Re: elevator= kernel argument for recent kernels

From: Jan Kara <jack@suse.cz>
To: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>,
	linux-block@vger.kernel.org, mgorman@suse.de, hare@suse.de
Subject: Re: elevator= kernel argument for recent kernels
Date: Wed, 6 Nov 2019 16:01:05 +0100	[thread overview]
Message-ID: <20191106150105.GK16085@quack2.suse.cz> (raw)
In-Reply-To: <1a0539a7-75c2-1ad6-aa5c-bf07a92e1eb3@kernel.dk>

On Wed 06-11-19 07:15:35, Jens Axboe wrote:
> On 11/6/19 3:53 AM, Jan Kara wrote:
> > Hello,
> > 
> > with transition to blk-mq, the elevator= kernel argument was removed. I
> > understand the reasons for its removal but still I think this may come as a
> > surprise to some users since that argument has been there for ages and
> > although distributions generally transition to setting appropriate elevator
> > by udev rules, there are still people that use that argument with older
> > kernels and there are quite a few advices on the Internet to use it. So
> > shouldn't we at least warn loudly if someone uses elevator= argument on
> > kernels that don't support it and redirect people to sysfs? Something like
> > the attached patch? What do people think?
> 
> I'm fine with that, my objects have always been centered around trying
> to make the parameter work. A warning makes sense to point people in
> the right direction. I'll add this for 5.5.

Thanks!

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR