[PATCH] sched: Remove redundant code from can_migrate_task()

[PATCH] sched: Remove redundant code from can_migrate_task()

[Zhang Hang]

There is no opportunity to return 1 if tsk_cache_hot is true and the expression
(env->sd->nr_balance_failed > env->sd->cache_nice_tries) is false.
Meanwhile, it's unnecessary to judge whether tsk_cache_hot is true or
false after being filtered by previous judgment.

Signed-off-by: Zhang Hang <bob.zhanghang@huawei.com>
---
 kernel/sched/fair.c |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 7a33e59..4f7e1d0 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3929,11 +3929,8 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
 		return 1;
 	}

-	if (tsk_cache_hot) {
-		schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
-		return 0;
-	}
-	return 1;
+	schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
+	return 0;
 }

 /*
-- 
1.7.8.6

[tip:sched/core] sched: Simplify can_migrate_task()

[tip-bot for Zhang Hang]

Commit-ID:  4e2dcb73aecbde9fe4e3137c9ea35cb6aa6cb286
Gitweb:     http://git.kernel.org/tip/4e2dcb73aecbde9fe4e3137c9ea35cb6aa6cb286
Author:     Zhang Hang <bob.zhanghang@huawei.com>
AuthorDate: Wed, 10 Apr 2013 14:04:55 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 10 Apr 2013 11:15:45 +0200

sched: Simplify can_migrate_task()

At this point tsk_cache_hot is always true, so no need to check it.

Signed-off-by: Zhang Hang <bob.zhanghang@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51650107.9040606@huawei.com
[ Also remove unnecessary schedstat #ifdefs. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/fair.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 539760e..bf8ab4f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3921,20 +3921,17 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
 	tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd);
 	if (!tsk_cache_hot ||
 		env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
-#ifdef CONFIG_SCHEDSTATS
+
 		if (tsk_cache_hot) {
 			schedstat_inc(env->sd, lb_hot_gained[env->idle]);
 			schedstat_inc(p, se.statistics.nr_forced_migrations);
 		}
-#endif
+
 		return 1;
 	}
 
-	if (tsk_cache_hot) {
-		schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
-		return 0;
-	}
-	return 1;
+	schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
+	return 0;
 }
 
 /*