Re: [patch V4 4/8] sched: Make migrate_disable/enable() independent of RT

[Steven Rostedt]

On Thu, 19 Nov 2020 12:14:13 +0000
Mel Gorman <mgorman@xxxxxxx> wrote:

> * Usage of migrate_disable is heavily discouraged as it is extremely
> * hazardous on PREEMPT_RT kernels and any usage needs to be heavily

I don't believe it's just PREEMPT_RT. It's RT tasks that are concerned,
especially when you are dealing with SCHED_DEADLINE.

PREEMPT_RT just allows better determinism for RT tasks, but the issue with
migrate_disable is not limited to just PREEMPT_RT.

-- Steve


> * justified. Before even thinking about using this, read
> * "Migrate-Disable and why it is undesired" in
> * include/linux/preempt.h and include both a comment and document
> * in the changelog why the use case is an exception.