memcg: remove direct page_cgroup-to-page pointer
[linux-2.6.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 void __meminit init_page_cgroup(struct page_cgroup *pc, unsigned long id)
15 {
16         pc->flags = 0;
17         set_page_cgroup_array_id(pc, id);
18         pc->mem_cgroup = NULL;
19         INIT_LIST_HEAD(&pc->lru);
20 }
21 static unsigned long total_usage;
22
23 #if !defined(CONFIG_SPARSEMEM)
24
25
26 void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
27 {
28         pgdat->node_page_cgroup = NULL;
29 }
30
31 struct page_cgroup *lookup_page_cgroup(struct page *page)
32 {
33         unsigned long pfn = page_to_pfn(page);
34         unsigned long offset;
35         struct page_cgroup *base;
36
37         base = NODE_DATA(page_to_nid(page))->node_page_cgroup;
38         if (unlikely(!base))
39                 return NULL;
40
41         offset = pfn - NODE_DATA(page_to_nid(page))->node_start_pfn;
42         return base + offset;
43 }
44
45 struct page *lookup_cgroup_page(struct page_cgroup *pc)
46 {
47         unsigned long pfn;
48         struct page *page;
49         pg_data_t *pgdat;
50
51         pgdat = NODE_DATA(page_cgroup_array_id(pc));
52         pfn = pc - pgdat->node_page_cgroup + pgdat->node_start_pfn;
53         page = pfn_to_page(pfn);
54         VM_BUG_ON(pc != lookup_page_cgroup(page));
55         return page;
56 }
57
58 static int __init alloc_node_page_cgroup(int nid)
59 {
60         struct page_cgroup *base, *pc;
61         unsigned long table_size;
62         unsigned long start_pfn, nr_pages, index;
63
64         start_pfn = NODE_DATA(nid)->node_start_pfn;
65         nr_pages = NODE_DATA(nid)->node_spanned_pages;
66
67         if (!nr_pages)
68                 return 0;
69
70         table_size = sizeof(struct page_cgroup) * nr_pages;
71
72         base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
73                         table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
74         if (!base)
75                 return -ENOMEM;
76         for (index = 0; index < nr_pages; index++) {
77                 pc = base + index;
78                 init_page_cgroup(pc, nid);
79         }
80         NODE_DATA(nid)->node_page_cgroup = base;
81         total_usage += table_size;
82         return 0;
83 }
84
85 void __init page_cgroup_init_flatmem(void)
86 {
87
88         int nid, fail;
89
90         if (mem_cgroup_disabled())
91                 return;
92
93         for_each_online_node(nid)  {
94                 fail = alloc_node_page_cgroup(nid);
95                 if (fail)
96                         goto fail;
97         }
98         printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
99         printk(KERN_INFO "please try 'cgroup_disable=memory' option if you"
100         " don't want memory cgroups\n");
101         return;
102 fail:
103         printk(KERN_CRIT "allocation of page_cgroup failed.\n");
104         printk(KERN_CRIT "please try 'cgroup_disable=memory' boot option\n");
105         panic("Out of memory");
106 }
107
108 #else /* CONFIG_FLAT_NODE_MEM_MAP */
109
110 struct page_cgroup *lookup_page_cgroup(struct page *page)
111 {
112         unsigned long pfn = page_to_pfn(page);
113         struct mem_section *section = __pfn_to_section(pfn);
114
115         if (!section->page_cgroup)
116                 return NULL;
117         return section->page_cgroup + pfn;
118 }
119
120 struct page *lookup_cgroup_page(struct page_cgroup *pc)
121 {
122         struct mem_section *section;
123         struct page *page;
124         unsigned long nr;
125
126         nr = page_cgroup_array_id(pc);
127         section = __nr_to_section(nr);
128         page = pfn_to_page(pc - section->page_cgroup);
129         VM_BUG_ON(pc != lookup_page_cgroup(page));
130         return page;
131 }
132
133 /* __alloc_bootmem...() is protected by !slab_available() */
134 static int __init_refok init_section_page_cgroup(unsigned long pfn)
135 {
136         struct page_cgroup *base, *pc;
137         struct mem_section *section;
138         unsigned long table_size;
139         unsigned long nr;
140         int nid, index;
141
142         nr = pfn_to_section_nr(pfn);
143         section = __nr_to_section(nr);
144
145         if (section->page_cgroup)
146                 return 0;
147
148         nid = page_to_nid(pfn_to_page(pfn));
149         table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
150         VM_BUG_ON(!slab_is_available());
151         if (node_state(nid, N_HIGH_MEMORY)) {
152                 base = kmalloc_node(table_size,
153                                     GFP_KERNEL | __GFP_NOWARN, nid);
154                 if (!base)
155                         base = vmalloc_node(table_size, nid);
156         } else {
157                 base = kmalloc(table_size, GFP_KERNEL | __GFP_NOWARN);
158                 if (!base)
159                         base = vmalloc(table_size);
160         }
161         /*
162          * The value stored in section->page_cgroup is (base - pfn)
163          * and it does not point to the memory block allocated above,
164          * causing kmemleak false positives.
