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
14static 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}
22static unsigned long total_usage;
23
24#if !defined(CONFIG_SPARSEMEM)
25
26
27void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
28{
29	pgdat->node_page_cgroup = NULL;
30}
31
32struct 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
46static 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
73void __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;
90fail:
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
98struct 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() */
109static 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
164void __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
185int __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
210int __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
224static 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
256void __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
280void __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
290static DEFINE_MUTEX(swap_cgroup_mutex);
291struct swap_cgroup_ctrl {
292	struct page **map;
293	unsigned long length;
294	spinlock_t	lock;
295};
296
297struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
298
299struct 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 */
322static 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;
337not_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 */
354unsigned 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 */
390unsigned 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 */
421unsigned 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
440int 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;
474nomem:
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
481void 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
505