Messages in this thread | | | Date | Mon, 24 Aug 2009 15:08:16 -0700 (PDT) | From | Davide Libenzi <> | Subject | Re: [PATCH 0/2] eventfd: new EFD_STATE flag |
| |
On Mon, 24 Aug 2009, Avi Kivity wrote:
> On 08/24/2009 09:25 PM, Davide Libenzi wrote: > > 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. > > > > There are libraries that provide notifications (or fire watches) when some > value changes. They're much less frequently used than events or semaphores, > though.
There are userspace libraries that do almost everything, but you hardly see things like pthread_(EFD_STATE-like)_create() or similar system interfaces based on such abstraction. Is that really difficult to understand where I'm standing, leaving the KVM hat off for a moment?
- Davide
| |