From: Adrian Bunk <bunk@stusta•de>
To: Linus Torvalds <torvalds@linux-foundation•org>
Cc: Andrew Morton <akpm@linux-foundation•org>,
Alexey Dobriyan <adobriyan@gmail•com>,
linux-kernel@vger•kernel.org, netdev@vger•kernel.org
Subject: Re: 2.6.23-rc1: BUG_ON in kmap_atomic_prot()
Date: Tue, 24 Jul 2007 19:59:51 +0200 [thread overview]
Message-ID: <20070724175951.GC6019@stusta.de> (raw)
In-Reply-To: <alpine.LFD.0.999.0707231415511.3607@woody.linux-foundation.org>
On Mon, Jul 23, 2007 at 02:28:11PM -0700, Linus Torvalds wrote:
>
>
> On Mon, 23 Jul 2007, Andrew Morton wrote:
> >
> > It'd be nice to get a clean trace. Are you able to obtain the full
> > trace with CONFIG_FRAME_POINTER=y?
>
> If you are talking about
>
> http://userweb.kernel.org/~akpm/dsc03659.jpg
>
> then I think that _is_ a full trace. It's certainly not very messy, and it
> seems accurate. It's just that inlining makes it much harder to see the
> call-graphs, but that's what inlining does..
>
> For example, missing from the call graph is
>
> get_page_from_freelist ->
> buffered_rmqueue -> [ missing - inlined ]
> prep_new_page -> [ missing - inlined ]
> prep_zero_page -> [ missing - inlined ]
> clear_highpage -> [ missing - inlined ]
> kmap_atomic -> [ missing - tailcall ]
> kmap_atomic_prot
>
> but I'm pretty sure the call trace is good (and I'm also pretty sure gcc
> is overly aggressive at inlining, and that it causes us pain for
> debugging, but whatever)
>...
For prep_zero_page() and clear_highpage() we can't blame gcc since we
force gcc to always inline them.
buffered_rmqueue() and prep_new_page() are static functions with only
one caller each, and for the normal non-debug case it's a really nice
optimization to have them inlined automatically. But it might make sense
to add -fno-inline-functions-called-once to the CFLAGS depending on some
debug option?
> Linus
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
next prev parent reply other threads:[~2007-07-24 18:00 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <alpine.LFD.0.999.0707221351030.3607@woody.linux-foundation.org>
[not found] ` <20070723183839.GA5874@martell.zuzino.mipt.ru>
[not found] ` <20070723190152.GA5755@martell.zuzino.mipt.ru>
2007-07-23 20:24 ` 2.6.23-rc1: BUG_ON in kmap_atomic_prot() Andrew Morton
2007-07-23 20:40 ` Alexey Dobriyan
2007-07-23 21:01 ` Alexey Dobriyan
2007-07-23 21:11 ` Andrew Morton
2007-07-23 21:28 ` Linus Torvalds
2007-07-23 21:37 ` Sam Ravnborg
2007-07-24 17:59 ` Adrian Bunk [this message]
2007-07-24 18:14 ` Linus Torvalds
2007-07-24 18:28 ` Andrew Morton
2007-07-24 19:15 ` Linus Torvalds
2007-07-24 19:40 ` Adrian Bunk
2007-07-24 19:48 ` Linus Torvalds
2007-07-26 18:07 ` Adrian Bunk
2007-07-26 18:19 ` Linus Torvalds
2007-07-24 20:27 ` Andi Kleen
2007-07-24 19:45 ` Linus Torvalds
2007-07-26 6:09 ` commit 7e92b4fc34 - x86, serial: convert legacy COM ports to platform devices - broke my serial console H. Peter Anvin
2007-07-23 22:04 ` 2.6.23-rc1: BUG_ON in kmap_atomic_prot() Alexey Dobriyan
2007-07-23 22:27 ` Andrew Morton
2007-07-24 5:20 ` Alexey Dobriyan
2007-07-24 8:17 ` Jens Axboe
2007-07-24 8:22 ` Jens Axboe
2007-07-24 8:34 ` Andrew Morton
2007-07-24 14:00 ` Dan Williams
2007-07-24 13:55 ` Dan Williams
2007-07-24 10:01 ` Mike Galbraith
2007-07-24 10:37 ` Mike Galbraith
2007-07-24 16:28 ` Andrew Morton
2007-07-24 18:25 ` Linus Torvalds
2007-07-24 20:05 ` Alexey Dobriyan
2007-07-25 5:09 ` Mike Galbraith
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