linux/mm/page_cgroup.c
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   1#include <linux/mm.h>
   2#include <linux/mmzone.h>
   3#include <linux/bootmem.h>
   4#include <linux/bit_spinlock.h>
   5#include <linux/page_cgroup.h>
   6#include <linux/hash.h>
   7#include <linux/slab.h>
   8#include <linux/memory.h>
   9#include <linux/vmalloc.h>
  10#include <linux/cgroup.h>
  11#include <linux/swapops.h>
  12#include <linux/kmemleak.h>
  13
  14static unsigned long total_usage;
  15
  16#if !defined(CONFIG_SPARSEMEM)
  17
  18
  19void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
  20{
  21        pgdat->node_page_cgroup = NULL;
  22}
  23
  24struct page_cgroup *lookup_page_cgroup(struct page *page)
  25{
  26        unsigned long pfn = page_to_pfn(page);
  27        unsigned long offset;
  28        struct page_cgroup *base;
  29
  30        base = NODE_DATA(page_to_nid(page))->node_page_cgroup;
  31#ifdef CONFIG_DEBUG_VM
  32        /*
  33         * The sanity checks the page allocator does upon freeing a
  34         * page can reach here before the page_cgroup arrays are
  35         * allocated when feeding a range of pages to the allocator
  36         * for the first time during bootup or memory hotplug.
  37         */
  38        if (unlikely(!base))
  39                return NULL;
  40#endif
  41        offset = pfn - NODE_DATA(page_to_nid(page))->node_start_pfn;
  42        return base + offset;
  43}
  44
  45static int __init alloc_node_page_cgroup(int nid)
  46{
  47        struct page_cgroup *base;
  48        unsigned long table_size;
  49        unsigned long nr_pages;
  50
  51        nr_pages = NODE_DATA(nid)->node_spanned_pages;
  52        if (!nr_pages)
  53                return 0;
  54
  55        table_size = sizeof(struct page_cgroup) * nr_pages;
  56
  57        base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
  58                        table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
  59        if (!base)
  60                return -ENOMEM;
  61        NODE_DATA(nid)->node_page_cgroup = base;
  62        total_usage += table_size;
  63        return 0;
  64}
  65
  66void __init page_cgroup_init_flatmem(void)
  67{
  68
  69        int nid, fail;
  70
  71        if (mem_cgroup_disabled())
  72                return;
  73
  74        for_each_online_node(nid)  {
  75                fail = alloc_node_page_cgroup(nid);
  76                if (fail)
  77                        goto fail;
  78        }
  79        printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
  80        printk(KERN_INFO "please try 'cgroup_disable=memory' option if you"
  81        " don't want memory cgroups\n");
  82        return;
  83fail:
  84        printk(KERN_CRIT "allocation of page_cgroup failed.\n");
  85        printk(KERN_CRIT "please try 'cgroup_disable=memory' boot option\n");
  86        panic("Out of memory");
  87}
  88
  89#else /* CONFIG_FLAT_NODE_MEM_MAP */
  90
  91struct page_cgroup *lookup_page_cgroup(struct page *page)
  92{
  93        unsigned long pfn = page_to_pfn(page);
  94        struct mem_section *section = __pfn_to_section(pfn);
  95#ifdef CONFIG_DEBUG_VM
  96        /*
  97         * The sanity checks the page allocator does upon freeing a
  98         * page can reach here before the page_cgroup arrays are
  99         * allocated when feeding a range of pages to the allocator
 100         * for the first time during bootup or memory hotplug.
 101         */
 102        if (!section->page_cgroup)
 103                return NULL;
 104#endif
 105        return section->page_cgroup + pfn;
 106}
 107
 108static void *__meminit alloc_page_cgroup(size_t size, int nid)
 109{
 110        gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
 111        void *addr = NULL;
 112
 113        addr = alloc_pages_exact_nid(nid, size, flags);
 114        if (addr) {
 115                kmemleak_alloc(addr, size, 1, flags);
 116                return addr;
 117        }
 118
 119        if (node_state(nid, N_HIGH_MEMORY))
 120                addr = vzalloc_node(size, nid);
 121        else
 122                addr = vzalloc(size);
 123
 124        return addr;
 125}
 126
 127static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
 128{
 129        struct mem_section *section;
 130        struct page_cgroup *base;
 131        unsigned long table_size;
 132
 133        section = __pfn_to_section(pfn);
 134
 135        if (section->page_cgroup)
 136                return 0;
 137
 138        table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
 139        base = alloc_page_cgroup(table_size, nid);
 140
 141        /*
 142         * The value stored in section->page_cgroup is (base - pfn)
 143         * and it does not point to the memory block allocated above,
 144         * causing kmemleak false positives.
