1 files changed, 494 insertions, 0 deletions

diff --git a/arch/x86/mm/numa_emulation.c b/arch/x86/mm/numa_emulation.c
new file mode 100644
index 00000000000..ad091e4cff1
--- /dev/null
+++ b/arch/x86/mm/numa_emulation.c
@@ -0,0 +1,494 @@
+/*
+ * NUMA emulation
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/topology.h>
+#include <linux/memblock.h>
+#include <asm/dma.h>
+
+#include "numa_internal.h"
+
+static int emu_nid_to_phys[MAX_NUMNODES] __cpuinitdata;
+static char *emu_cmdline __initdata;
+
+void __init numa_emu_cmdline(char *str)
+{
+        emu_cmdline = str;
+}
+
+static int __init emu_find_memblk_by_nid(int nid, const struct numa_meminfo *mi)
+{
+        int i;
+
+        for (i = 0; i < mi->nr_blks; i++)
+                if (mi->blk[i].nid == nid)
+                        return i;
+        return -ENOENT;
+}
+
+/*
+ * Sets up nid to range from @start to @end.  The return value is -errno if
+ * something went wrong, 0 otherwise.
+ */
+static int __init emu_setup_memblk(struct numa_meminfo *ei,
+                                   struct numa_meminfo *pi,
+                                   int nid, int phys_blk, u64 size)
+{
+        struct numa_memblk *eb = &ei->blk[ei->nr_blks];
+        struct numa_memblk *pb = &pi->blk[phys_blk];
+
+        if (ei->nr_blks >= NR_NODE_MEMBLKS) {
+                pr_err("NUMA: Too many emulated memblks, failing emulation\n");
+                return -EINVAL;
+        }
+
+        ei->nr_blks++;
+        eb->start = pb->start;
+        eb->end = pb->start + size;
+        eb->nid = nid;
+
+        if (emu_nid_to_phys[nid] == NUMA_NO_NODE)
+                emu_nid_to_phys[nid] = pb->nid;
+
+        pb->start += size;
+        if (pb->start >= pb->end) {
+                WARN_ON_ONCE(pb->start > pb->end);
+                numa_remove_memblk_from(phys_blk, pi);
+        }
+
+        printk(KERN_INFO "Faking node %d at %016Lx-%016Lx (%LuMB)\n", nid,
+               eb->start, eb->end, (eb->end - eb->start) >> 20);
+        return 0;
+}
+
+/*
+ * Sets up nr_nodes fake nodes interleaved over physical nodes ranging from addr
+ * to max_addr.  The return value is the number of nodes allocated.
+ */
+static int __init split_nodes_interleave(struct numa_meminfo *ei,
+                                         struct numa_meminfo *pi,
+                                         u64 addr, u64 max_addr, int nr_nodes)
+{
+        nodemask_t physnode_mask = NODE_MASK_NONE;
+        u64 size;
+        int big;
+        int nid = 0;
+        int i, ret;
+
+        if (nr_nodes <= 0)
+                return -1;
+        if (nr_nodes > MAX_NUMNODES) {
+                pr_info("numa=fake=%d too large, reducing to %d\n",
+                        nr_nodes, MAX_NUMNODES);
+                nr_nodes = MAX_NUMNODES;
+        }
+
+        size = (max_addr - addr - memblock_x86_hole_size(addr, max_addr)) / nr_nodes;
+        /*
+         * Calculate the number of big nodes that can be allocated as a result
+         * of consolidating the remainder.
+         */
+        big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
+                FAKE_NODE_MIN_SIZE;
+
+        size &= FAKE_NODE_MIN_HASH_MASK;
+        if (!size) {
+                pr_err("Not enough memory for each node.  "
+                        "NUMA emulation disabled.\n");
+                return -1;
+        }
+
+        for (i = 0; i < pi->nr_blks; i++)
+                node_set(pi->blk[i].nid, physnode_mask);
+
+        /*
+         * Continue to fill physical nodes with fake nodes until there is no
+         * memory left on any of them.
+         */
+        while (nodes_weight(physnode_mask)) {
+                for_each_node_mask(i, physnode_mask) {
+                        u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
+                        u64 start, limit, end;
+                        int phys_blk;
+
+                        phys_blk = emu_find_memblk_by_nid(i, pi);
+                        if (phys_blk < 0) {
+                                node_clear(i, physnode_mask);
+                                continue;
+                        }
+                        start = pi->blk[phys_blk].start;
+                        limit = pi->blk[phys_blk].end;
+                        end = start + size;
+
+                        if (nid < big)
+                                end += FAKE_NODE_MIN_SIZE;
+
+                        /*
+                         * Continue to add memory to this fake node if its
+                         * non-reserved memory is less than the per-node size.
