Il giorno 11 giu 2019, alle ore 23:17, Tejun Heo [off-list ref] ha scritto:

On Tue, Jun 11, 2019 at 12:49:59PM -0700, Tejun Heo wrote:

quoted

(Description mostly stolen from 19e9da9e86c4 ("block, bfq: add weight
symlink to the bfq.weight cgroup parameter")

Many userspace tools and services use the proportional-share policy of
the blkio/io cgroups controller. The CFQ I/O scheduler implemented
this policy for the legacy block layer. To modify the weight of a
group in case CFQ was in charge, the 'weight' parameter of the group
must be modified. On the other hand, the BFQ I/O scheduler implements
the same policy in blk-mq, but, with BFQ, the parameter to modify has
a different name: bfq.weight (forced choice until legacy block was
present, because two different policies cannot share a common
parameter in cgroups).

Sorry, please don't apply this patch.  The cgroup interface currently
implemented by bfq doesn't follow the io.weight interface spec.

Could you elaborate a little more on this?

bfq code for setting up and handling io.weight (more precisely
io.bfq.weight) is a copy and paste of cfq code.

Thanks,
Paolo

It's
different from cfq interface and symlinking to or renaming it won't do
anybody any good.

For now, the only thing we can do looks like keeping it as-is.

Thanks.

--
tejun