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From: Dave Chinner <david@fromorbit.com>
To: Yang Shi <shy828301@gmail.com>
Cc: guro@fb.com, ktkhai@virtuozzo.com, shakeelb@google.com,
	hannes@cmpxchg.org, 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 13:09:57 +1100	[thread overview]
Message-ID: <20201215020957.GK3913616@dread.disaster.area> (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.

I'm not sure this is a good idea. This couples the shrinker
infrastructure to internal details of how cgroups are initialised
and managed. Sure, certain operations might be done in certain
shrinker lock contexts, but that doesn't mean we should share global
locks across otherwise independent subsystems....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

  reply	other threads:[~2020-12-15  2:10 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 [this message]
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
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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