3 files changed, 161 insertions, 110 deletions

diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index 85f51e5a749f..7500aad95f3c 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -149,7 +149,13 @@ NUMA
 
   numa=noacpi   Don't parse the SRAT table for NUMA setup
 
-  numa=fake=X   Fake X nodes and ignore NUMA setup of the actual machine.
+  numa=fake=CMDLINE
+                If a number, fakes CMDLINE nodes and ignores NUMA setup of the
+                actual machine.  Otherwise, system memory is configured
+                depending on the sizes and coefficients listed.  For example:
+                        numa=fake=2*512,1024,4*256
+                gives two 512M nodes, a 1024M node, and four 256M nodes.  The
+                remaining system RAM is allocated to an additional node.
 
   numa=hotadd=percent
                 Only allow hotadd memory to preallocate page structures upto
diff --git a/arch/x86_64/mm/numa.c b/arch/x86_64/mm/numa.c
index 41b8fb069924..c55936bc6be6 100644
--- a/arch/x86_64/mm/numa.c
+++ b/arch/x86_64/mm/numa.c
@@ -273,125 +273,172 @@ void __init numa_init_array(void)
 
 #ifdef CONFIG_NUMA_EMU
 /* Numa emulation */
-int numa_fake __initdata = 0;
+#define E820_ADDR_HOLE_SIZE(start, end)                                 \
+        (e820_hole_size((start) >> PAGE_SHIFT, (end) >> PAGE_SHIFT) <<  \
+        PAGE_SHIFT)
+char *cmdline __initdata;
 
 /*
- * This function is used to find out if the start and end correspond to
- * different zones.
+ * Setups up nid to range from addr to addr + size.  If the end boundary is
+ * greater than max_addr, then max_addr is used instead.  The return value is 0
+ * if there is additional memory left for allocation past addr and -1 otherwise.
+ * addr is adjusted to be at the end of the node.
  */
-int zone_cross_over(unsigned long start, unsigned long end)
+static int __init setup_node_range(int nid, struct bootnode *nodes, u64 *addr,
+                                   u64 size, u64 max_addr)
 {
-        if ((start < (MAX_DMA32_PFN << PAGE_SHIFT)) &&
-                        (end >= (MAX_DMA32_PFN << PAGE_SHIFT)))
-                return 1;
-        return 0;
+        int ret = 0;
+        nodes[nid].start = *addr;
+        *addr += size;
+        if (*addr >= max_addr) {
+                *addr = max_addr;
+                ret = -1;
+        }
+        nodes[nid].end = *addr;
+        node_set_online(nid);
+        printk(KERN_INFO "Faking node %d at %016Lx-%016Lx (%LuMB)\n", nid,
+               nodes[nid].start, nodes[nid].end,
+               (nodes[nid].end - nodes[nid].start) >> 20);
+        return ret;
 }
 
-static int __init numa_emulation(unsigned long start_pfn, unsigned long end_pfn)
+/*
+ * Splits num_nodes nodes up equally starting at node_start.  The return value
+ * is the number of nodes split up and addr is adjusted to be at the end of the
+ * last node allocated.
+ */
+static int __init split_nodes_equally(struct bootnode *nodes, u64 *addr,
+                                      u64 max_addr, int node_start,
+                                      int num_nodes)
 {
-        int i, big;
-        struct bootnode nodes[MAX_NUMNODES];
-        unsigned long sz, old_sz;
-        unsigned long hole_size;
-        unsigned long start, end;
-        unsigned long max_addr = (end_pfn << PAGE_SHIFT);
-
-        start = (start_pfn << PAGE_SHIFT);
-        hole_size = e820_hole_size(start, max_addr);
-        sz = (max_addr - start - hole_size) / numa_fake;
-
-        /* Kludge needed for the hash function */
-
-        old_sz = sz;
-        /*
-         * Round down to the nearest FAKE_NODE_MIN_SIZE.
-         */
-        sz &= FAKE_NODE_MIN_HASH_MASK;
+        unsigned int big;
+        u64 size;
+        int i;
 
