On Wed, Apr 21, 2010 at 08:58:48PM +0300, Gleb Natapov wrote: > On Wed, Apr 21, 2010 at 02:37:34PM -0300, Marcelo Tosatti wrote: > > On Wed, Apr 21, 2010 at 08:12:27PM +0300, Gleb Natapov wrote: > > > On Wed, Apr 21, 2010 at 12:58:41PM -0300, Marcelo Tosatti wrote: > > > > > Or could we make kvm_set_irq() atomic? Though the code path is a little long > > > > > for spinlock. > > > > > > > > Yes, given the sleep-inside-RCU-protected section bug from > > > > kvm_notify_acked_irq, either that or convert IRQ locking to SRCU. > > > > > > > > But as you said, the code paths are long and potentially slow, so > > > > probably SRCU is a better alternative. > > > > > > > > Gleb? > > > kvm_set_irq() was converted to rcu from mutex to make msix interrupt > > > injection scalable. > > > > We meant ioapic lock. See the last report from Ralf on this thread. > Can we solve the problem by calling ack notifier outside rcu read > section in kvm_notify_acked_irq()? The unregister path does - remove_from_list(entry) - synchronize_rcu - kfree(entry) So if kvm_notify_acked_irq sleeps, synchronize_rcu can succeed, and the notifier entry can be freed. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
