File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/ia64/mm/numa.c b/arch/ia64/mm/numa.c
new file mode 100644
index 0000000..aa19b7a
--- /dev/null
+++ b/arch/ia64/mm/numa.c
@@ -0,0 +1,105 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * This file contains NUMA specific variables and functions which can
+ * be split away from DISCONTIGMEM and are used on NUMA machines with
+ * contiguous memory.
+ * 
+ *                         2002/08/07 Erich Focht <efocht@ess.nec.de>
+ */
+
+#include <linux/cpu.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/node.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/module.h>
+#include <asm/mmzone.h>
+#include <asm/numa.h>
+
+
+/*
+ * The following structures are usually initialized by ACPI or
+ * similar mechanisms and describe the NUMA characteristics of the machine.
+ */
+int num_node_memblks;
+struct node_memblk_s node_memblk[NR_NODE_MEMBLKS];
+struct node_cpuid_s node_cpuid[NR_CPUS] =
+	{ [0 ... NR_CPUS-1] = { .phys_id = 0, .nid = NUMA_NO_NODE } };
+
+/*
+ * This is a matrix with "distances" between nodes, they should be
+ * proportional to the memory access latency ratios.
+ */
+u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES];
+
+/* Identify which cnode a physical address resides on */
+int
+paddr_to_nid(unsigned long paddr)
+{
+	int	i;
+
+	for (i = 0; i < num_node_memblks; i++)
+		if (paddr >= node_memblk[i].start_paddr &&
+		    paddr < node_memblk[i].start_paddr + node_memblk[i].size)
+			break;
+
+	return (i < num_node_memblks) ? node_memblk[i].nid : (num_node_memblks ? -1 : 0);
+}
+
+#if defined(CONFIG_SPARSEMEM) && defined(CONFIG_NUMA)
+/*
+ * Because of holes evaluate on section limits.
+ * If the section of memory exists, then return the node where the section
+ * resides.  Otherwise return node 0 as the default.  This is used by
+ * SPARSEMEM to allocate the SPARSEMEM sectionmap on the NUMA node where
+ * the section resides.
+ */
+int __meminit __early_pfn_to_nid(unsigned long pfn,
+					struct mminit_pfnnid_cache *state)
+{
+	int i, section = pfn >> PFN_SECTION_SHIFT, ssec, esec;
+
+	if (section >= state->last_start && section < state->last_end)
+		return state->last_nid;
+
+	for (i = 0; i < num_node_memblks; i++) {
+		ssec = node_memblk[i].start_paddr >> PA_SECTION_SHIFT;
+		esec = (node_memblk[i].start_paddr + node_memblk[i].size +
+			((1L << PA_SECTION_SHIFT) - 1)) >> PA_SECTION_SHIFT;
+		if (section >= ssec && section < esec) {
+			state->last_start = ssec;
+			state->last_end = esec;
+			state->last_nid = node_memblk[i].nid;
+			return node_memblk[i].nid;
+		}
+	}
+
+	return -1;
+}
+
+void numa_clear_node(int cpu)
+{
+	unmap_cpu_from_node(cpu, NUMA_NO_NODE);
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+/*
+ *  SRAT information is stored in node_memblk[], then we can use SRAT
+ *  information at memory-hot-add if necessary.
+ */
+
+int memory_add_physaddr_to_nid(u64 addr)
+{
+	int nid = paddr_to_nid(addr);
+	if (nid < 0)
+		return 0;
+	return nid;
+}
+
+EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
+#endif
+#endif