diff options
| author | Andrea Righi <arighi@nvidia.com> | 2025-10-18 16:10:14 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2025-10-18 13:01:35 -1000 |
| commit | 67fa319f5fff523a17993eafe990ad11aa5d6be9 (patch) | |
| tree | 733f5ac0681b74191c122b82ae19927ff9f09c0e | |
| parent | 70d837c3e017a0dc2bc52abf07abfeebd006c946 (diff) | |
sched_ext: Allow forcibly picking an scx task
Refactor pick_task_scx() adding a new argument to forcibly pick a
SCHED_EXT task, ignoring any higher-priority sched class activity.
This refactoring prepares the code for future scenarios, e.g., allowing
the ext dl_server to force a SCHED_EXT task selection.
No functional changes.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | kernel/sched/ext.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index adff739b396c..35bc37c7ee19 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -2351,7 +2351,8 @@ static struct task_struct *first_local_task(struct rq *rq) struct task_struct, scx.dsq_list.node); } -static struct task_struct *pick_task_scx(struct rq *rq, struct rq_flags *rf) +static struct task_struct * +do_pick_task_scx(struct rq *rq, struct rq_flags *rf, bool force_scx) { struct task_struct *prev = rq->curr; bool keep_prev, kick_idle = false; @@ -2365,7 +2366,15 @@ static struct task_struct *pick_task_scx(struct rq *rq, struct rq_flags *rf) maybe_queue_balance_callback(rq); - if (rq_modified_above(rq, &ext_sched_class)) + /* + * If any higher-priority sched class enqueued a runnable task on + * this rq during balance_one(), abort and return RETRY_TASK, so + * that the scheduler loop can restart. + * + * If @force_scx is true, always try to pick a SCHED_EXT task, + * regardless of any higher-priority sched classes activity. + */ + if (!force_scx && rq_modified_above(rq, &ext_sched_class)) return RETRY_TASK; keep_prev = rq->scx.flags & SCX_RQ_BAL_KEEP; @@ -2408,6 +2417,11 @@ static struct task_struct *pick_task_scx(struct rq *rq, struct rq_flags *rf) return p; } +static struct task_struct *pick_task_scx(struct rq *rq, struct rq_flags *rf) +{ + return do_pick_task_scx(rq, rf, false); +} + #ifdef CONFIG_SCHED_CORE /** * scx_prio_less - Task ordering for core-sched |