From 02e0431a3db554019b816936b597d618256b705d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 15 Oct 2007 17:00:07 +0200 Subject: [PATCH] sched: better min_vruntime tracking Better min_vruntime tracking: update it every time 'curr' is updated - not just when a task is enqueued into the tree. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar Signed-off-by: Mike Galbraith Reviewed-by: Thomas Gleixner --- kernel/sched_fair.c | 40 +++++++++++++++++++++++++++++++++------- 1 file changed, 33 insertions(+), 7 deletions(-) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index e3081fb65d63..ec445cadbb01 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -116,22 +116,28 @@ static inline struct task_struct *task_of(struct sched_entity *se) * Scheduling class tree data structure manipulation methods: */ +static inline u64 +max_vruntime(u64 min_vruntime, u64 vruntime) +{ + if ((vruntime > min_vruntime) || + (min_vruntime > (1ULL << 61) && vruntime < (1ULL << 50))) + min_vruntime = vruntime; + + return min_vruntime; +} + static inline void set_leftmost(struct cfs_rq *cfs_rq, struct rb_node *leftmost) { struct sched_entity *se; cfs_rq->rb_leftmost = leftmost; - if (leftmost) { + if (leftmost) se = rb_entry(leftmost, struct sched_entity, run_node); - if ((se->vruntime > cfs_rq->min_vruntime) || - (cfs_rq->min_vruntime > (1ULL << 61) && - se->vruntime < (1ULL << 50))) - cfs_rq->min_vruntime = se->vruntime; - } } -s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) +static inline s64 +entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) { return se->fair_key - cfs_rq->min_vruntime; } @@ -254,6 +260,7 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, unsigned long delta_exec) { unsigned long delta_exec_weighted; + u64 next_vruntime, min_vruntime; schedstat_set(curr->exec_max, max((u64)delta_exec, curr->exec_max)); @@ -265,6 +272,25 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, &curr->load); } curr->vruntime += delta_exec_weighted; + + /* + * maintain cfs_rq->min_vruntime to be a monotonic increasing + * value tracking the leftmost vruntime in the tree. + */ + if (first_fair(cfs_rq)) { + next_vruntime = __pick_next_entity(cfs_rq)->vruntime; + + /* min_vruntime() := !max_vruntime() */ + min_vruntime = max_vruntime(curr->vruntime, next_vruntime); + if (min_vruntime == next_vruntime) + min_vruntime = curr->vruntime; + else + min_vruntime = next_vruntime; + } else + min_vruntime = curr->vruntime; + + cfs_rq->min_vruntime = + max_vruntime(cfs_rq->min_vruntime, min_vruntime); } static void update_curr(struct cfs_rq *cfs_rq) -- 2.30.2