Date:   Wed, 15 Mar 2023 19:25:44 +0000
From:   Qais Yousef <qyousef@layalina.io>
To:     Juri Lelli <juri.lelli@redhat.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Waiman Long <longman@redhat.com>, Tejun Heo <tj@kernel.org>,
        Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Hao Luo <haoluo@google.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        linux-kernel@vger.kernel.org, luca.abeni@santannapisa.it,
        claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it,
        bristot@redhat.com, mathieu.poirier@linaro.org,
        cgroups@vger.kernel.org,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Wei Wang <wvw@google.com>, Rick Yiu <rickyiu@google.com>,
        Quentin Perret <qperret@google.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Sudeep Holla <sudeep.holla@arm.com>
Subject: Re: [RFC PATCH 2/3] sched/cpuset: Keep track of SCHED_DEADLINE tasks
 in cpusets
Message-ID: <20230315192544.44ufekpbebs2ysub@airbuntu>
References: <20230315121812.206079-1-juri.lelli@redhat.com>
 <20230315121812.206079-3-juri.lelli@redhat.com>
 <20230315144927.624cbwc3yep3fwor@airbuntu>
 <ZBH+AaJV36y/HNXk@localhost.localdomain>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <ZBH+AaJV36y/HNXk@localhost.localdomain>
Precedence: bulk

On 03/15/23 17:18, Juri Lelli wrote:
> On 15/03/23 14:49, Qais Yousef wrote:
> > On 03/15/23 12:18, Juri Lelli wrote:
> 
> ...
> 
> > > +void inc_dl_tasks_cs(struct task_struct *p)
> > > +{
> > > +	struct cpuset *cs = task_cs(p);
> > 
> > nit:
> > 
> > I *think* task_cs() assumes rcu_read_lock() is held, right?
> > 
> > Would it make sense to WARN_ON(!rcu_read_lock_held()) to at least
> > annotate the deps?
> 
> Think we have that check in task_css_set_check()?

Yes you're right, I didn't go forward enough in the call stack.

It seems to depend on PROVE_RCU, which sounds irrelevant, but I see PROVE_RCU
is actually an alias for PROVE_LOCKING.


Cheers

--
Qais Yousef