x86/numa: Allow specifying node_distance() for numa=fake

Allows emulating more interesting NUMA configurations like a quad
socket AMD Magny-Cour:

 "numa=fake=8:10,16,16,22,16,22,16,22,
              16,10,22,16,22,16,22,16,
              16,22,10,16,16,22,16,22,
              22,16,16,10,22,16,22,16,
              16,22,16,22,10,16,16,22,
              22,16,22,16,16,10,22,16,
              16,22,16,22,16,22,10,16,
              22,16,22,16,22,16,16,10"

Which has a non-fully-connected topology.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/n/tip-e1136ef7kdffj7yf9tjhydln@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/arch/x86/mm/numa_emulation.c b/arch/x86/mm/numa_emulation.c
index 53489ff6bf82..871dd8868170 100644
--- a/arch/x86/mm/numa_emulation.c
+++ b/arch/x86/mm/numa_emulation.c
@@ -339,9 +339,11 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
         } else {
                 unsigned long n;
 
-                n = simple_strtoul(emu_cmdline, NULL, 0);
+                n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
                 ret = split_nodes_interleave(&ei, &pi, 0, max_addr, n);
         }
+        if (*emu_cmdline == ':')
+                emu_cmdline++;
 
         if (ret < 0)
                 goto no_emu;
@@ -418,7 +420,9 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
                         int physj = emu_nid_to_phys[j];
                         int dist;
 
-                        if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
+                        if (get_option(&emu_cmdline, &dist) == 2)
+                                ;
+                        else if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
                                 dist = physi == physj ?
                                         LOCAL_DISTANCE : REMOTE_DISTANCE;
                         else