On Tue, Mar 17, 2020 at 02:41:52PM +0900, js1304@xxxxxxxxx wrote:
> From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
>
> Swapcache doesn't handle the value since there is no case using the value.
> In the following patch, workingset detection for anonymous page will be
> implemented and it stores the value into the swapcache. So, we need to
> handle it and this patch implement handling.
"value" is too generic, it's not quite clear what this refers to
here. "Exceptional entries" or "shadow entries" would be better.
> @@ -155,24 +163,33 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp)
> * This must be called only on pages that have
> * been verified to be in the swap cache.
> */
> -void __delete_from_swap_cache(struct page *page, swp_entry_t entry)
> +void __delete_from_swap_cache(struct page *page,
> + swp_entry_t entry, void *shadow)
> {
> struct address_space *address_space = swap_address_space(entry);
> int i, nr = hpage_nr_pages(page);
> pgoff_t idx = swp_offset(entry);
> XA_STATE(xas, &address_space->i_pages, idx);
>
> + /* Do not apply workingset detection for the hugh page */
> + if (nr > 1)
> + shadow = NULL;
Hm, why is that? Should that be an XXX/TODO item? The comment should
explain the reason, not necessarily what the code is doing.
Also, s/hugh/huge/
The rest of the patch looks straight-forward to me.
