From: Andrew Morton <akpm@osdl.org>
To: andrew.j.wade@gmail.com
Cc: tim.c.chen@linux.intel.com, 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: Thu, 5 Oct 2006 01:36:35 -0700 [thread overview]
Message-ID: <20061005013635.e016bf2b.akpm@osdl.org> (raw)
In-Reply-To: <200610050417.39518.ajwade@cpe001346162bf9-cm0011ae8cd564.cpe.net.cable.rogers.com>
On Thu, 5 Oct 2006 04:13:07 -0400
Andrew James Wade <andrew.j.wade@gmail.com> wrote:
> (from earlier)
> > Perhaps the `static int __warn_once' is getting put in the same cacheline
> > as some frequently-modified thing.
>
> hmm:
>
> 00000460 l O .data 00000044 task_exit_notifier
> 000004c0 l O .data 0000002c task_free_notifier
> 000004ec l O .data 00000004 warnlimit.15904
> 000004f0 l O .data 00000004 firsttime.15774
> 000004f4 l O .data 00000004 __warn_once.15180
> 000004f8 l O .data 00000004 __warn_once.15174
> 000004fc l O .data 00000004 __warn_once.15213
> 00000500 l O .data 00000004 __warn_once.15207
> 00000504 l O .data 00000004 __warn_once.15145
> 00000508 l O .data 00000004 __warn_once.15309
> 0000050c l O .data 00000004 __warn_once.15256
> 00000510 l O .data 00000004 __warn_once.15250
> 000005a0 l O .data 0000006c proc_iomem_operations
> (extracted from objdump -t kernel/built-in.o)
That all looks OK (by sheer luck).
Well. What's the cache line size on that machine? Every exit() will cause
a down_read() on task_exit_notifier's lock which might affect things. And
I think you snipped the above list a bit short (depending on that line
size).
But still, we know that moving those things into __read_mostly didn't fix
it, yes?
next prev parent reply other threads:[~2006-10-05 8:40 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
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 [this message]
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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