Re: [take24 0/6] kevent: Generic event handling mechanism.

[Evgeniy Polyakov]

On Thu, Nov 23, 2006 at 12:34:50PM -0800, Ulrich Drepper (drepper@xxxxxxxxxx) wrote:
> Evgeniy Polyakov wrote:
> >>>Btw, what about putting aditional multiplexer into add/remove/modify
> >>>switch? There will be logical 'ready' addon?
> >>Is it needed?  Usually this is done with a *_wait call with a timeout of 
> >>zero.  That code path might have to be optimized but it should already 
> >>be there.
> >
> >It does not allow to mark events as ready.
> >And current interfaces wake up when either timeout is zero (in this case
> >thread itself does not sleep and can process events), or when there is
> >_new_ work - since there is no _new_ work, when thread awakened to
> >process it was killed, kernel does not think that something is wrong.
> 
> Rather than mark an existing entry as ready, how about a call to inject 
> a new ready event?
> 
> This would be useful to implement functionality at userlevel and still 
> use an event queue to announce the availability.  Without this type of 
> functionality we'd need to use indirect notification via signal or pipe 
> or something like that.

With provided patch it is possible to wakeup 'for-free' - just call
kevent_ctl(ready) with zero number of ready events, so thread will be
awakened if it was in poll(kevent_fd), kevent_wait() or
kevent_get_events().

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

-- 
	Evgeniy Polyakov
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