Re: [PATCH v5] mm, drm/i915: mark pinned shmemfs pages as unevictable

From: Michal Hocko
Date: Tue Nov 06 2018 - 04:08:44 EST


On Tue 06-11-18 17:03:51, Kuo-Hsin Yang wrote:
> The i915 driver uses shmemfs to allocate backing storage for gem
> objects. These shmemfs pages can be pinned (increased ref count) by
> shmem_read_mapping_page_gfp(). When a lot of pages are pinned, vmscan
> wastes a lot of time scanning these pinned pages. In some extreme case,
> all pages in the inactive anon lru are pinned, and only the inactive
> anon lru is scanned due to inactive_ratio, the system cannot swap and
> invokes the oom-killer. Mark these pinned pages as unevictable to speed
> up vmscan.
>
> Export pagevec API check_move_unevictable_pages().
>
> This patch was inspired by Chris Wilson's change [1].
>
> [1]: https://patchwork.kernel.org/patch/9768741/
>
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
> Signed-off-by: Kuo-Hsin Yang <vovoy@xxxxxxxxxxxx>
> Acked-by: Michal Hocko <mhocko@xxxxxxxx>

please make it explicit that the ack applies to mm part as i've
mentioned when giving my ack to the previous version.

E.g.
Acked-by: Michal Hocko <mhocko@xxxxxxx> # mm part

because i am not familiar with the drm code to ack any changes there.
--
Michal Hocko
SUSE Labs