Re: [PATCH 10/10] softirq: Remove __ARCH_SET_SOFTIRQ_PENDING

From: Martin Schwidefsky
Date: Tue Apr 03 2018 - 01:52:50 EST


On Thu, 29 Mar 2018 20:08:36 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Thu, Mar 29, 2018 at 04:53:43PM +0200, Martin Schwidefsky wrote:
> > The lowcore optimization for softirq_pending field is not really needed,
> > just nice to have. But if there is a strong reason to make a common
> > definition for it we can certainly do that.
>
> A slightly related question; would it make sense to move all kernel
> static per-cpu stuff into lowcore, or is that asking for too much
> trickery?

The space in lowcore is quite limited, for zArch the structure is 8K with
many pre-defined fields. I fear that putting all of the static per-cpu
stuff in there is too much.

So far I used the lowcore as optimization for selected per-cpu fields
which are performance relevant.

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.