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authorPeter Zijlstra <peterz@infradead.org>2015-08-01 19:25:08 +0200
committerIngo Molnar <mingo@kernel.org>2016-05-05 09:23:59 +0200
commite7904a28f5331c21d17af638cb477c83662e3cb6 (patch)
tree4fd496dcdf41f61964125682664f57d50f3527e2 /kernel/sched/rt.c
parenteb58075149b7f0300ff19142e6245fe75db2a081 (diff)
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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/rt.c')
-rw-r--r--kernel/sched/rt.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 19e1306..68deaf9 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1524,7 +1524,7 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq)
}
static struct task_struct *
-pick_next_task_rt(struct rq *rq, struct task_struct *prev)
+pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie)
{
struct task_struct *p;
struct rt_rq *rt_rq = &rq->rt;
@@ -1536,9 +1536,9 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev)
* disabled avoiding 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);
pull_rt_task(rq);
- lockdep_pin_lock(&rq->lock);
+ lockdep_repin_lock(&rq->lock, cookie);
/*
* pull_rt_task() can drop (and re-acquire) rq->lock; this
* means a dl or stop task can slip in, in which case we need
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