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authorPeter Zijlstra <peterz@infradead.org>2015-08-01 17:25:08 (GMT)
committerIngo Molnar <mingo@kernel.org>2016-05-05 07:23:59 (GMT)
commite7904a28f5331c21d17af638cb477c83662e3cb6 (patch)
tree4fd496dcdf41f61964125682664f57d50f3527e2 /kernel/sched/fair.c
parenteb58075149b7f0300ff19142e6245fe75db2a081 (diff)
downloadlinux-e7904a28f5331c21d17af638cb477c83662e3cb6.tar.xz
locking/lockdep, sched/core: Implement a better lock pinning scheme
The problem with the existing lock pinning is that each pin is of value 1; this mean you can simply unpin if you know its pinned, without having any extra information. This scheme generates a random (16 bit) cookie for each pin and requires this same cookie to unpin. This means you have to keep the cookie in context. No objsize difference for !LOCKDEP kernels. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/fair.c')
-rw-r--r--kernel/sched/fair.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b8a33ab..91395e1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5542,7 +5542,7 @@ preempt:
}
static struct task_struct *
-pick_next_task_fair(struct rq *rq, struct task_struct *prev)
+pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie)
{
struct cfs_rq *cfs_rq = &rq->cfs;
struct sched_entity *se;
@@ -5655,9 +5655,9 @@ idle:
* further scheduler activity on it and we're being very careful to
* re-start the picking loop.
*/
- lockdep_unpin_lock(&rq->lock);
+ lockdep_unpin_lock(&rq->lock, cookie);
new_tasks = idle_balance(rq);
- lockdep_pin_lock(&rq->lock);
+ lockdep_repin_lock(&rq->lock, cookie);
/*
* Because idle_balance() releases (and re-acquires) rq->lock, it is
* possible for any higher priority task to appear. In that case we