From: Waiman Long <longman@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, kernel-team@fb.com, pjt@google.com,
luto@amacapital.net, efault@gmx.de,
torvalds@linux-foundation.org, Roman Gushchin <guro@fb.com>
Subject: Re: [PATCH v5 2/2] cpuset: Add cpuset.flags control knob to v2
Date: Tue, 20 Mar 2018 16:12:25 -0400 [thread overview]
Message-ID: <cbe9b852-80b6-8341-b51c-4d754d00ce53@redhat.com> (raw)
In-Reply-To: <8e553b7e-cab6-1b5d-9110-cc5770ae16c4@redhat.com>
On 03/19/2018 12:33 PM, Waiman Long wrote:
> On 03/19/2018 12:26 PM, Tejun Heo wrote:
>> Hello, Waiman.
>>
>> On Thu, Mar 15, 2018 at 05:20:42PM -0400, Waiman Long wrote:
>>> + The currently supported flag is:
>>> +
>>> + sched_load_balance
>>> + When it is not set, there will be no load balancing
>>> + among CPUs on this cpuset. Tasks will stay in the
>>> + CPUs they are running on and will not be moved to
>>> + other CPUs.
>>> +
>>> + When it is set, tasks within this cpuset will be
>>> + load-balanced by the kernel scheduler. Tasks will be
>>> + moved from CPUs with high load to other CPUs within
>>> + the same cpuset with less load periodically.
>> Hmm... looks like this is something which can be decided by the cgroup
>> itself and should be made delegatable. Given that different flags
>> might need different delegation settings and the precedence of
>> memory.oom_group, I think it'd be better to make the flags separate
>> bool files - ie. cpuset.sched_load_balance which contains 0/1 and
>> marked delegatable.
>>
>> Thanks.
>>
> Sure. Will do that.
After some thought, I am planning to impose the following additional
constraints on how sched_load_balance works in v2.
1) sched_load_balance will be made hierarchical, the child will inherit
the flag from its parent.
2) cpu_exclusive will be implicitly associated with sched_load_balance.
IOW, sched_load_balance => !cpu_exclusive, and !sched_load_balance =>
cpu_exclusive.
3) sched_load_balance cannot be 1 on a child if it is 0 on the parent.
With these changes, sched_load_balance will have to be set by the parent
and so will not be delegatable. Please let me know your thought on that.
Cheers,
Longman
next prev parent reply other threads:[~2018-03-20 20:12 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-15 21:20 [PATCH v5 0/2] cpuset: Enable cpuset controller in default hierarchy Waiman Long
2018-03-15 21:20 ` [PATCH v5 1/2] " Waiman Long
2018-03-19 15:59 ` Tejun Heo
2018-03-20 13:51 ` Waiman Long
2018-03-20 20:10 ` Tejun Heo
2018-03-20 20:53 ` Waiman Long
2018-03-20 21:14 ` Tejun Heo
2018-03-20 22:01 ` Waiman Long
2018-03-15 21:20 ` [PATCH v5 2/2] cpuset: Add cpuset.flags control knob to v2 Waiman Long
2018-03-19 16:26 ` Tejun Heo
2018-03-19 16:33 ` Waiman Long
2018-03-20 20:12 ` Waiman Long [this message]
2018-03-20 20:22 ` Tejun Heo
2018-03-20 20:43 ` Waiman Long
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