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SubjectRe: [PATCH 06/20] x86/ticketlock: make __ticket_spin_trylock common
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.


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