mm/page_cgroup.c

   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
  14 static unsigned long total_usage;
  15
  16 #if !defined(CONFIG_SPARSEMEM)
  17
  18
  19 void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
  20 {
  21         pgdat->node_page_cgroup = NULL;
  22 }
  23
  24 struct 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
  45 static 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
  66 void __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;
  83 fail:
  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
  91 struct 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
 108 static 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
 127 static 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
 163 static 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
 177 void __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
 190 int __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
 225 int __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
 239 static 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
 269 void __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_HIGH_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;
 310 oom:
 311         printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
 312         panic("Out of memory");
 313 }
 314
 315 void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
 316 {
 317         return;
 318 }
 319
 320 #endif
 321
 322
 323 #ifdef CONFIG_MEMCG_SWAP
 324
 325 static DEFINE_MUTEX(swap_cgroup_mutex);
 326 struct swap_cgroup_ctrl {
 327         struct page **map;
 328         unsigned long length;
 329         spinlock_t      lock;
 330 };
 331
 332 static struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
 333
 334 struct 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  */
 356 static 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;
 371 not_enough_page:
 372         max = idx;
 373         for (idx = 0; idx < max; idx++)
 374                 __free_page(ctrl->map[idx]);
 375
 376         return -ENOMEM;
 377 }
 378
 379 static 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  */
 405 unsigned 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  */
 433 unsigned 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  */
 456 unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
 457 {
 458         return lookup_swap_cgroup(ent, NULL)->id;
 459 }
 460
 461 int 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;
 494 nomem:
 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
 501 void 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