X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fsched.c;h=50e1a312269945284bc0ce769eb9b2acd629b7f2;hb=d0f9b55ece0ec1ffc9e2e57fd7a79200994aead4;hp=a3a04085e79407a94a0fa79b8b2da7e77be33185;hpb=18062a91d2ddc40e19fc674afeb7cad58cfa23ab;p=linux-2.6-omap-h63xx.git diff --git a/kernel/sched.c b/kernel/sched.c index a3a04085e79..50e1a312269 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -169,7 +169,7 @@ unsigned long long __attribute__((weak)) sched_clock(void) (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1)) #define TASK_PREEMPTS_CURR(p, rq) \ - (((p)->prio < (rq)->curr->prio) && ((p)->array == (rq)->active)) + ((p)->prio < (rq)->curr->prio) #define SCALE_PRIO(x, prio) \ max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_TIMESLICE) @@ -305,6 +305,7 @@ struct rq { }; static DEFINE_PER_CPU(struct rq, runqueues) ____cacheline_aligned_in_smp; +static DEFINE_MUTEX(sched_hotcpu_mutex); static inline int cpu_of(struct rq *rq) { @@ -1158,21 +1159,72 @@ void wait_task_inactive(struct task_struct *p) { unsigned long flags; struct rq *rq; - int preempted; + struct prio_array *array; + int running; repeat: + /* + * We do the initial early heuristics without holding + * any task-queue locks at all. We'll only try to get + * the runqueue lock when things look like they will + * work out! + */ + rq = task_rq(p); + + /* + * If the task is actively running on another CPU + * still, just relax and busy-wait without holding + * any locks. + * + * NOTE! Since we don't hold any locks, it's not + * even sure that "rq" stays as the right runqueue! + * But we don't care, since "task_running()" will + * return false if the runqueue has changed and p + * is actually now running somewhere else! + */ + while (task_running(rq, p)) + cpu_relax(); + + /* + * Ok, time to look more closely! We need the rq + * lock now, to be *sure*. If we're wrong, we'll + * just go back and repeat. + */ rq = task_rq_lock(p, &flags); - /* Must be off runqueue entirely, not preempted. */ - if (unlikely(p->array || task_running(rq, p))) { - /* If it's preempted, we yield. It could be a while. */ - preempted = !task_running(rq, p); - task_rq_unlock(rq, &flags); + running = task_running(rq, p); + array = p->array; + task_rq_unlock(rq, &flags); + + /* + * Was it really running after all now that we + * checked with the proper locks actually held? + * + * Oops. Go back and try again.. + */ + if (unlikely(running)) { cpu_relax(); - if (preempted) - yield(); goto repeat; } - task_rq_unlock(rq, &flags); + + /* + * It's not enough that it's not actively running, + * it must be off the runqueue _entirely_, and not + * preempted! + * + * So if it wa still runnable (but just not actively + * running right now), it's preempted, and we should + * yield - it could be a while. + */ + if (unlikely(array)) { + yield(); + goto repeat; + } + + /* + * Ahh, all good. It wasn't running, and it wasn't + * runnable, which means that it will never become + * running in the future either. We're all done! + */ } /*** @@ -2886,17 +2938,21 @@ static void idle_balance(int this_cpu, struct rq *this_rq) unsigned long next_balance = jiffies + 60 * HZ; for_each_domain(this_cpu, sd) { - if (sd->flags & SD_BALANCE_NEWIDLE) { + unsigned long interval; + + if (!