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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: 7eggert@gmx.de
Subject: Re: GFP_ATOMIC page allocation failures.
Date: Fri, 4 Apr 2008 21:59:53 +1100
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Cc: Jeff Garzik <jeff@garzik.org>, Andrew Morton <akpm@linux-foundation.org>,
       Chris Snook <csnook@redhat.com>, Dave Jones <davej@codemonkey.org.uk>,
       Linux Kernel <linux-kernel@vger.kernel.org>,
       NetDev <netdev@vger.kernel.org>, David Miller <davem@davemloft.net>,
       Linus Torvalds <torvalds@linux-foundation.org>
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On Friday 04 April 2008 20:52, Bodo Eggert wrote:
> Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> > On Thursday 03 April 2008 05:18, Jeff Garzik wrote:
> >> Turning to Nick's comment,
> >>
> >> > It's still actually nice to know how often it is happening even for
> >> > these known good sites because too much can indicate a problem and
> >> > that you could actually bring performance up by tuning some things.
> >>
> >> then create a counter or acculuation buffer somewhere.
> >>
> >> We don't need spew every time there is memory pressure of this
> >> magnitude.
> >
> > Not a complete solution. Counter would be nice, but you need backtraces
> > and want a way to more proactively warn the user/tester/developer.
> >
> > I agree that I don't exactly like adding nowarns around, and I don't
> > think places like driver writers should have to know about this stuff.
>
> What about reverse ratelimiting: If the limit is reached, a backtrace will
> be generated (and, off cause, positively ratelimited)?

I was thinking about that. I got as far as writing a simple patch to
printk  so that it would not start to trigger until it gets a 2nd event
within 'n' jiffies of the first.

But actually developers do sometimes want see the event even if it is
relatively infrequent...