Re: Lockdep warning for iprune_mutex at shrink_icache_memory

[Ingo Molnar <mingo@elte.hu>]

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, 2008-11-27 at 09:05 +0100, Peter Zijlstra wrote:
> > On Thu, 2008-11-27 at 08:34 +1100, Dave Chinner wrote:
> > > Is changing the lock class dynamically possible/allowed?
> > 
> > Currently, no, but I'll see what I can do, it requires a bit of trickery
> > to make that happen..
> > 
> > I'll let you know when I've sorted that out.
> 
> Ok, that wasn't hard at all..
> 
> Dave, Christoph, can you have a play with this and post this patch along
> with a potential user - I think it best if we don't merge this without
> at least one user in tree :-)
> 
> ---
> Subject: lockdep: change a held lock's class
> From: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Date: Thu Dec 04 08:34:56 CET 2008
> 
> Impact: introduce new lockdep API
> 
> Allow to change a held lock's class. Basically the same as the existing
> code to change a subclass therefore reuse all that.
> 
> The XFS code will be able to use this to annotate their inode locking.
> 
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> ---
>  include/linux/lockdep.h |   12 ++++++++++--
>  kernel/lockdep.c        |   24 +++++++++---------------
>  2 files changed, 19 insertions(+), 17 deletions(-)

i've applied it to tip/core/locking, but it's just a new API without 
really disturbing the current code - but it would be nice to know whether 
it solves the XFS annotation problems.

	Ingo