Re: [PATCH 03/12] blkcg: convert blkg_lookup_create to find closest blkg

From: Tejun Heo
Date: Tue Sep 11 2018 - 19:50:18 EST


On Tue, Sep 11, 2018 at 02:41:28PM -0400, Dennis Zhou wrote:
> From: "Dennis Zhou (Facebook)" <dennisszhou@xxxxxxxxx>
>
> There are several scenarios where blkg_lookup_create can fail. Examples
> include the blkcg dying, request_queue is dying, or simply being OOM. At
> the end of the day, most handle this by simply falling back to the
> q->root_blkg and calling it a day.
>
> This patch implements the notion of closest blkg. During
> blkg_lookup_create, if it fails to create, return the closest blkg
> found or the q->root_blkg. blkg_try_get_closest is introduced and used
> during association so a bio is always attached to a blkg.
>
> Signed-off-by: Dennis Zhou <dennisszhou@xxxxxxxxx>

Acked-by: Tejun Heo <tj@xxxxxxxxxx>

Thanks.

--
tejun