On 11/13/2010 02:48 AM, Eric Dumazet wrote: > Le samedi 13 novembre 2010 à 18:17 +0800, Américo Wang a écrit : >> On Wed, Nov 03, 2010 at 10:59:47AM -0400, Jeremy Fitzhardinge wrote: >> >>> + union { >>> + struct __raw_tickets tickets; >>> + __ticketpair_t slock; >>> + } tmp, new; >>> + int ret; >>> + >>> + tmp.tickets = ACCESS_ONCE(lock->tickets); >>> + if (tmp.tickets.head != tmp.tickets.tail) >>> + return 0; >>> + >>> + new.slock = tmp.slock + (1 << TICKET_SHIFT); >>> + >>> + ret = cmpxchg(&lock->ticketpair, tmp.slock, new.slock) == tmp.slock; >>> + barrier(); /* just make nothing creeps before lock is >>> claimed */ >> This one should be smp_wmb(), right? No CONFIG_X86_OOSTORE protected. > cmpxchg() is a full memory barrier, no need for smp_wmb() or barrier()
Agreed. J _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization