Re: [PATCH] Alternate futex non-page-pinning and COW fix

[Linus Torvalds]

On Thu, 4 Sep 2003, Jamie Lokier wrote:
> 
>     * A futex on a MAP_PRIVATE must be mm-local: the canonical
>     * example being MAP_PRIVATE of /dev/zero.

Actually, /dev/zero is a special case in itself. It is an anonymous 
mapping, and is equivalent to MAP_ANON for private mappings. For 
MAP_SHARED it is something _totally_ different.

So /dev/zero isn't even an interesting case.

> Unfortunately I think the above 5 conditions do not have a consistent
> solution.  Please prove me wrong :)

I don't think there is any inconsistency.

		Linus

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