[PATCH] x86_64: Handle empty node zero

From: Daniel Yeisley <dan.yeisley@unisys.com>

It is possible to boot a Unisys ES7000 with CPUs from multiple cells, and not
also include the memory from those cells.  This can create a scenario where
node 0 has cpus, but no associated memory.  The system will boot fine in a
configuration where node 0 has memory, but nodes 2 and 3 do not.

[AK: I rechecked the code and generic code seems to indeed handle that already.
Dan's original patch had a change for mm/slab.c that seems to be already in now.]

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/x86_64/kernel/pci-dma.c b/arch/x86_64/kernel/pci-dma.c
index af035ed..a9275c9 100644 (file)
--- a/arch/x86_64/kernel/pci-dma.c
+++ b/arch/x86_64/kernel/pci-dma.c
@@ -54,6 +54,10 @@ dma_alloc_pages(struct device *dev, gfp_t gfp, unsigned order)
        else
 #endif
                node = numa_node_id();
+
+       if (node < first_node(node_online_map))
+               node = first_node(node_online_map);
+
        page = alloc_pages_node(node, gfp, order);
        return page ? page_address(page) : NULL;
 }

diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index f0870be..655b919 100644 (file)
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -1051,7 +1051,7 @@ static void srat_detect_node(void)
           for now. */
        node = apicid_to_node[hard_smp_processor_id()];
        if (node == NUMA_NO_NODE)
-               node = 0;
+               node = first_node(node_online_map);
        numa_set_node(cpu, node);
 
        if (acpi_numa > 0)

diff --git a/arch/x86_64/mm/srat.c b/arch/x86_64/mm/srat.c
index e151353..474df22 100644 (file)
--- a/arch/x86_64/mm/srat.c
+++ b/arch/x86_64/mm/srat.c
@@ -399,8 +399,10 @@ int __init acpi_scan_nodes(unsigned long start, unsigned long end)
        /* First clean up the node list */
        for (i = 0; i < MAX_NUMNODES; i++) {
                cutoff_node(i, start, end);
-               if ((nodes[i].end - nodes[i].start) < NODE_MIN_SIZE)
+               if ((nodes[i].end - nodes[i].start) < NODE_MIN_SIZE) {
                        unparse_node(i);
+                       node_set_offline(i);
+               }
        }
 
        if (acpi_numa <= 0)