lkml.org 
[lkml]   [2009]   [Aug]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] spinlock: __raw_spin_is_locked() should return true for UP
On Tue, Aug 18, 2009 at 07:40:16PM -0700, Linus Torvalds wrote:
>
>
> On Tue, 18 Aug 2009, Kumar Gala wrote:
> >
> > I agree its a little too easy to abuse spin_is_locked. However we should be
> > consistent between spin_is_locked on UP between with and without
> > CONFIG_DEBUG_SPINLOCK enabled.
>
> No we shouldn't.
>
> With CONFIG_DEBUG_SPINLOCK, you have an actual lock variable for debugging
> purposes, so spin_is_locked() can clearly return a _valid_ answer, and
> should do so.
>
> Without DEBUG_SPINLOCK, there isn't any answer to return.
>
> So there's no way we can or should be consistent. In one case an answer
> exists, in another one the answer is meaningless and doesn't exist.

I always thought behaviour should be consistent between code with
debugging on and code without. Otherwise you may end up with cases of
"it starts working when I turn on debugging" which are a pain to fix.
Has something changed?

Or in other words, do you think lockdep should try solving deadlocks
instead of just reporting them for instance?

OG.


\
 
 \ /
  Last update: 2009-08-19 11:43    [W:0.105 / U:0.124 seconds]
©2003-2011 Jasper Spaans. Advertise on this site