Re: [PATCH] mm: fix the NULL mapping case in __isolate_lru_page()

[Minchan Kim]

On Wed, May 30, 2018 at 08:23:16PM -0700, Hugh Dickins wrote:
> George Boole would have noticed a slight error in 4.16 commit 69d763fc6d3a
> ("mm: pin address_space before dereferencing it while isolating an LRU page").
> Fix it, to match both the comment above it, and the original behaviour.
> 
> Although anonymous pages are not marked PageDirty at first, we have an
> old habit of calling SetPageDirty when a page is removed from swap cache:
> so there's a category of ex-swap pages that are easily migratable, but
> were inadvertently excluded from compaction's async migration in 4.16.
> 
> Fixes: 69d763fc6d3a ("mm: pin address_space before dereferencing it while isolating an LRU page")
> Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>

Thanks, Hugh.