Eric Lee / linux-smarc-t335x-v3.2

Download as
Browse Code ยป

Commit c7af77b584b02d3e321b00203a618a9c93782121

Authored by Livio Soares
Committed by Ingo Molnar
1 parent 051a1d1afa
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

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>

Showing 2 changed files with 4 additions and 3 deletions Side-by-side Diff

... ... @@ -6,6 +6,7 @@
6 6  
7 7 #include <linux/types.h>
8 8 #include <linux/kernel.h>
  9 +#include <linux/sched.h>
9 10 #include <linux/module.h>
10 11 #include <linux/rwsem.h>
11 12  
... ... @@ -15,7 +16,7 @@
15 16 /*
16 17 * lock for reading
17 18 */
18   -void down_read(struct rw_semaphore *sem)
  19 +void __sched down_read(struct rw_semaphore *sem)
19 20 {
20 21 might_sleep();
21 22 rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
... ... @@ -42,7 +43,7 @@
42 43 /*
43 44 * lock for writing
44 45 */
45   -void down_write(struct rw_semaphore *sem)
  46 +void __sched down_write(struct rw_semaphore *sem)
46 47 {
47 48 might_sleep();
48 49 rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
... ... @@ -146,7 +146,7 @@
146 146 /*
147 147 * wait for a lock to be granted
148 148 */
149   -static struct rw_semaphore *
  149 +static struct rw_semaphore __sched *
150 150 rwsem_down_failed_common(struct rw_semaphore *sem,
151 151 struct rwsem_waiter *waiter, signed long adjustment)
152 152 {