node.c

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/*
 * Basic Node interface support
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/memory.h>
#include <linux/vmstat.h>
#include <linux/node.h>
#include <linux/hugetlb.h>
#include <linux/compaction.h>
#include <linux/cpumask.h>
#include <linux/topology.h>
#include <linux/nodemask.h>
#include <linux/cpu.h>
#include <linux/device.h>
#include <linux/swap.h>
#include <linux/slab.h>

static struct bus_type node_subsys = {
    .name = "node",
    .dev_name = "node",
};


static ssize_t node_read_cpumap(struct device *dev, int type, char *buf)
{
    struct node *node_dev = to_node(dev);
    const struct cpumask *mask = cpumask_of_node(node_dev->dev.id);
    int len;

    /* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */
    BUILD_BUG_ON((NR_CPUS/32 * 9) > (PAGE_SIZE-1));

    len = type?
        cpulist_scnprintf(buf, PAGE_SIZE-2, mask) :
        cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
    buf[len++] = '\n';
    buf[len] = '\0';
    return len;
}

static inline ssize_t node_read_cpumask(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    return node_read_cpumap(dev, 0, buf);
}
static inline ssize_t node_read_cpulist(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    return node_read_cpumap(dev, 1, buf);
}

static DEVICE_ATTR(cpumap,  S_IRUGO, node_read_cpumask, NULL);
static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL);

#define K(x) ((x) << (PAGE_SHIFT - 10))
static ssize_t node_read_meminfo(struct device *dev,
            struct device_attribute *attr, char *buf)
{
    int n;
    int nid = dev->id;
    struct sysinfo i;

    si_meminfo_node(&i, nid);
    n = sprintf(buf,
               "Node %d MemTotal:       %8lu kB\n"
               "Node %d MemFree:        %8lu kB\n"
               "Node %d MemUsed:        %8lu kB\n"
               "Node %d Active:         %8lu kB\n"
               "Node %d Inactive:       %8lu kB\n"
               "Node %d Active(anon):   %8lu kB\n"
               "Node %d Inactive(anon): %8lu kB\n"
               "Node %d Active(file):   %8lu kB\n"
               "Node %d Inactive(file): %8lu kB\n"
               "Node %d Unevictable:    %8lu kB\n"
               "Node %d Mlocked:        %8lu kB\n",
               nid, K(i.totalram),
               nid, K(i.freeram),
               nid, K(i.totalram - i.freeram),
               nid, K(node_page_state(nid, NR_ACTIVE_ANON) +
                node_page_state(nid, NR_ACTIVE_FILE)),
               nid, K(node_page_state(nid, NR_INACTIVE_ANON) +
                node_page_state(nid, NR_INACTIVE_FILE)),
               nid, K(node_page_state(nid, NR_ACTIVE_ANON)),
               nid, K(node_page_state(nid, NR_INACTIVE_ANON)),
               nid, K(node_page_state(nid, NR_ACTIVE_FILE)),
               nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
               nid, K(node_page_state(nid, NR_UNEVICTABLE)),
               nid, K(node_page_state(nid, NR_MLOCK)));

#ifdef CONFIG_HIGHMEM
    n += sprintf(buf + n,
               "Node %d HighTotal:      %8lu kB\n"
               "Node %d HighFree:       %8lu kB\n"
               "Node %d LowTotal:       %8lu kB\n"
               "Node %d LowFree:        %8lu kB\n",
               nid, K(i.totalhigh),
               nid, K(i.freehigh),
               nid, K(i.totalram - i.totalhigh),
               nid, K(i.freeram - i.freehigh));
#endif
    n += sprintf(buf + n,
               "Node %d Dirty:          %8lu kB\n"
               "Node %d Writeback:      %8lu kB\n"
               "Node %d FilePages:      %8lu kB\n"
               "Node %d Mapped:         %8lu kB\n"
               "Node %d AnonPages:      %8lu kB\n"
               "Node %d Shmem:          %8lu kB\n"
               "Node %d KernelStack:    %8lu kB\n"
               "Node %d PageTables:     %8lu kB\n"
               "Node %d NFS_Unstable:   %8lu kB\n"
               "Node %d Bounce:         %8lu kB\n"
               "Node %d WritebackTmp:   %8lu kB\n"
               "Node %d Slab:           %8lu kB\n"
               "Node %d SReclaimable:   %8lu kB\n"
               "Node %d SUnreclaim:     %8lu kB\n"
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
               "Node %d AnonHugePages:  %8lu kB\n"
#endif
            ,
               nid, K(node_page_state(nid, NR_FILE_DIRTY)),
               nid, K(node_page_state(nid, NR_WRITEBACK)),
               nid, K(node_page_state(nid, NR_FILE_PAGES)),
               nid, K(node_page_state(nid, NR_FILE_MAPPED)),
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
               nid, K(node_page_state(nid, NR_ANON_PAGES)
            + node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
            HPAGE_PMD_NR),
#else
               nid, K(node_page_state(nid, NR_ANON_PAGES)),
#endif
               nid, K(node_page_state(nid, NR_SHMEM)),
               nid, node_page_state(nid, NR_KERNEL_STACK) *
                THREAD_SIZE / 1024,
               nid, K(node_page_state(nid, NR_PAGETABLE)),
               nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
               nid, K(node_page_state(nid, NR_BOUNCE)),
               nid, K(node_page_state(nid, NR_WRITEBACK_TEMP)),
               nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
                node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
               nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
               nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE))
            , nid,
            K(node_page_state(nid, NR_ANON_TRANSPARENT_HUGEPAGES) *
            HPAGE_PMD_NR));
#else
               nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
#endif
    n += hugetlb_report_node_meminfo(nid, buf + n);
    return n;
}

