Re: [RFC] vmstat: Avoid waking up idle-cpu to service shepherd work

From: Viresh Kumar
Date: Fri Mar 27 2015 - 00:50:12 EST


On 27 March 2015 at 01:48, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> Shouldn't this be viewed as a shortcoming of the core timer code?

Yeah, it is. Some (not so pretty) solutions were tried earlier to fix that, but
they are rejected for obviously reasons [1].

> vmstat_shepherd() is merely rescheduling itself with
> schedule_delayed_work(). That's a dead bog simple operation and if
> it's producing suboptimal behaviour then we shouldn't be fixing it with
> elaborate workarounds in the caller?

I understand that, and that's why I sent it as an RFC to get the discussion
started. Does anyone else have got another (acceptable) idea to get this
resolved ?

--
viresh

[1] http://lists.linaro.org/pipermail/linaro-kernel/2013-November/008866.html
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