Re: [PATCH for-6.12-fixes] sched_ext: Remove unnecessary cpu_relax()

[Tejun Heo]

On Mon, Oct 14, 2024 at 12:58:30PM -0500, David Vernet wrote:
> As described in commit b07996c7abac ("sched_ext: Don't hold
> scx_tasks_lock for too long"), we're doing a cond_resched() every 32
> calls to scx_task_iter_next() to avoid RCU and other stalls. That commit
> also added a cpu_relax() to the codepath where we drop and reacquire the
> lock, but as Waiman described in [0], cpu_relax() should only be
> necessary in busy loops to avoid pounding on a cacheline (or to allow a
> hypertwin to more fully utilize a core).
> 
> Let's remove the unnecessary cpu_relax().
> 
> [0]: https://lore.kernel.org/all/35b3889b-904a-4d26-981f-c8aa1557a7c7@xxxxxxxxxx/
> 
> Cc: Waiman Long <llong@xxxxxxxxxx>
> Signed-off-by: David Vernet <void@xxxxxxxxxxxxx>

Applied to sched_ext/for-6.12-fixes.

Thanks.

-- 
tejun