165          */
166         kmemleak_not_leak(base);
167
168         if (!base) {
169                 printk(KERN_ERR "page cgroup allocation failure\n");
170                 return -ENOMEM;
171         }
172
173         for (index = 0; index < PAGES_PER_SECTION; index++) {
174                 pc = base + index;
175                 init_page_cgroup(pc, nr);
176         }
177
178         section->page_cgroup = base - pfn;
179         total_usage += table_size;
180         return 0;
181 }
182 #ifdef CONFIG_MEMORY_HOTPLUG
183 void __free_page_cgroup(unsigned long pfn)
184 {
185         struct mem_section *ms;
186         struct page_cgroup *base;
187
188         ms = __pfn_to_section(pfn);
189         if (!ms || !ms->page_cgroup)
190                 return;
191         base = ms->page_cgroup + pfn;
192         if (is_vmalloc_addr(base)) {
193                 vfree(base);
194                 ms->page_cgroup = NULL;
195         } else {
196                 struct page *page = virt_to_page(base);
197                 if (!PageReserved(page)) { /* Is bootmem ? */
198                         kfree(base);
199                         ms->page_cgroup = NULL;
200                 }
201         }
202 }
203
204 int __meminit online_page_cgroup(unsigned long start_pfn,
205                         unsigned long nr_pages,
206                         int nid)
207 {
208         unsigned long start, end, pfn;
209         int fail = 0;
210
211         start = start_pfn & ~(PAGES_PER_SECTION - 1);
212         end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);
213
214         for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
215                 if (!pfn_present(pfn))
216                         continue;
217                 fail = init_section_page_cgroup(pfn);
218         }
219         if (!fail)
220                 return 0;
221
222         /* rollback */
223         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
224                 __free_page_cgroup(pfn);
225
226         return -ENOMEM;
227 }
228
229 int __meminit offline_page_cgroup(unsigned long start_pfn,
230                 unsigned long nr_pages, int nid)
231 {
232         unsigned long start, end, pfn;
233
234         start = start_pfn & ~(PAGES_PER_SECTION - 1);
235         end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);
236
237         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
238                 __free_page_cgroup(pfn);
239         return 0;
240
241 }
242
243 static int __meminit page_cgroup_callback(struct notifier_block *self,
244                                unsigned long action, void *arg)
245 {
246         struct memory_notify *mn = arg;
247         int ret = 0;
248         switch (action) {
249         case MEM_GOING_ONLINE:
250                 ret = online_page_cgroup(mn->start_pfn,
251                                    mn->nr_pages, mn->status_change_nid);
252                 break;
253         case MEM_OFFLINE:
254                 offline_page_cgroup(mn->start_pfn,
255                                 mn->nr_pages, mn->status_change_nid);
256                 break;
257         case MEM_CANCEL_ONLINE:
258         case MEM_GOING_OFFLINE:
259                 break;
260         case MEM_ONLINE:
261         case MEM_CANCEL_OFFLINE:
262                 break;
263         }
264
265         return notifier_from_errno(ret);
266 }
267
268 #endif
269
270 void __init page_cgroup_init(void)
271 {
272         unsigned long pfn;
273         int fail = 0;
274
275         if (mem_cgroup_disabled())
276                 return;
277
278         for (pfn = 0; !fail && pfn < max_pfn; pfn += PAGES_PER_SECTION) {
279                 if (!pfn_present(pfn))
280                         continue;
