2012-02-17 03:05:41

by Nikunj A Dadhania

Subject: [PATCH] sched: Remove rcu_read_lock/unlock() from select_idle_sibling()

select_idle_sibling() is called from select_task_rq_fair(), which
already has the RCU read lock held.

Signed-off-by: Nikunj A. Dadhania <[email protected]>
---

kernel/sched/fair.c | 4 ----
1 files changed, 0 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 4ab60a2..6ce9992 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2670,8 +2670,6 @@ static int select_idle_sibling(struct task_struct *p, int target)
/*
* Otherwise, iterate the domains and find an elegible idle cpu.
*/
- rcu_read_lock();
-
sd = rcu_dereference(per_cpu(sd_llc, target));
for_each_lower_domain(sd) {
sg = sd->groups;
@@ -2693,8 +2691,6 @@ next:
} while (sg != sd->groups);
}
done:
- rcu_read_unlock();
-
return target;
}

2012-02-22 16:12:36

by Nikunj A Dadhania

Subject: [tip:sched/core] sched: Remove rcu_read_lock/unlock() from select_idle_sibling()

Commit-ID: 62f6536a630affe3176deb48554d27ee58b65077
Gitweb: http://git.kernel.org/tip/62f6536a630affe3176deb48554d27ee58b65077
Author: Nikunj A. Dadhania <[email protected]>
AuthorDate: Fri, 17 Feb 2012 08:34:30 +0530
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 22 Feb 2012 12:28:28 +0100

sched: Remove rcu_read_lock/unlock() from select_idle_sibling()

select_idle_sibling() is called from select_task_rq_fair(), which
already has the RCU read lock held.

Signed-off-by: Nikunj A. Dadhania <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/20120217030409.11748.12491.stgit@abhimanyu
Signed-off-by: Ingo Molnar <[email protected]>
---
kernel/sched/fair.c | 4 ----
1 files changed, 0 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 4ab60a2..6ce9992 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2670,8 +2670,6 @@ static int select_idle_sibling(struct task_struct *p, int target)
/*
* Otherwise, iterate the domains and find an elegible idle cpu.
*/
- rcu_read_lock();
-
sd = rcu_dereference(per_cpu(sd_llc, target));
for_each_lower_domain(sd) {
sg = sd->groups;
@@ -2693,8 +2691,6 @@ next:
} while (sg != sd->groups);
}
done:
- rcu_read_unlock();
-
return target;
}