On Thu, Oct 22, 2020 at 04:58:42PM -0400, Gabriel Krisman Bertazi wrote:
> Similarly to commit 457e490f2b741 ("blkcg: allocate struct blkcg_gq
> outside request queue spinlock"), blkg_create can also trigger
> occasional -ENOMEM failures at the radix insertion because any
> allocation inside blkg_create has to be non-blocking, making it more
> likely to fail. This causes trouble for userspace tools trying to
> configure io weights who need to deal with this condition.
>
> This patch reduces the occurrence of -ENOMEMs on this path by preloading
> the radix tree element on a GFP_KERNEL context, such that we guarantee
> the later non-blocking insertion won't fail.
>
> A similar solution exists in blkcg_init_queue for the same situation.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Thanks.
--
tejun
