[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v9 05/19] qspinlock: Optimize for smaller NR_CPUS
On Thu, Apr 17, 2014 at 11:03:57AM -0400, Waiman Long wrote: > +struct __qspinlock { > + union { > + atomic_t val; > + struct { > +#ifdef __LITTLE_ENDIAN > + u16 locked_pending; > + u16 tail; > +#else > + u16 tail; > + u16 locked_pending; > +#endif > + }; > + }; > +}; > + > +/** > + * clear_pending_set_locked - take ownership and clear the pending bit. > + * @lock: Pointer to queue spinlock structure > + * @val : Current value of the queue spinlock 32-bit word > + * > + * *,1,0 -> *,0,1 > + */ > +static __always_inline void > +clear_pending_set_locked(struct qspinlock *lock, u32 val) > +{ > + struct __qspinlock *l = (void *)lock; > + > + ACCESS_ONCE(l->locked_pending) = 1; You lost the __constant_le16_to_cpu(_Q_LOCKED_VAL) there. The unconditional 1 is wrong. You also have to flip the bytes in locked_pending. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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