Re: [PATCH 0/3] zram: Replace pr_* with dev_*

Sergey Senozhatsky
2015-08-07T01:41:38Z

Hello Joe,

On (08/06/15 18:17), Joe Perches wrote:
[..]
> > "Can't change algorithm for initialized device\n"
> > --> "Can't change algorithm to %s for initialized device\n"
> >
> >
> > People already can have scripts doing `grep "zram:"` on dmesg or
> > whatever. We cannot change this anymore.
>
> That's not true at all.
>
> Using grep on dmesg is specifically _not_ guaranteed
> to remain stable between kernel versions.

It depends, I guess. People do use grep after all and people don't
like when things are getting changed underneath; and we don't want
to do this. I think Minchan is with me here. We even didn't add some
additional pr_info/pr_err noise recently because we don't want
people to depend on that part.

http://lkml.iu.edu/hypermail/linux/kernel/1505.3/01759.html

Minchan Kim <minchan@kernel.org>:

|I meant if we remove the pr_err in future by some reason,
|someone might shout
|
|"No, it's ABI so if you guys removes it, it will break user interface's
|semantic". Maybe he seems to depends on parse on dmesg.
|That is not what I want.

And I saw some time ago people doing that type of thing. So I'd like
to avoid unnecessary pain for zram users even if the messages are not
guaranteed to remain stable between kernel releases. Just my opinion.

-ss