Re: [PATCH 3/3] ppc64-specific memory notifier support

On Thu, 2008-02-28 at 18:39 -0600, Nathan Lynch wrote:

Michael Ellerman wrote:

quoted

On Thu, 2008-02-28 at 08:46 -0800, Badari Pulavarty wrote:

quoted

Hotplug memory notifier for ppc64. This gets invoked by writing
the device-node that needs to be removed to /proc/ppc64/ofdt.
We need to adjust the sections and remove sysfs entries by
calling __remove_pages(). Then call arch specific code to
get rid of htab mappings for the section of memory.

Signed-off-by: Badari Pulavarty <redacted>
---
 arch/powerpc/platforms/pseries/Makefile         |    1 
 arch/powerpc/platforms/pseries/hotplug-memory.c |   98 ++++++++++++++++++++++++
 2 files changed, 99 insertions(+)

Index: linux-2.6.25-rc2/arch/powerpc/platforms/pseries/hotplug-memory.c
===================================================================

--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.25-rc2/arch/powerpc/platforms/pseries/hotplug-memory.c	2008-02-28 08:20:14.000000000 -0800

quoted

+
+static struct notifier_block pseries_smp_nb = {
+	.notifier_call = pseries_memory_notifier,
+};
+
+static int __init pseries_memory_hotplug_init(void)
+{
+	if (firmware_has_feature(FW_FEATURE_LPAR))
+		pSeries_reconfig_notifier_register(&pseries_smp_nb);
+
+	return 0;
+}
+arch_initcall(pseries_memory_hotplug_init);

This is going to fire on non-pseries LPAR platforms, like iSeries and
PS3. Which is not what you want I think.

Well, the notifier will be registered, yes, but it will never be
called because that path is reachable only from a write to
/proc/ppc64/ofdt, which is not created on non-pseries.

Sure. Still seems better not to register it in the first place.

Maybe it should be

machine_device_initcall(pseries, pseries_memory_hotplug_init);

I think so.

(and pseries_cpu_hotplug_init in hotplug-cpu.c should be changed to
machine_arch_initcall)

Yeah I noticed that was not guarded as well, and I think I'm culpable
for that :)

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

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we borrow it from our children. - S.M.A.R.T Person