Message-ID: <5058560d-f193-971f-501e-1a4d8501dfc7@redhat.com>
Date:   Wed, 8 Mar 2023 14:21:59 -0500
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Subject: Re: [PATCH v3] sched: cpuset: Don't rebuild root domains on
 suspend-resume
Content-Language: en-US
To:     Juri Lelli <juri.lelli@redhat.com>,
        Qais Yousef <qyousef@layalina.io>
Cc:     Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Steven Rostedt <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,
        cgroups@vger.kernel.org,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Wei Wang <wvw@google.com>, Rick Yiu <rickyiu@google.com>,
        Quentin Perret <qperret@google.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Zefan Li <lizefan.x@bytedance.com>, linux-s390@vger.kernel.org,
        x86@kernel.org
References: <20230206221428.2125324-1-qyousef@layalina.io>
 <20230223153859.37tqoqk33oc6tv7o@airbuntu>
 <5f087dd8-3e39-ce83-fe24-afa5179c05d9@arm.com>
 <20230227205725.dipvh3i7dvyrv4tv@airbuntu>
 <5a1e58bf-7eb2-bd7a-7e19-7864428a2b83@arm.com>
 <20230228174627.vja5aejq27dsta2u@airbuntu>
 <Y/7/SLzvK8LfB29z@localhost.localdomain>
 <20230301122852.zgzreby42lh2zf6w@airbuntu>
 <Y/9gmDRlGOChIwpf@localhost.localdomain>
 <20230301170322.xthlso7jfkixlyex@airbuntu>
 <ZAhhGi55BkYkc3ss@localhost.localdomain>
From:   Waiman Long <longman@redhat.com>
In-Reply-To: <ZAhhGi55BkYkc3ss@localhost.localdomain>
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On 3/8/23 05:19, Juri Lelli wrote:
> On 01/03/23 17:03, Qais Yousef wrote:
>> On 03/01/23 15:26, Juri Lelli wrote:
>>> On 01/03/23 12:28, Qais Yousef wrote:
>>>> On 03/01/23 08:31, Juri Lelli wrote:
>>> ...
>>>
>>>>> Not ignoring you guys here, but it turns out I'm quite bogged down with
>>>>> other stuff at the moment. :/ So, apologies and I'll try to get to this
>>>>> asap. Thanks a lot for all your efforts and time reviewing so far!
>>>> Np, I can feel you :-)
>>> Eh. :/
>> I hope I did not offend. That was meant as no pressure, I understand.
> No offence at all! I meant "we are all on the same boat it seems". :)
>
>>> BTW, do you have a repro script of some sort handy I might play with?
>> Sorry no. You'll just need to suspend to ram. I had a simple patch to measure
>> the time around the call and trace_printk'ed the result.
>>
>> I was working on a android phone which just suspends to ram if you turn the
>> screen off and disconnect the usb.
> Looks like I could come up with the following
>
> https://github.com/jlelli/linux.git deadline/rework-cpusets
> https://github.com/jlelli/linux/tree/deadline/rework-cpusets
>
> which I don't think it's at a point that I feel comfortable to propose
> as an RFC (not even sure if it actually makes sense), but it survived my
> very light testing.

I like your patch to revert the cpuset_rwsem change. In fact, I was 
planning to ask you about that. It is causing a lot more latency in 
workloads that need to change cpuset configuration rather frequently.

Cheers,
Longman