From: Vineeth Pillai <[email protected]>
During a CPU hotplug event, schedule would be called with the hotplugged CPU
not in the cpumask. So use for_each_cpu(_wrap)_or to include the current cpu in
the task pick loop.
Signed-off-by: Vineeth Pillai <[email protected]>
Co-developed-by: Joel Fernandes (Google) <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>
---
kernel/sched/core.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ff13254ed317..3e9df8221c62 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4663,7 +4663,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
/* reset state */
rq->core->core_cookie = 0UL;
- for_each_cpu(i, smt_mask) {
+ for_each_cpu_or(i, smt_mask, cpumask_of(cpu)) {
struct rq *rq_i = cpu_rq(i);
trace_printk("CPU %d is in smt_mask, resetting\n", i);
@@ -4685,7 +4685,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
*/
for_each_class(class) {
again:
- for_each_cpu_wrap(i, smt_mask, cpu) {
+ for_each_cpu_wrap_or(i, smt_mask, cpumask_of(cpu), cpu) {
struct rq *rq_i = cpu_rq(i);
struct task_struct *p;
@@ -4774,6 +4774,9 @@ next_class:;
rq->core->core_pick_seq = rq->core->core_task_seq;
next = rq->core_pick;
rq->core_sched_seq = rq->core->core_pick_seq;
+
+ /* Something should have been selected for current CPU */
+ WARN_ON_ONCE(!next);
trace_printk("picked: %s/%d %lx\n", next->comm, next->pid, next->core_cookie);
/*
@@ -4784,7 +4787,7 @@ next_class:;
* their task. This ensures there is no inter-sibling overlap between
* non-matching user state.
*/
- for_each_cpu(i, smt_mask) {
+ for_each_cpu_or(i, smt_mask, cpumask_of(cpu)) {
struct rq *rq_i = cpu_rq(i);
WARN_ON_ONCE(!rq_i->core_pick);
--
2.28.0.220.ged08abb693-goog