A new BPF extensible sched_class will need to dynamically change how a task
picks its sched_class. For example, if the loaded BPF scheduler progs fail,
the tasks will be forced back on CFS even if the task's policy is set to the
new sched_class. To support such mapping, add normal_policy() which wraps
testing for %SCHED_NORMAL. This doesn't cause any behavior changes.
v2: Update the description with more details on the expected use.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Reviewed-by: David Vernet <dvernet@xxxxxxxx>
Acked-by: Josh Don <joshdon@xxxxxxxxxx>
Acked-by: Hao Luo <haoluo@xxxxxxxxxx>
Acked-by: Barret Rhoden <brho@xxxxxxxxxx>
---
kernel/sched/fair.c | 2 +-
kernel/sched/sched.h | 8 +++++++-
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index bd9ff4fa77b8..c9ad47f0ec1f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8147,7 +8147,7 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int
* Batch and idle tasks do not preempt non-idle tasks (their preemption
* is driven by the tick):
*/
- if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION))
+ if (unlikely(!normal_policy(p->policy)) || !sched_feat(WAKEUP_PREEMPTION))
return;
find_matching_se(&se, &pse);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index d02ea254aa87..8474448d4125 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -171,9 +171,15 @@ static inline int idle_policy(int policy)
{
return policy == SCHED_IDLE;
}
+
+static inline int normal_policy(int policy)
+{
+ return policy == SCHED_NORMAL;
+}
+
static inline int fair_policy(int policy)
{
- return policy == SCHED_NORMAL || policy == SCHED_BATCH;
+ return normal_policy(policy) || policy == SCHED_BATCH;
}
static inline int rt_policy(int policy)
--
2.42.0
