Messages in this thread Patch in this message | | | Date | Wed, 15 Jan 2014 08:44:20 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC 1/3] mutex: In mutex_can_spin_on_owner(), return false if task need_resched() |
| |
On Tue, Jan 14, 2014 at 04:33:08PM -0800, Jason Low wrote: > The mutex_can_spin_on_owner() function should also return false if the > task needs to be rescheduled. >
While I was staring at mutex_can_spin_on_owner(); don't we need this?
kernel/locking/mutex.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 4dd6e4c219de..480d2f437964 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -214,8 +214,10 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock) rcu_read_lock(); owner = ACCESS_ONCE(lock->owner); - if (owner) + if (owner) { + smp_read_barrier_depends(); retval = owner->on_cpu; + } rcu_read_unlock(); /* * if lock->owner is not set, the mutex owner may have just acquired
| |