Re: Change in functionality of futex() system call.

[Eric Dumazet]

Le jeudi 09 juin 2011 Ã 00:43 -0400, George Spelvin a Ãcrit :

> Just for example, consider a circular buffer that a few (trusted)
> processes can write to, but many (less trusted) can read.  Obviously,
> being able to sleep on the head pointer is useful.


If its useful, then it needs a futex extension (and this must be
emulated on old kernels without this extension)

Remember futex_wake() call would just have to wakeup _all_ threads
instead of one, if kernel lacks this function.

If you dont trust futex_wait() users, just use futex_wake(ALL)

Its should not be a consequence of a previous (unrelated) patch, it
should be an added functionality, dully documented.



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