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authorDavid S. Miller <davem@davemloft.net>2015-03-03 21:16:48 -0500
committerDavid S. Miller <davem@davemloft.net>2015-03-03 21:16:48 -0500
commit71a83a6db6138b9d41d8a0b6b91cb59f6dc4742c (patch)
treef74b6e4e48257ec6ce40b95645ecb8533b9cc1f8 /kernel/sched/sched.h
parentb97526f3ff95f92b107f0fb52cbb8627e395429b (diff)
parenta6c5170d1edea97c538c81e377e56c7b5c5b7e63 (diff)
downloadblackbird-obmc-linux-71a83a6db6138b9d41d8a0b6b91cb59f6dc4742c.tar.gz
blackbird-obmc-linux-71a83a6db6138b9d41d8a0b6b91cb59f6dc4742c.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts: drivers/net/ethernet/rocker/rocker.c The rocker commit was two overlapping changes, one to rename the ->vport member to ->pport, and another making the bitmask expression use '1ULL' instead of plain '1'. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/sched/sched.h')
-rw-r--r--kernel/sched/sched.h76
1 files changed, 76 insertions, 0 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 0870db23d79c..dc0f435a2779 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1380,6 +1380,82 @@ static inline void sched_avg_update(struct rq *rq) { }
extern void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period);
+/*
+ * __task_rq_lock - lock the rq @p resides on.
+ */
+static inline struct rq *__task_rq_lock(struct task_struct *p)
+ __acquires(rq->lock)
+{
+ struct rq *rq;
+
+ lockdep_assert_held(&p->pi_lock);
+
+ for (;;) {
+ rq = task_rq(p);
+ raw_spin_lock(&rq->lock);
+ if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
+ return rq;
+ raw_spin_unlock(&rq->lock);
+
+ while (unlikely(task_on_rq_migrating(p)))
+ cpu_relax();
+ }
+}
+
+/*
+ * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
+ */
+static inline struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
+ __acquires(p->pi_lock)
+ __acquires(rq->lock)
+{
+ struct rq *rq;
+
+ for (;;) {
+ raw_spin_lock_irqsave(&p->pi_lock, *flags);
+ rq = task_rq(p);
+ raw_spin_lock(&rq->lock);
+ /*
+ * move_queued_task() task_rq_lock()
+ *
+ * ACQUIRE (rq->lock)
+ * [S] ->on_rq = MIGRATING [L] rq = task_rq()
+ * WMB (__set_task_cpu()) ACQUIRE (rq->lock);
+ * [S] ->cpu = new_cpu [L] task_rq()
+ * [L] ->on_rq
+ * RELEASE (rq->lock)
+ *
+ * If we observe the old cpu in task_rq_lock, the acquire of
+ * the old rq->lock will fully serialize against the stores.
+ *
+ * If we observe the new cpu in task_rq_lock, the acquire will
+ * pair with the WMB to ensure we must then also see migrating.
+ */
+ if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
+ return rq;
+ raw_spin_unlock(&rq->lock);
+ raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
+
+ while (unlikely(task_on_rq_migrating(p)))
+ cpu_relax();
+ }
+}
+
+static inline void __task_rq_unlock(struct rq *rq)
+ __releases(rq->lock)
+{
+ raw_spin_unlock(&rq->lock);
+}
+
+static inline void
+task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
+ __releases(rq->lock)
+ __releases(p->pi_lock)
+{
+ raw_spin_unlock(&rq->lock);
+ raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
+}
+
#ifdef CONFIG_SMP
#ifdef CONFIG_PREEMPT
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