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 | 7 ++++++-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 715d7c1f55df..d59537416865 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8391,7 +8391,7 @@ 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 a5a4f59151db..25660dc9f639 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -192,9 +192,14 @@ 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)
--
2.45.2
