Re: [ANNOUNCE] [PATCH] Node Hotplug Support

[Keiichiro Tokunaga]

On Wed, 12 May 2004 19:04:47 -0700
Dave Hansen <haveblue@xxxxxxxxxx> wrote:

> On Wed, 2004-05-12 at 18:27, Keiichiro Tokunaga wrote:
> > On Sun, 09 May 2004 22:45:42 -0700
> > Dave Hansen <haveblue@xxxxxxxxxx> wrote:
> > 
> > > On Sun, 2004-05-09 at 18:47, Keiichiro Tokunaga wrote:
> > > > There is no NUMA support in the current code yet.  I'll post a
> > > > rough patch to show my idea soon.  I'm thinking to regard a
> > > > container device that has PXM as a NUMA node so far.
> > > 
> > > Don't you think it would be a good idea to work with some of the current
> > > code, instead of trying to wrap around it?  
> > 
> > Are you saying that LHNS should use the current NUMA code
> > (or coming code in the future) to support NUMA node hotplug?
> 
> Absolutely.  Why do we need wrappers when we can offline entire nodes
> with 6-line shell scripts?  The CPU hotplug interfaces are here today
> and the memory stuff will be here soon.  Perhaps you could help with the
> NUMA part.
> 
> #!/bin/sh
> NODENUM=$1
> NODEDIR=/sys/devices/system/node/node${NODENUM}
> for i in $NODEDIR/cpu* $NODEDIR/memory*; do
> 	echo 0 > $i/control/online
> fi
> echo 0 > $NODEDIR/control/online
> 
> We don't currently export bus to node mappings in sysfs, but we have
> them in the kernel, so that won't be too hard to export as well.  

LHNS is focusing on "container device hotplug". Container device
could contain CPUs, memory, and/or IO devices.  Container device
could contain only IO devices.  In this case, LHNS cannot use
$NODED/control/online (NUMA stuff) for the container device.

By the way, what happen when you issue
"echo 0 > $NODEDIR/control/online"?  Can you detach it
from the system after echo-ing?

Thanks,
Kei
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