 145         */
 146        kmemleak_not_leak(base);
 147
 148        if (!base) {
 149                printk(KERN_ERR "page cgroup allocation failure\n");
 150                return -ENOMEM;
 151        }
 152
 153        /*
 154         * The passed "pfn" may not be aligned to SECTION.  For the calculation
 155         * we need to apply a mask.
 156         */
 157        pfn &= PAGE_SECTION_MASK;
 158        section->page_cgroup = base - pfn;
 159        total_usage += table_size;
 160        return 0;
 161}
 162#ifdef CONFIG_MEMORY_HOTPLUG
 163static void free_page_cgroup(void *addr)
 164{
 165        if (is_vmalloc_addr(addr)) {
 166                vfree(addr);
 167        } else {
 168                struct page *page = virt_to_page(addr);
 169                size_t table_size =
 170                        sizeof(struct page_cgroup) * PAGES_PER_SECTION;
 171
 172                BUG_ON(PageReserved(page));
 173                free_pages_exact(addr, table_size);
 174        }
 175}
 176
 177void __free_page_cgroup(unsigned long pfn)
 178{
 179        struct mem_section *ms;
 180        struct page_cgroup *base;
 181
 182        ms = __pfn_to_section(pfn);
 183        if (!ms || !ms->page_cgroup)
 184                return;
 185        base = ms->page_cgroup + pfn;
 186        free_page_cgroup(base);
 187        ms->page_cgroup = NULL;
 188}
 189
 190int __meminit online_page_cgroup(unsigned long start_pfn,
 191                        unsigned long nr_pages,
 192                        int nid)
 193{
 194        unsigned long start, end, pfn;
 195        int fail = 0;
 196
 197        start = SECTION_ALIGN_DOWN(start_pfn);
 198        end = SECTION_ALIGN_UP(start_pfn + nr_pages);
 199
 200        if (nid == -1) {
 201                /*
 202                 * In this case, "nid" already exists and contains valid memory.
 203                 * "start_pfn" passed to us is a pfn which is an arg for
 204                 * online__pages(), and start_pfn should exist.
 205                 */
 206                nid = pfn_to_nid(start_pfn);
 207                VM_BUG_ON(!node_state(nid, N_ONLINE));
 208        }
 209
 210        for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
 211                if (!pfn_present(pfn))
 212                        continue;
 213                fail = init_section_page_cgroup(pfn, nid);
 214        }
 215        if (!fail)
 216                return 0;
 217
 218        /* rollback */
 219        for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
 220                __free_page_cgroup(pfn);
 221
 222        return -ENOMEM;
 223}
 224
 225int __meminit offline_page_cgroup(unsigned long start_pfn,
 226                unsigned long nr_pages, int nid)
 227{
 228        unsigned long start, end, pfn;
 229
 230        start = SECTION_ALIGN_DOWN(start_pfn);
 231        end = SECTION_ALIGN_UP(start_pfn + nr_pages);
 232
 233        for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
 234                __free_page_cgroup(pfn);
 235        return 0;
 236
 237}
 238
 239static int __meminit page_cgroup_callback(struct notifier_block *self,
 240                               unsigned long action, void *arg)
 241{
 242        struct memory_notify *mn = arg;
 243        int ret = 0;
 244        switch (action) {
 245        case MEM_GOING_ONLINE:
 246                ret = online_page_cgroup(mn->start_pfn,
 247                                   mn->nr_pages, mn->status_change_nid);
 248                break;
 249        case MEM_OFFLINE:
 250                offline_page_cgroup(mn->start_pfn,
 251                                mn->nr_pages, mn->status_change_nid);
 252                break;
 253        case MEM_CANCEL_ONLINE:
 254                offline_page_cgroup(mn->start_pfn,
 255                                mn->nr_pages, mn->status_change_nid);
 256                break;
 257        case MEM_GOING_OFFLINE:
 258                break;
 259        case MEM_ONLINE:
 260        case MEM_CANCEL_OFFLINE:
 261                break;
 262        }
 263
 264        return notifier_from_errno(ret);
 265}
 266
 267#endif
 268
 269void __init page_cgroup_init(void)
 270{
 271        unsigned long pfn;
 272        int nid;
 273
 274        if (mem_cgroup_disabled())
 275                return;
 276
 277        for_each_node_state(nid, N_MEMORY) {
 278                unsigned long start_pfn, end_pfn;
 279
 280                start_pfn = node_start_pfn(nid);
 281                end_pfn = node_end_pfn(nid);
 282                /*
 283                 * start_pfn and end_pfn may not be aligned to SECTION and the
 284                 * page->flags of out of node pages are not initialized.  So we
 285                 * scan [start_pfn, the biggest section's pfn < end_pfn) here.
