Commit dec9554d authored by John Stultz's avatar John Stultz Committed by Peter Zijlstra
Browse files

sched: Move attach_one_task and attach_task helpers to sched.h 



The fair scheduler locally introduced attach_one_task() and
attach_task() helpers, but these could be generically useful so
move this code to sched.h so we can use them elsewhere.

One minor tweak made to utilize guard(rq_lock)(rq) to simplifiy
the function.

Suggested-by: default avatarK Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: default avatarJohn Stultz <jstultz@google.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarK Prateek Nayak <kprateek.nayak@amd.com>
Link: https://patch.msgid.link/20260324191337.1841376-10-jstultz@google.com
parent 48fda62d

kernel/sched/fair.c

+0 −26
Original line number Diff line number Diff line
@@ -9946,32 +9946,6 @@ static int detach_tasks(struct lb_env *env) 
	return detached;

}



/*

 * attach_task() -- attach the task detached by detach_task() to its new rq.

 */

static void attach_task(struct rq *rq, struct task_struct *p)

{

	lockdep_assert_rq_held(rq);



	WARN_ON_ONCE(task_rq(p) != rq);

	activate_task(rq, p, ENQUEUE_NOCLOCK);

	wakeup_preempt(rq, p, 0);

}



/*

 * attach_one_task() -- attaches the task returned from detach_one_task() to

 * its new rq.

 */

static void attach_one_task(struct rq *rq, struct task_struct *p)

{

	struct rq_flags rf;



	rq_lock(rq, &rf);

	update_rq_clock(rq);

	attach_task(rq, p);

	rq_unlock(rq, &rf);

}



/*

 * attach_tasks() -- attaches all tasks detached by detach_tasks() to their

 * new rq.

kernel/sched/sched.h

+23 −0
Original line number Diff line number Diff line
@@ -3012,6 +3012,29 @@ extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags); 


extern void wakeup_preempt(struct rq *rq, struct task_struct *p, int flags);



/*

 * attach_task() -- attach the task detached by detach_task() to its new rq.

 */

static inline void attach_task(struct rq *rq, struct task_struct *p)

{

	lockdep_assert_rq_held(rq);



	WARN_ON_ONCE(task_rq(p) != rq);

	activate_task(rq, p, ENQUEUE_NOCLOCK);

	wakeup_preempt(rq, p, 0);

}



/*

 * attach_one_task() -- attaches the task returned from detach_one_task() to

 * its new rq.

 */

static inline void attach_one_task(struct rq *rq, struct task_struct *p)

{

	guard(rq_lock)(rq);

	update_rq_clock(rq);

	attach_task(rq, p);

}



#ifdef CONFIG_PREEMPT_RT

# define SCHED_NR_MIGRATE_BREAK 8

#else