On Tue, Jan 28, 2014 at 11:13:12AM -0800, Jason Low wrote: > The mutex_can_spin_on_owner() function should also return false if the > task needs to be rescheduled to avoid entering the MCS queue when it > needs to reschedule. > > Signed-off-by: Jason Low <jason.l...@hp.com>
Reviewed-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> But I cannot help asking how this affects performance. (My guess is "not much", but always good to know.) > --- > kernel/locking/mutex.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c > index 4dd6e4c..85c6be1 100644 > --- a/kernel/locking/mutex.c > +++ b/kernel/locking/mutex.c > @@ -212,6 +212,9 @@ static inline int mutex_can_spin_on_owner(struct mutex > *lock) > struct task_struct *owner; > int retval = 1; > > + if (need_resched()) > + return 0; > + > rcu_read_lock(); > owner = ACCESS_ONCE(lock->owner); > if (owner) > -- > 1.7.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
