[Xen-devel] [PATCH] numa: fix problems with memory-less nodes

[Andre Przywara <andre.przywara@xxxxxxx>]

Hi,

If we decided to not report memory-less nodes in physinfo we should also 
skip them in the node_to_{cpu,memory,dma32_mem} Python lists. Currently 
Xen will not start guests on machines with memory-less nodes which are 
not the last ones. On an 8-node machine with empty nodes 4 and 5 "xm 
info" was reporting wrongly, also the node assignment algorithm crashed 
with a division by zero error.
The attached patch fixes this by skipping empty nodes in the enumeration 
of resources.
Regards,
Andre.


Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>

--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448 3567 12
----to satisfy European Law for business letters:
Advanced Micro Devices GmbH
Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen
Geschaeftsfuehrer: Andrew Bowd; Thomas M. McCoy; Giuliano Meroni
Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen
Registergericht Muenchen, HRB Nr. 43632

diff -r 0e3910f1de64 tools/python/xen/lowlevel/xc/xc.c
--- a/tools/python/xen/lowlevel/xc/xc.c Tue Jan 12 07:17:40 2010 +0000
+++ b/tools/python/xen/lowlevel/xc/xc.c Tue Jan 12 17:28:55 2010 +0100
@@ -1129,20 +1129,23 @@
             Py_DECREF(pyint);
             node_exists = 1;
         }
-        PyList_Append(node_to_cpu_obj, cpus); 
+        if (node_exists)
+            PyList_Append(node_to_cpu_obj, cpus); 
         Py_DECREF(cpus);
 
         /* Memory. */
         xc_availheap(self->xc_handle, 0, 0, i, &free_heap);
         node_exists = node_exists || (free_heap != 0);
         pyint = PyInt_FromLong(free_heap / 1024);
-        PyList_Append(node_to_memory_obj, pyint);
+        if (node_exists)
+            PyList_Append(node_to_memory_obj, pyint);
         Py_DECREF(pyint);
 
         /* DMA memory. */
         xc_availheap(self->xc_handle, 0, 32, i, &free_heap);
         pyint = PyInt_FromLong(free_heap / 1024);
-        PyList_Append(node_to_dma32_mem_obj, pyint);
+        if (node_exists)
+            PyList_Append(node_to_dma32_mem_obj, pyint);
         Py_DECREF(pyint);
 
         if ( node_exists )

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