diff options
| author | Tejun Heo <tj@kernel.org> | 2025-10-22 10:56:27 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2025-10-22 11:42:14 -1000 |
| commit | a9c1fbbd6dadbaa38c157a07d5d11005460b86b9 (patch) | |
| tree | 8118ede9bec40ca7f07799a461b0c27a90d38362 /kernel/sched/ext.c | |
| parent | 2dbbdeda77a61b39dc4a34dfce873907cfea2c4b (diff) | |
sched_ext: Don't kick CPUs running higher classes
When a sched_ext scheduler tries to kick a CPU, the CPU may be running a
higher class task. sched_ext has no control over such CPUs. A sched_ext
scheduler couldn't have expected to get access to the CPU after kicking it
anyway. Skip kicking when the target CPU is running a higher class.
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/sched/ext.c')
| -rw-r--r-- | kernel/sched/ext.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index dc86ce0be32a..12e00f77a848 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -5122,18 +5122,23 @@ static bool kick_one_cpu(s32 cpu, struct rq *this_rq, unsigned long *pseqs) { struct rq *rq = cpu_rq(cpu); struct scx_rq *this_scx = &this_rq->scx; + const struct sched_class *cur_class; bool should_wait = false; unsigned long flags; raw_spin_rq_lock_irqsave(rq, flags); + cur_class = rq->curr->sched_class; /* * During CPU hotplug, a CPU may depend on kicking itself to make - * forward progress. Allow kicking self regardless of online state. + * forward progress. Allow kicking self regardless of online state. If + * @cpu is running a higher class task, we have no control over @cpu. + * Skip kicking. */ - if (cpu_online(cpu) || cpu == cpu_of(this_rq)) { + if ((cpu_online(cpu) || cpu == cpu_of(this_rq)) && + !sched_class_above(cur_class, &ext_sched_class)) { if (cpumask_test_cpu(cpu, this_scx->cpus_to_preempt)) { - if (rq->curr->sched_class == &ext_sched_class) + if (cur_class == &ext_sched_class) rq->curr->scx.slice = 0; cpumask_clear_cpu(cpu, this_scx->cpus_to_preempt); } |