 286                 */
 287                for (pfn = start_pfn;
 288                     pfn < end_pfn;
 289                     pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
 290
 291                        if (!pfn_valid(pfn))
 292                                continue;
 293                        /*
 294                         * Nodes's pfns can be overlapping.
 295                         * We know some arch can have a nodes layout such as
 296                         * -------------pfn-------------->
 297                         * N0 | N1 | N2 | N0 | N1 | N2|....
 298                         */
 299                        if (pfn_to_nid(pfn) != nid)
 300                                continue;
 301                        if (init_section_page_cgroup(pfn, nid))
 302                                goto oom;
 303                }
 304        }
 305        hotplug_memory_notifier(page_cgroup_callback, 0);
 306        printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
 307        printk(KERN_INFO "please try 'cgroup_disable=memory' option if you "
 308                         "don't want memory cgroups\n");
 309        return;
 310oom:
 311        printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
 312        panic("Out of memory");
 313}
 314
 315void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
 316{
 317        return;
 318}
 319
 320#endif
 321
 322
 323#ifdef CONFIG_MEMCG_SWAP
 324
 325static DEFINE_MUTEX(swap_cgroup_mutex);
 326struct swap_cgroup_ctrl {
 327        struct page **map;
 328        unsigned long length;
 329        spinlock_t      lock;
 330};
 331
 332static struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
 333
 334struct swap_cgroup {
 335        unsigned short          id;
 336};
 337#define SC_PER_PAGE     (PAGE_SIZE/sizeof(struct swap_cgroup))
 338
 339/*
 340 * SwapCgroup implements "lookup" and "exchange" operations.
 341 * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
 342 * against SwapCache. At swap_free(), this is accessed directly from swap.
 343 *
 344 * This means,
 345 *  - we have no race in "exchange" when we're accessed via SwapCache because
 346 *    SwapCache(and its swp_entry) is under lock.
 347 *  - When called via swap_free(), there is no user of this entry and no race.
 348 * Then, we don't need lock around "exchange".
 349 *
 350 * TODO: we can push these buffers out to HIGHMEM.
 351 */
 352
 353/*
 354 * allocate buffer for swap_cgroup.
 355 */
 356static int swap_cgroup_prepare(int type)
 357{
 358        struct page *page;
 359        struct swap_cgroup_ctrl *ctrl;
 360        unsigned long idx, max;
 361
 362        ctrl = &swap_cgroup_ctrl[type];
 363
 364        for (idx = 0; idx < ctrl->length; idx++) {
 365                page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 366                if (!page)
 367                        goto not_enough_page;
 368                ctrl->map[idx] = page;
 369        }
 370        return 0;
 371not_enough_page:
 372        max = idx;
 373        for (idx = 0; idx < max; idx++)
 374                __free_page(ctrl->map[idx]);
 375
 376        return -ENOMEM;
 377}
 378
 379static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent,
 380                                        struct swap_cgroup_ctrl **ctrlp)
 381{
 382        pgoff_t offset = swp_offset(ent);
 383        struct swap_cgroup_ctrl *ctrl;
 384        struct page *mappage;
 385        struct swap_cgroup *sc;
 386
 387        ctrl = &swap_cgroup_ctrl[swp_type(ent)];
 388        if (ctrlp)
 389                *ctrlp = ctrl;
 390
 391        mappage = ctrl->map[offset / SC_PER_PAGE];
 392        sc = page_address(mappage);
 393        return sc + offset % SC_PER_PAGE;
 394}
 395
 396/**
 397 * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
 398 * @ent: swap entry to be cmpxchged
 399 * @old: old id
 400 * @new: new id
 401 *
 402 * Returns old id at success, 0 at failure.
