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