On Sat, Feb 07, 2009 at 03:50:39PM -0500, Chuck Ebbert wrote:
> fs/btrfs/locking.c: In function 'btrfs_path_lock_waiting':
> fs/btrfs/locking.c:254: error: implicit declaration of function '__raw_spin_is_contended'
> 
> Looks like spin_is_contended() is only available on mips and x86??
> 

Looks to be if there are other folks in line for the ticket lock.

Arguably this should probably be something silly in spinlock.h like,

#ifndef __raw_spin_is_contended
# define spin_is_contended (0)
#else
# define spin_is_contended(x) __raw_spin_is_contended((x))
#endif

or something since in theory anybody has a chance of acquiring it next
(well, lies because caches bias, but there's no waiters at least.)

Either that, or we just define it to be spin_is_locked if the assumption
is that the lock will continue to be locked...

regards, Kyle