+        if (num_nodes <= 0)
+                return -1;
+        if (num_nodes > MAX_NUMNODES)
+                num_nodes = MAX_NUMNODES;
+        size = (max_addr - *addr - E820_ADDR_HOLE_SIZE(*addr, max_addr)) /
+               num_nodes;
         /*
-         * We ensure that each node is at least 64MB big.  Smaller than this
-         * size can cause VM hiccups.
+         * Calculate the number of big nodes that can be allocated as a result
+         * of consolidating the leftovers.
          */
-        if (sz == 0) {
-                printk(KERN_INFO "Not enough memory for %d nodes.  Reducing "
-                                "the number of nodes\n", numa_fake);
-                numa_fake = (max_addr - start - hole_size) / FAKE_NODE_MIN_SIZE;
-                printk(KERN_INFO "Number of fake nodes will be = %d\n",
-                                numa_fake);
-                sz = FAKE_NODE_MIN_SIZE;
+        big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * num_nodes) /
+              FAKE_NODE_MIN_SIZE;
+
+        /* Round down to nearest FAKE_NODE_MIN_SIZE. */
+        size &= FAKE_NODE_MIN_HASH_MASK;
+        if (!size) {
+                printk(KERN_ERR "Not enough memory for each node.  "
+                       "NUMA emulation disabled.\n");
+                return -1;
         }
-        /*
-         * Find out how many nodes can get an extra NODE_MIN_SIZE granule.
-         * This logic ensures the extra memory gets distributed among as many
-         * nodes as possible (as compared to one single node getting all that
-         * extra memory.
-         */
-        big = ((old_sz - sz) * numa_fake) / FAKE_NODE_MIN_SIZE;
-        printk(KERN_INFO "Fake node Size: %luMB hole_size: %luMB big nodes: "
-                        "%d\n",
-                        (sz >> 20), (hole_size >> 20), big);
-        memset(&nodes,0,sizeof(nodes));
-        end = start;
-        for (i = 0; i < numa_fake; i++) {
-                /*
-                 * In case we are not able to allocate enough memory for all
-                 * the nodes, we reduce the number of fake nodes.
-                 */
-                if (end >= max_addr) {
-                        numa_fake = i - 1;
-                        break;
-                }
-                start = nodes[i].start = end;
-                /*
-                 * Final node can have all the remaining memory.
-                 */
-                if (i == numa_fake-1)
-                        sz = max_addr - start;
-                end = nodes[i].start + sz;
-                /*
-                 * Fir "big" number of nodes get extra granule.
-                 */
+
+        for (i = node_start; i < num_nodes + node_start; i++) {
+                u64 end = *addr + size;
                 if (i < big)
                         end += FAKE_NODE_MIN_SIZE;
                 /*
-                 * Iterate over the range to ensure that this node gets at
-                 * least sz amount of RAM (excluding holes)
+                 * The final node can have the remaining system RAM.  Other
+                 * nodes receive roughly the same amount of available pages.
                  */
-                while ((end - start - e820_hole_size(start, end)) < sz) {
-                        end += FAKE_NODE_MIN_SIZE;
-                        if (end >= max_addr)
-                                break;
+                if (i == num_nodes + node_start - 1)
+                        end = max_addr;
+                else
+                        while (end - *addr - E820_ADDR_HOLE_SIZE(*addr, end) <
+                               size) {
+                                end += FAKE_NODE_MIN_SIZE;
+                                if (end > max_addr) {
+                                        end = max_addr;
+                                        break;
+                                }
+                        }
+                if (setup_node_range(i, nodes, addr, end - *addr, max_addr) < 0)
+                        break;
+        }
+        return i - node_start + 1;
+}
+
+/*
+ * Sets up the system RAM area from start_pfn to end_pfn according to the
+ * numa=fake command-line option.
+ */
+static int __init numa_emulation(unsigned long start_pfn, unsigned long end_pfn)
+{
+        struct bootnode nodes[MAX_NUMNODES];
+        u64 addr = start_pfn << PAGE_SHIFT;
+        u64 max_addr = end_pfn << PAGE_SHIFT;
+        unsigned int coeff;
+        unsigned int num = 0;
+        int num_nodes = 0;
+        u64 size;
+        int i;
+
+        memset(&nodes, 0, sizeof(nodes));
+        /*
+         * If the numa=fake command-line is just a single number N, split the
+         * system RAM into N fake nodes.
+         */
+        if (!strchr(cmdline, '*') && !strchr(cmdline, ',')) {
+                num_nodes = split_nodes_equally(nodes, &addr, max_addr, 0,
+                                                simple_strtol(cmdline, NULL, 0));
+                if (num_nodes < 0)
+                        return num_nodes;
+                goto out;
+        }
+
+        /* Parse the command line. */
+        for (coeff = 1; ; cmdline++) {
+                if (*cmdline && isdigit(*cmdline)) {
+                        num = num * 10 + *cmdline - '0';
+                        continue;
                 }
-                /*
-                 * Look at the next node to make sure there is some real memory
-                 * to map.  Bad things happen when the only memory present
-                 * in a zone on a fake node is IO hole.
-                 */
-                while (e820_hole_size(end, end + FAKE_NODE_MIN_SIZE) > 0) {
-                        if (zone_cross_over(start, end + sz)) {
-                                end = (MAX_DMA32_PFN << PAGE_SHIFT);
-                                break;
+                if (*cmdline == '*')
+                        coeff = num;
+                if (!*cmdline || *cmdline == ',') {
+                        /*
+                         * Round down to the nearest FAKE_NODE_MIN_SIZE.
+                         * Command-line coefficients are in megabytes.
+                         */
+                        size = ((u64)num << 20) & FAKE_NODE_MIN_HASH_MASK;
+                        if (size) {
+                                for (i = 0; i < coeff; i++, num_nodes++)
+                                        if (setup_node_range(num_nodes, nodes,
+                                                &addr, size, max_addr) < 0)
+                                                goto done;
+                                coeff = 1;
                         }
-                        if (end >= max_addr)
-                                break;
-                        end += FAKE_NODE_MIN_SIZE;
                 }
-                if (end > max_addr)
-                        end = max_addr;
-                nodes[i].end = end;
-                printk(KERN_INFO "Faking node %d at %016Lx-%016Lx (%LuMB)\n",
-                       i,
-                       nodes[i].start, nodes[i].end,
-                       (nodes[i].end - nodes[i].start) >> 20);
-                node_set_online(i);
-        }
-        memnode_shift = compute_hash_shift(nodes, numa_fake);
-        if (memnode_shift < 0) {
-                memnode_shift = 0;
-                printk(KERN_ERR "No NUMA hash function found. Emulation disabled.\n");
-                return -1;
-        }
-        for_each_online_node(i) {
+                if (!*cmdline)
+                        break;
+                num = 0;
+        }
+done:
+        if (!num_nodes)
+                return -1;
+        /* Fill remainder of system RAM with a final node, if appropriate. */
+        if (addr < max_addr) {
+                setup_node_range(num_nodes, nodes, &addr, max_addr - addr,
+                                 max_addr);
+                num_nodes++;
+        }
+out:
+        memnode_shift = compute_hash_shift(nodes, num_nodes);
+        if (memnode_shift < 0) {
+                memnode_shift = 0;
+                printk(KERN_ERR "No NUMA hash function found.  NUMA emulation "
+                       "disabled.\n");
+                return -1;
+        }
+
+        /*
+         * We need to vacate all active ranges that may have been registered by
+         * SRAT.
+         */
+        remove_all_active_ranges();
+        for_each_online_node(i) {
                 e820_register_active_regions(i, nodes[i].start >> PAGE_SHIFT,
                                                 nodes[i].end >> PAGE_SHIFT);
                 setup_node_bootmem(i, nodes[i].start, nodes[i].end);
@@ -399,14 +446,15 @@ static int __init numa_emulation(unsigned long start_pfn, unsigned long end_pfn)
         numa_init_array();
         return 0;
 }
-#endif
+#undef E820_ADDR_HOLE_SIZE
+#endif /* CONFIG_NUMA_EMU */
 
