On 02/26, Waiman Long wrote:
>
> +#define _ARCH_SUPPORTS_ATOMIC_8_16_BITS_OPS
> +
> +/*
> + * x86-64 specific queue spinlock union structure
> + */
> +union arch_qspinlock {
> + struct qspinlock slock;
> + u8 lock; /* Lock bit */
> +};
And this enables the optimized version of queue_spin_setlock().
But why does it check ACCESS_ONCE(qlock->lock) == 0 ? This is called
right after queue_get_lock_qcode() returns 0, this locked should be
likely unlocked.
Oleg.
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