[PATCH] powerpc: numa placement for dynamically added memory

This places dynamically added memory within the appropriate
numa node.  A new routine hot_add_scn_to_nid() replicates most of
the memory scanning code in parse_numa_properties().

Signed-off-by: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 65 insertions, 11 deletions

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index ed6ed2e30dac..5e5bff5616a8 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -114,18 +114,17 @@ void online_page(struct page *page)
         num_physpages++;
 }
 
-/*
- * This works only for the non-NUMA case.  Later, we'll need a lookup
- * to convert from real physical addresses to nid, that doesn't use
- * pfn_to_nid().
- */
 int __devinit add_memory(u64 start, u64 size)
 {
-        struct pglist_data *pgdata = NODE_DATA(0);
+        struct pglist_data *pgdata;
         struct zone *zone;
+        int nid;
         unsigned long start_pfn = start >> PAGE_SHIFT;
         unsigned long nr_pages = size >> PAGE_SHIFT;
 
+        nid = hot_add_scn_to_nid(start);
+        pgdata = NODE_DATA(nid);
+
         start += KERNELBASE;
         create_section_mapping(start, start + size);
 
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index e812d3d0d6ae..40c99deb691b 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -37,6 +37,7 @@ EXPORT_SYMBOL(node_data);
 
 static bootmem_data_t __initdata plat_node_bdata[MAX_NUMNODES];
 static int min_common_depth;
+static int n_mem_addr_cells, n_mem_size_cells;
 
 /*
  * We need somewhere to store start/end/node for each region until we have
@@ -267,7 +268,7 @@ static void __init get_n_mem_cells(int *n_addr_cells, int *n_size_cells)
         of_node_put(memory);
 }
 
-static unsigned long __init read_n_cells(int n, unsigned int **buf)
+static unsigned long __devinit read_n_cells(int n, unsigned int **buf)
 {
         unsigned long result = 0;
 
@@ -374,7 +375,6 @@ static int __init parse_numa_properties(void)
 {
         struct device_node *cpu = NULL;
         struct device_node *memory = NULL;
-        int n_addr_cells, n_size_cells;
         int max_domain;
         unsigned long i;
 
@@ -413,7 +413,7 @@ static int __init parse_numa_properties(void)
                 }
         }
 
-        get_n_mem_cells(&n_addr_cells, &n_size_cells);
+        get_n_mem_cells(&n_mem_addr_cells, &n_mem_size_cells);
         memory = NULL;
         while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
                 unsigned long start;
@@ -430,8 +430,8 @@ static int __init parse_numa_properties(void)
                 ranges = memory->n_addrs;
 new_range:
                 /* these are order-sensitive, and modify the buffer pointer */
-                start = read_n_cells(n_addr_cells, &memcell_buf);
-                size = read_n_cells(n_size_cells, &memcell_buf);
+                start = read_n_cells(n_mem_addr_cells, &memcell_buf);
+                size = read_n_cells(n_mem_size_cells, &memcell_buf);
 
                 numa_domain = of_node_numa_domain(memory);
 
@@ -717,3 +717,50 @@ static int __init early_numa(char *p)
         return 0;
 }
 early_param("numa", early_numa);
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+/*
+ * Find the node associated with a hot added memory section.  Section
+ * corresponds to a SPARSEMEM section, not an LMB.  It is assumed that
+ * sections are fully contained within a single LMB.
+ */
+int hot_add_scn_to_nid(unsigned long scn_addr)
+{
+        struct device_node *memory = NULL;
+
+        if (!numa_enabled || (min_common_depth < 0))
+                return 0;
+
+        while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
+                unsigned long start, size;
+                int numa_domain, ranges;
+                unsigned int *memcell_buf;
+                unsigned int len;
+
+                memcell_buf = (unsigned int *)get_property(memory, "reg", &len);
+                if (!memcell_buf || len <= 0)
+                        continue;
+
+                ranges = memory->n_addrs;       /* ranges in cell */
+ha_new_range:
+                start = read_n_cells(n_mem_addr_cells, &memcell_buf);
+                size = read_n_cells(n_mem_size_cells, &memcell_buf);
+                numa_domain = of_node_numa_domain(memory);
+
+                /* Domains not present at boot default to 0 */
+                if (!node_online(numa_domain))
+                        numa_domain = any_online_node(NODE_MASK_ALL);
+
+                if ((scn_addr >= start) && (scn_addr < (start + size))) {
+                        of_node_put(memory);
+                        return numa_domain;
+                }
+
+                if (--ranges)           /* process all ranges in cell */
+                        goto ha_new_range;
+        }
+
+        BUG();  /* section address should be found above */
+        return 0;
+}
+#endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/include/asm-powerpc/sparsemem.h b/include/asm-powerpc/sparsemem.h
index ba1b34fdb967..c3f17d442f7d 100644
--- a/include/asm-powerpc/sparsemem.h
+++ b/include/asm-powerpc/sparsemem.h
@@ -13,6 +13,14 @@
 
 #ifdef CONFIG_MEMORY_HOTPLUG
 extern void create_section_mapping(unsigned long start, unsigned long end);
+#ifdef CONFIG_NUMA
+extern int hot_add_scn_to_nid(unsigned long scn_addr);
+#else
+static inline int hot_add_scn_to_nid(unsigned long scn_addr)
+{
+        return 0;
+}
+#endif /* CONFIG_NUMA */
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 #endif /* CONFIG_SPARSEMEM */