Re: [PATCH] mm: memcontrol: restore proper dirty throttling when memory.high changes

[Shakeel Butt]

On Tue, Jul 28, 2020 at 6:53 AM Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
>
> Commit 8c8c383c04f6 ("mm: memcontrol: try harder to set a new
> memory.high") inadvertently removed a callback to recalculate the
> writeback cache size in light of a newly configured memory.high limit.
>
> Without letting the writeback cache know about a potentially heavily
> reduced limit, it may permit too many dirty pages, which can cause
> unnecessary reclaim latencies or even avoidable OOM situations.
>
> This was spotted while reading the code, it hasn't knowingly caused
> any problems in practice so far.
>
> Fixes: 8c8c383c04f6 ("mm: memcontrol: try harder to set a new memory.high")
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>