On Wed, Apr 17, 2019 at 02:29:02PM -0400, Waiman Long wrote: > On 04/17/2019 08:47 AM, Peter Zijlstra wrote: > >> > >> enum owner_state { > >> OWNER_NULL = 1 << 0, > >> OWNER_WRITER = 1 << 1, > >> OWNER_READER = 1 << 2, > >> OWNER_NONSPINNABLE = 1 << 3, > >> }; > >> #define OWNER_SPINNABLE (OWNER_NULL | OWNER_WRITER) > > Hmm, we should not spin on OWNER_NULL. Or at least not mixed in with the > > patch that changes the shape of all this. That should go in the RT > > thingy patch, which comes after this. > > We do spin on OWNER_NULL right now, not in rwsem_spin_on_owner() but in > the main rwsem_optimistic_spin() function. > > RT task will quit if owner is NULL.
Yeah, I figured it out eventually :-)