From 30cfdcfc5f180fc21a3dad6ae3b7b2a9ee112186 Mon Sep 17 00:00:00 2001 From: Dmitry Adamushko Date: Mon, 15 Oct 2007 17:00:07 +0200 Subject: [PATCH] sched: do not keep current in the tree and get rid of sched_entity::fair_key Get rid of 'sched_entity::fair_key'. As a side effect, 'current' is not kept withing the tree for SCHED_NORMAL/BATCH tasks anymore. This simplifies some parts of code (e.g. entity_tick() and yield_task_fair()) and also somewhat optimizes them (e.g. a single update_curr() now vs. dequeue/enqueue() before in entity_tick()). Signed-off-by: Dmitry Adamushko Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Reviewed-by: Thomas Gleixner --- include/linux/sched.h | 1 - kernel/sched.c | 1 - kernel/sched_debug.c | 2 +- kernel/sched_fair.c | 54 ++++++++++++++++++++++++++++--------------- 4 files changed, 36 insertions(+), 22 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 572df1bbaeec..f776a30b403e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -891,7 +891,6 @@ struct load_weight { * 6 se->load.weight */ struct sched_entity { - s64 fair_key; struct load_weight load; /* for load-balancing */ struct rb_node run_node; unsigned int on_rq; diff --git a/kernel/sched.c b/kernel/sched.c index 6d1892192e21..3b104635a8ea 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6610,7 +6610,6 @@ void normalize_rt_tasks(void) read_lock_irq(&tasklist_lock); do_each_thread(g, p) { - p->se.fair_key = 0; p->se.exec_start = 0; #ifdef CONFIG_SCHEDSTATS p->se.wait_start = 0; diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index e3b62324ac31..bb34b8188f61 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -38,7 +38,7 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) SEQ_printf(m, "%15s %5d %15Ld %13Ld %5d ", p->comm, p->pid, - (long long)p->se.fair_key, + (long long)p->se.vruntime, (long long)(p->nvcsw + p->nivcsw), p->prio); #ifdef CONFIG_SCHEDSTATS diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 144f3ef97380..b9e426a8a09f 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -139,7 +139,7 @@ set_leftmost(struct cfs_rq *cfs_rq, struct rb_node *leftmost) static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) { - return se->fair_key - cfs_rq->min_vruntime; + return se->vruntime - cfs_rq->min_vruntime; } /* @@ -181,9 +181,6 @@ __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) rb_link_node(&se->run_node, parent, link); rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); - update_load_add(&cfs_rq->load, se->load.weight); - cfs_rq->nr_running++; - se->on_rq = 1; } static void @@ -193,9 +190,6 @@ __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) set_leftmost(cfs_rq, rb_next(&se->run_node)); rb_erase(&se->run_node, &cfs_rq->tasks_timeline); - update_load_sub(&cfs_rq->load, se->load.weight); - cfs_rq->nr_running--; - se->on_rq = 0; } static inline struct rb_node *first_fair(struct cfs_rq *cfs_rq) @@ -341,10 +335,6 @@ static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) */ if (se != cfs_rq->curr) update_stats_wait_start(cfs_rq, se); - /* - * Update the key: - */ - se->fair_key = se->vruntime; } static void @@ -392,6 +382,22 @@ update_stats_curr_end(struct cfs_rq *cfs_rq, struct sched_entity *se) * Scheduling class queueing methods: */ +static void +account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + update_load_add(&cfs_rq->load, se->load.weight); + cfs_rq->nr_running++; + se->on_rq = 1; +} + +static void +account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + update_load_sub(&cfs_rq->load, se->load.weight); + cfs_rq->nr_running--; + se->on_rq = 0; +} + static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) { #ifdef CONFIG_SCHEDSTATS @@ -479,7 +485,9 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) } update_stats_enqueue(cfs_rq, se); - __enqueue_entity(cfs_rq, se); + if (se != cfs_rq->curr) + __enqueue_entity(cfs_rq, se); + account_entity_enqueue(cfs_rq, se); } static void @@ -498,7 +506,9 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) } } #endif - __dequeue_entity(cfs_rq, se); + if (se != cfs_rq->curr) + __dequeue_entity(cfs_rq, se); + account_entity_dequeue(cfs_rq, se); } /* @@ -544,6 +554,10 @@ static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) { struct sched_entity *se = __pick_next_entity(cfs_rq); + /* 'current' is not kept within the tree. */ + if (se) + __dequeue_entity(cfs_rq, se); + set_next_entity(cfs_rq, se); return se; @@ -560,19 +574,20 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) update_stats_curr_end(cfs_rq, prev); - if (prev->on_rq) + if (prev->on_rq) { update_stats_wait_start(cfs_rq, prev); + /* Put 'current' back into the tree. */ + __enqueue_entity(cfs_rq, prev); + } cfs_rq->curr = NULL; } static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) { /* - * Dequeue and enqueue the task to update its - * position within the tree: + * Update run-time statistics of the 'current'. */ - dequeue_entity(cfs_rq, curr, 0); - enqueue_entity(cfs_rq, curr, 0); + update_curr(cfs_rq); if (cfs_rq->nr_running > 1) check_preempt_tick(cfs_rq, curr); @@ -749,7 +764,7 @@ static void yield_task_fair(struct rq *rq, struct task_struct *p) /* * Minimally necessary key value to be last in the tree: */ - se->fair_key = rightmost->fair_key + 1; + se->vruntime = rightmost->vruntime + 1; if (cfs_rq->rb_leftmost == &se->run_node) cfs_rq->rb_leftmost = rb_next(&se->run_node); @@ -965,6 +980,7 @@ static void task_new_fair(struct rq *rq, struct task_struct *p) update_stats_enqueue(cfs_rq, se); __enqueue_entity(cfs_rq, se); + account_entity_enqueue(cfs_rq, se); resched_task(rq->curr); }