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From: Tim Chen <tim.c.chen@linux.intel.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@osdl.org>,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org,
	leonid.i.ananiev@intel.com
Subject: Re: [PATCH] Fix WARN_ON / WARN_ON_ONCE regression
Date: Tue, 10 Oct 2006 08:41:46 -0700	[thread overview]
Message-ID: <1160494906.4548.22.camel@localhost.localdomain> (raw)
In-Reply-To: <1160485474.22525.6.camel@localhost.localdomain>

On Tue, 2006-10-10 at 09:04 -0400, Steven Rostedt wrote:

> 
> Holy crap!  I wonder where else in the kernel gcc is doing this. (of
> course I'm using gcc4 so I don't know).  Is there another gcc attribute
> to actually tell gcc that a variable is really mostly read only (besides
> placing it in a mostly read only elf section)?
> 
> What was wrong with the original WARN_ON_ONCE with
> 
>   if (unlikely(condition) && __warn_once)
> 
> This didn't have the cache crash problem too, did it?
> I don't have a gcc3 around to test.

In the original WARN_ON_ONCE, gcc3 only writes to __warn_once when
(condition) is true.  So it does not cause cache bouncing by always
writing to __warn_once.

Tim

  reply	other threads:[~2006-10-10 16:31 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-03 23:04 [PATCH] Fix WARN_ON / WARN_ON_ONCE regression Tim Chen
2006-10-03 23:19 ` Tim Chen
2006-10-04  0:06 ` Jeremy Fitzhardinge
2006-10-03 23:47   ` Tim Chen
2006-10-04  4:39     ` Jeremy Fitzhardinge
2006-10-04 13:21       ` Tim Chen
2006-10-04 16:30         ` Andrew Morton
2006-10-04 16:22           ` Tim Chen
2006-10-04 17:34             ` Andrew Morton
2006-10-04 20:43               ` Tim Chen
2006-10-10  1:09               ` Tim Chen
2006-10-10 13:04                 ` Steven Rostedt
2006-10-10 15:41                   ` Tim Chen [this message]
2006-10-10 20:03                   ` Jeremy Fitzhardinge
2006-10-04  0:07 ` Andrew Morton
2006-10-03 23:42   ` Tim Chen
2006-10-04  0:09   ` Tim Chen
2006-10-04  1:14     ` Andrew Morton
2006-10-04  1:47       ` Nick Piggin
2006-10-04  3:24       ` Andrew James Wade
2006-10-04  3:32         ` Andrew Morton
2006-10-04 16:47           ` Andrew James Wade
2006-10-04 22:06             ` Andrew Morton
2006-10-05  8:13               ` Andrew James Wade
2006-10-05  8:36                 ` Andrew Morton
2006-10-05 21:31                   ` Andrew James Wade
2006-10-05 21:01                     ` Tim Chen
  -- strict thread matches above, loose matches on Subject: below --
2006-10-04 16:57 Ananiev, Leonid I
2006-10-04 17:28 ` Andrew Morton
2006-10-08  0:28   ` Steven Rostedt
2006-10-08  0:39     ` Jeremy Fitzhardinge
2006-10-04 21:55 Ananiev, Leonid I
2006-10-05 21:37 ` Andrew Morton
2006-10-05 21:43   ` Jeremy Fitzhardinge
2006-10-05 21:52     ` Andrew Morton
2006-10-05 22:02       ` Herbert Xu
2006-10-05 22:40         ` Jeremy Fitzhardinge
2006-10-05 21:51   ` Tim Chen
2006-10-06 16:11   ` Andrew James Wade
2006-10-06  4:06 Ananiev, Leonid I
2006-10-10 21:05 Ananiev, Leonid I
2006-10-10 21:17 ` Steven Rostedt
2006-10-10 21:41   ` Roland Dreier
2006-10-10 22:59   ` Jeremy Fitzhardinge

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