#undef K
static DEVICE_ATTR(meminfo, S_IRUGO, node_read_meminfo, NULL);

static ssize_t node_read_numastat(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    return sprintf(buf,
               "numa_hit %lu\n"
               "numa_miss %lu\n"
               "numa_foreign %lu\n"
               "interleave_hit %lu\n"
               "local_node %lu\n"
               "other_node %lu\n",
               node_page_state(dev->id, NUMA_HIT),
               node_page_state(dev->id, NUMA_MISS),
               node_page_state(dev->id, NUMA_FOREIGN),
               node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
               node_page_state(dev->id, NUMA_LOCAL),
               node_page_state(dev->id, NUMA_OTHER));
}
static DEVICE_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);

static ssize_t node_read_vmstat(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    int nid = dev->id;
    int i;
    int n = 0;

    for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
        n += sprintf(buf+n, "%s %lu\n", vmstat_text[i],
                 node_page_state(nid, i));

    return n;
}
static DEVICE_ATTR(vmstat, S_IRUGO, node_read_vmstat, NULL);

static ssize_t node_read_distance(struct device *dev,
            struct device_attribute *attr, char * buf)
{
    int nid = dev->id;
    int len = 0;
    int i;

    /*
     * buf is currently PAGE_SIZE in length and each node needs 4 chars
     * at the most (distance + space or newline).
     */
    BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);

    for_each_online_node(i)
        len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));

    len += sprintf(buf + len, "\n");
    return len;
}
static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL);

#ifdef CONFIG_HUGETLBFS
/*
 * hugetlbfs per node attributes registration interface:
 * When/if hugetlb[fs] subsystem initializes [sometime after this module],
 * it will register its per node attributes for all online nodes with
 * memory.  It will also call register_hugetlbfs_with_node(), below, to
 * register its attribute registration functions with this node driver.
 * Once these hooks have been initialized, the node driver will call into
 * the hugetlb module to [un]register attributes for hot-plugged nodes.
 */
static node_registration_func_t __hugetlb_register_node;
static node_registration_func_t __hugetlb_unregister_node;

static inline bool hugetlb_register_node(struct node *node)
{
    if (__hugetlb_register_node &&
            node_state(node->dev.id, N_HIGH_MEMORY)) {
        __hugetlb_register_node(node);
        return true;
    }
    return false;
}

static inline void hugetlb_unregister_node(struct node *node)
{
    if (__hugetlb_unregister_node)
        __hugetlb_unregister_node(node);
}

void register_hugetlbfs_with_node(node_registration_func_t doregister,
                  node_registration_func_t unregister)
{
    __hugetlb_register_node   = doregister;
    __hugetlb_unregister_node = unregister;
}
#else
static inline void hugetlb_register_node(struct node *node) {}

static inline void hugetlb_unregister_node(struct node *node) {}
#endif


/*
 * register_node - Setup a sysfs device for a node.
 * @num - Node number to use when creating the device.
 *
 * Initialize and register the node device.
 */
int register_node(struct node *node, int num, struct node *parent)
{
    int error;

    node->dev.id = num;
    node->dev.bus = &node_subsys;
    error = device_register(&node->dev);

    if (!error){
        device_create_file(&node->dev, &dev_attr_cpumap);
        device_create_file(&node->dev, &dev_attr_cpulist);
        device_create_file(&node->dev, &dev_attr_meminfo);
        device_create_file(&node->dev, &dev_attr_numastat);
        device_create_file(&node->dev, &dev_attr_distance);
        device_create_file(&node->dev, &dev_attr_vmstat);

        scan_unevictable_register_node(node);

        hugetlb_register_node(node);

        compaction_register_node(node);
    }
    return error;
}

void unregister_node(struct node *node)
{
    device_remove_file(&node->dev, &dev_attr_cpumap);
    device_remove_file(&node->dev, &dev_attr_cpulist);
    device_remove_file(&node->dev, &dev_attr_meminfo);
    device_remove_file(&node->dev, &dev_attr_numastat);
    device_remove_file(&node->dev, &dev_attr_distance);
    device_remove_file(&node->dev, &dev_attr_vmstat);

    scan_unevictable_unregister_node(node);
    hugetlb_unregister_node(node);      /* no-op, if memoryless node */

    device_unregister(&node->dev);
}

struct node node_devices[MAX_NUMNODES];

