On 10 Jun 2020, at 16:12, Matthew Wilcox wrote:

> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> PG_private_2 is defined as being PF_ANY (applicable to tail pages
> as well as regular & head pages).  That means that the first tail
> page of a double-map page will appear to have Private2 set.  Use the
> Workingset bit instead which is defined as PF_HEAD so any attempt to
> access the Workingset bit on a tail page will redirect to the head page's
> Workingset bit.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---

Make sense to me.

Reviewed-by: Zi Yan <ziy@nvidia.com>

—
Best Regards,
Yan Zi