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Commit 7ebd479a authored by Steve Muckle's avatar Steve Muckle
Browse files

sched: fix misalignment between requested and actual windows 



When set_window_start() is first executed sched_clock() has not yet
stabilized. Refresh the sched_init_jiffy and sched_clock_at_init_jiffy
values until it is known that sched_clock has stabilized - this will
be the case by the time a client calls the sched_set_window() API.

Change-Id: Icd057707ff44c3b240e5e7e96891b23c95733daa
Signed-off-by: default avatarSteve Muckle <smuckle@codeaurora.org>
parent efcad24c

kernel/sched/core.c

+10 −3
Original line number Diff line number Diff line
@@ -1596,18 +1596,23 @@ static inline void mark_task_starting(struct task_struct *p) 
	p->ravg.flags |= PREV_WINDOW_CONTRIB;

}



static int update_alignment;



static inline void set_window_start(struct rq *rq)

{

	int cpu = cpu_of(rq);

	struct rq *sync_rq = cpu_rq(sync_cpu);



	if (cpu == sync_cpu && !update_alignment) {

		sched_init_jiffy = get_jiffies_64();

		sched_clock_at_init_jiffy = sched_clock();

	}



	if (rq->window_start || !sched_enable_hmp)

		return;



	if (cpu == sync_cpu) {

		rq->window_start = sched_clock();

		sched_init_jiffy = get_jiffies_64();

		sched_clock_at_init_jiffy = rq->window_start;

		rq->window_start = sched_clock_at_init_jiffy;

	} else {

		raw_spin_unlock(&rq->lock);

		double_rq_lock(rq, sync_rq);
@@ -1719,6 +1724,8 @@ int sched_set_window(u64 window_start, unsigned int window_size) 
		 (window_size * TICK_NSEC <  MIN_SCHED_RAVG_WINDOW))

			return -EINVAL;



	update_alignment = 1;



	local_irq_save(flags);



	now = get_jiffies_64();