docker-ce: missing kernel configuration symbol

On startup

WARN[2020-06-02T19:13:22.619792818+01:00] Your kernel does not support cgroup blkio weight 
WARN[2020-06-02T19:13:22.619998687+01:00] Your kernel does not support cgroup blkio weight_device

After which my entire system hangs and reboots, although to be fair, I'm not sure it's this that's causing the reboot. I'll update once I've compiled a kernel with the relevant symbols enabled.

The symbol that needs to be enabled is CONFIG_BLK_CGROUP_IOCOST=y

CONFIG_BLK_CGROUP_IOCOST:                                                                                                                                                                                                
  Enabling this option enables the .weight interface for 
  cost  model based proportional IO control.  The IO controller
  distributes IO capacity between different groups based on
  their share of the overall weight distribution.

diff --git a/utils/docker-ce/Config.in b/utils/docker-ce/Config.in
index dba32c4..d9184d0 100644
--- a/utils/docker-ce/Config.in
+++ b/utils/docker-ce/Config.in
@@ -31,6 +31,7 @@ menu "Kernel features for Docker"
                select KERNEL_MEMCG_SWAP
                select KERNEL_MEMCG_SWAP_ENABLED
                select KERNEL_BLK_DEV_THROTTLING
+               select KERNEL_BLK_CGROUP_IOCOST
                select KERNEL_CFQ_GROUP_IOSCHED
                select KERNEL_CGROUP_PERF
                select KERNEL_FAIR_GROUP_SCHED
@@ -83,3 +84,7 @@ menu "Kernel features for Docker"
                        select KERNEL_BTRFS_FS_POSIX_ACL
        endmenu
 endmenu
+
+config KERNEL_BLK_CGROUP_IOCOST
+       bool
+       default n

Platform is x86_64

@G-M0N3Y-2503

Start in utils/docker-ce/Config.in and inspect how the Docker kernel feature menu selects symbols, especially the existing blkio-related options. Check the OpenWrt kernel configuration and Docker startup warnings to confirm whether CONFIG_BLK_CGROUP_IOCOST is the missing dependency. Done means the symbol is selected appropriately and the resulting configuration no longer produces the reported warning.