281                 fail = init_section_page_cgroup(pfn);
282         }
283         if (fail) {
284                 printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
285                 panic("Out of memory");
286         } else {
287                 hotplug_memory_notifier(page_cgroup_callback, 0);
288         }
289         printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
290         printk(KERN_INFO "please try 'cgroup_disable=memory' option if you don't"
291         " want memory cgroups\n");
292 }
293
294 void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
295 {
296         return;
297 }
298
299 #endif
300
301
302 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
303
304 static DEFINE_MUTEX(swap_cgroup_mutex);
305 struct swap_cgroup_ctrl {
306         struct page **map;
307         unsigned long length;
308         spinlock_t      lock;
309 };
310
311 struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
312
313 struct swap_cgroup {
314         unsigned short          id;
315 };
316 #define SC_PER_PAGE     (PAGE_SIZE/sizeof(struct swap_cgroup))
317 #define SC_POS_MASK     (SC_PER_PAGE - 1)
318
319 /*
320  * SwapCgroup implements "lookup" and "exchange" operations.
321  * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
322  * against SwapCache. At swap_free(), this is accessed directly from swap.
323  *
324  * This means,
325  *  - we have no race in "exchange" when we're accessed via SwapCache because
326  *    SwapCache(and its swp_entry) is under lock.
327  *  - When called via swap_free(), there is no user of this entry and no race.
328  * Then, we don't need lock around "exchange".
329  *
330  * TODO: we can push these buffers out to HIGHMEM.
331  */
332
333 /*
334  * allocate buffer for swap_cgroup.
335  */
336 static int swap_cgroup_prepare(int type)
337 {
338         struct page *page;
339         struct swap_cgroup_ctrl *ctrl;
340         unsigned long idx, max;
341
342         ctrl = &swap_cgroup_ctrl[type];
343
344         for (idx = 0; idx < ctrl->length; idx++) {
345                 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
346                 if (!page)
347                         goto not_enough_page;
348                 ctrl->map[idx] = page;
349         }
350         return 0;
351 not_enough_page:
352         max = idx;
353         for (idx = 0; idx < max; idx++)
354                 __free_page(ctrl->map[idx]);
355
356         return -ENOMEM;
357 }
358
359 /**
360  * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
361  * @end: swap entry to be cmpxchged
362  * @old: old id
363  * @new: new id
364  *
365  * Returns old id at success, 0 at failure.
366  * (There is no mem_cgroup useing 0 as its id)
367  */
368 unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
369                                         unsigned short old, unsigned short new)
370 {
371         int type = swp_type(ent);
372         unsigned long offset = swp_offset(ent);
373         unsigned long idx = offset / SC_PER_PAGE;
374         unsigned long pos = offset & SC_POS_MASK;
375         struct swap_cgroup_ctrl *ctrl;
376         struct page *mappage;
377         struct swap_cgroup *sc;
378         unsigned long flags;
379         unsigned short retval;
380
381         ctrl = &swap_cgroup_ctrl[type];
382
383         mappage = ctrl->map[idx];
384         sc = page_address(mappage);
385         sc += pos;
386         spin_lock_irqsave(&ctrl->lock, flags);
387         retval = sc->id;
388         if (retval == old)
389                 sc->id = new;
390         else
391                 retval = 0;
392         spin_unlock_irqrestore(&ctrl->lock, flags);
393         return retval;
394 }
395
396 /**
397  * swap_cgroup_record - record mem_cgroup for this swp_entry.