/*
 * register cpu under node
 */
int register_cpu_under_node(unsigned int cpu, unsigned int nid)
{
    int ret;
    struct device *obj;

    if (!node_online(nid))
        return 0;

    obj = get_cpu_device(cpu);
    if (!obj)
        return 0;

    ret = sysfs_create_link(&node_devices[nid].dev.kobj,
                &obj->kobj,
                kobject_name(&obj->kobj));
    if (ret)
        return ret;

    return sysfs_create_link(&obj->kobj,
                 &node_devices[nid].dev.kobj,
                 kobject_name(&node_devices[nid].dev.kobj));
}

int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
{
    struct device *obj;

    if (!node_online(nid))
        return 0;

    obj = get_cpu_device(cpu);
    if (!obj)
        return 0;

    sysfs_remove_link(&node_devices[nid].dev.kobj,
              kobject_name(&obj->kobj));
    sysfs_remove_link(&obj->kobj,
              kobject_name(&node_devices[nid].dev.kobj));

    return 0;
}

#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
#define page_initialized(page)  (page->lru.next)

static int get_nid_for_pfn(unsigned long pfn)
{
    struct page *page;

    if (!pfn_valid_within(pfn))
        return -1;
    page = pfn_to_page(pfn);
    if (!page_initialized(page))
        return -1;
    return pfn_to_nid(pfn);
}

/* register memory section under specified node if it spans that node */
int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
{
    int ret;
    unsigned long pfn, sect_start_pfn, sect_end_pfn;

    if (!mem_blk)
        return -EFAULT;
    if (!node_online(nid))
        return 0;

    sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
    sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
    sect_end_pfn += PAGES_PER_SECTION - 1;
    for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
        int page_nid;

        page_nid = get_nid_for_pfn(pfn);
        if (page_nid < 0)
            continue;
        if (page_nid != nid)
            continue;
        ret = sysfs_create_link_nowarn(&node_devices[nid].dev.kobj,
                    &mem_blk->dev.kobj,
                    kobject_name(&mem_blk->dev.kobj));
        if (ret)
            return ret;

        return sysfs_create_link_nowarn(&mem_blk->dev.kobj,
                &node_devices[nid].dev.kobj,
                kobject_name(&node_devices[nid].dev.kobj));
    }
    /* mem section does not span the specified node */
    return 0;
}

/* unregister memory section under all nodes that it spans */
int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
                    unsigned long phys_index)
{
    NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
    unsigned long pfn, sect_start_pfn, sect_end_pfn;

    if (!mem_blk) {
        NODEMASK_FREE(unlinked_nodes);
        return -EFAULT;
    }
    if (!unlinked_nodes)
        return -ENOMEM;
    nodes_clear(*unlinked_nodes);

    sect_start_pfn = section_nr_to_pfn(phys_index);
    sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
    for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
        int nid;

        nid = get_nid_for_pfn(pfn);
        if (nid < 0)
            continue;
        if (!node_online(nid))
            continue;
        if (node_test_and_set(nid, *unlinked_nodes))
            continue;
        sysfs_remove_link(&node_devices[nid].dev.kobj,
             kobject_name(&mem_blk->dev.kobj));
        sysfs_remove_link(&mem_blk->dev.kobj,
             kobject_name(&node_devices[nid].dev.kobj));
    }
    NODEMASK_FREE(unlinked_nodes);
    return 0;
}

static int link_mem_sections(int nid)
{
    unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
    unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
    unsigned long pfn;
    struct memory_block *mem_blk = NULL;
    int err = 0;

    for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
        unsigned long section_nr = pfn_to_section_nr(pfn);
        struct mem_section *mem_sect;
        int ret;

        if (!present_section_nr(section_nr))
            continue;
        mem_sect = __nr_to_section(section_nr);

        /* same memblock ? */
        if (mem_blk)
            if ((section_nr >= mem_blk->start_section_nr) &&
                (section_nr <= mem_blk->end_section_nr))
                continue;

        mem_blk = find_memory_block_hinted(mem_sect, mem_blk);

        ret = register_mem_sect_under_node(mem_blk, nid);
        if (!err)
            err = ret;

        /* discard ref obtained in find_memory_block() */
    }

    if (mem_blk)
        kobject_put(&mem_blk->dev.kobj);
    return err;
}

#ifdef CONFIG_HUGETLBFS
/*
 * Handle per node hstate attribute [un]registration on transistions
 * to/from memoryless state.
 */
static void node_hugetlb_work(struct work_struct *work)
{
    struct node *node = container_of(work, struct node, node_work);

