On 9/1/2016 6:06 AM, Peter Zijlstra wrote:

On Tue, Aug 30, 2016 at 11:32:16AM -0400, Chris Metcalf wrote:

quoted

On 8/30/2016 3:58 AM, Peter Zijlstra wrote:

quoted

What !? I really don't get this, what are you waiting for? Why is
rescheduling making things better.

We need to wait for the last dyntick to fire before we can return to
userspace.  There are plenty of options as to what we can do in the
meanwhile.

Why not keep your _TIF_TASK_ISOLATION_FOO flag set and re-enter the
loop?

I really don't see how setting TIF_NEED_RESCHED is helping anything.

Yes, I think I addressed that in an earlier reply to Frederic; and you're right,
I don't think TIF_NEED_RESCHED or schedule() are the way to go.

https://lkml.kernel.org/g/107bd666-dbcf-7fa5-ff9c-f79358899712@mellanox.com

Any thoughts on the question of "just re-enter the loop" vs. schedule_timeout()?

-- 
Chris Metcalf, Mellanox Technologies
http://www.mellanox.com

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