UPSTREAM mm: memcg: enable memcg OOM killer only for user faults
[linux-3.10.git] / 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_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