Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: Correct printk whitespace in warning from cpu down task check sched: Fix incorrect sanity check sched: Fix fork vs hotplug vs cpuset namespaces
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commit
8ea85c2817
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@ -151,11 +151,11 @@ static inline void check_for_tasks(int cpu)
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write_lock_irq(&tasklist_lock);
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for_each_process(p) {
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if (task_cpu(p) == cpu &&
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if (task_cpu(p) == cpu && p->state == TASK_RUNNING &&
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(!cputime_eq(p->utime, cputime_zero) ||
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!cputime_eq(p->stime, cputime_zero)))
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printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\
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(state = %ld, flags = %x) \n",
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printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d "
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"(state = %ld, flags = %x)\n",
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p->comm, task_pid_nr(p), cpu,
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p->state, p->flags);
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}
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@ -1241,21 +1241,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
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/* Need tasklist lock for parent etc handling! */
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write_lock_irq(&tasklist_lock);
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/*
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* The task hasn't been attached yet, so its cpus_allowed mask will
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* not be changed, nor will its assigned CPU.
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*
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* The cpus_allowed mask of the parent may have changed after it was
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* copied first time - so re-copy it here, then check the child's CPU
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* to ensure it is on a valid CPU (and if not, just force it back to
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* parent's CPU). This avoids alot of nasty races.
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*/
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p->cpus_allowed = current->cpus_allowed;
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p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed;
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if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) ||
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!cpu_online(task_cpu(p))))
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set_task_cpu(p, smp_processor_id());
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/* CLONE_PARENT re-uses the old parent */
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if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
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p->real_parent = current->real_parent;
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@ -2320,14 +2320,12 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
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}
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/*
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* Called from:
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* Gets called from 3 sites (exec, fork, wakeup), since it is called without
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* holding rq->lock we need to ensure ->cpus_allowed is stable, this is done
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* by:
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*
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* - fork, @p is stable because it isn't on the tasklist yet
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*
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* - exec, @p is unstable, retry loop
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*
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* - wake-up, we serialize ->cpus_allowed against TASK_WAKING so
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* we should be good.
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* exec: is unstable, retry loop
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* fork & wake-up: serialize ->cpus_allowed against TASK_WAKING
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*/
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static inline
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int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
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@ -2620,9 +2618,6 @@ void sched_fork(struct task_struct *p, int clone_flags)
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if (p->sched_class->task_fork)
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p->sched_class->task_fork(p);
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#ifdef CONFIG_SMP
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cpu = select_task_rq(p, SD_BALANCE_FORK, 0);
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#endif
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set_task_cpu(p, cpu);
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#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
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@ -2652,6 +2647,21 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
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{
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unsigned long flags;
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struct rq *rq;
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int cpu = get_cpu();
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#ifdef CONFIG_SMP
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/*
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* Fork balancing, do it here and not earlier because:
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* - cpus_allowed can change in the fork path
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* - any previously selected cpu might disappear through hotplug
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*
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* We still have TASK_WAKING but PF_STARTING is gone now, meaning
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* ->cpus_allowed is stable, we have preemption disabled, meaning
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* cpu_online_mask is stable.
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*/
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cpu = select_task_rq(p, SD_BALANCE_FORK, 0);
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set_task_cpu(p, cpu);
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#endif
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rq = task_rq_lock(p, &flags);
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BUG_ON(p->state != TASK_WAKING);
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@ -2665,6 +2675,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
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p->sched_class->task_woken(rq, p);
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#endif
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task_rq_unlock(rq, &flags);
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put_cpu();
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}
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#ifdef CONFIG_PREEMPT_NOTIFIERS
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@ -7139,14 +7150,18 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
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* the ->cpus_allowed mask from under waking tasks, which would be
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* possible when we change rq->lock in ttwu(), so synchronize against
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* TASK_WAKING to avoid that.
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*
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* Make an exception for freshly cloned tasks, since cpuset namespaces
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* might move the task about, we have to validate the target in
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* wake_up_new_task() anyway since the cpu might have gone away.
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*/
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again:
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while (p->state == TASK_WAKING)
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while (p->state == TASK_WAKING && !(p->flags & PF_STARTING))
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cpu_relax();
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rq = task_rq_lock(p, &flags);
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if (p->state == TASK_WAKING) {
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if (p->state == TASK_WAKING && !(p->flags & PF_STARTING)) {
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task_rq_unlock(rq, &flags);
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goto again;
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}
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