Messages in this thread Patch in this message | | | Date | Mon, 26 Sep 2016 17:26:39 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH -v2 2/9] sched/rtmutex/deadline: Fix a PI crash for deadline tasks |
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On Mon, Sep 26, 2016 at 11:20:58AM -0400, Steven Rostedt wrote: > > --- a/kernel/locking/rtmutex.c > > +++ b/kernel/locking/rtmutex.c > > @@ -256,6 +256,16 @@ rt_mutex_dequeue_pi(struct task_struct * > > RB_CLEAR_NODE(&waiter->pi_tree_entry); > > } > > > > Shouldn't we add a comment about what locks are expected to be held > when calling this? Especially if it can be called outside this file.
Comments are somewhat useless.. I would like to do the below, except I cannot.
> > +void rt_mutex_update_top_task(struct task_struct *p) > > +{
lockdep_assert_held(&p->pi_lock); lockdep_assert_held(&task_rq(p)->lock); // except that we cannot access rq :/
> > + if (!task_has_pi_waiters(p)) { > > + p->pi_top_task = NULL; > > + return; > > + } > > + > > + p->pi_top_task = task_top_pi_waiter(p)->task; > > +} > > + > > /* > > * Calculate task priority from the waiter tree priority > > * > > @@ -273,10 +283,7 @@ int rt_mutex_getprio(struct task_struct > > > > Any specific locks that must be held when calling this?
#ifdef CONFIG_LOCKDEP WARN_ON_ONCE(debug_locks && !lock_is_held(&p->pi_lock) && !lock_is_held(&task_rq(p)->lock)); // again, cannot do this :/ #endif
> > struct task_struct *rt_mutex_get_top_task(struct task_struct *task) > > { > > - if (likely(!task_has_pi_waiters(task))) > > - return NULL; > > - > > - return task_top_pi_waiter(task)->task; > > + return task->pi_top_task; > > } > > -- Steve >
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