398  * @ent: swap entry to be recorded into
399  * @mem: mem_cgroup to be recorded
400  *
401  * Returns old value at success, 0 at failure.
402  * (Of course, old value can be 0.)
403  */
404 unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
405 {
406         int type = swp_type(ent);
407         unsigned long offset = swp_offset(ent);
408         unsigned long idx = offset / SC_PER_PAGE;
409         unsigned long pos = offset & SC_POS_MASK;
410         struct swap_cgroup_ctrl *ctrl;
411         struct page *mappage;
412         struct swap_cgroup *sc;
413         unsigned short old;
414         unsigned long flags;
415
416         ctrl = &swap_cgroup_ctrl[type];
417
418         mappage = ctrl->map[idx];
419         sc = page_address(mappage);
420         sc += pos;
421         spin_lock_irqsave(&ctrl->lock, flags);
422         old = sc->id;
423         sc->id = id;
424         spin_unlock_irqrestore(&ctrl->lock, flags);
425
426         return old;
427 }
428
429 /**
430  * lookup_swap_cgroup - lookup mem_cgroup tied to swap entry
431  * @ent: swap entry to be looked up.
432  *
433  * Returns CSS ID of mem_cgroup at success. 0 at failure. (0 is invalid ID)
434  */
435 unsigned short lookup_swap_cgroup(swp_entry_t ent)
436 {
437         int type = swp_type(ent);
438         unsigned long offset = swp_offset(ent);
439         unsigned long idx = offset / SC_PER_PAGE;
440         unsigned long pos = offset & SC_POS_MASK;
441         struct swap_cgroup_ctrl *ctrl;
442         struct page *mappage;
443         struct swap_cgroup *sc;
444         unsigned short ret;
445
446         ctrl = &swap_cgroup_ctrl[type];
447         mappage = ctrl->map[idx];
448         sc = page_address(mappage);
449         sc += pos;
450         ret = sc->id;
451         return ret;
452 }
453
454 int swap_cgroup_swapon(int type, unsigned long max_pages)
455 {
456         void *array;
457         unsigned long array_size;
458         unsigned long length;
459         struct swap_cgroup_ctrl *ctrl;
460
461         if (!do_swap_account)
462                 return 0;
463
464         length = ((max_pages/SC_PER_PAGE) + 1);
465         array_size = length * sizeof(void *);
466
467         array = vmalloc(array_size);
468         if (!array)
469                 goto nomem;
470
471         memset(array, 0, array_size);
472         ctrl = &swap_cgroup_ctrl[type];
473         mutex_lock(&swap_cgroup_mutex);
474         ctrl->length = length;
475         ctrl->map = array;
476         spin_lock_init(&ctrl->lock);
477         if (swap_cgroup_prepare(type)) {
478                 /* memory shortage */
479                 ctrl->map = NULL;
480                 ctrl->length = 0;
481                 vfree(array);
482                 mutex_unlock(&swap_cgroup_mutex);
483                 goto nomem;
484         }
485         mutex_unlock(&swap_cgroup_mutex);
486
487         return 0;
488 nomem:
489         printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.\n");
490         printk(KERN_INFO
491                 "swap_cgroup can be disabled by noswapaccount boot option\n");
492         return -ENOMEM;
493 }
494
495 void swap_cgroup_swapoff(int type)
496 {
497         int i;
498         struct swap_cgroup_ctrl *ctrl;
499
500         if (!do_swap_account)
501                 return;
502
503         mutex_lock(&swap_cgroup_mutex);
504         ctrl = &swap_cgroup_ctrl[type];
505         if (ctrl->map) {
506                 for (i = 0; i < ctrl->length; i++) {
507                         struct page *page = ctrl->map[i];
508                         if (page)
509                                 __free_page(page);
510                 }
511                 vfree(ctrl->map);
512                 ctrl->map = NULL;
513                 ctrl->length = 0;
514         }
515         mutex_unlock(&swap_cgroup_mutex);
516 }
517
518 #endif