sched: re-instate vruntime based wakeup preemption (464b7527) · Commits · e / devices / android_kernel_fairphone_FP3

kernel/sched_fair.c

+92 −6

Original line number	Original line	Diff line number	Diff line
	@@ -143,6 +143,49 @@ static inline struct sched_entity parent_entity(struct sched_entity se)
	return se->parent;		return se->parent;
	}		}

			/* return depth at which a sched entity is present in the hierarchy */
			static inline int depth_se(struct sched_entity *se)
			{
			int depth = 0;

			for_each_sched_entity(se)
			depth++;

			return depth;
			}

			static void
			find_matching_se(struct sched_entity se, struct sched_entity pse)
			{
			int se_depth, pse_depth;

			/*
			* preemption test can be made between sibling entities who are in the
			* same cfs_rq i.e who have a common parent. Walk up the hierarchy of
			* both tasks until we find their ancestors who are siblings of common
			* parent.
			*/

			/* First walk up until both entities are at same depth */
			se_depth = depth_se(*se);
			pse_depth = depth_se(*pse);

			while (se_depth > pse_depth) {
			se_depth--;
			se = parent_entity(se);
			}

			while (pse_depth > se_depth) {
			pse_depth--;
			pse = parent_entity(pse);
			}

			while (!is_same_group(se, pse)) {
			se = parent_entity(se);
			pse = parent_entity(pse);
			}
			}

	#else /* CONFIG_FAIR_GROUP_SCHED */		#else /* CONFIG_FAIR_GROUP_SCHED */

	static inline struct rq rq_of(struct cfs_rq cfs_rq)		static inline struct rq rq_of(struct cfs_rq cfs_rq)
	@@ -193,6 +236,11 @@ static inline struct sched_entity parent_entity(struct sched_entity se)
	return NULL;		return NULL;
	}		}

			static inline void
			find_matching_se(struct sched_entity se, struct sched_entity pse)
			{
			}

	#endif /* CONFIG_FAIR_GROUP_SCHED */		#endif /* CONFIG_FAIR_GROUP_SCHED */


	@@ -1244,12 +1292,41 @@ static unsigned long wakeup_gran(struct sched_entity *se)
	* More easily preempt - nice tasks, while not making it harder for		* More easily preempt - nice tasks, while not making it harder for
	* + nice tasks.		* + nice tasks.
	*/		*/
	if (sched_feat(ASYM_GRAN))		if (!sched_feat(ASYM_GRAN) \|\| se->load.weight > NICE_0_LOAD)
	gran = calc_delta_mine(gran, NICE_0_LOAD, &se->load);		gran = calc_delta_fair(sysctl_sched_wakeup_granularity, se);

	return gran;		return gran;
	}		}

			/*
			* Should 'se' preempt 'curr'.
			*
			* \|s1
			* \|s2
			* \|s3
			* g
			* \|<--->\|c
			*
			* w(c, s1) = -1
			* w(c, s2) = 0
			* w(c, s3) = 1
			*
			*/
			static int
			wakeup_preempt_entity(struct sched_entity curr, struct sched_entity se)
			{
			s64 gran, vdiff = curr->vruntime - se->vruntime;

			if (vdiff <= 0)
			return -1;

			gran = wakeup_gran(curr);
			if (vdiff > gran)
			return 1;

			return 0;
			}

	/*		/*
	* Preempt the current task with a newly woken task if needed:		* Preempt the current task with a newly woken task if needed:
	*/		*/
	@@ -1258,7 +1335,6 @@ static void check_preempt_wakeup(struct rq rq, struct task_struct p, int sync)
	struct task_struct *curr = rq->curr;		struct task_struct *curr = rq->curr;
	struct cfs_rq *cfs_rq = task_cfs_rq(curr);		struct cfs_rq *cfs_rq = task_cfs_rq(curr);
	struct sched_entity se = &curr->se, pse = &p->se;		struct sched_entity se = &curr->se, pse = &p->se;
	s64 delta_exec;

	if (unlikely(rt_prio(p->prio))) {		if (unlikely(rt_prio(p->prio))) {
	update_rq_clock(rq);		update_rq_clock(rq);
	@@ -1296,9 +1372,19 @@ static void check_preempt_wakeup(struct rq rq, struct task_struct p, int sync)
	return;		return;
	}		}

	delta_exec = se->sum_exec_runtime - se->prev_sum_exec_runtime;		find_matching_se(&se, &pse);
	if (delta_exec > wakeup_gran(pse))
			while (se) {
			BUG_ON(!pse);

			if (wakeup_preempt_entity(se, pse) == 1) {
	resched_task(curr);		resched_task(curr);
			break;
			}

			se = parent_entity(se);
			pse = parent_entity(pse);
			}
	}		}

	static struct task_struct pick_next_task_fair(struct rq rq)		static struct task_struct pick_next_task_fair(struct rq rq)