From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.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, Mike Galbraith <efault@gmx.de>,
torvalds@linux-foundation.org, Roman Gushchin <guro@fb.com>,
Juri Lelli <juri.lelli@redhat.com>
Subject: Re: [PATCH v8 2/6] cpuset: Add new v2 cpuset.sched.domain flag
Date: Fri, 25 May 2018 09:15:24 +0200 [thread overview]
Message-ID: <20180525071524.GQ12198@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <675f0f38-9154-4e73-1679-179eefdb7c9f@redhat.com>
On Thu, May 24, 2018 at 02:53:31PM -0400, Waiman Long wrote:
> On 05/24/2018 11:41 AM, Peter Zijlstra wrote:
> > On Thu, May 17, 2018 at 04:55:41PM -0400, Waiman Long wrote:
> >> A new cpuset.sched.domain boolean flag is added to cpuset v2. This new
> >> flag indicates that the CPUs in the current cpuset should be treated
> >> as a separate scheduling domain.
> > The traditional name for this is a partition.
>
> Do you want to call it cpuset.sched.partition? That name sounds strange
> to me.
Let me explore the whole domain x load-balance space first. I'm thinking
the two parameters are mostly redundant, but I might be overlooking
something (trivial or otherwise).
> >> + cpuset.sched.domain
> >> + A read-write single value file which exists on non-root
> >> + cpuset-enabled cgroups. It is a binary value flag that accepts
> >> + either "0" (off) or a non-zero value (on).
> > I would be conservative and only allow 0/1.
>
> I stated that because echoing other integer value like 2 into the flag
> file won't return any error. I will modify it to say just 0 and 1.
Ah, I would make the file error on >1.
Because then you can always extend the meaning afterwards because you
know it won't be written to with the new value.
> >> + 3) There is no child cgroups with cpuset enabled.
> >> +
> >> + Setting this flag will take the CPUs away from the effective
> >> + CPUs of the parent cgroup. Once it is set, this flag cannot be
> >> + cleared if there are any child cgroups with cpuset enabled.
> > This I'm not clear on. Why?
> >
> That is for pragmatic reason as it is easier to code this way. We could
> remove this restriction but that will make the code more complex.
Best to mention that I think.
next prev parent reply other threads:[~2018-05-25 7:15 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-17 20:55 [PATCH v8 0/6] Enable cpuset controller in default hierarchy Waiman Long
2018-05-17 20:55 ` [PATCH v8 1/6] cpuset: " Waiman Long
2018-05-21 11:55 ` Patrick Bellasi
2018-05-21 13:55 ` Waiman Long
2018-05-21 15:09 ` Patrick Bellasi
2018-05-21 16:10 ` Waiman Long
2018-05-17 20:55 ` [PATCH v8 2/6] cpuset: Add new v2 cpuset.sched.domain flag Waiman Long
2018-05-22 12:57 ` Juri Lelli
2018-05-22 13:20 ` Waiman Long
2018-05-29 0:55 ` Waiman Long
2018-05-24 15:41 ` Peter Zijlstra
2018-05-24 18:53 ` Waiman Long
2018-05-25 7:15 ` Peter Zijlstra [this message]
2018-05-17 20:55 ` [PATCH v8 3/6] cpuset: Add cpuset.sched.load_balance flag to v2 Waiman Long
2018-05-24 14:36 ` Juri Lelli
2018-05-24 15:09 ` Waiman Long
2018-05-24 15:16 ` Juri Lelli
2018-05-24 15:22 ` Waiman Long
2018-05-25 9:40 ` Patrick Bellasi
2018-05-25 14:45 ` Waiman Long
2018-05-24 15:43 ` Peter Zijlstra
2018-05-24 18:55 ` Waiman Long
2018-05-28 12:45 ` Peter Zijlstra
2018-05-28 18:31 ` Waiman Long
2018-05-17 20:55 ` [PATCH v8 4/6] cpuset: Make generate_sched_domains() recognize isolated_cpus Waiman Long
2018-05-23 17:34 ` Patrick Bellasi
2018-05-23 20:18 ` Waiman Long
2018-05-24 9:04 ` Patrick Bellasi
2018-05-24 10:39 ` Juri Lelli
2018-05-25 10:31 ` Patrick Bellasi
2018-05-25 12:52 ` Juri Lelli
2018-05-24 10:28 ` Juri Lelli
2018-05-29 1:12 ` Waiman Long
2018-05-29 1:24 ` Waiman Long
2018-05-29 6:27 ` Juri Lelli
2018-05-29 12:40 ` Waiman Long
2018-05-29 13:12 ` Juri Lelli
2018-05-17 20:55 ` [PATCH v8 5/6] cpuset: Expose cpus.effective and mems.effective on cgroup v2 root Waiman Long
2018-05-17 20:55 ` [PATCH v8 6/6] cpuset: Allow reporting of sched domain generation info Waiman Long
2018-05-22 13:53 ` Juri Lelli
2018-05-29 1:04 ` Waiman Long
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