diff options
| author | David Vernet | 2024-10-14 12:58:30 -0500 |
|---|---|---|
| committer | Tejun Heo | 2024-10-14 13:23:49 -1000 |
| commit | 60e339be100d7d49e13616bd8b4b1b864f0a64a0 (patch) | |
| tree | 0abc72d60145c53ea2b4a3d82199dc3257f3e840 /kernel/sched | |
| parent | b07996c7abac0fe3f70bf74b0b3f76eb7852ef5a (diff) | |
sched_ext: Remove unnecessary cpu_relax()
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@redhat.com/
Cc: Waiman Long <llong@redhat.com>
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/ext.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index cb1ab668e965..6eae3b69bf6e 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -1374,7 +1374,6 @@ static struct task_struct *scx_task_iter_next(struct scx_task_iter *iter) if (!(++iter->cnt % SCX_OPS_TASK_ITER_BATCH)) { scx_task_iter_unlock(iter); - cpu_relax(); cond_resched(); scx_task_iter_relock(iter); } |