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From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andreas Schwab <schwab@suse.de>,
	Giuliano Pochini <pochini@denise.shiny.it>,
	linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org,
	Suresh Siddha <suresh.b.siddha@intel.com>
Subject: Re: /sys/devices/system/cpu/cpuX/online are missing
Date: Tue, 13 Mar 2007 09:40:39 +0000	[thread overview]
Message-ID: <20070313094038.GA20518@flint.arm.linux.org.uk> (raw)
In-Reply-To: <20070313091159.GB9890@osiris.boeblingen.de.ibm.com>

On Tue, Mar 13, 2007 at 10:11:59AM +0100, Heiko Carstens wrote:
> On Tue, Mar 13, 2007 at 10:03:50AM +0100, Heiko Carstens wrote:
> > On Tue, Mar 13, 2007 at 01:39:25AM +0100, Andreas Schwab wrote:
> > > Giuliano Pochini <pochini@denise.shiny.it> writes:
> > > 
> > > > I had a look at arch/powerpc/kernel/smp.c but I'm not familiar at all with 
> > > > those parts of the kernel.
> > > 
> > > See arch/powerpc/kernel/sysfs.c:topology_init.  I don't think there is
> > > anything to do here.  You probably don't have CONFIG_HOTPLUG_CPU enabled.
> > 
> > I was referring to arch/ppc not arch/powerpc. But it seems that arch/ppc
> > doesn't support cpu hotplug anyway. So I guess it's indeed just a missing
> > config option.
> > 
> > Grepping a bit further shows that arm suffered by the change that inverted
> > the logic if the 'online' attribute for cpus should appear. Since arm
> > supports cpu hotplug but the patch left arm out, it doesn't work there
> > anymore (cc'ing arm people: changeset 72486f1f8f0a2bc828b9d30cf4690cf2dd6807fc
> > is most probably disabling cpu hotplug support on arm like it did on s390).
> 
> Should have cc'ed Suresh Siddha who caused the breakage ;)

Welcome to why cleanups are bad news. ;(  Yes, ARM also needs to be fixed
and I'd ask that in future people doing cleanups in core code take a little
more time to review the code before submitting patches *AND* give heads-up
to *EVERYONE* who might be affected by the change.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:

  reply	other threads:[~2007-03-13  9:40 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-11 21:26 /sys/devices/system/cpu/cpuX/online are missing Giuliano Pochini
2007-03-11 21:42 ` Lee Revell
2007-03-12  8:58 ` Heiko Carstens
2007-03-12 22:48   ` Giuliano Pochini
2007-03-13  0:39     ` Andreas Schwab
2007-03-13  9:03       ` Heiko Carstens
2007-03-13  9:11         ` Heiko Carstens
2007-03-13  9:40           ` Russell King [this message]
2007-03-13  9:56             ` Russell King
2007-03-14 23:30               ` Giuliano Pochini
2007-03-13  9:44         ` Andreas Schwab

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