Am 28.06.2016 um 12:01 schrieb Huang Rui: > On Tue, Jun 28, 2016 at 05:36:39PM +0800, Christian König wrote: >> Am 28.06.2016 um 09:27 schrieb Huang Rui: >>> On Tue, Jun 28, 2016 at 03:04:18PM +0800, Chunming Zhou wrote: >>>> ring_mirror_list is only used kthread context, no need to spinlock. >>>> otherwise deadlock happens when kthread_park. >>>> >>> Yes, in process context, we prefer to use mutex, because it avoids to >>> grab the CPU all the time. >>> >>> Reviewed-by: Huang Rui <ray.huang at amd.com> >> NAK, the patch won't apply because I've changed the irq save spin lock >> to a normal one quite a while ago. But, I'm not sure if Alex picked up >> that patch yet. >> >> You shouldn't use a mutex here when you don't have a reason to do so. >> Spin locks have less overhead and we won't expect any contention here. >> > If the CPU core numbers are large, spinlock will grab the cpu and > might cause some potential deaklock or busy waiting. I think it should > be use mutex if it is not in interrupt context. Clearly not a good idea. Mutex should only be used if you expect contention on the lock or if you need to sleep while within the lock. For things like protecting a linked list like in this case using a mutex is clearly the wrong approach. Regards, Christian. > > Thanks, > Rui
