[PATCH 1/1] sched: remove duplicated init_task's preempt_notifiers init

[PATCH 1/1] sched: remove duplicated init_task's preempt_notifiers init

[seokhoon.yoon]

init_task's preempt_notifiers is initialized at two times.

1) sched_init()
   -> INIT_HLIST_HEAD(&init_task.preempt_notifiers)
2) sched_init()
   -> init_idle(current,) <--- current task is init_task at this time
    -> __sched_fork(,current)
     -> INIT_HLIST_HEAD(&p->preempt_notifiers)

I think first one is needless, remove it.

Signed-off-by: seokhoon.yoon <iamyooon@gmail.com>
---
 kernel/sched/core.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5c883fe..5760f62 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7482,10 +7482,6 @@ void __init sched_init(void)
 
 	set_load_weight(&init_task);
 
-#ifdef CONFIG_PREEMPT_NOTIFIERS
-	INIT_HLIST_HEAD(&init_task.preempt_notifiers);
-#endif
-
 	/*
 	 * The boot idle thread does lazy MMU switching as well:
 	 */
-- 
1.9.1

[tip:sched/core] schedcore: Remove duplicated init_task's preempt_notifiers init

[tip-bot for seokhoon.yoon]

Commit-ID:  efca03ecbe29a46c2c5ae539563b6326af9dcba7
Gitweb:     http://git.kernel.org/tip/efca03ecbe29a46c2c5ae539563b6326af9dcba7
Author:     seokhoon.yoon <iamyooon@gmail.com>
AuthorDate: Tue, 16 Aug 2016 18:26:08 +0900
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 5 Sep 2016 13:29:44 +0200

schedcore: Remove duplicated init_task's preempt_notifiers init

init_task's preempt_notifiers is initialized twice:

1) sched_init()
   -> INIT_HLIST_HEAD(&init_task.preempt_notifiers)

2) sched_init()
   -> init_idle(current,) <--- current task is init_task at this time
    -> __sched_fork(,current)
     -> INIT_HLIST_HEAD(&p->preempt_notifiers)

I think the first one is unnecessary, so remove it.

Signed-off-by: seokhoon.yoon <iamyooon@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471339568-5790-1-git-send-email-iamyooon@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/core.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7d602f5..90b1961 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7554,10 +7554,6 @@ void __init sched_init(void)
 
 	set_load_weight(&init_task);
 
-#ifdef CONFIG_PREEMPT_NOTIFIERS
-	INIT_HLIST_HEAD(&init_task.preempt_notifiers);
-#endif
-
 	/*
 	 * The boot idle thread does lazy MMU switching as well:
 	 */