Re: [PATCH] MAINTAINERS: move the BFQ io scheduler to orphan state

[Jens Axboe <axboe@kernel.dk>]

On 9/5/24 7:03 AM, Linus Walleij wrote:
> On Wed, Sep 4, 2024 at 4:07?PM Jens Axboe <axboe@kernel.dk> wrote:
>> On 9/4/24 7:59 AM, Ulf Hansson wrote:
> 
>>>  Surely BFQ is being
>>> used out there, so it would really be a pity if nobody takes good care
>>> of it.
>>
>> Probably not a whole lot I think, at least on the prod side experiences
>> with BFQ haven't been good.
> 
> Which production? For singlequeue devices it is pretty widespread.

We tried it at one point internally at Meta, and it was not pretty. Now
it's just disabled so people don't inadvertently pick it (as some people
like to do when fiddling with things).

> It is used in Fedora, RedHat and SuSE as default scheduler for any
> /dev/sdN, /dev/srN and /dev/mmcblkN (i.e. anything singlequeue).
> 
> Example from my main development machine with Fedora 40:
> $ cat /sys/block/sda/queue/scheduler
> none mq-deadline kyber [bfq]
> Laptop with MMC card reader:
> $ cat /sys/block/mmcblk0/queue/scheduler
> none mq-deadline kyber [bfq]
> 
> Maybe we should propose these rules to the main udev repository
> so that they also go into Debian and we get even wider use?

I know you like to push for it to be the default, and I always push back
because I don't think it's stable enough for that, and now we have the
added complication that it hasn't been maintained for quite a while.
So no, I don't think so.

There are some bugzilla entries too that never got resolved or moved
very far. Some of those may now be invalid, maybe not. Impossible to
know.

-- 
Jens Axboe