[PATCH 08/17] sched/rt: Don't select paravirt CPU for wakeup and push/pull rt task
From: Shrikanth Hegde <hidden>
Date: 2025-11-19 12:46:03
Also in:
lkml
Subsystem:
scheduler, the rest · Maintainers:
Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
For RT class, - During wakeup don't select a paravirt CPU. - Don't pull a task towards a paravirt CPU. - Don't push a task to a paravirt CPU. Signed-off-by: Shrikanth Hegde <redacted> --- kernel/sched/rt.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index f1867fe8e5c5..0b78c74dbbe3 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c@@ -1552,6 +1552,9 @@ select_task_rq_rt(struct task_struct *p, int cpu, int flags) if (!test && target != -1 && !rt_task_fits_capacity(p, target)) goto out_unlock; + /* Avoid moving to a paravirt CPU */ + if (cpu_paravirt(target)) + goto out_unlock; /* * Don't bother moving it if the destination CPU is * not running a lower priority task.
@@ -1876,7 +1879,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq) for (tries = 0; tries < RT_MAX_TRIES; tries++) { cpu = find_lowest_rq(task); - if ((cpu == -1) || (cpu == rq->cpu)) + if ((cpu == -1) || (cpu == rq->cpu) || cpu_paravirt(cpu)) break; lowest_rq = cpu_rq(cpu);
@@ -1974,7 +1977,7 @@ static int push_rt_task(struct rq *rq, bool pull) return 0; cpu = find_lowest_rq(rq->curr); - if (cpu == -1 || cpu == rq->cpu) + if (cpu == -1 || cpu == rq->cpu || cpu_paravirt(cpu)) return 0; /*
@@ -2237,6 +2240,10 @@ static void pull_rt_task(struct rq *this_rq) if (likely(!rt_overload_count)) return; + /* There is no point in pulling the task towards a paravirt cpu */ + if (cpu_paravirt(this_rq->cpu)) + return; + /* * Match the barrier from rt_set_overloaded; this guarantees that if we * see overloaded we must also see the rto_mask bit.
--
2.47.3