 void __init numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn)
 { 
         int i;
 
 #ifdef CONFIG_NUMA_EMU
-        if (numa_fake && !numa_emulation(start_pfn, end_pfn))
+        if (cmdline && !numa_emulation(start_pfn, end_pfn))
                 return;
 #endif
 
@@ -486,11 +534,8 @@ static __init int numa_setup(char *opt)
         if (!strncmp(opt,"off",3))
                 numa_off = 1;
 #ifdef CONFIG_NUMA_EMU
-        if(!strncmp(opt, "fake=", 5)) {
-                numa_fake = simple_strtoul(opt+5,NULL,0); ;
-                if (numa_fake >= MAX_NUMNODES)
-                        numa_fake = MAX_NUMNODES;
-        }
+        if (!strncmp(opt, "fake=", 5))
+                cmdline = opt + 5;
 #endif
 #ifdef CONFIG_ACPI_NUMA
         if (!strncmp(opt,"noacpi",6))
diff --git a/include/asm-x86_64/mmzone.h b/include/asm-x86_64/mmzone.h
index fb558fb1d211..19a89377b123 100644
--- a/include/asm-x86_64/mmzone.h
+++ b/include/asm-x86_64/mmzone.h
@@ -49,7 +49,7 @@ extern int pfn_valid(unsigned long pfn);
 
 #ifdef CONFIG_NUMA_EMU
 #define FAKE_NODE_MIN_SIZE      (64*1024*1024)
-#define FAKE_NODE_MIN_HASH_MASK (~(FAKE_NODE_MIN_SIZE - 1ul))
+#define FAKE_NODE_MIN_HASH_MASK (~(FAKE_NODE_MIN_SIZE - 1uL))
 #endif
 
 #endif