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         case MEM_GOING_OFFLINE:
 255                 break;
 256         case MEM_ONLINE:
 257         case MEM_CANCEL_OFFLINE:
 258                 break;
 259         }
 260
 261         return notifier_from_errno(ret);
 262 }
 263
 264 #endif
 265
 266 void __init page_cgroup_init(void)
 267 {
 268         unsigned long pfn;
 269         int nid;
 270
 271         if (mem_cgroup_disabled())
 272                 return;
 273
 274         for_each_node_state(nid, N_HIGH_MEMORY) {
 275                 unsigned long start_pfn, end_pfn;
 276
 277                 start_pfn = node_start_pfn(nid);
 278                 end_pfn = node_end_pfn(nid);
 279                 /*
 280                  * start_pfn and end_pfn may not be aligned to SECTION and the
 281                  * page->flags of out of node pages are not initialized.  So we
 282                  * scan [start_pfn, the biggest section's pfn < end_pfn) here.
 283                  */
 284                 for (pfn = start_pfn;
 285                      pfn < end_pfn;
 286                      pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
 287
 288                         if (!pfn_valid(pfn))
 289                                 continue;
 290                         /*
 291                          * Nodes's pfns can be overlapping.
 292                          * We know some arch can have a nodes layout such as
 293                          * -------------pfn-------------->
 294                          * N0 | N1 | N2 | N0 | N1 | N2|....
 295                          */
 296                         if (pfn_to_nid(pfn) != nid)
 297                                 continue;
 298                         if (init_section_page_cgroup(pfn, nid))
 299                                 goto oom;
 300                 }
 301         }
 302         hotplug_memory_notifier(page_cgroup_callback, 0);
 303         printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
 304         printk(KERN_INFO "please try 'cgroup_disable=memory' option if you "
 305                          "don't want memory cgroups\n");
 306         return;
 307 oom:
 308         printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
 309         panic("Out of memory");
 310 }
 311
 312 void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
 313 {
 314         return;
 315 }
 316
 317 #endif
 318
 319
 320 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 321
 322 static DEFINE_MUTEX(swap_cgroup_mutex);
 323 struct swap_cgroup_ctrl {
 324         struct page **map;
 325         unsigned long length;
 326         spinlock_t      lock;
 327 };
 328
 329 static struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
 330
 331 struct swap_cgroup {
 332         unsigned short          id;
 333 };
 334 #define SC_PER_PAGE     (PAGE_SIZE/sizeof(struct swap_cgroup))
 335
 336 /*
 337  * SwapCgroup implements "lookup" and "exchange" operations.
 338  * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
 339  * against SwapCache. At swap_free(), this is accessed directly from swap.
 340  *
 341  * This means,
 342  *  - we have no race in "exchange" when we're accessed via SwapCache because
 343  *    SwapCache(and its swp_entry) is under lock.
 344  *  - When called via swap_free(), there is no user of this entry and no race.
 345  * Then, we don't need lock around "exchange".
 346  *
 347  * TODO: we can push these buffers out to HIGHMEM.
 348  */
 349
 350 /*
 351  * allocate buffer for swap_cgroup.
 352  */
 353 static int swap_cgroup_prepare(int type)
 354 {
 355         struct page *page;
 356         struct swap_cgroup_ctrl *ctrl;
 357         unsigned long idx, max;
 358
 359         ctrl = &swap_cgroup_ctrl[type];
 360
 361         for (idx = 0; idx < ctrl->length; idx++) {
 362                 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
 363                 if (!page)
 364                         goto not_enough_page;
 365                 ctrl->map[idx] = page;
 366         }
 367         return 0;
 368 not_enough_page:
 369         max = idx;
 370         for (idx = 0; idx < max; idx++)
 371                 __free_page(ctrl->map[idx]);
 372
 373         return -ENOMEM;
 374 }
 375
 376 static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent,
 377                                         struct swap_cgroup_ctrl **ctrlp)
 378 {
 379         pgoff_t offset = swp_offset(ent);
 380         struct swap_cgroup_ctrl *ctrl;
 381         struct page *mappage;
 382         struct swap_cgroup *sc;
 383
 384         ctrl = &swap_cgroup_ctrl[swp_type(ent)];
 385         if (ctrlp)
 386                 *ctrlp = ctrl;
 387
 388         mappage = ctrl->map[offset / SC_PER_PAGE];
 389         sc = page_address(mappage);
 390         return sc + offset % SC_PER_PAGE;
 391 }
 392
 393 /**
 394  * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
 395  * @ent: swap entry to be cmpxchged
 396  * @old: old id
 397  * @new: new id
 398  *
 399  * Returns old id at success, 0 at failure.
 400  * (There is no mem_cgroup using 0 as its id)
 401  */
 402 unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
 403                                         unsigned short old, unsigned short new)
 404 {
 405         struct swap_cgroup_ctrl *ctrl;
 406         struct swap_cgroup *sc;
 407         unsigned long flags;
 408         unsigned short retval;
 409
 410         sc = lookup_swap_cgroup(ent, &ctrl);
 411
 412         spin_lock_irqsave(&ctrl->lock, flags);
 413         retval = sc->id;
 414         if (retval == old)
 415                 sc->id = new;
 416         else
 417                 retval = 0;
 418         spin_unlock_irqrestore(&ctrl->lock, flags);
 419         return retval;
 420 }
 421
 422 /**
 423  * swap_cgroup_record - record mem_cgroup for this swp_entry.
 424  * @ent: swap entry to be recorded into
 425  * @id: mem_cgroup to be recorded
 426  *
 427  * Returns old value at success, 0 at failure.
 428  * (Of course, old value can be 0.)
 429  */
 430 unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
 431 {
 432         struct swap_cgroup_ctrl *ctrl;
 433         struct swap_cgroup *sc;
 434         unsigned short old;
 435         unsigned long flags;
 436
 437         sc = lookup_swap_cgroup(ent, &ctrl);
 438
 439         spin_lock_irqsave(&ctrl->lock, flags);
 440         old = sc->id;
 441         sc->id = id;
 442         spin_unlock_irqrestore(&ctrl->lock, flags);
 443
 444         return old;
 445 }
 446
 447 /**
 448  * lookup_swap_cgroup_id - lookup mem_cgroup id tied to swap entry
 449  * @ent: swap entry to be looked up.
 450  *
 451  * Returns CSS ID of mem_cgroup at success. 0 at failure. (0 is invalid ID)
 452  */
 453 unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
 454 {
 455         return lookup_swap_cgroup(ent, NULL)->id;
 456 }
 457
 458 int swap_cgroup_swapon(int type, unsigned long max_pages)
 459 {
 460         void *array;
 461         unsigned long array_size;
 462         unsigned long length;
 463         struct swap_cgroup_ctrl *ctrl;
 464
 465         if (!do_swap_account)
 466                 return 0;
 467
 468         length = DIV_ROUND_UP(max_pages, SC_PER_PAGE);
 469         array_size = length * sizeof(void *);
 470
 471         array = vzalloc(array_size);
 472         if (!array)
 473                 goto nomem;
 474
 475         ctrl = &swap_cgroup_ctrl[type];
 476         mutex_lock(&swap_cgroup_mutex);
 477         ctrl->length = length;
 478         ctrl->map = array;
 479         spin_lock_init(&ctrl->lock);
 480         if (swap_cgroup_prepare(type)) {
 481                 /* memory shortage */
 482                 ctrl->map = NULL;
 483                 ctrl->length = 0;
 484                 mutex_unlock(&swap_cgroup_mutex);
 485                 vfree(array);
 486                 goto nomem;
 487         }
 488         mutex_unlock(&swap_cgroup_mutex);
 489
 490         return 0;
 491 nomem:
 492         printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.\n");
 493         printk(KERN_INFO
 494                 "swap_cgroup can be disabled by swapaccount=0 boot option\n");
 495         return -ENOMEM;
 496 }
 497
 498 void swap_cgroup_swapoff(int type)
 499 {
 500         struct page **map;
 501         unsigned long i, length;
 502         struct swap_cgroup_ctrl *ctrl;
 503
 504         if (!do_swap_account)
 505                 return;
 506
 507         mutex_lock(&swap_cgroup_mutex);
 508         ctrl = &swap_cgroup_ctrl[type];
 509         map = ctrl->map;
 510         length = ctrl->length;
 511         ctrl->map = NULL;
 512         ctrl->length = 0;
 513         mutex_unlock(&swap_cgroup_mutex);
 514
 515         if (map) {
 516                 for (i = 0; i < length; i++) {
 517                         struct page *page = map[i];
 518                         if (page)
 519                                 __free_page(page);
 520                 }
 521                 vfree(map);
 522         }
 523 }
 524
 525 #endif