+                         */
+                        while (end - start -
+                               memblock_x86_hole_size(start, end) < size) {
+                                end += FAKE_NODE_MIN_SIZE;
+                                if (end > limit) {
+                                        end = limit;
+                                        break;
+                                }
+                        }
+
+                        /*
+                         * If there won't be at least FAKE_NODE_MIN_SIZE of
+                         * non-reserved memory in ZONE_DMA32 for the next node,
+                         * this one must extend to the boundary.
+                         */
+                        if (end < dma32_end && dma32_end - end -
+                            memblock_x86_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
+                                end = dma32_end;
+
+                        /*
+                         * If there won't be enough non-reserved memory for the
+                         * next node, this one must extend to the end of the
+                         * physical node.
+                         */
+                        if (limit - end -
+                            memblock_x86_hole_size(end, limit) < size)
+                                end = limit;
+
+                        ret = emu_setup_memblk(ei, pi, nid++ % nr_nodes,
+                                               phys_blk,
+                                               min(end, limit) - start);
+                        if (ret < 0)
+                                return ret;
+                }
+        }
+        return 0;
+}
+
+/*
+ * Returns the end address of a node so that there is at least `size' amount of
+ * non-reserved memory or `max_addr' is reached.
+ */
+static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
+{
+        u64 end = start + size;
+
+        while (end - start - memblock_x86_hole_size(start, end) < size) {
+                end += FAKE_NODE_MIN_SIZE;
+                if (end > max_addr) {
+                        end = max_addr;
+                        break;
+                }
+        }
+        return end;
+}
+
+/*
+ * Sets up fake nodes of `size' interleaved over physical nodes ranging from
+ * `addr' to `max_addr'.  The return value is the number of nodes allocated.
+ */
+static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
+                                              struct numa_meminfo *pi,
+                                              u64 addr, u64 max_addr, u64 size)
+{
+        nodemask_t physnode_mask = NODE_MASK_NONE;
+        u64 min_size;
+        int nid = 0;
+        int i, ret;
+
+        if (!size)
+                return -1;
+        /*
+         * The limit on emulated nodes is MAX_NUMNODES, so the size per node is
+         * increased accordingly if the requested size is too small.  This
+         * creates a uniform distribution of node sizes across the entire
+         * machine (but not necessarily over physical nodes).
+         */
+        min_size = (max_addr - addr - memblock_x86_hole_size(addr, max_addr)) /
+                                                MAX_NUMNODES;
+        min_size = max(min_size, FAKE_NODE_MIN_SIZE);
+        if ((min_size & FAKE_NODE_MIN_HASH_MASK) < min_size)
+                min_size = (min_size + FAKE_NODE_MIN_SIZE) &
+                                                FAKE_NODE_MIN_HASH_MASK;
+        if (size < min_size) {
+                pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
+                        size >> 20, min_size >> 20);
+                size = min_size;
+        }
+        size &= FAKE_NODE_MIN_HASH_MASK;
+
+        for (i = 0; i < pi->nr_blks; i++)
+                node_set(pi->blk[i].nid, physnode_mask);
+
+        /*
+         * Fill physical nodes with fake nodes of size until there is no memory
+         * left on any of them.
+         */
+        while (nodes_weight(physnode_mask)) {
+                for_each_node_mask(i, physnode_mask) {
+                        u64 dma32_end = MAX_DMA32_PFN << PAGE_SHIFT;
+                        u64 start, limit, end;
+                        int phys_blk;
+
+                        phys_blk = emu_find_memblk_by_nid(i, pi);
+                        if (phys_blk < 0) {
+                                node_clear(i, physnode_mask);
+                                continue;
+                        }
+                        start = pi->blk[phys_blk].start;
+                        limit = pi->blk[phys_blk].end;
+
+                        end = find_end_of_node(start, limit, size);
+                        /*
+                         * If there won't be at least FAKE_NODE_MIN_SIZE of
+                         * non-reserved memory in ZONE_DMA32 for the next node,
+                         * this one must extend to the boundary.
