From: Peter Zijlstra <peterz@infradead.org>
To: Juri Lelli <juri.lelli@redhat.com>
Cc: mingo@redhat.com, rostedt@goodmis.org, tj@kernel.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,
lizefan@huawei.com, cgroups@vger.kernel.org
Subject: Re: [PATCH v8 5/8] cgroup/cpuset: convert cpuset_mutex to percpu_rwsem
Date: Fri, 28 Jun 2019 14:45:53 +0200 [thread overview]
Message-ID: <20190628124553.GT3419@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190628080618.522-6-juri.lelli@redhat.com>
On Fri, Jun 28, 2019 at 10:06:15AM +0200, Juri Lelli wrote:
> @@ -2154,7 +2154,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
> cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css));
> cs = css_cs(css);
>
> - mutex_lock(&cpuset_mutex);
> + percpu_down_read(&cpuset_rwsem);
>
> /* allow moving tasks into an empty cpuset if on default hierarchy */
> ret = -ENOSPC;
> @@ -2178,7 +2178,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
> cs->attach_in_progress++;
> ret = 0;
> out_unlock:
> - mutex_unlock(&cpuset_mutex);
> + percpu_up_read(&cpuset_rwsem);
> return ret;
> }
>
> @@ -2188,9 +2188,9 @@ static void cpuset_cancel_attach(struct cgroup_taskset *tset)
>
> cgroup_taskset_first(tset, &css);
>
> - mutex_lock(&cpuset_mutex);
> + percpu_down_read(&cpuset_rwsem);
> css_cs(css)->attach_in_progress--;
> - mutex_unlock(&cpuset_mutex);
> + percpu_up_read(&cpuset_rwsem);
> }
These are the only percpu_down_read()s introduced in this patch; are we
sure this is correct? Specifically, what serializes
->attach_in_progress?
next prev parent reply other threads:[~2019-06-28 12:46 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-28 8:06 [PATCH v8 0/8] sched/deadline: fix cpusets bandwidth accounting Juri Lelli
2019-06-28 8:06 ` [PATCH v8 1/8] sched/topology: Adding function partition_sched_domains_locked() Juri Lelli
2019-06-28 8:06 ` [PATCH v8 2/8] sched/core: Streamlining calls to task_rq_unlock() Juri Lelli
2019-06-28 8:06 ` [PATCH v8 3/8] cpuset: Rebuild root domain deadline accounting information Juri Lelli
2019-06-28 8:06 ` [PATCH v8 4/8] sched/deadline: Fix bandwidth accounting at all levels after offline migration Juri Lelli
2019-06-28 8:06 ` [PATCH v8 5/8] cgroup/cpuset: convert cpuset_mutex to percpu_rwsem Juri Lelli
2019-06-28 12:45 ` Peter Zijlstra [this message]
2019-06-28 14:31 ` Juri Lelli
2019-06-28 8:06 ` [PATCH v8 6/8] cgroup/cpuset: Change cpuset_rwsem and hotplug lock order Juri Lelli
2019-06-28 13:03 ` Peter Zijlstra
2019-07-01 6:52 ` Juri Lelli
2019-07-01 8:27 ` Peter Zijlstra
2019-07-01 14:51 ` Tejun Heo
2019-07-04 8:49 ` Juri Lelli
2019-07-12 14:04 ` Juri Lelli
2019-07-16 15:36 ` Tejun Heo
2019-06-28 8:06 ` [PATCH v8 7/8] sched/core: Prevent race condition between cpuset and __sched_setscheduler() Juri Lelli
2019-07-01 19:11 ` Peter Zijlstra
2019-07-02 7:01 ` Juri Lelli
2019-06-28 8:06 ` [PATCH v8 8/8] rcu/tree: Setschedule gp ktread to SCHED_FIFO outside of atomic region Juri Lelli
2019-07-01 19:13 ` Peter Zijlstra
2019-07-02 7:01 ` Juri Lelli
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