v2 PATCH 2/9] mm: memcontrol: use shrinker_rwsem to protect shrinker_maps allocation Yang Shi
2020-12-15 2:09 ` Dave Chinner
2020-12-15 13:53 ` Johannes Weiner
2020-12-15 21:59 ` Dave Chinner
2020-12-16 13:17 ` Kirill Tkhai
2020-12-16 19:12 ` Johannes Weiner
2020-12-16 21:56 ` Yang Shi
2020-12-16 21:56 ` Yang Shi
2020-12-16 19:39 ` Roman Gushchin
2020-12-15 14:07 ` Johannes Weiner
2020-12-15 20:32 ` Yang Shi
2020-12-15 20:32 ` Yang Shi
2020-12-14 22:37 ` [v2 PATCH 3/9] mm: vmscan: guarantee shrinker_slab_memcg() sees valid shrinker_maps for online memcg Yang Shi
2020-12-15 2:04 ` Dave Chinner
2020-12-15 12:38 ` Johannes Weiner
2020-12-15 12:58 ` Kirill Tkhai
2020-12-15 16:45 ` Johannes Weiner
2020-12-15 17:14 ` Johannes Weiner
2020-12-15 20:31 ` Yang Shi
2020-12-28 20:03 ` Yang Shi
2020-12-28 20:03 ` Yang Shi
2020-12-14 22:37 ` [v2 PATCH 4/9] mm: vmscan: use a new flag to indicate shrinker is registered Yang Shi
2020-12-14 22:37 ` [v2 PATCH 5/9] mm: memcontrol: add per memcg shrinker nr_deferred Yang Shi
2020-12-15 2:22 ` Dave Chinner
2020-12-15 14:45 ` Johannes Weiner
2020-12-15 21:57 ` Yang Shi
2020-12-15 21:57 ` Yang Shi
2020-12-14 22:37 ` [v2 PATCH 6/9] mm: vmscan: use per memcg nr_deferred of shrinker Yang Shi
2020-12-15 2:46 ` Dave Chinner
2020-12-15 22:27 ` Yang Shi
2020-12-15 22:27 ` Yang Shi
2020-12-15 23:48 ` Dave Chinner
2020-12-14 22:37 ` [v2 PATCH 7/9] mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers Yang Shi
2020-12-15 3:05 ` Dave Chinner
2020-12-15 23:07 ` Yang Shi
2020-12-15 23:07 ` Yang Shi
2020-12-18 0:56 ` Yang Shi
2020-12-18 0:56 ` Yang Shi
2020-12-18 1:09 ` Dave Chinner [this message]
2020-12-14 22:37 ` [v2 PATCH 8/9] mm: memcontrol: reparent nr_deferred when memcg offline Yang Shi
2020-12-15 3:07 ` Dave Chinner
2020-12-15 23:10 ` Yang Shi
2020-12-15 23:10 ` Yang Shi
2020-12-14 22:37 ` [v2 PATCH 9/9] mm: vmscan: shrink deferred objects proportional to priority Yang Shi
2020-12-15 3:23 ` Dave Chinner
2020-12-15 23:59 ` Yang Shi
2020-12-15 23:59 ` Yang Shi
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