+                         */
+                        if (end < dma32_end && dma32_end - end -
+                            memblock_x86_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
+                                end = dma32_end;
+
+                        /*
+                         * If there won't be enough non-reserved memory for the
+                         * next node, this one must extend to the end of the
+                         * physical node.
+                         */
+                        if (limit - end -
+                            memblock_x86_hole_size(end, limit) < size)
+                                end = limit;
+
+                        ret = emu_setup_memblk(ei, pi, nid++ % MAX_NUMNODES,
+                                               phys_blk,
+                                               min(end, limit) - start);
+                        if (ret < 0)
+                                return ret;
+                }
+        }
+        return 0;
+}
+
+/**
+ * numa_emulation - Emulate NUMA nodes
+ * @numa_meminfo: NUMA configuration to massage
+ * @numa_dist_cnt: The size of the physical NUMA distance table
+ *
+ * Emulate NUMA nodes according to the numa=fake kernel parameter.
+ * @numa_meminfo contains the physical memory configuration and is modified
+ * to reflect the emulated configuration on success.  @numa_dist_cnt is
+ * used to determine the size of the physical distance table.
+ *
+ * On success, the following modifications are made.
+ *
+ * - @numa_meminfo is updated to reflect the emulated nodes.
+ *
+ * - __apicid_to_node[] is updated such that APIC IDs are mapped to the
+ *   emulated nodes.
+ *
+ * - NUMA distance table is rebuilt to represent distances between emulated
+ *   nodes.  The distances are determined considering how emulated nodes
+ *   are mapped to physical nodes and match the actual distances.
+ *
+ * - emu_nid_to_phys[] reflects how emulated nodes are mapped to physical
+ *   nodes.  This is used by numa_add_cpu() and numa_remove_cpu().
+ *
+ * If emulation is not enabled or fails, emu_nid_to_phys[] is filled with
+ * identity mapping and no other modification is made.
+ */
+void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
+{
+        static struct numa_meminfo ei __initdata;
+        static struct numa_meminfo pi __initdata;
+        const u64 max_addr = max_pfn << PAGE_SHIFT;
+        u8 *phys_dist = NULL;
+        size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);
+        int max_emu_nid, dfl_phys_nid;
+        int i, j, ret;
+
+        if (!emu_cmdline)
+                goto no_emu;
+
+        memset(&ei, 0, sizeof(ei));
+        pi = *numa_meminfo;
+
+        for (i = 0; i < MAX_NUMNODES; i++)
+                emu_nid_to_phys[i] = NUMA_NO_NODE;
+
+        /*
+         * If the numa=fake command-line contains a 'M' or 'G', it represents
+         * the fixed node size.  Otherwise, if it is just a single number N,
+         * split the system RAM into N fake nodes.
+         */
+        if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
+                u64 size;
+
+                size = memparse(emu_cmdline, &emu_cmdline);
+                ret = split_nodes_size_interleave(&ei, &pi, 0, max_addr, size);
+        } else {
+                unsigned long n;
+
+                n = simple_strtoul(emu_cmdline, NULL, 0);
+                ret = split_nodes_interleave(&ei, &pi, 0, max_addr, n);
+        }
+
+        if (ret < 0)
+                goto no_emu;
+
+        if (numa_cleanup_meminfo(&ei) < 0) {
+                pr_warning("NUMA: Warning: constructed meminfo invalid, disabling emulation\n");
+                goto no_emu;
+        }
+
+        /* copy the physical distance table */
+        if (numa_dist_cnt) {
+                u64 phys;
+
+                phys = memblock_find_in_range(0,
+                                              (u64)max_pfn_mapped << PAGE_SHIFT,
+                                              phys_size, PAGE_SIZE);
+                if (phys == MEMBLOCK_ERROR) {
+                        pr_warning("NUMA: Warning: can't allocate copy of distance table, disabling emulation\n");
+                        goto no_emu;
+                }
+                memblock_x86_reserve_range(phys, phys + phys_size, "TMP NUMA DIST");
+                phys_dist = __va(phys);
+
+                for (i = 0; i < numa_dist_cnt; i++)
+                        for (j = 0; j < numa_dist_cnt; j++)
+                                phys_dist[i * numa_dist_cnt + j] =
+                                        node_distance(i, j);
+        }
+
+        /*
+         * Determine the max emulated nid and the default phys nid to use
+         * for unmapped nodes.
