Re: [RFC][PATCH 2/7] smp: Optimize flush_smp_call_function_queue()

From: Frederic Weisbecker
Date: Thu May 28 2020 - 08:28:52 EST


On Tue, May 26, 2020 at 06:10:59PM +0200, Peter Zijlstra wrote:
> The call_single_queue can contain (two) different callbacks,
> synchronous and asynchronous. The current interrupt handler runs them
> in-order, which means that remote CPUs that are waiting for their
> synchronous call can be delayed by running asynchronous callbacks.
>
> Rework the interrupt handler to first run the synchonous callbacks.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>

I hope we are not unlucky enough to have dependencies between
some async and sync callbacks that require the whole execution
in order.

Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>

(Sweet llist dance, I think I need fresh air and coffee now).