Re: [PATCH v2 7/9] sched: define TIF_ALLOW_RESCHED

Matthew Wilcox
2023-09-12T12:34:07Z

On Tue, Sep 12, 2023 at 10:26:06AM +0200, Peter Zijlstra wrote:
> > How expensive would be always having PREEMPT_COUNT=y?
>
> Effectively I think that is true today. At the very least Debian and
> SuSE (I can't find a RHEL .config in a hurry but I would think they too)
> ship with PREEMPT_DYNAMIC=y.

$ grep PREEMPT uek-rpm/ol9/config-x86_64
# CONFIG_PREEMPT_NONE is not set
CONFIG_PREEMPT_VOLUNTARY=y
# CONFIG_PREEMPT is not set
CONFIG_HAVE_PREEMPT_DYNAMIC=y
CONFIG_PREEMPT_NOTIFIERS=y
CONFIG_DRM_I915_PREEMPT_TIMEOUT=640
# CONFIG_PREEMPTIRQ_DELAY_TEST is not set

$ grep PREEMPT uek-rpm/ol9/config-aarch64
# CONFIG_PREEMPT_NONE is not set
CONFIG_PREEMPT_VOLUNTARY=y
# CONFIG_PREEMPT is not set
CONFIG_PREEMPT_NOTIFIERS=y
# CONFIG_PREEMPTIRQ_DELAY_TEST is not set