+         */
+        max_emu_nid = 0;
+        dfl_phys_nid = NUMA_NO_NODE;
+        for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++) {
+                if (emu_nid_to_phys[i] != NUMA_NO_NODE) {
+                        max_emu_nid = i;
+                        if (dfl_phys_nid == NUMA_NO_NODE)
+                                dfl_phys_nid = emu_nid_to_phys[i];
+                }
+        }
+        if (dfl_phys_nid == NUMA_NO_NODE) {
+                pr_warning("NUMA: Warning: can't determine default physical node, disabling emulation\n");
+                goto no_emu;
+        }
+
+        /* commit */
+        *numa_meminfo = ei;
+
+        /*
+         * Transform __apicid_to_node table to use emulated nids by
+         * reverse-mapping phys_nid.  The maps should always exist but fall
+         * back to zero just in case.
+         */
+        for (i = 0; i < ARRAY_SIZE(__apicid_to_node); i++) {
+                if (__apicid_to_node[i] == NUMA_NO_NODE)
+                        continue;
+                for (j = 0; j < ARRAY_SIZE(emu_nid_to_phys); j++)
+                        if (__apicid_to_node[i] == emu_nid_to_phys[j])
+                                break;
+                __apicid_to_node[i] = j < ARRAY_SIZE(emu_nid_to_phys) ? j : 0;
+        }
+
+        /* make sure all emulated nodes are mapped to a physical node */
+        for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
+                if (emu_nid_to_phys[i] == NUMA_NO_NODE)
+                        emu_nid_to_phys[i] = dfl_phys_nid;
+
+        /* transform distance table */
+        numa_reset_distance();
+        for (i = 0; i < max_emu_nid + 1; i++) {
+                for (j = 0; j < max_emu_nid + 1; j++) {
+                        int physi = emu_nid_to_phys[i];
+                        int physj = emu_nid_to_phys[j];
+                        int dist;
+
+                        if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
+                                dist = physi == physj ?
+                                        LOCAL_DISTANCE : REMOTE_DISTANCE;
+                        else
+                                dist = phys_dist[physi * numa_dist_cnt + physj];
+
+                        numa_set_distance(i, j, dist);
+                }
+        }
+
+        /* free the copied physical distance table */
+        if (phys_dist)
+                memblock_x86_free_range(__pa(phys_dist), __pa(phys_dist) + phys_size);
+        return;
+
+no_emu:
+        /* No emulation.  Build identity emu_nid_to_phys[] for numa_add_cpu() */
+        for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
+                emu_nid_to_phys[i] = i;
+}
+
+#ifndef CONFIG_DEBUG_PER_CPU_MAPS
+void __cpuinit numa_add_cpu(int cpu)
+{
+        int physnid, nid;
+
+        nid = early_cpu_to_node(cpu);
+        BUG_ON(nid == NUMA_NO_NODE || !node_online(nid));
+
+        physnid = emu_nid_to_phys[nid];
+
+        /*
+         * Map the cpu to each emulated node that is allocated on the physical
+         * node of the cpu's apic id.
+         */
+        for_each_online_node(nid)
+                if (emu_nid_to_phys[nid] == physnid)
+                        cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
+}
+
+void __cpuinit numa_remove_cpu(int cpu)
+{
+        int i;
+
+        for_each_online_node(i)
+                cpumask_clear_cpu(cpu, node_to_cpumask_map[i]);
+}
+#else   /* !CONFIG_DEBUG_PER_CPU_MAPS */
+static void __cpuinit numa_set_cpumask(int cpu, int enable)
+{
+        struct cpumask *mask;
+        int nid, physnid, i;
+
+        nid = early_cpu_to_node(cpu);
+        if (nid == NUMA_NO_NODE) {
+                /* early_cpu_to_node() already emits a warning and trace */
+                return;
+        }
+
+        physnid = emu_nid_to_phys[nid];
+
+        for_each_online_node(i) {
+                if (emu_nid_to_phys[nid] != physnid)
+                        continue;
+
+                mask = debug_cpumask_set_cpu(cpu, enable);
+                if (!mask)
+                        return;
+
+                if (enable)
+                        cpumask_set_cpu(cpu, mask);
+                else
+                        cpumask_clear_cpu(cpu, mask);
+        }
+}
+
+void __cpuinit numa_add_cpu(int cpu)
+{
+        numa_set_cpumask(cpu, 1);
+}
+
+void __cpuinit numa_remove_cpu(int cpu)
+{
+        numa_set_cpumask(cpu, 0);
+}
+#endif  /* !CONFIG_DEBUG_PER_CPU_MAPS */