 403 * (There is no mem_cgroup using 0 as its id)
 404 */
 405unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
 406                                        unsigned short old, unsigned short new)
 407{
 408        struct swap_cgroup_ctrl *ctrl;
 409        struct swap_cgroup *sc;
 410        unsigned long flags;
 411        unsigned short retval;
 412
 413        sc = lookup_swap_cgroup(ent, &ctrl);
 414
 415        spin_lock_irqsave(&ctrl->lock, flags);
 416        retval = sc->id;
 417        if (retval == old)
 418                sc->id = new;
 419        else
 420                retval = 0;
 421        spin_unlock_irqrestore(&ctrl->lock, flags);
 422        return retval;
 423}
 424
 425/**
 426 * swap_cgroup_record - record mem_cgroup for this swp_entry.
 427 * @ent: swap entry to be recorded into
 428 * @id: mem_cgroup to be recorded
 429 *
 430 * Returns old value at success, 0 at failure.
 431 * (Of course, old value can be 0.)
 432 */
 433unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
 434{
 435        struct swap_cgroup_ctrl *ctrl;
 436        struct swap_cgroup *sc;
 437        unsigned short old;
 438        unsigned long flags;
 439
 440        sc = lookup_swap_cgroup(ent, &ctrl);
 441
 442        spin_lock_irqsave(&ctrl->lock, flags);
 443        old = sc->id;
 444        sc->id = id;
 445        spin_unlock_irqrestore(&ctrl->lock, flags);
 446
 447        return old;
 448}
 449
 450/**
 451 * lookup_swap_cgroup_id - lookup mem_cgroup id tied to swap entry
 452 * @ent: swap entry to be looked up.
 453 *
 454 * Returns CSS ID of mem_cgroup at success. 0 at failure. (0 is invalid ID)
 455 */
 456unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
 457{
 458        return lookup_swap_cgroup(ent, NULL)->id;
 459}
 460
 461int swap_cgroup_swapon(int type, unsigned long max_pages)
 462{
 463        void *array;
 464        unsigned long array_size;
 465        unsigned long length;
 466        struct swap_cgroup_ctrl *ctrl;
 467
 468        if (!do_swap_account)
 469                return 0;
 470
 471        length = DIV_ROUND_UP(max_pages, SC_PER_PAGE);
 472        array_size = length * sizeof(void *);
 473
 474        array = vzalloc(array_size);
 475        if (!array)
 476                goto nomem;
 477
 478        ctrl = &swap_cgroup_ctrl[type];
 479        mutex_lock(&swap_cgroup_mutex);
 480        ctrl->length = length;
 481        ctrl->map = array;
 482        spin_lock_init(&ctrl->lock);
 483        if (swap_cgroup_prepare(type)) {
 484                /* memory shortage */
 485                ctrl->map = NULL;
 486                ctrl->length = 0;
 487                mutex_unlock(&swap_cgroup_mutex);
 488                vfree(array);
 489                goto nomem;
 490        }
 491        mutex_unlock(&swap_cgroup_mutex);
 492
 493        return 0;
 494nomem:
 495        printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.\n");
 496        printk(KERN_INFO
 497                "swap_cgroup can be disabled by swapaccount=0 boot option\n");
 498        return -ENOMEM;
 499}
 500
 501void swap_cgroup_swapoff(int type)
 502{
 503        struct page **map;
 504        unsigned long i, length;
 505        struct swap_cgroup_ctrl *ctrl;
 506
 507        if (!do_swap_account)
 508                return;
 509
 510        mutex_lock(&swap_cgroup_mutex);
 511        ctrl = &swap_cgroup_ctrl[type];
 512        map = ctrl->map;
 513        length = ctrl->length;
 514        ctrl->map = NULL;
 515        ctrl->length = 0;
 516        mutex_unlock(&swap_cgroup_mutex);
 517
 518        if (map) {
 519                for (i = 0; i < length; i++) {
 520                        struct page *page = map[i];
 521                        if (page)
 522                                __free_page(page);
 523                }
 524                vfree(map);
 525        }
 526}
 527
 528#endif
 529
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