Re: [PATCH v4.4] x86/kconfig: Fall back to ticket spinlocks

From: Thomas Gleixner
Date: Thu Nov 01 2018 - 05:17:49 EST


On Wed, 31 Oct 2018, Daniel Wagner wrote:
> Backporting all qspinlock related patches is very likely to introduce
> regressions on v4.4. Therefore, the recommended solution by Peter and
> Thomas is to drop back to ticket spinlocks for v4.4.
>
> Link :https://lkml.kernel.org/r/20180921120226.6xjgr4oiho22ex75@xxxxxxxxxxxxx
> Link: https://lkml.kernel.org/r/20180926110117.405325143@xxxxxxxxxxxxx
> Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

> Signed-off-by: Daniel Wagner <daniel.wagner@xxxxxxxxxxx>
> ---
>
> Thomas suggest following plan for fixing the issues on the varous
> stable trees:
>
> 4.4: Trivial by switching back to ticket locks.
>
> 4.9: Decide whether bringing back ticket locks or backporting all qrlock
> fixes. Sebastian has done the latter already and it's probably the
> right solution
>
> 4.14:
> 4.18: Backporting the qrlock fixes
>
> 4.19: Either the fix ends up in 4.19 final or it needs to be backported

Looks about right. Sebastian, can you please provide the 4.9 backport as a
patch series?

Thanks,

tglx