    /*
     * We only get here when a node transitions to/from memoryless state.
     * We can detect which transition occurred by examining whether the
     * node has memory now.  hugetlb_register_node() already check this
     * so we try to register the attributes.  If that fails, then the
     * node has transitioned to memoryless, try to unregister the
     * attributes.
     */
    if (!hugetlb_register_node(node))
        hugetlb_unregister_node(node);
}

static void init_node_hugetlb_work(int nid)
{
    INIT_WORK(&node_devices[nid].node_work, node_hugetlb_work);
}

static int node_memory_callback(struct notifier_block *self,
                unsigned long action, void *arg)
{
    struct memory_notify *mnb = arg;
    int nid = mnb->status_change_nid;

    switch (action) {
    case MEM_ONLINE:
    case MEM_OFFLINE:
        /*
         * offload per node hstate [un]registration to a work thread
         * when transitioning to/from memoryless state.
         */
        if (nid != NUMA_NO_NODE)
            schedule_work(&node_devices[nid].node_work);
        break;

    case MEM_GOING_ONLINE:
    case MEM_GOING_OFFLINE:
    case MEM_CANCEL_ONLINE:
    case MEM_CANCEL_OFFLINE:
    default:
        break;
    }

    return NOTIFY_OK;
}
#endif  /* CONFIG_HUGETLBFS */
#else   /* !CONFIG_MEMORY_HOTPLUG_SPARSE */

static int link_mem_sections(int nid) { return 0; }
#endif  /* CONFIG_MEMORY_HOTPLUG_SPARSE */

#if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
    !defined(CONFIG_HUGETLBFS)
static inline int node_memory_callback(struct notifier_block *self,
                unsigned long action, void *arg)
{
    return NOTIFY_OK;
}

static void init_node_hugetlb_work(int nid) { }

#endif

int register_one_node(int nid)
{
    int error = 0;
    int cpu;

    if (node_online(nid)) {
        int p_node = parent_node(nid);
        struct node *parent = NULL;

        if (p_node != nid)
            parent = &node_devices[p_node];

        error = register_node(&node_devices[nid], nid, parent);

        /* link cpu under this node */
        for_each_present_cpu(cpu) {
            if (cpu_to_node(cpu) == nid)
                register_cpu_under_node(cpu, nid);
        }

        /* link memory sections under this node */
        error = link_mem_sections(nid);

        /* initialize work queue for memory hot plug */
        init_node_hugetlb_work(nid);
    }

    return error;

}

void unregister_one_node(int nid)
{
    unregister_node(&node_devices[nid]);
}

/*
 * node states attributes
 */

static ssize_t print_nodes_state(enum node_states state, char *buf)
{
    int n;

    n = nodelist_scnprintf(buf, PAGE_SIZE-2, node_states[state]);
    buf[n++] = '\n';
    buf[n] = '\0';
    return n;
}

struct node_attr {
    struct device_attribute attr;
    enum node_states state;
};

static ssize_t show_node_state(struct device *dev,
                   struct device_attribute *attr, char *buf)
{
    struct node_attr *na = container_of(attr, struct node_attr, attr);
    return print_nodes_state(na->state, buf);
}

#define _NODE_ATTR(name, state) \
    { __ATTR(name, 0444, show_node_state, NULL), state }

static struct node_attr node_state_attr[] = {
    _NODE_ATTR(possible, N_POSSIBLE),
    _NODE_ATTR(online, N_ONLINE),
    _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
    _NODE_ATTR(has_cpu, N_CPU),
#ifdef CONFIG_HIGHMEM
    _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
#endif
};

static struct attribute *node_state_attrs[] = {
    &node_state_attr[0].attr.attr,
    &node_state_attr[1].attr.attr,
    &node_state_attr[2].attr.attr,
    &node_state_attr[3].attr.attr,
#ifdef CONFIG_HIGHMEM
    &node_state_attr[4].attr.attr,
#endif
    NULL
};

static struct attribute_group memory_root_attr_group = {
    .attrs = node_state_attrs,
};

static const struct attribute_group *cpu_root_attr_groups[] = {
    &memory_root_attr_group,
    NULL,
};

#define NODE_CALLBACK_PRI   2   /* lower than SLAB */
static int __init register_node_type(void)
{
    int ret;

    BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
    BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);

    ret = subsys_system_register(&node_subsys, cpu_root_attr_groups);
    if (!ret) {
        hotplug_memory_notifier(node_memory_callback,
                    NODE_CALLBACK_PRI);
    }

    /*
     * Note:  we're not going to unregister the node class if we fail
     * to register the node state class attribute files.
     */
    return ret;
}
postcore_initcall(register_node_type);