page_cgroup: add helper function to get swap_cgroup
[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 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 #ifdef CONFIG_MEMORY_HOTPLUG
128 static void free_page_cgroup(void *addr)
129 {
130         if (is_vmalloc_addr(addr)) {
131                 vfree(addr);
132         } else {
133                 struct page *page = virt_to_page(addr);
134                 size_t table_size =
135                         sizeof(struct page_cgroup) * PAGES_PER_SECTION;
136
137                 BUG_ON(PageReserved(page));
138                 free_pages_exact(addr, table_size);
139         }
140 }
141 #endif
142
143 static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
144 {
145         struct mem_section *section;
146         struct page_cgroup *base;
147         unsigned long table_size;
148
149         section = __pfn_to_section(pfn);
150
151         if (section->page_cgroup)
152                 return 0;
153
154         table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
155         base = alloc_page_cgroup(table_size, nid);
156
157         /*
158          * The value stored in section->page_cgroup is (base - pfn)
159          * and it does not point to the memory block allocated above,
160          * causing kmemleak false positives.
161          */
162         kmemleak_not_leak(base);
163
164         if (!base) {
165                 printk(KERN_ERR "page cgroup allocation failure\n");
166                 return -ENOMEM;
167         }
168
169         /*
170          * The passed "pfn" may not be aligned to SECTION.  For the calculation
171          * we need to apply a mask.
172          */
173         pfn &= PAGE_SECTION_MASK;
174         section->page_cgroup = base - pfn;
175         total_usage += table_size;
176         return 0;
177 }
178 #ifdef CONFIG_MEMORY_HOTPLUG
179 void __free_page_cgroup(unsigned long pfn)
180 {
181         struct mem_section *ms;
182         struct page_cgroup *base;
183
184         ms = __pfn_to_section(pfn);
185         if (!ms || !ms->page_cgroup)
186                 return;
187         base = ms->page_cgroup + pfn;
188         free_page_cgroup(base);
189         ms->page_cgroup = NULL;
190 }
191
192 int __meminit online_page_cgroup(unsigned long start_pfn,
193                         unsigned long nr_pages,
194                         int nid)
195 {
196         unsigned long start, end, pfn;
197         int fail = 0;
198
199         start = SECTION_ALIGN_DOWN(start_pfn);
200         end = SECTION_ALIGN_UP(start_pfn + nr_pages);
201
202         if (nid == -1) {
203                 /*
204                  * In this case, "nid" already exists and contains valid memory.
205                  * "start_pfn" passed to us is a pfn which is an arg for
206                  * online__pages(), and start_pfn should exist.
207                  */
208                 nid = pfn_to_nid(start_pfn);
209                 VM_BUG_ON(!node_state(nid, N_ONLINE));
210         }
211
212         for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
213                 if (!pfn_present(pfn))
214                         continue;
215                 fail = init_section_page_cgroup(pfn, nid);
216         }
217         if (!fail)
218                 return 0;
219
220         /* rollback */
221         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
222                 __free_page_cgroup(pfn);
223
224         return -ENOMEM;
225 }
226
227 int __meminit offline_page_cgroup(unsigned long start_pfn,
228                 unsigned long nr_pages, int nid)
229 {
230         unsigned long start, end, pfn;
231
232         start = SECTION_ALIGN_DOWN(start_pfn);
233         end = SECTION_ALIGN_UP(start_pfn + nr_pages);
234
235         for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
236                 __free_page_cgroup(pfn);
237         return 0;
238
239 }
240
241 static int __meminit page_cgroup_callback(struct notifier_block *self,
242                                unsigned long action, void *arg)
243 {
244         struct memory_notify *mn = arg;
245         int ret = 0;
246         switch (action) {
247         case MEM_GOING_ONLINE:
248                 ret = online_page_cgroup(mn->start_pfn,
249                                    mn->nr_pages, mn->status_change_nid);
250                 break;
251         case MEM_OFFLINE:
252                 offline_page_cgroup(mn->start_pfn,
253                                 mn->nr_pages, mn->status_change_nid);
254                 break;
255         case MEM_CANCEL_ONLINE:
256         case MEM_GOING_OFFLINE:
257                 break;
258         case MEM_ONLINE:
259         case MEM_CANCEL_OFFLINE:
260                 break;
261         }
262
263         return notifier_from_errno(ret);
264 }
265
266 #endif
267
268 void __init page_cgroup_init(void)
269 {
270         unsigned long pfn;
271         int nid;
272
273         if (mem_cgroup_disabled())
274                 return;
275
276         for_each_node_state(nid, N_HIGH_MEMORY) {
277                 unsigned long start_pfn, end_pfn;
278
279                 start_pfn = node_start_pfn(nid);
280                 end_pfn = node_end_pfn(nid);
281                 /*
282                  * start_pfn and end_pfn may not be aligned to SECTION and the
283                  * page->flags of out of node pages are not initialized.  So we
284                  * scan [start_pfn, the biggest section's pfn < end_pfn) here.
