On Tue, 25 Aug 2009, Michael S. Tsirkin wrote: > On Mon, Aug 24, 2009 at 11:25:01AM -0700, Davide Libenzi wrote: > > On Sun, 23 Aug 2009, Michael S. Tsirkin wrote: > > > > > On Sun, Aug 23, 2009 at 04:40:51PM +0300, Avi Kivity wrote: > > > > On 08/23/2009 04:36 PM, Michael S. Tsirkin wrote: > > > >> More important here is realization that eventfd is a mutex/semaphore > > > >> implementation, not a generic event reporting interface as we are > > > >> trying > > > >> to use it. > > > >> > > > > > > > > Well it is a generic event reporting interface (for example, aio uses > > > > it). > > > > > > Davide, I think it's a valid point. For example, what read on eventfd > > > does (zero a counter and return) is not like any semaphore I saw. > > > > > > Indeed, the default eventfd behaviour is like, well, an event. Signaling > > (kernel side) or writing (userspace side), signals the event. > > Waiting (reading) it, will reset the event. > > If you use EFD_SEMAPHORE, you get a semaphore-like behavior. > > Events and sempahores are two widely known and used abstractions. > > The EFD_STATE proposed one, well, no. Not at all. > > Hmm. All we try to do is, associate a small key with the event > that we signal. Is it really that uncommon/KVM specific?
All I'm trying to do, is to avoid that eventfd will become an horrible multiplexor for every freaky one-time-use behaviors arising inside kernel modules. - Davide -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
