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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 1/2] cpuset: Enable cpuset controller in default hierarchy
Date: Tue, 20 Mar 2018 09:51:20 -0400	[thread overview]
Message-ID: <1881c1da-56ec-d76b-b736-fd0919737ec6@redhat.com> (raw)
In-Reply-To: <20180319155937.GQ2943022@devbig577.frc2.facebook.com>

On 03/19/2018 11:59 AM, Tejun Heo wrote:
> Hello, Waiman.
>
> This looks great.  A couple nitpicks below.
>
>> +     5-3. Cpuset
>> +       5.3-1. Cpuset Interface Files
> Can we put cpuset below pid?  It feels weird to break up cpu, memory
> and io as they represent the three major resources and are in a
> similar fashion.
Sure. I will move it down below pid.

>> +  cpuset.effective_cpus
>> +	A read-only multiple values file which exists on non-root
>> +	cgroups.
>> +
>> +	It lists the onlined CPUs that are actually allowed to be
>> +	used by tasks within the current cgroup. It is a subset of
>> +	"cpuset.cpus".  Its value will be affected by CPU hotplug
>> +	events.
> Can we do cpuset.cpus.availble which lists the cpus available to the
> cgroup instead of the eventual computed mask for the cgroup?  That'd
> be more useful as it doesn't lose the information by and'ing what's
> available with the cgroup's mask and it's trivial to determine the
> effective from the two masks.

I don't get what you want here. cpus is the cpuset's cpus_allowed mask.
effective_cpus is the effective_cpus mask. When you say cpus available
to the cgroup, do you mean the cpu_online_mask or the list of cpus from
the parent? Or do you just want to change the name to cpus.available
instead of effective_cpus?

>> +  cpuset.effective_mems
>> +	A read-only multiple values file which exists on non-root
>> +	cgroups.
>> +
>> +	It lists the onlined memory nodes that are actually allowed
>> +	to be used by tasks within the current cgroup.  It is a subset
>> +	of "cpuset.mems".  Its value will be affected by memory nodes
>> +	hotplug events.
> Ditto.
>
>> +static struct cftype dfl_files[] = {
>> +	{
>> +		.name = "cpus",
>> +		.seq_show = cpuset_common_seq_show,
>> +		.write = cpuset_write_resmask,
>> +		.max_write_len = (100U + 6 * NR_CPUS),
>> +		.private = FILE_CPULIST,
>> +	},
> Is it missing CFTYPE_NOT_ON_ROOT?  Other files too.

Right, I will set CFTYPE_NOT_ON_ROOT to "cpus" and "mems" as we are not
supposed to change them in the root. The effective_cpus and
effective_mems will be there in the root to show what are available.

Cheers,
Longman

  reply	other threads:[~2018-03-20 13:51 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-15 21:20 [PATCH v5 0/2] " 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 [this message]
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
2018-03-20 20:22         ` Tejun Heo
2018-03-20 20:43           ` Waiman Long

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