Re: epoll (was Re: [PATCH] async poll for 2.5)

[John Gardiner Myers]

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Dan Kegel wrote:

> The choice I see is between:
> 1. re-arming the one-shot notification when the user gets EAGAIN
> 2. re-arming the one-shot notification when the user reads all the data
>    that was waiting (such that the very next read would return EGAIN).
>
> #1 is what Davide wants; I think John and Mark are arguing for #2. 

No, this is not what I'm arguing.  Once an event arrives for a fd, my 
proposed semantics are no different than Mr. Libenzi's.  The only 
difference is what happens upon registration of interest for a fd.  With 
my semantics, the kernel guarantees that if the fd is ready then at 
least one event has been generated.  With Mr Libenzi's semantics, there 
is no such guarantee and the application is required to behave as if an 
event had been generated upon registration.

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