#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/bootmem.h>
#include <linux/bit_spinlock.h>
#include <linux/page_cgroup.h>
#include <linux/hash.h>
#include <linux/slab.h>
#include <linux/memory.h>
#include <linux/vmalloc.h>
#include <linux/cgroup.h>

static void __meminit
__init_page_cgroup(struct page_cgroup *pc, unsigned long pfn)
{
        pc->flags = 0;
        pc->mem_cgroup = NULL;
        pc->page = pfn_to_page(pfn);
}
static unsigned long total_usage;

#if !defined(CONFIG_SPARSEMEM)


void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
{
        pgdat->node_page_cgroup = NULL;
}

struct page_cgroup *lookup_page_cgroup(struct page *page)
{
        unsigned long pfn = page_to_pfn(page);
        unsigned long offset;
        struct page_cgroup *base;

        base = NODE_DATA(page_to_nid(page))->node_page_cgroup;
        if (unlikely(!base))
                return NULL;

        offset = pfn - NODE_DATA(page_to_nid(page))->node_start_pfn;
        return base + offset;
}

static int __init alloc_node_page_cgroup(int nid)
{
        struct page_cgroup *base, *pc;
        unsigned long table_size;
        unsigned long start_pfn, nr_pages, index;

        start_pfn = NODE_DATA(nid)->node_start_pfn;
        nr_pages = NODE_DATA(nid)->node_spanned_pages;

        if (!nr_pages)
                return 0;

        table_size = sizeof(struct page_cgroup) * nr_pages;

        base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
                        table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
        if (!base)
                return -ENOMEM;
        for (index = 0; index < nr_pages; index++) {
                pc = base + index;
                __init_page_cgroup(pc, start_pfn + index);
        }
        NODE_DATA(nid)->node_page_cgroup = base;
        total_usage += table_size;
        return 0;
}

void __init page_cgroup_init(void)
{

        int nid, fail;

        if (mem_cgroup_subsys.disabled)
                return;

        for_each_online_node(nid)  {
                fail = alloc_node_page_cgroup(nid);
                if (fail)
                        goto fail;
        }
        printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
        printk(KERN_INFO "please try cgroup_disable=memory option if you"
        " don't want\n");
        return;
fail:
        printk(KERN_CRIT "allocation of page_cgroup was failed.\n");
        printk(KERN_CRIT "please try cgroup_disable=memory boot option\n");
        panic("Out of memory");
}

#else /* CONFIG_FLAT_NODE_MEM_MAP */

struct page_cgroup *lookup_page_cgroup(struct page *page)
{
        unsigned long pfn = page_to_pfn(page);
        struct mem_section *section = __pfn_to_section(pfn);

        return section->page_cgroup + pfn;
}

/* __alloc_bootmem...() is protected by !slab_available() */
int __init_refok init_section_page_cgroup(unsigned long pfn)
{
        struct mem_section *section;
        struct page_cgroup *base, *pc;
        unsigned long table_size;
        int nid, index;

        section = __pfn_to_section(pfn);

        if (!section->page_cgroup) {
                nid = page_to_nid(pfn_to_page(pfn));
                table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
                if (slab_is_available()) {
                        base = kmalloc_node(table_size, GFP_KERNEL, nid);
                        if (!base)
                                base = vmalloc_node(table_size, nid);
                } else {
                        base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
                                table_size,
                                PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
                }
        } else {
                /*
                 * We don't have to allocate page_cgroup again, but
                 * address of memmap may be changed. So, we have to initialize
                 * again.
                 */
                base = section->page_cgroup + pfn;
                table_size = 0;
                /* check address of memmap is changed or not. */
                if (base->page == pfn_to_page(pfn))
                        return 0;
        }

        if (!base) {
                printk(KERN_ERR "page cgroup allocation failure\n");
                return -ENOMEM;
        }

        for (index = 0; index < PAGES_PER_SECTION; index++) {
                pc = base + index;
                __init_page_cgroup(pc, pfn + index);
        }

        section = __pfn_to_section(pfn);
        section->page_cgroup = base - pfn;
        total_usage += table_size;
        return 0;
}
#ifdef CONFIG_MEMORY_HOTPLUG
void __free_page_cgroup(unsigned long pfn)
{
        struct mem_section *ms;
        struct page_cgroup *base;

        ms = __pfn_to_section(pfn);
        if (!ms || !ms->page_cgroup)
                return;
        base = ms->page_cgroup + pfn;
        if (is_vmalloc_addr(base)) {
                vfree(base);
                ms->page_cgroup = NULL;
        } else {
                struct page *page = virt_to_page(base);
                if (!PageReserved(page)) { /* Is bootmem ? */
                        kfree(base);
                        ms->page_cgroup = NULL;
                }
        }
}

int __meminit online_page_cgroup(unsigned long start_pfn,
                        unsigned long nr_pages,
                        int nid)
{
        unsigned long start, end, pfn;
        int fail = 0;

        start = start_pfn & ~(PAGES_PER_SECTION - 1);
        end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);

        for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
                if (!pfn_present(pfn))
                        continue;
                fail = init_section_page_cgroup(pfn);
        }
        if (!fail)
                return 0;

        /* rollback */
        for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
                __free_page_cgroup(pfn);

        return -ENOMEM;
}

int __meminit offline_page_cgroup(unsigned long start_pfn,
                unsigned long nr_pages, int nid)
{
        unsigned long start, end, pfn;

        start = start_pfn & ~(PAGES_PER_SECTION - 1);
        end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);

        for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
                __free_page_cgroup(pfn);
        return 0;

}

static int __meminit page_cgroup_callback(struct notifier_block *self,
                               unsigned long action, void *arg)
{
        struct memory_notify *mn = arg;
        int ret = 0;
        switch (action) {
        case MEM_GOING_ONLINE:
                ret = online_page_cgroup(mn->start_pfn,
                                   mn->nr_pages, mn->status_change_nid);
                break;
        case MEM_OFFLINE:
                offline_page_cgroup(mn->start_pfn,
                                mn->nr_pages, mn->status_change_nid);
                break;
        case MEM_CANCEL_ONLINE:
        case MEM_GOING_OFFLINE:
                break;
        case MEM_ONLINE:
        case MEM_CANCEL_OFFLINE:
                break;
        }

        if (ret)
                ret = notifier_from_errno(ret);
        else
                ret = NOTIFY_OK;

        return ret;
}

#endif

void __init page_cgroup_init(void)
{
        unsigned long pfn;
        int fail = 0;

        if (mem_cgroup_subsys.disabled)
                return;

        for (pfn = 0; !fail && pfn < max_pfn; pfn += PAGES_PER_SECTION) {
                if (!pfn_present(pfn))
                        continue;
                fail = init_section_page_cgroup(pfn);
        }
        if (fail) {
                printk(KERN_CRIT "try cgroup_disable=memory boot option\n");
                panic("Out of memory");
        } else {
                hotplug_memory_notifier(page_cgroup_callback, 0);
        }
        printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
        printk(KERN_INFO "please try cgroup_disable=memory option if you don't"
        " want\n");
}

void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
{
        return;
}

#endif