Re: [kvm-devel] [PATCH 01 of 12] Core of mmu notifiers

[Eric D. <da...@co...>]

Andrea Arcangeli a écrit :
> +
> +static int mm_lock_cmp(const void *a, const void *b)
> +{
> +	cond_resched();
> +	if ((unsigned long)*(spinlock_t **)a <
> +	    (unsigned long)*(spinlock_t **)b)
> +		return -1;
> +	else if (a == b)
> +		return 0;
> +	else
> +		return 1;
> +}
> +
This compare function looks unusual...
It should work, but sort() could be faster if the
if (a == b) test had a chance to be true eventually...

static int mm_lock_cmp(const void *a, const void *b)
{
	unsigned long la = (unsigned long)*(spinlock_t **)a;
	unsigned long lb = (unsigned long)*(spinlock_t **)b;

	cond_resched();
	if (la < lb)
		return -1;
	if (la > lb)
		return 1;
	return 0;
}