sched: mark rwsem functions as __sched for wchan/profiling

This following commit

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=fdf8cb0909b531f9ae8f9b9d7e4eb35ba3505f07

un-inlined a low-level rwsem function, but did not mark it as __sched.
The result is that it now shows up as thread wchan (which also affects
/proc/profile stats).  The following simple patch fixes this by properly
marking rwsem_down_failed_common() as a __sched function.

Also in this patch, which is up for discussion, marks down_read() and
down_write() proper as __sched.  For profiling, it is pretty much
useless to know that a semaphore is beig help - it is necessary to know
_which_ one.  By going up another frame on the stack, the information
becomes much more useful.

In summary, the below change to lib/rwsem.c should be applied; the
changes to kernel/rwsem.c could be applied if other kernel hackers agree
with my proposal that down_read()/down_write() in the profile is not
enough.

[ akpm@linux-foundation.org: build fix ]

Signed-off-by: Livio Soares <livio@eecg.toronto.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/rwsem.c b/lib/rwsem.c
index cdb4e3d0560..7d02700a4b0 100644
--- a/lib/rwsem.c
+++ b/lib/rwsem.c
@@ -146,7 +146,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, int downgrading)
 /*
  * wait for a lock to be granted
  */
-static struct rw_semaphore *
+static struct rw_semaphore __sched *
 rwsem_down_failed_common(struct rw_semaphore *sem,
                         struct rwsem_waiter *waiter, signed long adjustment)
 {