[PATCH v14 08/14] mm: multi-gen LRU: support page table walks

[Peter Zijlstra]

On Mon, Aug 15, 2022 at 01:13:27AM -0600, Yu Zhao wrote:
> +	for (i = pmd_index(start), addr = start; addr != end; i++, addr = next) {
> +		pmd_t val = pmd_read_atomic(pmd + i);
> +
> +		/* for pmd_read_atomic() */
> +		barrier();

Please clarify the above. This is an entirely inadequate ordering
comment.

> +
> +		next = pmd_addr_end(addr, end);