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