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SubjectRe: epoll (was Re: [PATCH] async poll for 2.5)
Date (John Myers) writes:

> Close. What we would have is a modification of the epoll_addf()
> semantics such that it would have an additional postcondition that if
> the new_fd is in the ready state (has data available) then at least
> one notification has been generated. In the code above, the three
> lines comprising the if statement labeled "7*" would be removed.

I see.

I assume the kernel implementation is no big deal: epoll_addf() has to
call the kernel internal equivalent to poll() with a zero timeout.

This wouldn't break the first "solution" in my earlier post, but it
would cause every new connection to experience one extra EAGAIN.

I see three possibilities:

1) keep the current epoll_addf()
2) modify it as John suggests, posting the initial ready state in
the next epoll_getevents()
3) both: add an option to epoll_addf() that says which of 1 or 2 is desired.

-- Buck

How hard would it be to modify the current epoll code to work that
way? I'd assume it's just a matter having epoll_addf call the legacy
poll() code to check the condition (with a zero timeout).

-- Buck

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