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From: Juri Lelli <juri.lelli@redhat.com>
To: peterz@infradead.org, mingo@redhat.com, rostedt@goodmis.org
Cc: 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 0/5] sched/deadline: fix cpusets bandwidth accounting
Date: Tue, 25 Sep 2018 10:14:48 +0200	[thread overview]
Message-ID: <20180925081448.GA4287@localhost.localdomain> (raw)
In-Reply-To: <20180903142801.20046-1-juri.lelli@redhat.com>

Hi,

On 03/09/18 16:27, Juri Lelli wrote:
> Hi,
> 
> v5 of a series of patches, originally authored by Mathieu, with the intent
> of fixing a long standing issue of SCHED_DEADLINE bandwidth accounting.
> As originally reported by Steve [1], when hotplug and/or (certain)
> cpuset reconfiguration operations take place, DEADLINE bandwidth
> accounting information is lost since root domains are destroyed and
> recreated.
> 
> Mathieu's approach is based on restoring bandwidth accounting info on
> the newly created root domains by iterating through the (DEADLINE) tasks
> belonging to the configured cpuset(s).
> 
> Main problem of v4 was caused by the trylocking of cpuset_mutex. As
> noticed by Steve [2], if multiple tasks are created at they same time
> only the first gets to grab the mutex, the other get -EBUSY and need to
> retry. Not really nice. So, in v5 I'm proposing to use callback_lock
> instead of cpuset_mutex, which AFAIU should be enough to grant read-only
> safe access to cpusets.
> 
> 01/05 has been dropped because it wasn't really adding much and was
> only causing false positives.
> 
> 05/05 is still too much DEADLINE specific I guess, but let's first agree
> on foundations patches.
> 
> Set also available at
> 
>  https://github.com/jlelli/linux.git fixes/deadline/root-domain-accounting-v5

Gentle ping about this.

Best,

- Juri

      parent reply	other threads:[~2018-09-25  8:14 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
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 ` Juri Lelli [this message]

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