Re: [PATCH 0/4] Convert khugepaged to a task_work function

From: Andi Kleen
Date: Tue Oct 28 2014 - 08:13:09 EST


Alex Thorlton <athorlton@xxxxxxx> writes:

> Last week, while discussing possible fixes for some unexpected/unwanted behavior
> from khugepaged (see: https://lkml.org/lkml/2014/10/8/515) several people
> mentioned possibly changing changing khugepaged to work as a task_work function
> instead of a kernel thread. This will give us finer grained control over the
> page collapse scans, eliminate some unnecessary scans since tasks that are
> relatively inactive will not be scanned often, and eliminate the unwanted
> behavior described in the email thread I mentioned.

With your change, what would happen in a single threaded case?

Previously one core would scan and another would run the workload.
With your change both scanning and running would be on the same
core.

Would seem like a step backwards to me.

-Andi

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only
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