X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fsched_fair.c;h=c9fbe8e73a45c66f36bb2ddf8bf5eaf24d93c141;hb=325d50b660519398dc875b4cffedd0fc2cc4f425;hp=ee3771850aaf1548e41bdcf224e95301d797a5e1;hpb=a3ce8ea66ae9379235334a989ed78a1ea518b0b3;p=linux-2.6-omap-h63xx.git diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index ee3771850aa..c9fbe8e73a4 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -42,6 +42,14 @@ unsigned int sysctl_sched_latency __read_mostly = 20000000ULL; */ unsigned int sysctl_sched_min_granularity __read_mostly = 2000000ULL; +/* + * sys_sched_yield() compat mode + * + * This option switches the agressive yield implementation of the + * old scheduler back on. + */ +unsigned int __read_mostly sysctl_sched_compat_yield; + /* * SCHED_BATCH wake-up granularity. * (default: 25 msec, units: nanoseconds) @@ -194,6 +202,8 @@ __enqueue_entity(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; + + schedstat_add(cfs_rq, wait_runtime, se->wait_runtime); } static inline void @@ -205,6 +215,8 @@ __dequeue_entity(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; + + schedstat_add(cfs_rq, wait_runtime, -se->wait_runtime); } static inline struct rb_node *first_fair(struct cfs_rq *cfs_rq) @@ -291,7 +303,7 @@ niced_granularity(struct sched_entity *curr, unsigned long granularity) /* * It will always fit into 'long': */ - return (long) (tmp >> WMULT_SHIFT); + return (long) (tmp >> (WMULT_SHIFT-NICE_0_SHIFT)); } static inline void @@ -354,7 +366,7 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr) delta_fair = calc_delta_fair(delta_exec, lw); delta_mine = calc_delta_mine(delta_exec, curr->load.weight, lw); - if (cfs_rq->sleeper_bonus > sysctl_sched_latency) { + if (cfs_rq->sleeper_bonus > sysctl_sched_min_granularity) { delta = min((u64)delta_mine, cfs_rq->sleeper_bonus); delta = min(delta, (unsigned long)( (long)sysctl_sched_runtime_limit - curr->wait_runtime)); @@ -489,6 +501,9 @@ update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) { unsigned long delta_fair; + if (unlikely(!se->wait_start_fair)) + return; + delta_fair = (unsigned long)min((u64)(2*sysctl_sched_runtime_limit), (u64)(cfs_rq->fair_clock - se->wait_start_fair)); @@ -571,7 +586,6 @@ static void __enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) prev_runtime = se->wait_runtime; __add_wait_runtime(cfs_rq, se, delta_fair); - schedstat_add(cfs_rq, wait_runtime, se->wait_runtime); delta_fair = se->wait_runtime - prev_runtime; /* @@ -659,7 +673,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) if (tsk->state & TASK_UNINTERRUPTIBLE) se->block_start = rq_of(cfs_rq)->clock; } - cfs_rq->wait_runtime -= se->wait_runtime; #endif } __dequeue_entity(cfs_rq, se); @@ -673,11 +686,31 @@ __check_preempt_curr_fair(struct cfs_rq *cfs_rq, struct sched_entity *se, struct sched_entity *curr, unsigned long granularity) { s64 __delta = curr->fair_key - se->fair_key; + unsigned long ideal_runtime, delta_exec; + + /* + * ideal_runtime is compared against sum_exec_runtime, which is + * walltime, hence do not scale. + */ + ideal_runtime = max(sysctl_sched_latency / cfs_rq->nr_running, + (unsigned long)sysctl_sched_min_granularity); + + /* + * If we executed more than what the latency constraint suggests, + * reduce the rescheduling granularity. This way the total latency + * of how much a task is not scheduled converges to + * sysctl_sched_latency: + */ + delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; + if (delta_exec > ideal_runtime) + granularity = 0; /* * Take scheduling granularity into account - do not * preempt the current task unless the best task has * a larger than sched_granularity fairness advantage: + * + * scale granularity as key space is in fair_clock. */ if (__delta > niced_granularity(curr, granularity)) resched_task(rq_of(cfs_rq)->curr); @@ -696,6 +729,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) update_stats_wait_end(cfs_rq, se); update_stats_curr_start(cfs_rq, se); set_cfs_rq_curr(cfs_rq, se); + se->prev_sum_exec_runtime = se->sum_exec_runtime; } static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq) @@ -871,19 +905,62 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep) } /* - * sched_yield() support is very simple - we dequeue and enqueue + * sched_yield() support is very simple - we dequeue and enqueue. + * + * If compat_yield is turned on then we requeue to the end of the tree. */ static void yield_task_fair(struct rq *rq, struct task_struct *p) { struct cfs_rq *cfs_rq = task_cfs_rq(p); + struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; + struct sched_entity *rightmost, *se = &p->se; + struct rb_node *parent; - __update_rq_clock(rq); /* - * Dequeue and enqueue the task to update its - * position within the tree: + * Are we the only task in the tree? */ - dequeue_entity(cfs_rq, &p->se, 0); - enqueue_entity(cfs_rq, &p->se, 0); + if (unlikely(cfs_rq->nr_running == 1)) + return; + + if (likely(!sysctl_sched_compat_yield)) { + __update_rq_clock(rq); + /* + * Dequeue and enqueue the task to update its + * position within the tree: + */ + dequeue_entity(cfs_rq, &p->se, 0); + enqueue_entity(cfs_rq, &p->se, 0); + + return; + } + /* + * Find the rightmost entry in the rbtree: + */ + do { + parent = *link; + link = &parent->rb_right; + } while (*link); + + rightmost = rb_entry(parent, struct sched_entity, run_node); + /* + * Already in the rightmost position? + */ + if (unlikely(rightmost == se)) + return; + + /* + * Minimally necessary key value to be last in the tree: + */ + se->fair_key = rightmost->fair_key + 1; + + if (cfs_rq->rb_leftmost == &se->run_node) + cfs_rq->rb_leftmost = rb_next(&se->run_node); + /* + * Relink the task to the rightmost position: + */ + rb_erase(&se->run_node, &cfs_rq->tasks_timeline); + rb_link_node(&se->run_node, parent, link); + rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); } /* @@ -1076,31 +1153,32 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr) static void task_new_fair(struct rq *rq, struct task_struct *p) { struct cfs_rq *cfs_rq = task_cfs_rq(p); - struct sched_entity *se = &p->se; + struct sched_entity *se = &p->se, *curr = cfs_rq_curr(cfs_rq); sched_info_queued(p); + update_curr(cfs_rq); update_stats_enqueue(cfs_rq, se); /* * Child runs first: we let it run before the parent * until it reschedules once. We set up the key so that * it will preempt the parent: */ - p->se.fair_key = current->se.fair_key - - niced_granularity(&rq->curr->se, sched_granularity(cfs_rq)) - 1; + se->fair_key = curr->fair_key - + niced_granularity(curr, sched_granularity(cfs_rq)) - 1; /* * The first wait is dominated by the child-runs-first logic, * so do not credit it with that waiting time yet: */ if (sysctl_sched_features & SCHED_FEAT_SKIP_INITIAL) - p->se.wait_start_fair = 0; + se->wait_start_fair = 0; /* * The statistical average of wait_runtime is about * -granularity/2, so initialize the task with that: */ if (sysctl_sched_features & SCHED_FEAT_START_DEBIT) - p->se.wait_runtime = -(sched_granularity(cfs_rq) / 2); + se->wait_runtime = -(sched_granularity(cfs_rq) / 2); __enqueue_entity(cfs_rq, se); }