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From: Johannes Weiner <hannes@cmpxchg.org>
To: Yang Shi <shy828301@gmail.com>
Cc: guro@fb.com, ktkhai@virtuozzo.com, shakeelb@google.com,
	david@fromorbit.com, mhocko@suse.com, akpm@linux-foundation.org,
	linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [v2 PATCH 2/9] mm: memcontrol: use shrinker_rwsem to protect shrinker_maps allocation
Date: Tue, 15 Dec 2020 15:07:54 +0100	[thread overview]
Message-ID: <20201215140754.GD379720@cmpxchg.org> (raw)
In-Reply-To: <20201214223722.232537-3-shy828301@gmail.com>

On Mon, Dec 14, 2020 at 02:37:15PM -0800, Yang Shi wrote:
> Since memcg_shrinker_map_size just can be changd under holding shrinker_rwsem
> exclusively, the read side can be protected by holding read lock, so it sounds
> superfluous to have a dedicated mutex.  This should not exacerbate the contention
> to shrinker_rwsem since just one read side critical section is added.
> 
> Signed-off-by: Yang Shi <shy828301@gmail.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

Thanks Yang, this is a step in the right direction. It would still be
nice to also drop memcg_shrinker_map_size and (trivially) derive that
value from shrinker_nr_max where necessary. It is duplicate state.


  parent reply	other threads:[~2020-12-15 14:10 UTC|newest]

Thread overview: 37+ 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 19:39         ` Roman Gushchin
2020-12-15 14:07   ` Johannes Weiner [this message]
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
     [not found]   ` <20201215123802.GA379720@cmpxchg.org>
2020-12-15 12:58     ` Kirill Tkhai
2020-12-15 17:14   ` Johannes Weiner
     [not found]     ` <CAHbLzkrzv48S3ks-x8M=2sHxRS_+c-hLXdt4ScaWD6mC4ZFe8w@mail.gmail.com>
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
2020-12-14 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 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
2020-12-18  0:56       ` Yang Shi
2020-12-18  1:09         ` Dave Chinner
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
2020-12-14 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

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