diff options
| -rw-r--r-- | kernel/sched.c | 327 |
1 files changed, 162 insertions, 165 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index e8051bd59ac..4c15b172619 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -562,16 +562,13 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) static inline struct rq *__task_rq_lock(struct task_struct *p) __acquires(rq->lock) { - struct rq *rq; - -repeat_lock_task: - rq = task_rq(p); - spin_lock(&rq->lock); - if (unlikely(rq != task_rq(p))) { + for (;;) { + struct rq *rq = task_rq(p); + spin_lock(&rq->lock); + if (likely(rq == task_rq(p))) + return rq; spin_unlock(&rq->lock); - goto repeat_lock_task; } - return rq; } /* @@ -584,15 +581,14 @@ static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) { struct rq *rq; -repeat_lock_task: - local_irq_save(*flags); - rq = task_rq(p); - spin_lock(&rq->lock); - if (unlikely(rq != task_rq(p))) { + for (;;) { + local_irq_save(*flags); + rq = task_rq(p); + spin_lock(&rq->lock); + if (likely(rq == task_rq(p))) + return rq; spin_unlock_irqrestore(&rq->lock, *flags); - goto repeat_lock_task; } - return rq; } static void __task_rq_unlock(struct rq *rq) @@ -1083,69 +1079,71 @@ void wait_task_inactive(struct task_struct *p) int running, on_rq; struct rq *rq; -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); + for (;;) { + /* + * 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(); + /* + * 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); - running = task_running(rq, p); - on_rq = p->se.on_rq; - task_rq_unlock(rq, &flags); + /* + * 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); + running = task_running(rq, p); + on_rq = p->se.on_rq; + 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(); - goto repeat; - } + /* + * 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(); + continue; + } - /* - * 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(on_rq)) { - schedule_timeout_uninterruptible(1); - goto repeat; - } + /* + * 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(on_rq)) { + schedule_timeout_uninterruptible(1); + continue; + } - /* - * 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! - */ + /* + * 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! + */ + break; + } } /*** @@ -1236,7 +1234,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) /* Skip over this group if it has no CPUs allowed */ if (!cpus_intersects(group->cpumask, p->cpus_allowed)) - goto nextgroup; + continue; local_group = cpu_isset(this_cpu, group->cpumask); @@ -1264,9 +1262,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) min_load = avg_load; idlest = group; } -nextgroup: - group = group->next; - } while (group != sd->groups); + } while (group = group->next, group != sd->groups); if (!idlest || 100*this_load < imbalance*min_load) return NULL; @@ -3517,27 +3513,30 @@ asmlinkage void __sched preempt_schedule(void) if (likely(ti->preempt_count || irqs_disabled())) return; -need_resched: - add_preempt_count(PREEMPT_ACTIVE); - /* - * We keep the big kernel semaphore locked, but we - * clear ->lock_depth so that schedule() doesnt - * auto-release the semaphore: - */ + do { + add_preempt_count(PREEMPT_ACTIVE); + + /* + * We keep the big kernel semaphore locked, but we + * clear ->lock_depth so that schedule() doesnt + * auto-release the semaphore: + */ #ifdef CONFIG_PREEMPT_BKL - saved_lock_depth = task->lock_depth; - task->lock_depth = -1; + saved_lock_depth = task->lock_depth; + task->lock_depth = -1; #endif - schedule(); + schedule(); #ifdef CONFIG_PREEMPT_BKL - task->lock_depth = saved_lock_depth; + task->lock_depth = saved_lock_depth; #endif - sub_preempt_count(PREEMPT_ACTIVE); + sub_preempt_count(PREEMPT_ACTIVE); - /* we could miss a preemption opportunity between schedule and now */ - barrier(); - if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) - goto need_resched; + /* + * Check again in case we missed a preemption opportunity + * between schedule and now. + */ + barrier(); + } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); } EXPORT_SYMBOL(preempt_schedule); @@ -3557,29 +3556,32 @@ asmlinkage void __sched preempt_schedule_irq(void) /* Catch callers which need to be fixed */ BUG_ON(ti->preempt_count || !irqs_disabled()); -need_resched: - add_preempt_count(PREEMPT_ACTIVE); - /* - * We keep the big kernel semaphore locked, but we - * clear ->lock_depth so that schedule() doesnt - * auto-release the semaphore: - */ + do { + add_preempt_count(PREEMPT_ACTIVE); + + /* + * We keep the big kernel semaphore locked, but we + * clear ->lock_depth so that schedule() doesnt + * auto-release the semaphore: + */ #ifdef CONFIG_PREEMPT_BKL - saved_lock_depth = task->lock_depth; - task->lock_depth = -1; + saved_lock_depth = task->lock_depth; + task->lock_depth = -1; #endif - local_irq_enable(); - schedule(); - local_irq_disable(); + local_irq_enable(); + schedule(); + local_irq_disable(); #ifdef CONFIG_PREEMPT_BKL - task->lock_depth = saved_lock_depth; + task->lock_depth = saved_lock_depth; #endif - sub_preempt_count(PREEMPT_ACTIVE); + sub_preempt_count(PREEMPT_ACTIVE); - /* we could miss a preemption opportunity between schedule and now */ - barrier(); - if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) - goto need_resched; + /* + * Check again in case we missed a preemption opportunity + * between schedule and now. + */ + barrier(); + } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); } #endif /* CONFIG_PREEMPT */ @@ -4324,10 +4326,10 @@ asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) asmlinkage long sys_sched_getscheduler(pid_t pid) { struct task_struct *p; - int retval = -EINVAL; + int retval; if (pid < 0) - goto out_nounlock; + return -EINVAL; retval = -ESRCH; read_lock(&tasklist_lock); @@ -4338,8 +4340,6 @@ asmlinkage long sys_sched_getscheduler(pid_t pid) retval = p->policy; } read_unlock(&tasklist_lock); - -out_nounlock: return retval; } @@ -4352,10 +4352,10 @@ asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) { struct sched_param lp; struct task_struct *p; - int retval = -EINVAL; + int retval; if (!param || pid < 0) - goto out_nounlock; + return -EINVAL; read_lock(&tasklist_lock); p = find_process_by_pid(pid); @@ -4375,7 +4375,6 @@ asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) */ retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; -out_nounlock: return retval; out_unlock: @@ -4731,11 +4730,11 @@ long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) { struct task_struct *p; unsigned int time_slice; - int retval = -EINVAL; + int retval; struct timespec t; if (pid < 0) - goto out_nounlock; + return -EINVAL; retval = -ESRCH; read_lock(&tasklist_lock); @@ -4763,8 +4762,8 @@ long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) read_unlock(&tasklist_lock); jiffies_to_timespec(time_slice, &t); retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; -out_nounlock: return retval; + out_unlock: read_unlock(&tasklist_lock); return retval; @@ -5070,35 +5069,34 @@ static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) struct rq *rq; int dest_cpu; -restart: - /* On same node? */ - mask = node_to_cpumask(cpu_to_node(dead_cpu)); - cpus_and(mask, mask, p->cpus_allowed); - dest_cpu = any_online_cpu(mask); - - /* On any allowed CPU? */ - if (dest_cpu == NR_CPUS) - dest_cpu = any_online_cpu(p->cpus_allowed); - - /* No more Mr. Nice Guy. */ - if (dest_cpu == NR_CPUS) { - rq = task_rq_lock(p, &flags); - cpus_setall(p->cpus_allowed); - dest_cpu = any_online_cpu(p->cpus_allowed); - task_rq_unlock(rq, &flags); + do { + /* On same node? */ + mask = node_to_cpumask(cpu_to_node(dead_cpu)); + cpus_and(mask, mask, p->cpus_allowed); + dest_cpu = any_online_cpu(mask); + + /* On any allowed CPU? */ + if (dest_cpu == NR_CPUS) + dest_cpu = any_online_cpu(p->cpus_allowed); + + /* No more Mr. Nice Guy. */ + if (dest_cpu == NR_CPUS) { + rq = task_rq_lock(p, &flags); + cpus_setall(p->cpus_allowed); + dest_cpu = any_online_cpu(p->cpus_allowed); + task_rq_unlock(rq, &flags); - /* - * Don't tell them about moving exiting tasks or - * kernel threads (both mm NULL), since they never - * leave kernel. - */ - if (p->mm && printk_ratelimit()) - printk(KERN_INFO "process %d (%s) no " - "longer affine to cpu%d\n", - p->pid, p->comm, dead_cpu); - } - if (!__migrate_task(p, dead_cpu, dest_cpu)) - goto restart; + /* + * Don't tell them about moving exiting tasks or + * kernel threads (both mm NULL), since they never + * leave kernel. + */ + if (p->mm && printk_ratelimit()) + printk(KERN_INFO "process %d (%s) no " + "longer affine to cpu%d\n", + p->pid, p->comm, dead_cpu); + } + } while (!__migrate_task(p, dead_cpu, dest_cpu)); } /* @@ -5913,24 +5911,23 @@ static void init_numa_sched_groups_power(struct sched_group *group_head) if (!sg) return; -next_sg: - for_each_cpu_mask(j, sg->cpumask) { - struct sched_domain *sd; + do { + for_each_cpu_mask(j, sg->cpumask) { + struct sched_domain *sd; - sd = &per_cpu(phys_domains, j); - if (j != first_cpu(sd->groups->cpumask)) { - /* - * Only add "power" once for each - * physical package. - */ - continue; - } + sd = &per_cpu(phys_domains, j); + if (j != first_cpu(sd->groups->cpumask)) { + /* + * Only add "power" once for each + * physical package. + */ + continue; + } - sg_inc_cpu_power(sg, sd->groups->__cpu_power); - } - sg = sg->next; - if (sg != group_head) - goto next_sg; + sg_inc_cpu_power(sg, sd->groups->__cpu_power); + } + sg = sg->next; + } while (sg != group_head); } #endif |