[patch] x86: set hotpluggable nodes in nodes_possible_map

From: David Rientjes
Date: Wed Jan 20 2010 - 15:11:07 EST

On Thu, 21 Jan 2010, Haicheng Li wrote:

> let's add more changes to fix naming issue as well since it's too confusing
> for people to understand
> the code logic. how about below patch?

That should be a seperate change; there's a bugfix here (my patch) and
then a cleanup patch that you could make incrementally on mine. I don't
personally like the name "rest_nodes_parsed" since it's poor English, I
suggest renaming nodes_parsed to mem_nodes_parsed as I originally asked
and then cpu_nodes_parsed to acpi_nodes_parsed or something similiar.

Ingo, the following is my bugfix patch that addresses the issue at
http://patchwork.kernel.org/patch/69499. Haicheng, can we add your
tested-by line?

x86: set hotpluggable nodes in nodes_possible_map

nodes_possible_map does not currently include nodes that have SRAT
entries that are all ACPI_SRAT_MEM_HOT_PLUGGABLE since the bit is cleared
in nodes_parsed if it does not have an online address range.

Unequivocally setting the bit in nodes_parsed is insufficient since
existing code, such as acpi_get_nodes(), assumes all nodes in the map
have online address ranges. In fact, all code using nodes_parsed assumes
such nodes represent an address range of online memory.

nodes_possible_map is created by unioning nodes_parsed and
cpu_nodes_parsed; the former represents nodes with online memory and the
latter represents memoryless nodes. We now set the bit for hotpluggable
nodes in cpu_nodes_parsed so that it also gets set in nodes_possible_map.

Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
arch/x86/mm/srat_64.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/arch/x86/mm/srat_64.c b/arch/x86/mm/srat_64.c
--- a/arch/x86/mm/srat_64.c
+++ b/arch/x86/mm/srat_64.c
@@ -229,9 +229,11 @@ update_nodes_add(int node, unsigned long start, unsigned long end)
printk(KERN_ERR "SRAT: Hotplug zone not continuous. Partly ignored\n");

- if (changed)
+ if (changed) {
+ node_set(node, cpu_nodes_parsed);
printk(KERN_INFO "SRAT: hot plug zone found %Lx - %Lx\n",
nd->start, nd->end);
+ }

/* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
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