Re: [take25 1/6] kevent: Description.

[Evgeniy Polyakov]

On Thu, Nov 23, 2006 at 11:45:36AM -0800, Ulrich Drepper (drepper@xxxxxxxxxx) wrote:
> Evgeniy Polyakov wrote:
> >Kernel does not put there a new entry, it is only done inside
> >kevent_wait(). Entries are put into queue (in any context), where they can 
> >be obtained
> >from only kevent_wait() or kevent_get_events().
> 
> I know this is how it's done now.  But it is not where it has to end. 
> IMO we have to get to a solution where new events are posted to the ring 
> buffer asynchronously, i.e., without a thread calling kevent_wait.  And 
> then you need the extra parameter and verification.  Even if it's today 
> not needed we have to future-proof the interface since it cannot be 
> changed once in use.

There is a special flag in kevent_user to wake it if there are no ready
events - kernel thread which has added new events will set it and thus
subsequent kevent_wait() will return with updated indexes - userspace
must check indexes after kevent_wait().

> -- 
> â Ulrich Drepper â Red Hat, Inc. â 444 Castro St â Mountain View, 
> CA â

-- 
	Evgeniy Polyakov
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