Messages in this thread | | | Date | Fri, 27 Feb 2015 12:54:28 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/1] futex: don't spin waiting for PF_EXITING -> PF_EXITPIDONE transition |
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On Fri, Feb 27, 2015 at 10:52:40AM +0100, Peter Zijlstra wrote: > On Mon, Feb 16, 2015 at 09:13:36PM +0100, Oleg Nesterov wrote: > > > diff --git a/kernel/futex.c b/kernel/futex.c > > index b101381..c1104a8 100644 > > +++ b/kernel/futex.c > > @@ -716,11 +716,13 @@ void exit_pi_state_list(struct task_struct *curr) > > > > if (!futex_cmpxchg_enabled) > > return; > > + > > /* > > + * attach_to_pi_owner() can no longer add the new entry. But > > + * we have to be careful versus waiters unqueueing themselves. > > */ > > + curr->flags |= PF_EXITPIDONE; > > + > > raw_spin_lock_irq(&curr->pi_lock); > > while (!list_empty(head)) { > > > > Should we not set PF_EXITPIDONE _inside_ the pi_lock? To properly > serialize against the below check?
It does not matter, n/m.
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