From: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx> Add a barrier() at the end of __raw_spin_unlock() to prevent instructions from after the locked region from being reordered into it. In theory doing so shouldn't cause any problems, but in practice, the system locks up under load... Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx> --- arch/x86/include/asm/spinlock.h | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index d6de5e7..158b330 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -189,6 +189,8 @@ static __always_inline void arch_spin_unlock(arch_spinlock_t *lock) next = lock->tickets.head + 1; __ticket_unlock_release(lock); __ticket_unlock_kick(lock, next); + + barrier(); /* prevent reordering into locked region */ } static inline int arch_spin_is_locked(arch_spinlock_t *lock) -- 1.7.2.3 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
