lkml.org 
[lkml]   [2002]   [Mar]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] Fast Userspace Mutexes III.
Date
In message <20020305151439.457E03FE06@smtp.linux.ibm.com> you write:
> I agree to put it there if its not used as a means to define whether
> user locks are permitted or not. If that is the intention, then the current
> futex will need to check every access through find_vma(), which we
> both know nobody wants to do.
>
> So it can only be used for architectural hints, agreed ?

Yes. It *might* work if you don't PROT_SEM the page the semaphore is
on, but it's still a bug waiting to happen. OTOH, it'd be nice if
PROT_SEM returns EINVAL was a reliably indicator of no futex support.
This way you actually need to call the futex syscall once to see if it
works.

Cheers!
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:24    [from the cache]
©2003-2011 Jasper Spaans