mm: io_uring: allow oom-killer from io_uring_setup

On an overcommitted system which is running multiple workloads of
varying priorities, it is preferred to trigger an oom-killer to kill a
low priority workload than to let the high priority workload receiving
ENOMEMs. On our memory overcommitted systems, we are seeing a lot of
ENOMEMs instead of oom-kills because io_uring_setup callchain is using
__GFP_NORETRY gfp flag which avoids the oom-killer. Let's remove it and
allow the oom-killer to kill a lower priority job.

Signed-off-by: Shakeel Butt <shakeelb@google.com>
Link: https://lore.kernel.org/r/20220125051736.2981459-1-shakeelb@google.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>