Commit 67fa319f authored by Andrea Righi's avatar Andrea Righi Committed by Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarAndrea Righi <arighi@nvidia.com>
Reviewed-by: default avatarEmil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 70d837c3

kernel/sched/ext.c

+16 −2
Original line number Diff line number Diff line
@@ -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