[Xen-changelog] [xen-unstable] x86/numa: Correct assumption that each NUMA node has memory

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
# Date 1342709211 -3600
# Node ID 8575d677b472c0849d05fc563157299c7455bd54
# Parent  75eb78d6cf545a79878e3cf42d0fdadf32c8d7ce
x86/numa: Correct assumption that each NUMA node has memory

It is now quite easy to buy servers with incorrectly populated DIMMs,
especially with AMD Magny-Cours and Interlagos systems which have two
NUMA nodes per socket.

Currently, Xen will assign all CPUs on nodes without memory to node 0,
which leads to interestingly wrong NUMA information, causing numa
aware functionality such as alloc_domheap_pages() to get things very
wrong.

This patch splits the current logic to accept NUMA nodes without
memory, which corrects the accounting of CPUs to online NUMA nodes.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Committed-by: Keir Fraser <keir@xxxxxxx>
---


diff -r 75eb78d6cf54 -r 8575d677b472 xen/arch/x86/setup.c
--- a/xen/arch/x86/setup.c      Thu Jul 19 15:46:02 2012 +0100
+++ b/xen/arch/x86/setup.c      Thu Jul 19 15:46:51 2012 +0100
@@ -195,8 +195,10 @@ void __devinit srat_detect_node(int cpu)
     u32 apicid = x86_cpu_to_apicid[cpu];
 
     node = apicid_to_node[apicid];
-    if ( node == NUMA_NO_NODE || !node_online(node) )
+    if ( node == NUMA_NO_NODE )
         node = 0;
+
+    node_set_online(node);
     numa_set_node(cpu, node);
 
     if ( opt_cpu_info && acpi_numa > 0 )
diff -r 75eb78d6cf54 -r 8575d677b472 xen/arch/x86/srat.c
--- a/xen/arch/x86/srat.c       Thu Jul 19 15:46:02 2012 +0100
+++ b/xen/arch/x86/srat.c       Thu Jul 19 15:46:51 2012 +0100
@@ -23,7 +23,8 @@
 
 static struct acpi_table_slit *__read_mostly acpi_slit;
 
-static nodemask_t nodes_parsed __initdata;
+static nodemask_t memory_nodes_parsed __initdata;
+static nodemask_t processor_nodes_parsed __initdata;
 static nodemask_t nodes_found __initdata;
 static struct node nodes[MAX_NUMNODES] __initdata;
 static u8 __read_mostly pxm2node[256] = { [0 ... 255] = NUMA_NO_NODE };
@@ -221,6 +222,7 @@ acpi_numa_processor_affinity_init(struct
                return;
        }
        apicid_to_node[pa->apic_id] = node;
+       node_set(node, processor_nodes_parsed);
        acpi_numa = 1;
        printk(KERN_INFO "SRAT: PXM %u -> APIC %u -> Node %u\n",
               pxm, pa->apic_id, node);
@@ -287,7 +289,7 @@ acpi_numa_memory_affinity_init(struct ac
                return;
        }
        nd = &nodes[node];
-       if (!node_test_and_set(node, nodes_parsed)) {
+       if (!node_test_and_set(node, memory_nodes_parsed)) {
                nd->start = start;
                nd->end = end;
        } else {
@@ -324,7 +326,7 @@ static int nodes_cover_memory(void)
 
                do {
                        found = 0;
-                       for_each_node_mask(j, nodes_parsed)
+                       for_each_node_mask(j, memory_nodes_parsed)
                                if (start < nodes[j].end
                                    && end > nodes[j].start) {
                                        if (start >= nodes[j].start) {
@@ -418,6 +420,7 @@ void __init srat_parse_regions(u64 addr)
 int __init acpi_scan_nodes(u64 start, u64 end)
 {
        int i;
+       nodemask_t all_nodes_parsed;
 
        /* First clean up the node list */
        for (i = 0; i < MAX_NUMNODES; i++)
@@ -441,17 +444,26 @@ int __init acpi_scan_nodes(u64 start, u6
                return -1;
        }
 
+       nodes_or(all_nodes_parsed, memory_nodes_parsed, processor_nodes_parsed);
+
        /* Finally register nodes */
-       for_each_node_mask(i, nodes_parsed)
+       for_each_node_mask(i, all_nodes_parsed)
        {
-               if ((nodes[i].end - nodes[i].start) < NODE_MIN_SIZE)
-                       continue;
+               u64 size = nodes[i].end - nodes[i].start;
+               if ( size == 0 )
+                       printk(KERN_WARNING "SRAT: Node %u has no memory. "
+                              "BIOS Bug or mis-configured hardware?\n", i);
+
+               else if (size < NODE_MIN_SIZE)
+                       printk(KERN_WARNING "SRAT: Node %u has only %"PRIu64
+                              " bytes of memory. BIOS Bug?\n", i, size);
+
                setup_node_bootmem(i, nodes[i].start, nodes[i].end);
        }
        for (i = 0; i < nr_cpu_ids; i++) {
                if (cpu_to_node[i] == NUMA_NO_NODE)
                        continue;
-               if (!node_isset(cpu_to_node[i], nodes_parsed))
+               if (!node_isset(cpu_to_node[i], processor_nodes_parsed))
                        numa_set_node(i, NUMA_NO_NODE);
        }
        numa_init_array();

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