285                  */
286                 for (pfn = start_pfn;
287                      pfn < end_pfn;
288                      pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
289
290                         if (!pfn_valid(pfn))
291                                 continue;
292                         /*
293                          * Nodes's pfns can be overlapping.
294                          * We know some arch can have a nodes layout such as
295                          * -------------pfn-------------->
296                          * N0 | N1 | N2 | N0 | N1 | N2|....
297                          */
298                         if (pfn_to_nid(pfn) != nid)
299                                 continue;
300                         if (init_section_page_cgroup(pfn, nid))
301                                 goto oom;
302                 }
303         }
304         hotplug_memory_notifier(page_cgroup_callback, 0);
305         printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
306         printk(KERN_INFO "please try 'cgroup_disable=memory' option if you "
307                          "don't want memory cgroups\n");
308         return;
309 oom:
310         printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
311         panic("Out of memory");
312 }
313
314 void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
315 {
316         return;
317 }
318
319 #endif
320
321
322 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
323
324 static DEFINE_MUTEX(swap_cgroup_mutex);
325 struct swap_cgroup_ctrl {
326         struct page **map;
327         unsigned long length;
328         spinlock_t      lock;
329 };
330
331 static struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
332
333 struct swap_cgroup {
334         unsigned short          id;
335 };
336 #define SC_PER_PAGE     (PAGE_SIZE/sizeof(struct swap_cgroup))
337
338 /*
339  * SwapCgroup implements "lookup" and "exchange" operations.
340  * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
341  * against SwapCache. At swap_free(), this is accessed directly from swap.
342  *
343  * This means,
344  *  - we have no race in "exchange" when we're accessed via SwapCache because
345  *    SwapCache(and its swp_entry) is under lock.
346  *  - When called via swap_free(), there is no user of this entry and no race.
347  * Then, we don't need lock around "exchange".
348  *
349  * TODO: we can push these buffers out to HIGHMEM.
350  */
351
352 /*
353  * allocate buffer for swap_cgroup.
354  */
355 static int swap_cgroup_prepare(int type)
356 {
357         struct page *page;
358         struct swap_cgroup_ctrl *ctrl;
359         unsigned long idx, max;
360
361         ctrl = &swap_cgroup_ctrl[type];
362
363         for (idx = 0; idx < ctrl->length; idx++) {
364                 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
365                 if (!page)
366                         goto not_enough_page;
367                 ctrl->map[idx] = page;
368         }
369         return 0;
370 not_enough_page:
371         max = idx;
372         for (idx = 0; idx < max; idx++)
373                 __free_page(ctrl->map[idx]);
374
375         return -ENOMEM;
376 }
377
378 static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent,
379                                         struct swap_cgroup_ctrl **ctrlp)
380 {
381         pgoff_t offset = swp_offset(ent);
382         struct swap_cgroup_ctrl *ctrl;
383         struct page *mappage;
384
385         ctrl = &swap_cgroup_ctrl[swp_type(ent)];
386         if (ctrlp)
387                 *ctrlp = ctrl;
388
389         mappage = ctrl->map[offset / SC_PER_PAGE];
390         return page_address(mappage) + offset % SC_PER_PAGE;
391 }
392
393 /**
394  * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
395  * @end: 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  * @mem: 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