x86_64: disable srat when numa emulation succeeds

When NUMA emulation succeeds, acpi_numa needs to be set to -1 so that
srat_disabled() will always return true.  We won't be calling
acpi_scan_nodes() or registering the true nodes we've found.

[hugh@veritas.com: Fix x86_64 CONFIG_NUMA_EMU build: acpi_numa needs CONFIG_ACPI_NUMA]
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86_64/mm/numa.c b/arch/x86_64/mm/numa.c
index 0191b1c..6da2355 100644 (file)
--- a/arch/x86_64/mm/numa.c
+++ b/arch/x86_64/mm/numa.c
@@ -473,9 +473,13 @@ out:
 
        /*
         * We need to vacate all active ranges that may have been registered by
-        * SRAT.
+        * SRAT and set acpi_numa to -1 so that srat_disabled() always returns
+        * true.  NUMA emulation has succeeded so we will not scan ACPI nodes.
         */
        remove_all_active_ranges();
+#ifdef CONFIG_ACPI_NUMA
+       acpi_numa = -1;
+#endif
        for_each_node_mask(i, node_possible_map) {
                e820_register_active_regions(i, nodes[i].start >> PAGE_SHIFT,
                                                nodes[i].end >> PAGE_SHIFT);