Re: [REGRESSION] bfq probe failed on 4.19-rc3

From: Jeff Moyer
Date: Tue Sep 11 2018 - 12:48:15 EST


Jens Axboe <axboe@xxxxxxxxx> writes:

> On 9/11/18 10:03 AM, Takashi Iwai wrote:
>> Hi,
>>
>> I noticed that bfq doesn't appear in the I/O scheduler list on
>> 4.19-rc3. It seems that blkcg_policy_register() at the beginning of
>> bfq_init() returns -ENOSPC, hence the probe aborts silently.
>>
>> Is this already addressed?
>
> Haven't heard about this one before. What kernel did you last use that
> worked?

I'm guessing you just need to update the maximum number of policies:

/*
* Maximum number of blkcg policies allowed to be registered concurrently.
* Defined here to simplify include dependency.
*/
#define BLKCG_MAX_POLS 3

-Jeff