RE: [RFC PATCH v2 00/13] Add futex2 syscall

From: David Laight
Date: Mon Mar 08 2021 - 06:12:00 EST


From: Stefan Metzmacher
> Sent: 07 March 2021 11:35
>
> Hi André,
> > ** The wait on multiple problem
> >
> > The use case lies in the Wine implementation of the Windows NT interface
> > WaitMultipleObjects. This Windows API function allows a thread to sleep
> > waiting on the first of a set of event sources (mutexes, timers, signal,
> > console input, etc) to signal.

They are all events.
You can only wait on either events or sockets (using select).
There is a socket api to signal an event when data arrives (etc).
There is also the insane (these days) restriction of 64 events.

> With that in mind would it be good to have some interaction with epoll (and similar calls)?

Or hook something up so that pollwakeup can kick a futex as well
as waking up poll() and adding an event to epoll().

David

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