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From: Tejun Heo <tj@kernel.org>
To: "Michal Koutný" <mkoutny@suse.com>
Cc: JP Kobryn <inwardvessel@gmail.com>,
	shakeel.butt@linux.dev, yosryahmed@google.com,
	hannes@cmpxchg.org, akpm@linux-foundation.org,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	kernel-team@meta.com
Subject: Re: [PATCH v4 5/5] cgroup: use subsystem-specific rstat locks to avoid contention
Date: Tue, 15 Apr 2025 09:30:35 -1000	[thread overview]
Message-ID: <Z_6z2-qqLI7dbl8h@slm.duckdns.org> (raw)
In-Reply-To: <3ngzq64vgka2ukk2mscgclu6pcr6blwt3cwwmdptpdb7l7stgv@vhpyjbzbh63h>

On Tue, Apr 15, 2025 at 07:15:48PM +0200, Michal Koutný wrote:
> On Thu, Apr 03, 2025 at 06:10:50PM -0700, JP Kobryn <inwardvessel@gmail.com> wrote:
> > --- a/kernel/cgroup/rstat.c
> > +++ b/kernel/cgroup/rstat.c
> ...
> >  static inline void __css_rstat_lock(struct cgroup_subsys_state *css,
> >  		int cpu_in_loop)
> > -	__acquires(&cgroup_rstat_lock)
> > +	__acquires(lock)
> 
> Maybe
> 	__acquires(ss_rstat_lock(css->ss))
> 
> It shouldn't matter anyway but that may be more specific than a
> generic 'lock' expression [1].

I don't know whether this is a controversial opinion but I personally would
prefer to not have __acquires/__releases() notations at all. They add
unverifiable clutter and don't really add anything valuable on top of
lockdep.

Thanks.

-- 
tejun


  reply	other threads:[~2025-04-15 19:30 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-04  1:10 [PATCH v4 0/5] cgroup: separate rstat trees JP Kobryn
2025-04-04  1:10 ` [PATCH v4 1/5] cgroup: move rstat base stat objects into their own struct JP Kobryn
2025-04-15 17:16   ` Michal Koutný
2025-04-22 12:13   ` Yosry Ahmed
2025-05-29 18:58   ` Ihor Solodrai
2025-05-29 19:11     ` Yonghong Song
2025-04-04  1:10 ` [PATCH v4 2/5] cgroup: add helper for checking when css is cgroup::self JP Kobryn
2025-04-22 12:19   ` Yosry Ahmed
     [not found]   ` <68078968.5d0a0220.2c3c35.bab3SMTPIN_ADDED_BROKEN@mx.google.com>
2025-04-24 16:59     ` JP Kobryn
2025-04-04  1:10 ` [PATCH v4 3/5] cgroup: change rstat function signatures from cgroup-based to css-based JP Kobryn
2025-04-04 20:00   ` Tejun Heo
2025-04-04 20:09     ` Tejun Heo
2025-04-04 21:21       ` JP Kobryn
2025-04-22 12:35   ` Yosry Ahmed
2025-04-22 12:39   ` Yosry Ahmed
     [not found]   ` <68078d3c.050a0220.3d37e.6d82SMTPIN_ADDED_BROKEN@mx.google.com>
2025-04-24 17:10     ` JP Kobryn
2025-04-04  1:10 ` [PATCH v4 4/5] cgroup: use separate rstat trees for each subsystem JP Kobryn
2025-04-15 17:15   ` Michal Koutný
2025-04-16 21:43     ` JP Kobryn
2025-04-17  9:26       ` Michal Koutný
2025-04-17 19:05         ` JP Kobryn
2025-04-17 20:10           ` JP Kobryn
2025-04-21 18:18   ` JP Kobryn
2025-04-22 13:33   ` Yosry Ahmed
     [not found]   ` <68079aa7.df0a0220.30a1a0.cbb2SMTPIN_ADDED_BROKEN@mx.google.com>
2025-04-30 23:43     ` JP Kobryn
2025-05-06  9:37       ` Yosry Ahmed
2025-04-04  1:10 ` [PATCH v4 5/5] cgroup: use subsystem-specific rstat locks to avoid contention JP Kobryn
2025-04-04 20:28   ` Tejun Heo
2025-04-11  3:31     ` JP Kobryn
2025-04-15 17:15   ` Michal Koutný
2025-04-15 19:30     ` Tejun Heo [this message]
2025-04-16  9:50       ` Michal Koutný
2025-04-16 18:10         ` JP Kobryn
2025-04-16 18:14           ` Tejun Heo
2025-04-16 18:01     ` JP Kobryn
2025-04-22 14:01   ` Yosry Ahmed
2025-04-24 17:25     ` Shakeel Butt
     [not found]   ` <6807a132.df0a0220.28dc80.a1f0SMTPIN_ADDED_BROKEN@mx.google.com>
2025-04-25  0:18     ` JP Kobryn

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