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Message-ID: <alpine.DEB.2.00.1105040934570.5495@router.home>
Date: Wed, 4 May 2011 09:35:30 -0500 (CDT)
From: Christoph Lameter <cl@...ux.com>
To: Tejun Heo <tj@...nel.org>
cc: Thomas Gleixner <tglx@...utronix.de>,
Pekka Enberg <penberg@...nel.org>, Ingo Molnar <mingo@...e.hu>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Jens Axboe <axboe@...nel.dk>,
Andrew Morton <akpm@...ux-foundation.org>,
werner <w.landgraf@...ru>, "H. Peter Anvin" <hpa@...or.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [block IO crash] Re: 2.6.39-rc5-git2 boot crashs
On Wed, 4 May 2011, Tejun Heo wrote:
> The cmpxchg_double optimization made the fast path go quite faster
> when CPU supports it but it may as well slow things down considerably
> if CPU doesn't, due to extra irq on/off's. Anyways, here's hoping
> that the slow down is acceptable compared to the base code without
> cmpxchg_double and the ugliness can be removed.
I think we are all in agreement. First path to fix the percpu macros:
Subject: percpu: Fix irqsafe_cpu_cmpxchg_double
The function in the macro was not updated when the function was given a bool return value.
Signed-off-by: Christoph Lameter <cl@...ux.com>
---
include/linux/percpu.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6/include/linux/percpu.h
===================================================================
--- linux-2.6.orig/include/linux/percpu.h 2011-05-04 09:33:08.000000000 -0500
+++ linux-2.6/include/linux/percpu.h 2011-05-04 09:33:39.000000000 -0500
@@ -948,7 +948,7 @@ do { \
irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# define irqsafe_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
- __pcpu_double_call_return_int(irqsafe_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
+ __pcpu_double_call_return_bool(irqsafe_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
#endif
#endif /* __LINUX_PERCPU_H */
--
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