(sd->flags & SD_LOAD_BALANCE)) + continue; + + if (sd->flags & SD_BALANCE_NEWIDLE) /* If we've pulled tasks over stop searching: */ pulled_task = load_balance_newidle(this_cpu, - this_rq, sd); - if (time_after(next_balance, - sd->last_balance + sd->balance_interval)) - next_balance = sd->last_balance - + sd->balance_interval; - if (pulled_task) - break; - } + this_rq, sd); + + interval = msecs_to_jiffies(sd->balance_interval); + if (time_after(next_balance, sd->last_balance + interval)) + next_balance = sd->last_balance + interval; + if (pulled_task) + break; } if (!pulled_task) /* @@ -4076,13 +4132,13 @@ void rt_mutex_setprio(struct task_struct *p, int prio) struct prio_array *array; unsigned long flags; struct rq *rq; - int delta; + int oldprio; BUG_ON(prio < 0 || prio > MAX_PRIO); rq = task_rq_lock(p, &flags); - delta = prio - p->prio; + oldprio = p->prio; array = p->array; if (array) dequeue_task(p, array); @@ -4098,11 +4154,13 @@ void rt_mutex_setprio(struct task_struct *p, int prio) enqueue_task(p, array); /* * Reschedule if we are currently running on this runqueue and - * our priority decreased, or if our priority became higher - * than the current's. + * our priority decreased, or if we are not currently running on + * this runqueue and our priority is higher than the current's */ - if (TASK_PREEMPTS_CURR(p, rq) || - (delta > 0 && task_running(rq, p))) + if (task_running(rq, p)) { + if (p->prio > oldprio) + resched_task(rq->curr); + } else if (TASK_PREEMPTS_CURR(p, rq)) resched_task(rq->curr); } task_rq_unlock(rq, &flags); @@ -4150,12 +4208,10 @@ void set_user_nice(struct task_struct *p, long nice) enqueue_task(p, array); inc_raw_weighted_load(rq, p); /* - * Reschedule if we are currently running on this runqueue and - * our priority decreased, or if our priority became higher - * than the current's. + * If the task increased its priority or is running and + * lowered its priority, then reschedule its CPU: */ - if (TASK_PREEMPTS_CURR(p, rq) || - (delta > 0 && task_running(rq, p))) + if (delta < 0 || (delta > 0 && task_running(rq, p))) resched_task(rq->curr); } out_unlock: @@ -4382,11 +4438,13 @@ recheck: __activate_task(p, rq); /* * Reschedule if we are currently running on this runqueue and - * our priority decreased, or our priority became higher - * than the current's. + * our priority decreased, or if we are not currently running on + * this runqueue and our priority is higher than the current's */ - if (TASK_PREEMPTS_CURR(p, rq) || - (task_running(rq, p) && p->prio > oldprio)) + if (task_running(rq, p)) { + if (p->prio > oldprio) + resched_task(rq->curr); + } else if (TASK_PREEMPTS_CURR(p, rq)) resched_task(rq->curr); } __task_rq_unlock(rq); @@ -4518,13 +4576,13 @@ long sched_setaffinity(pid_t pid, cpumask_t new_mask) struct task_struct *p; int retval; - lock_cpu_hotplug(); + mutex_lock(&sched_hotcpu_mutex); read_lock(&tasklist_lock); p = find_process_by_pid(pid); if (!p) { read_unlock(&tasklist_lock); - unlock_cpu_hotplug(); + mutex_unlock(&sched_hotcpu_mutex); return -ESRCH; } @@ -4551,7 +4609,7 @@ long sched_setaffinity(pid_t pid, cpumask_t new_mask) out_unlock: put_task_struct(p); - unlock_cpu_hotplug(); + mutex_unlock(&sched_hotcpu_mutex); return retval; } @@ -4608,7 +4666,7 @@ long sched_getaffinity(pid_t pid, cpumask_t *mask) struct task_struct *p; int retval; - lock_cpu_hotplug(); + mutex_lock(&sched_hotcpu_mutex); read_lock(&tasklist_lock); retval = -ESRCH; @@ -4624,7 +4682,7 @@ long sched_getaffinity(pid_t pid, cpumask_t *mask) out_unlock: read_unlock(&tasklist_lock); - unlock_cpu_hotplug(); + mutex_unlock(&sched_hotcpu_mutex); if (retval) return retval; @@ -4772,9 +4830,7 @@ int __sched cond_resched_softirq(void) BUG_ON(!in_softirq()); if (need_resched() && system_state == SYSTEM_RUNNING) { - raw_local_irq_disable(); - _local_bh_enable(); - raw_local_irq_enable(); + local_bh_enable(); __cond_resched(); local_bh_disable(); return 1; @@ -5386,7 +5442,12 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) struct rq *rq; switch (action) { + case CPU_LOCK_ACQUIRE: + mutex_lock(&sched_hotcpu_mutex); + break; + case CPU_UP_PREPARE: + case CPU_UP_PREPARE_FROZEN: p = kthread_create(migration_thread, hcpu, "migration/%d",cpu); if (IS_ERR(p)) return NOTIFY_BAD; @@ -5400,12 +5461,14 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) break; case CPU_ONLINE: + case CPU_ONLINE_FROZEN: /* Strictly unneccessary, as first user will wake it. */ wake_up_process(cpu_rq(cpu)->migration_thread); break; #ifdef CONFIG_HOTPLUG_CPU case CPU_UP_CANCELED: + case CPU_UP_CANCELED_FROZEN: if (!cpu_rq(cpu)->migration_thread) break; /* Unbind it from offline cpu so it can run. Fall thru. */ @@ -5416,6 +5479,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) break; case CPU_DEAD: + case CPU_DEAD_FROZEN: migrate_live_tasks(cpu); rq = cpu_rq(cpu); kthread_stop(rq->migration_thread); @@ -5431,7 +5495,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) BUG_ON(rq->nr_running != 0); /* No need to migrate the tasks: it was best-effort if - * they didn't do lock_cpu_hotplug(). Just wake up + * they didn't take sched_hotcpu_mutex. Just wake up * the requestors. */ spin_lock_irq(&rq->lock); while (!list_empty(&rq->migration_queue)) { @@ -5445,6 +5509,9 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) spin_unlock_irq(&rq->lock); break; #endif + case CPU_LOCK_RELEASE: + mutex_unlock(&sched_hotcpu_mutex); + break; } return NOTIFY_OK; } @@ -6820,10 +6887,10 @@ int arch_reinit_sched_domains(void) { int err; - lock_cpu_hotplug(); + mutex_lock(&sched_hotcpu_mutex); detach_destroy_domains(&cpu_online_map); err = arch_init_sched_domains(&cpu_online_map); - unlock_cpu_hotplug(); + mutex_unlock(&sched_hotcpu_mutex); return err; } @@ -6902,14 +6969,20 @@ static int update_sched_domains(struct notifier_block *nfb, { switch (action) { case CPU_UP_PREPARE: + case CPU_UP_PREPARE_FROZEN: case CPU_DOWN_PREPARE: + case CPU_DOWN_PREPARE_FROZEN: detach_destroy_domains(&cpu_online_map); return NOTIFY_OK; case CPU_UP_CANCELED: + case CPU_UP_CANCELED_FROZEN: case CPU_DOWN_FAILED: + case CPU_DOWN_FAILED_FROZEN: case CPU_ONLINE: + case CPU_ONLINE_FROZEN: case CPU_DEAD: + case CPU_DEAD_FROZEN: /* * Fall through and re-initialise the domains. */ @@ -6928,12 +7001,12 @@ void __init sched_init_smp(void) { cpumask_t non_isolated_cpus; - lock_cpu_hotplug(); + mutex_lock(&sched_hotcpu_mutex); arch_init_sched_domains(&cpu_online_map); cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); if (cpus_empty(non_isolated_cpus)) cpu_set(smp_processor_id(), non_isolated_cpus); - unlock_cpu_hotplug(); + mutex_unlock(&sched_hotcpu_mutex); /* XXX: Theoretical race here - CPU may be hotplugged now */ hotcpu_notifier(update_sched_domains, 0); @@ -7053,12 +7126,13 @@ EXPORT_SYMBOL(__might_sleep); void normalize_rt_tasks(void) { struct prio_array *array; - struct task_struct *p; + struct task_struct *g, *p; unsigned long flags; struct rq *rq; read_lock_irq(&tasklist_lock); - for_each_process(p) { + + do_each_thread(g, p) { if (!rt_task(p)) continue; @@ -7076,7 +7150,8 @@ void normalize_rt_tasks(void) __task_rq_unlock(rq); spin_unlock_irqrestore(&p->pi_lock, flags); - } + } while_each_thread(g, p); + read_unlock_irq(&tasklist_lock); }