[PATCH] sched debug: remove NULL checking in print_cfs/rt_rq()

[PATCH] sched debug: remove NULL checking in print_cfs/rt_rq()

[Li Zefan]

cfs->tg is initialized in init_tg_cfs_entry() with tg != NULL, and
will never be invalidated to NULL. And the underlying cgroup of a
valid task_group is always valid.

Same for rt->tg.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 kernel/sched_debug.c |   14 ++------------
 1 files changed, 2 insertions(+), 12 deletions(-)

diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 5ae1776..d25cefe 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -121,14 +121,9 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 
 #if defined(CONFIG_CGROUP_SCHED) && defined(CONFIG_FAIR_GROUP_SCHED)
 	char path[128] = "";
-	struct cgroup *cgroup = NULL;
 	struct task_group *tg = cfs_rq->tg;
 
-	if (tg)
-		cgroup = tg->css.cgroup;
-
-	if (cgroup)
-		cgroup_path(cgroup, path, sizeof(path));
+	cgroup_path(tg->css.cgroup, path, sizeof(path));
 
 	SEQ_printf(m, "\ncfs_rq[%d]:%s\n", cpu, path);
 #else
@@ -193,14 +188,9 @@ void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
 {
 #if defined(CONFIG_CGROUP_SCHED) && defined(CONFIG_RT_GROUP_SCHED)
 	char path[128] = "";
-	struct cgroup *cgroup = NULL;
 	struct task_group *tg = rt_rq->tg;
 
-	if (tg)
-		cgroup = tg->css.cgroup;
-
-	if (cgroup)
-		cgroup_path(cgroup, path, sizeof(path));
+	cgroup_path(tg->css.cgroup, path, sizeof(path));
 
 	SEQ_printf(m, "\nrt_rq[%d]:%s\n", cpu, path);
 #else
-- 
1.5.4.rc3

Re: [PATCH] sched debug: remove NULL checking in print_cfs/rt_rq()

[Ingo Molnar]

* Li Zefan <lizf@cn.fujitsu.com> wrote:

> cfs->tg is initialized in init_tg_cfs_entry() with tg != NULL, and
> will never be invalidated to NULL. And the underlying cgroup of a
> valid task_group is always valid.
> 
> Same for rt->tg.
> 
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
> ---
>  kernel/sched_debug.c |   14 ++------------
>  1 files changed, 2 insertions(+), 12 deletions(-)

applied to tip/sched/core, thanks!

	Ingo