Re: vmstat: make vmstat_updater deferrable again and shut down on idle

From	Christoph Lameter <cl@linux.com>
Newsgroups	linux.kernel
Subject	Re: vmstat: make vmstat_updater deferrable again and shut down on idle
Date	2016-01-21 16:50 +0100
Message-ID	<qTpEL-7eF-35@gated-at.bofh.it> (permalink)
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On Thu, 21 Jan 2016, Shiraz Hashim wrote:

> > On idle we fold counters immediately. So there is no loss of accuracy.
>
> vmstat is scheduled by shepherd or by itself (conditionally). In case shepherd
> is deferred and vmstat doesn't schedule itself, then vmstat needs to wait
> for shepherd to be up and then schedule it. This may end up in delayed status
> update for all live cpus. Isn't it ?

The shepherd runs on a processor with an active tick and thus should do
its duty every 2 seconds as scheduled. Small milisecond range deferrals do
not matter much.

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Re: vmstat: make vmstat_updater deferrable again and shut down on idle Shiraz Hashim <shiraz.linux.kernel@gmail.com> - 2016-01-20 15:00 +0100
  Re: vmstat: make vmstat_updater deferrable again and shut down on  idle Christoph Lameter <cl@linux.com> - 2016-01-20 16:20 +0100
    Re: vmstat: make vmstat_updater deferrable again and shut down on idle Shiraz Hashim <shiraz.linux.kernel@gmail.com> - 2016-01-21 07:30 +0100
      Re: vmstat: make vmstat_updater deferrable again and shut down on  idle Christoph Lameter <cl@linux.com> - 2016-01-21 16:50 +0100

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