linux-kernel - Re: [PATCH 7/8] badpage: ratelimit print_bad_pte and bad

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Message-ID: <Pine.LNX.4.64.0812031253060.6817@blonde.anvils>
Date:	Wed, 3 Dec 2008 13:04:17 +0000 (GMT)
From:	Hugh Dickins <hugh@...itas.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
cc:	nickpiggin@...oo.com.au, davej@...hat.com, arjan@...radead.org,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 7/8] badpage: ratelimit print_bad_pte and bad_page

On Tue, 2 Dec 2008, Andrew Morton wrote:
> On Mon, 1 Dec 2008 00:46:53 +0000 (GMT)
> Hugh Dickins <hugh@...itas.com> wrote:
> > +	/*
> > +	 * Allow a burst of 60 reports, then keep quiet for that minute;
> > +	 * or allow a steady drip of one report per second.
> > +	 */
> > +	if (nr_shown == 60) {
> > +		if (time_before(jiffies, resume)) {
> > +			nr_unshown++;
> > +			goto out;
> > +		}
> > +		if (nr_unshown) {
> > +			printk(KERN_EMERG
> > +				"Bad page state: %lu messages suppressed\n",
> > +				nr_unshown);
> > +			nr_unshown = 0;
> > +		}
> > +		nr_shown = 0;
> > +	}
> > +	if (nr_shown++ == 0)
> > +		resume = jiffies + 60 * HZ;
> > +
> 
> gee, that's pretty elaborate.  There's no way of using the
> possibly-enhanced ratelimit.h?

Thanks a lot for the pointer: I'd browsed around kernel/printk.c and
not found what I needed, hadn't realized there's a lib/ratelimit.c.

It looks eerily like what I'm trying to do, just a less specific
missed/suppressed message, never mind that.  I'll try making a patch
later to replace this (in its subsequent KERN_ALERT form) by that -
in doing so, perhaps I'll encounter a problem, but should be good.

Hugh
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