linux-kernel - Re: [PATCH 1/2] random: Omit double-printing ratelimit messages

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Date:   Wed, 16 May 2018 16:54:37 -0400
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Dmitry Safonov <dima@...sta.com>
Cc:     linux-kernel@...r.kernel.org, 0x7f454c46@...il.com,
        Arnd Bergmann <arnd@...db.de>
Subject: Re: [PATCH 1/2] random: Omit double-printing ratelimit messages

On Wed, May 16, 2018 at 04:46:13PM +0100, Dmitry Safonov wrote:
> > Yeah, but what you print is not total sum, it's since the last
> > interval because without mentioned flag ___ratelimit() will flush
> > missed counter and print "suppressed" message.  They might even
> > double if say other proccess has called get_random_bytes() got to
> > ___ratelimit() and got preempted. This thread finishes
> > initializing random driver and prints this not-proper-sum
> > statistics, and when the code flow is back in the first context,
> > it will print statistics again from ___ratelimit() function.
> 
> So, does it make sense to you, Theodore?
> If not - I'll just resend second patch rebasing and dropping this one.

Yes, it's correct that it's not the total sum.  I guess your complaint
is that some of the messages are using the "callbacks suppressed"
message, and the last one is using the random drvier's custom message
which I think is much more user-friendly.  That being said, although I
think "callbacks suppressed is a terrible message, I agree that using
a single message makes more sense.  So setting the
RATELIMIT_MSG_ON_RELEASE and then calling ratelimit_state_exit() from
crng_reseed() does make sense.

In the future I'd like to push for some way to customize --- or
perhaps just fix --- "callbacks suppressed" to something more sane
like, "messages ratelimited", but that's more of an aesthetics issue.

						- Ted