From: Thomas Gleixner <tglx@linutronix.de>
To: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>, Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>,
Andrew Morton <akpm@linux-foundation.org>,
werner <w.landgraf@ru.ru>, "H. Peter Anvin" <hpa@zytor.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Tejun Heo <tj@kernel.org>
Subject: Re: [block IO crash] Re: 2.6.39-rc5-git2 boot crashs
Date: Wed, 4 May 2011 16:21:10 +0200 (CEST) [thread overview]
Message-ID: <alpine.LFD.2.02.1105041610590.3005@ionos> (raw)
In-Reply-To: <alpine.DEB.2.00.1105040902210.5495@router.home>
On Wed, 4 May 2011, Christoph Lameter wrote:
>
> The above should not happen. If a kernel config indicates that there is no
> cmpxchg16b/cmpxchg8b available then we need to not compile the path that
> uses cmpxchg8b/cmpxchg16b. Guess we need CMPXCHG_DOUBLE_LOCAL or so.
Oh no, you have perfectly fine replacements for that in percpu.h with
irqsafe and preempt safe versions. So why adding another CONFIG from
hell which creates even more ifdef mess ?
The whole CONFIG_CMPXCHG_LOCAL ifdeffery in slub.c is horrible and I
think it's not necessary at all for two reasons:
1) irqsafe_cpu_cmpxchg() can be emulated cheap and we still have the
advantatage of shorter irq disabled sections. And the difference
between the current CONFIG_CMPXCHG_LOCAL=n and using the emulation
macros with the short irqsave/restore around the access is probably
not measurable at all.
2) that would actually test the code under all possible combinations
and not splitting the tester base into x86 and !x86. So that bug
would have been avoided in the first place.
Thanks,
tglx
next prev parent reply other threads:[~2011-05-04 14:21 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-02 22:28 werner
2011-05-02 23:24 ` Linus Torvalds
[not found] ` <web-516990066@zbackend1.aha.ru>
2011-05-03 15:22 ` Linus Torvalds
2011-05-03 19:08 ` Ingo Molnar
2011-05-03 20:17 ` Linus Torvalds
2011-05-03 20:20 ` H. Peter Anvin
2011-05-03 20:50 ` Ingo Molnar
2011-05-03 21:45 ` Linus Torvalds
2011-05-03 22:01 ` H. Peter Anvin
2011-05-04 7:19 ` Borislav Petkov
2011-05-04 7:38 ` Ingo Molnar
2011-05-04 7:55 ` Borislav Petkov
2011-05-04 8:35 ` [block IO crash] " Ingo Molnar
2011-05-04 9:52 ` Thomas Gleixner
2011-05-04 10:19 ` Ingo Molnar
2011-05-04 10:25 ` Ingo Molnar
2011-05-04 10:33 ` Ingo Molnar
2011-05-04 12:37 ` Ingo Molnar
2011-05-04 12:36 ` Ingo Molnar
2011-05-04 11:11 ` Thomas Gleixner
2011-05-04 11:16 ` Pekka Enberg
2011-05-04 11:27 ` Tejun Heo
2011-05-04 12:51 ` Pekka Enberg
2011-05-04 12:57 ` Ingo Molnar
2011-05-04 13:02 ` Thomas Gleixner
2011-05-04 13:00 ` Thomas Gleixner
2011-05-04 13:20 ` Tejun Heo
2011-05-04 14:10 ` Thomas Gleixner
2011-05-04 14:14 ` Ingo Molnar
2011-05-04 14:36 ` [PATCH] slub: Fix the lockless code on 32-bit platforms with no 64-bit cmpxchg Ingo Molnar
2011-05-04 14:42 ` Christoph Lameter
2011-05-04 16:30 ` Ingo Molnar
2011-05-04 21:52 ` Ben Greear
2011-05-04 22:00 ` Linus Torvalds
2011-05-04 22:22 ` Ben Greear
2011-05-04 14:19 ` [block IO crash] Re: 2.6.39-rc5-git2 boot crashs Christoph Lameter
2011-05-04 14:25 ` Tejun Heo
2011-05-04 14:35 ` Christoph Lameter
2011-05-04 15:20 ` Ingo Molnar
2011-05-04 14:46 ` Thomas Gleixner
2011-05-04 15:00 ` Christoph Lameter
2011-05-04 15:13 ` Linus Torvalds
2011-05-04 15:28 ` Christoph Lameter
2011-05-04 15:37 ` Pekka Enberg
2011-05-04 15:53 ` Linus Torvalds
2011-05-04 18:20 ` Linus Torvalds
2011-05-04 18:49 ` Christoph Lameter
2011-05-04 19:07 ` Linus Torvalds
2011-05-04 19:30 ` Christoph Lameter
2011-05-04 19:38 ` Linus Torvalds
2011-05-04 20:04 ` Christoph Lameter
2011-05-04 20:21 ` Valdis.Kletnieks
2011-05-04 20:32 ` Christoph Lameter
2011-05-04 20:49 ` Ingo Molnar
2011-05-04 21:06 ` Linus Torvalds
2011-05-04 21:19 ` Linus Torvalds
2011-05-04 21:40 ` Thomas Gleixner
2011-05-05 9:54 ` Tejun Heo
2011-05-05 10:18 ` Ingo Molnar
2011-05-05 10:45 ` Thomas Gleixner
2011-05-05 18:20 ` Christoph Lameter
2011-05-05 19:13 ` Ingo Molnar
2011-05-05 19:53 ` werner
2011-05-05 20:09 ` Christoph Lameter
2011-05-05 21:12 ` werner
2011-05-05 22:27 ` Thomas Gleixner
[not found] ` <web-518008166@zbackend1.aha.ru>
[not found] ` <web-518059420@zbackend1.aha.ru>
[not found] ` <20110505060204.GA28015@elte.hu>
2011-05-05 6:46 ` werner
2011-05-04 15:37 ` [block IO crash] " Linus Torvalds
2011-05-04 16:08 ` Christoph Lameter
2011-05-04 16:50 ` Ingo Molnar
2011-05-04 17:12 ` Thomas Gleixner
2011-05-04 15:41 ` Pekka Enberg
2011-05-04 13:22 ` Ingo Molnar
2011-05-04 14:21 ` Christoph Lameter
2011-05-04 14:04 ` Christoph Lameter
2011-05-04 14:07 ` Tejun Heo
2011-05-04 14:21 ` Thomas Gleixner [this message]
2011-05-04 10:13 ` Ingo Molnar
2011-05-04 10:41 ` Ingo Molnar
2011-05-04 10:45 ` Ingo Molnar
2011-05-04 11:06 ` Ingo Molnar
2011-05-04 12:37 ` Ingo Molnar
2011-05-04 12:47 ` Ingo Molnar
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