On 08/14/2017 03:27 AM, Oleksandr Natalenko wrote:

Setting I/O scheduler via kernel command line is not flexible enough
anymore. Different schedulers might be desirable for different types
of devices (SSDs and HDDs, for instance). Moreover, setting elevator
while using blk-mq framework does not work in this way already.

This commit enables warning if user specifies "elevator" boot param.
Removing this option at all might be considered in some future.

Not a huge fan of doing it like this, it'll just add a bunch of noise to
the dmesg output that people will ignore. It doesn't bring us closer to
being able to remove the option.

I think we should just let it die over time. This will happen naturally
since the blk-mq scheduling framework does not support it. Once we have
everything converted, the option will end up doing nothing. Then we can
eventually kill it.

-- 
Jens Axboe