Re: SLUB: simplify re on_each_cpu()

From: Robin Holt
Date: Thu Jul 17 2008 - 08:39:22 EST

On Thu, Jul 17, 2008 at 03:26:46PM +0300, Pekka Enberg wrote:
> Hi Robin,
> On Wed, Jul 16, 2008 at 09:29:02PM +0400, Alexey Dobriyan wrote:
> >> on_each_cpu() expands to function call on UP, too.
> On Thu, Jul 17, 2008 at 2:38 PM, Robin Holt <holt@xxxxxxx> wrote:
> > It looks to me like on_each_cpu is a #define for !SMP. Are you certain
> > of the need for this change? Are you looking at a different tree than
> > Linus'?
> I think it's actually you who is looking at an older tree.

I did a git-checkout of
which got me commit id 33af79d12e0fa25545d49e86afc67ea8ad5f2f40
and looked at include/linux/smp.h line 123. It has:

#define on_each_cpu(func,info,wait) \
({ \
local_irq_disable(); \
func(info); \
local_irq_enable(); \
0; \

This is the !CONFIG_SMP case (line 111). When I look at
kernel/softirq.c, I notice immediately prior to the comment the #ifdef

They appear equivalent. What am I missing?

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