On Thu, Apr 12, 2018 at 10:16:55AM -0400, Waiman Long wrote: > On 04/12/2018 10:06 AM, Will Deacon wrote: > > On Wed, Apr 11, 2018 at 03:53:16PM -0400, Waiman Long wrote: > >>> diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c > >>> index 396701e8c62d..a8fc402b3f3a 100644 > >>> --- a/kernel/locking/qspinlock.c > >>> +++ b/kernel/locking/qspinlock.c > >>> @@ -162,6 +162,17 @@ struct __qspinlock { > >>> > >>> #if _Q_PENDING_BITS == 8 > >>> /** > >>> + * clear_pending - clear the pending bit. > >>> + * @lock: Pointer to queued spinlock structure > >>> + * > >>> + * *,1,* -> *,0,* > >>> + */ > >>> +static __always_inline void clear_pending(struct qspinlock *lock) > >>> +{ > >>> + WRITE_ONCE(lock->pending, 0); > >>> +} > >>> + > >>> +/** > >>> * clear_pending_set_locked - take ownership and clear the pending bit. > >>> * @lock: Pointer to queued spinlock structure > >>> * > >>> @@ -201,6 +212,17 @@ static __always_inline u32 xchg_tail(struct > >>> qspinlock *lock, u32 tail) > >>> #else /* _Q_PENDING_BITS == 8 */ > >>> > >>> /** > >>> + * clear_pending - clear the pending bit. > >>> + * @lock: Pointer to queued spinlock structure > >>> + * > >>> + * *,1,* -> *,0,* > >>> + */ > >>> +static __always_inline void clear_pending(struct qspinlock *lock) > >>> +{ > >>> + atomic_andnot(_Q_PENDING_VAL, &lock->val); > >>> +} > >>> + > >>> +/** > >>> * clear_pending_set_locked - take ownership and clear the pending bit. > >>> * @lock: Pointer to queued spinlock structure > >>> * > >> BTW, there is a similar clear_pending() function in > >> qspinlock_paravirt.c. I think you need to remove that with this patch. > > Thanks, I'll do that. I did build and bisect this series... for arm64, which > > is completely useless as it doesn't get compiled until the final patch which > > I haven't posted here. > > > > Will > > You certainly need to get a x86 system and compiles with the patches > applied one-by-one with CONFIG_PARAVIRT_SPINLOCKS enabled.
Yup, doing that now. I just botched my test scripts before, which default to arm64. Will