Re: [PATCH] mm:swap: do not check readahead flag with THP anon

[Minchan Kim]

On Wed, Feb 28, 2018 at 08:26:11AM +0900, Minchan Kim wrote:
> Huang reported PG_readahead flag marked PF_NO_COMPOUND so that
> we cannot use the flag for THP page. So, we need to check first
> whether page is THP or not before using TestClearPageReadahead
> in lookup_swap_cache.
> 
> This patch fixes it.
> 
> Furthermore, swap_[cluster|vma]_readahead cannot mark PG_readahead
> for newly allocated page because the allocated page is always a
> normal page, not THP at this moment. So let's clean it up, too.
> 
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>

 Link:http://lkml.kernel.org/r/874lm83zho.fsf@xxxxxxxxxxxxxxxxxxxx