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>
diff --git a/kernel/rwsem.c b/kernel/rwsem.c
index 1ec620c0..cae050b 100644
--- a/kernel/rwsem.c
+++ b/kernel/rwsem.c
@@ -6,6 +6,7 @@
#include <linux/types.h>
#include <linux/kernel.h>
+#include <linux/sched.h>
#include <linux/module.h>
#include <linux/rwsem.h>
@@ -15,7 +16,7 @@
/*
* lock for reading
*/
-void down_read(struct rw_semaphore *sem)
+void __sched down_read(struct rw_semaphore *sem)
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
@@ -42,7 +43,7 @@
/*
* lock for writing
*/
-void down_write(struct rw_semaphore *sem)
+void __sched down_write(struct rw_semaphore *sem)
{
might_sleep();
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);