Commit 2b05a0b4 authored by Connor O'Brien's avatar Connor O'Brien Committed by Peter Zijlstra
Browse files

sched: Add move_queued_task_locked helper 



Switch logic that deactivates, sets the task cpu,
and reactivates a task on a different rq to use a
helper that will be later extended to push entire
blocked task chains.

This patch was broken out from a larger chain migration
patch originally by Connor O'Brien.

[jstultz: split out from larger chain migration patch]
Signed-off-by: default avatarConnor O'Brien <connoro@google.com>
Signed-off-by: default avatarJohn Stultz <jstultz@google.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarMetin Kaya <metin.kaya@arm.com>
Reviewed-by: default avatarValentin Schneider <vschneid@redhat.com>
Reviewed-by: default avatarQais Yousef <qyousef@layalina.io>
Tested-by: default avatarK Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: default avatarMetin Kaya <metin.kaya@arm.com>
Link: https://lore.kernel.org/r/20241009235352.1614323-5-jstultz@google.com
parent 3a9320ec

kernel/sched/core.c

+3 −10
Original line number Diff line number Diff line
@@ -2620,9 +2620,7 @@ int push_cpu_stop(void *arg) 


	// XXX validate p is still the highest prio task

	if (task_rq(p) == rq) {

		deactivate_task(rq, p, 0);

		set_task_cpu(p, lowest_rq->cpu);

		activate_task(lowest_rq, p, 0);

		move_queued_task_locked(rq, lowest_rq, p);

		resched_curr(lowest_rq);

	}
@@ -3309,9 +3307,7 @@ static void __migrate_swap_task(struct task_struct *p, int cpu) 
		rq_pin_lock(src_rq, &srf);

		rq_pin_lock(dst_rq, &drf);



		deactivate_task(src_rq, p, 0);

		set_task_cpu(p, cpu);

		activate_task(dst_rq, p, 0);

		move_queued_task_locked(src_rq, dst_rq, p);

		wakeup_preempt(dst_rq, p, 0);



		rq_unpin_lock(dst_rq, &drf);
@@ -6300,10 +6296,7 @@ static bool try_steal_cookie(int this, int that) 
		if (sched_task_is_throttled(p, this))

			goto next;



		deactivate_task(src, p, 0);

		set_task_cpu(p, this);

		activate_task(dst, p, 0);



		move_queued_task_locked(src, dst, p);

		resched_curr(dst);



		success = true;

kernel/sched/deadline.c

+2 −6
Original line number Diff line number Diff line
@@ -2751,9 +2751,7 @@ static int push_dl_task(struct rq *rq) 
		goto retry;

	}



	deactivate_task(rq, next_task, 0);

	set_task_cpu(next_task, later_rq->cpu);

	activate_task(later_rq, next_task, 0);

	move_queued_task_locked(rq, later_rq, next_task);

	ret = 1;



	resched_curr(later_rq);
@@ -2839,9 +2837,7 @@ static void pull_dl_task(struct rq *this_rq) 
			if (is_migration_disabled(p)) {

				push_task = get_push_task(src_rq);

			} else {

				deactivate_task(src_rq, p, 0);

				set_task_cpu(p, this_cpu);

				activate_task(this_rq, p, 0);

				move_queued_task_locked(src_rq, this_rq, p);

				dmin = p->dl.deadline;

				resched = true;

			}

kernel/sched/rt.c

+2 −6
Original line number Diff line number Diff line
@@ -2088,9 +2088,7 @@ static int push_rt_task(struct rq *rq, bool pull) 
		goto retry;

	}



	deactivate_task(rq, next_task, 0);

	set_task_cpu(next_task, lowest_rq->cpu);

	activate_task(lowest_rq, next_task, 0);

	move_queued_task_locked(rq, lowest_rq, next_task);

	resched_curr(lowest_rq);

	ret = 1;
@@ -2361,9 +2359,7 @@ static void pull_rt_task(struct rq *this_rq) 
			if (is_migration_disabled(p)) {

				push_task = get_push_task(src_rq);

			} else {

				deactivate_task(src_rq, p, 0);

				set_task_cpu(p, this_cpu);

				activate_task(this_rq, p, 0);

				move_queued_task_locked(src_rq, this_rq, p);

				resched = true;

			}

			/*

kernel/sched/sched.h

+12 −0
Original line number Diff line number Diff line
@@ -3788,6 +3788,18 @@ static inline void init_sched_mm_cid(struct task_struct *t) { } 


extern u64 avg_vruntime(struct cfs_rq *cfs_rq);

extern int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se);

#ifdef CONFIG_SMP

static inline

void move_queued_task_locked(struct rq *src_rq, struct rq *dst_rq, struct task_struct *task)

{

	lockdep_assert_rq_held(src_rq);

	lockdep_assert_rq_held(dst_rq);



	deactivate_task(src_rq, task, 0);

	set_task_cpu(task, dst_rq->cpu);

	activate_task(dst_rq, task, 0);

}

#endif



#ifdef CONFIG_RT_MUTEXES