From 076422d2af7e3d8e72c6e70843f6ea377714b082 Mon Sep 17 00:00:00 2001
From: Amul Shah <amul.shah@unisys.com>
Date: Tue, 13 Feb 2007 13:26:19 +0100
Subject: [PATCH] x86-64: Allocate the NUMA hash function nodemap dynamically

Remove the statically allocated memory to NUMA node hash map in favor of a
dynamically allocated memory to node hash map (it is cache aligned).

This patch has the nice side effect in that it allows the hash map to grow
for systems with large amounts of memory (256GB - 1TB), but suffer from
having small PCI space tacked onto the boot node (which is somewhere
between 192MB to 512MB on the ES7000).

Signed-off-by: Amul Shah <amul.shah@unisys.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Rohit Seth <rohitseth@google.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
 arch/x86_64/mm/numa.c | 74 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 65 insertions(+), 9 deletions(-)

(limited to 'arch/x86_64/mm/numa.c')

diff --git a/arch/x86_64/mm/numa.c b/arch/x86_64/mm/numa.c
index 2ee2e003606..7d9c428f409 100644
--- a/arch/x86_64/mm/numa.c
+++ b/arch/x86_64/mm/numa.c
@@ -36,6 +36,8 @@ unsigned char apicid_to_node[MAX_LOCAL_APIC] __cpuinitdata = {
 cpumask_t node_to_cpumask[MAX_NUMNODES] __read_mostly;
 
 int numa_off __initdata;
+unsigned long __initdata nodemap_addr;
+unsigned long __initdata nodemap_size;
 
 
 /*
@@ -52,34 +54,87 @@ populate_memnodemap(const struct bootnode *nodes, int numnodes, int shift)
 	int res = -1;
 	unsigned long addr, end;
 
-	if (shift >= 64)
-		return -1;
-	memset(memnodemap, 0xff, sizeof(memnodemap));
+	memset(memnodemap, 0xff, memnodemapsize);
 	for (i = 0; i < numnodes; i++) {
 		addr = nodes[i].start;
 		end = nodes[i].end;
 		if (addr >= end)
 			continue;
-		if ((end >> shift) >= NODEMAPSIZE)
+		if ((end >> shift) >= memnodemapsize)
 			return 0;
 		do {
 			if (memnodemap[addr >> shift] != 0xff)
 				return -1;
 			memnodemap[addr >> shift] = i;
-                       addr += (1UL << shift);
+			addr += (1UL << shift);
 		} while (addr < end);
 		res = 1;
 	} 
 	return res;
 }
 
-int __init compute_hash_shift(struct bootnode *nodes, int numnodes)
+static int __init allocate_cachealigned_memnodemap(void)
+{
+	unsigned long pad, pad_addr;
+
+	memnodemap = memnode.embedded_map;
+	if (memnodemapsize <= 48) {
+		printk(KERN_DEBUG "NUMA: Allocated memnodemap from %lx - %lx\n",
+		       nodemap_addr, nodemap_addr + nodemap_size);
+		return 0;
+	}
+
+	pad = L1_CACHE_BYTES - 1;
+	pad_addr = 0x8000;
+	nodemap_size = pad + memnodemapsize;
+	nodemap_addr = find_e820_area(pad_addr, end_pfn<<PAGE_SHIFT,
+				      nodemap_size);
+	if (nodemap_addr == -1UL) {
+		printk(KERN_ERR
+		       "NUMA: Unable to allocate Memory to Node hash map\n");
+		nodemap_addr = nodemap_size = 0;
+		return -1;
+	}
+	pad_addr = (nodemap_addr + pad) & ~pad;
+	memnodemap = phys_to_virt(pad_addr);
+
+	printk(KERN_DEBUG "NUMA: Allocated memnodemap from %lx - %lx\n",
+	       nodemap_addr, nodemap_addr + nodemap_size);
+	return 0;
+}
+
+/*
+ * The LSB of all start and end addresses in the node map is the value of the
+ * maximum possible shift.
+ */
+static int __init
+extract_lsb_from_nodes (const struct bootnode *nodes, int numnodes)
 {
-	int shift = 20;
+	int i;
+	unsigned long start, end;
+	unsigned long bitfield = 0, memtop = 0;
 
-	while (populate_memnodemap(nodes, numnodes, shift + 1) >= 0)
-		shift++;
+	for (i = 0; i < numnodes; i++) {
+		start = nodes[i].start;
+		end = nodes[i].end;
+		if (start >= end)
+			continue;
+		bitfield |= start | end;
+		if (end > memtop)
+			memtop = end;
+	}
+	i = find_first_bit(&bitfield, sizeof(unsigned long)*8);
+	memnodemapsize = (memtop >> i)+1;
+	return i;
+}
+
+int __init compute_hash_shift(struct bootnode *nodes, int numnodes)
+{
+	int shift;
 
+	shift = extract_lsb_from_nodes(nodes, numnodes);
+	if (allocate_cachealigned_memnodemap())
+		return -1;
 	printk(KERN_DEBUG "NUMA: Using %d for the hash shift.\n",
 		shift);
 
@@ -290,6 +345,7 @@ void __init numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn)
 	       end_pfn << PAGE_SHIFT); 
 		/* setup dummy node covering all memory */ 
 	memnode_shift = 63; 
+	memnodemap = memnode.embedded_map;
 	memnodemap[0] = 0;
 	nodes_clear(node_online_map);
 	node_set_online(0);
-- 
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