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From: Juri Lelli <juri.lelli@redhat.com>
To: Waiman Long <longman9394@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	peterz@infradead.org, mingo@redhat.com,
	linux-kernel@vger.kernel.org, luca.abeni@santannapisa.it,
	claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it,
	bristot@redhat.com, mathieu.poirier@linaro.org,
	lizefan@huawei.com, cgroups@vger.kernel.org
Subject: Re: [PATCH v5 4/5] sched/core: Prevent race condition between cpuset and __sched_setscheduler()
Date: Thu, 8 Nov 2018 17:23:48 +0100	[thread overview]
Message-ID: <20181108162348.GF18091@localhost.localdomain> (raw)
In-Reply-To: <16587a21-ed6e-809d-78a8-5f76d1787665@gmail.com>

Hi,

On 08/11/18 10:49, Waiman Long wrote:
> On 10/04/2018 05:04 AM, Juri Lelli wrote:

[...]

> > +/**
> > + * cpuset_read_only_lock - Grab the callback_lock from cpuset subsystem.
> > + *
> > + * Description: As described in full details the comment above cpuset_mutex
> > + * and callback_lock definitions, holding callback_lock gives the holder
> > + * read-only access to cpusets. Even though it might look counter-intuitive
> > + * (as callback_lock is a spinlock), in fact a task must hold both
> > + * callback_lock _and_ cpuset_mutex to modify cpusets (write access).
> > + */
> > +void cpuset_read_only_lock(void)
> > +{
> > +	raw_spin_lock(&callback_lock);
> > +}
> > +
> > +/**
> > + * cpuset_read_only_unlock - Release the callback_lock from cpuset subsystem.
> > + */
> > +void cpuset_read_only_unlock(void)
> > +{
> > +	raw_spin_unlock(&callback_lock);
> > +}
> > +
> 
> Maybe you can drop the "_only" part to be consistent with the rwlock
> APIs (read_lock/write_lock).

I called it this way because it looked more descriptive of which kind of
guarantee the holder gets using these. Can change of course, what others
think?

Thanks for reviewing!

Best,

- Juri

  reply	other threads:[~2018-11-08 16:23 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-03 14:27 [PATCH v5 0/5] sched/deadline: fix cpusets bandwidth accounting Juri Lelli
2018-09-03 14:27 ` [PATCH v5 1/5] sched/topology: Adding function partition_sched_domains_locked() Juri Lelli
2018-09-03 14:27 ` [PATCH v5 2/5] sched/core: Streamlining calls to task_rq_unlock() Juri Lelli
2018-09-03 14:27 ` [PATCH v5 3/5] cgroup/cpuset: make callback_lock raw Juri Lelli
2018-09-25 14:34   ` Juri Lelli
2018-11-07  9:59     ` Juri Lelli
2018-11-07 15:53     ` Tejun Heo
2018-11-07 16:38       ` Juri Lelli
2018-11-08 11:22         ` Juri Lelli
2018-11-08 19:11         ` Waiman Long
2018-11-09 10:34           ` Juri Lelli
2018-09-03 14:28 ` [PATCH v5 4/5] sched/core: Prevent race condition between cpuset and __sched_setscheduler() Juri Lelli
2018-10-03 19:42   ` Steven Rostedt
2018-10-04  9:04     ` Juri Lelli
2018-11-08 15:49       ` Waiman Long
2018-11-08 16:23         ` Juri Lelli [this message]
2018-09-03 14:28 ` [PATCH v5 5/5] cpuset: Rebuild root domain deadline accounting information Juri Lelli
2018-09-25 12:32   ` Peter Zijlstra
2018-09-25 13:07     ` Juri Lelli
2018-09-25 12:53   ` Peter Zijlstra
2018-09-25 13:08     ` Juri Lelli
2018-09-25  8:14 ` [PATCH v5 0/5] sched/deadline: fix cpusets bandwidth accounting Juri Lelli

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