/*
 * 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/notifier.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_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

static void node_device_release(struct device *dev)
{
        struct node *node = to_node(dev);

#if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_HUGETLBFS)
        /*
         * We schedule the work only when a memory section is
         * onlined/offlined on this node. When we come here,
         * all the memory on this node has been offlined,
         * so we won't enqueue new work to this work.
         *
         * The work is using node->node_work, so we should
         * flush work before freeing the memory.
         */
        flush_work(&node->node_work);
#endif
        kfree(node);
}

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

        node->dev.id = num;
        node->dev.bus = &node_subsys;
        node->dev.release = node_device_release;
        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;
}

/**
 * unregister_node - unregister a node device
 * @node: node going away
 *
 * Unregisters a node device @node.  All the devices on the node must be
 * unregistered before calling this function.
 */
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];

                node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
                if (!node_devices[nid])
                        return -ENOMEM;

                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_devices[nid] = NULL;
}

/*
 * 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[] = {
        [N_POSSIBLE] = _NODE_ATTR(possible, N_POSSIBLE),
        [N_ONLINE] = _NODE_ATTR(online, N_ONLINE),
        [N_NORMAL_MEMORY] = _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
#ifdef CONFIG_HIGHMEM
        [N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
#endif
#ifdef CONFIG_MOVABLE_NODE
        [N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
#endif
        [N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
};

static struct attribute *node_state_attrs[] = {
        &node_state_attr[N_POSSIBLE].attr.attr,
        &node_state_attr[N_ONLINE].attr.attr,
        &node_state_attr[N_NORMAL_MEMORY].attr.attr,
#ifdef CONFIG_HIGHMEM
        &node_state_attr[N_HIGH_MEMORY].attr.attr,
#endif
#ifdef CONFIG_MOVABLE_NODE
        &node_state_attr[N_MEMORY].attr.attr,
#endif
        &node_state_attr[N_CPU].attr.attr,
        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) {
                static struct notifier_block node_memory_callback_nb = {
                        .notifier_call = node_memory_callback,
                        .priority = NODE_CALLBACK_PRI,
                };
                register_hotmemory_notifier(&node_memory_callback_nb);
        }

        /*
         * 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);