Re: [RFC PATCH] cmdline: Hide "debug" from /proc/cmdline

Andrew Morton
2014-04-02T23:28:43Z

On Thu, 3 Apr 2014 01:23:15 +0200 (CEST) Jiri Kosina <jkosina@suse.cz> wrote:

> On Wed, 2 Apr 2014, Linus Torvalds wrote:
>
> > Steven, Borislav, one thing that strikes me might be a good idea is to
> > limit the amount of non-kernel noise in dmesg. We already have the
> > concept of rate-limiting various spammy internal kernel messages for
> > when device drivers misbehave etc. Maybe we can just add rate-limiting
> > to the interfaces that add messages to the kernel buffers, and work
> > around this problem that way instead while waiting for Gregs fix to
> > percolate? Or are the systemd debug messages going to so many other
> > places too that that wouldn't really help?
>
> I think that it's in principle a good idea, however ... the in-kernel
> ratelimiting always happens per sourcecode location, but this will be
> rather hard to achieve with interface such as /dev/kmsg.
>
> If /dev/kmsg is going to be ratelimited as a whole, it might potentially
> create a severely unfair situation between individual userspace programs
> trying to do logging (although there is apparently only one userspace
> service doing any logging through this interface whatsoever, right?).

Could be done per-fd: put a struct ratelimit_state into struct
devkmsg_user.