Root/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
14static unsigned long total_usage;
15
16#if !defined(CONFIG_SPARSEMEM)
17
18
19void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
20{
21    pgdat->node_page_cgroup = NULL;
22}
23
24struct 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
45static 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
66void __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;
83fail:
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
91struct 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
108static 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
127static 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
163static 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
177void __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
190int __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
225int __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
239static 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    case MEM_GOING_OFFLINE:
255        break;
256    case MEM_ONLINE:
257    case MEM_CANCEL_OFFLINE:
258        break;
259    }
260
261    return notifier_from_errno(ret);
262}
263
264#endif
265
266void __init page_cgroup_init(void)
267{
268    unsigned long pfn;
269    int nid;
270
271    if (mem_cgroup_disabled())
272        return;
273
274    for_each_node_state(nid, N_HIGH_MEMORY) {
275        unsigned long start_pfn, end_pfn;
276
277        start_pfn = node_start_pfn(nid);
278        end_pfn = node_end_pfn(nid);
279        /*
280         * start_pfn and end_pfn may not be aligned to SECTION and the
281         * page->flags of out of node pages are not initialized. So we
282         * scan [start_pfn, the biggest section's pfn < end_pfn) here.
283         */
284        for (pfn = start_pfn;
285             pfn < end_pfn;
286                     pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
287
288            if (!pfn_valid(pfn))
289                continue;
290            /*
291             * Nodes's pfns can be overlapping.
292             * We know some arch can have a nodes layout such as
293             * -------------pfn-------------->
294             * N0 | N1 | N2 | N0 | N1 | N2|....
295             */
296            if (pfn_to_nid(pfn) != nid)
297                continue;
298            if (init_section_page_cgroup(pfn, nid))
299                goto oom;
300        }
301    }
302    hotplug_memory_notifier(page_cgroup_callback, 0);
303    printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
304    printk(KERN_INFO "please try 'cgroup_disable=memory' option if you "
305             "don't want memory cgroups\n");
306    return;
307oom:
308    printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
309    panic("Out of memory");
310}
311
312void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
313{
314    return;
315}
316
317#endif
318
319
320#ifdef CONFIG_MEMCG_SWAP
321
322static DEFINE_MUTEX(swap_cgroup_mutex);
323struct swap_cgroup_ctrl {
324    struct page **map;
325    unsigned long length;
326    spinlock_t lock;
327};
328
329static struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
330
331struct swap_cgroup {
332    unsigned short id;
333};
334#define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup))
335
336/*
337 * SwapCgroup implements "lookup" and "exchange" operations.
338 * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
339 * against SwapCache. At swap_free(), this is accessed directly from swap.
340 *
341 * This means,
342 * - we have no race in "exchange" when we're accessed via SwapCache because
343 * SwapCache(and its swp_entry) is under lock.
344 * - When called via swap_free(), there is no user of this entry and no race.
345 * Then, we don't need lock around "exchange".
346 *
347 * TODO: we can push these buffers out to HIGHMEM.
348 */
349
350/*
351 * allocate buffer for swap_cgroup.
352 */
353static int swap_cgroup_prepare(int type)
354{
355    struct page *page;
356    struct swap_cgroup_ctrl *ctrl;
357    unsigned long idx, max;
358
359    ctrl = &swap_cgroup_ctrl[type];
360
361    for (idx = 0; idx < ctrl->length; idx++) {
362        page = alloc_page(GFP_KERNEL | __GFP_ZERO);
363        if (!page)
364            goto not_enough_page;
365        ctrl->map[idx] = page;
366    }
367    return 0;
368not_enough_page:
369    max = idx;
370    for (idx = 0; idx < max; idx++)
371        __free_page(ctrl->map[idx]);
372
373    return -ENOMEM;
374}
375
376static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent,
377                    struct swap_cgroup_ctrl **ctrlp)
378{
379    pgoff_t offset = swp_offset(ent);
380    struct swap_cgroup_ctrl *ctrl;
381    struct page *mappage;
382    struct swap_cgroup *sc;
383
384    ctrl = &swap_cgroup_ctrl[swp_type(ent)];
385    if (ctrlp)
386        *ctrlp = ctrl;
387
388    mappage = ctrl->map[offset / SC_PER_PAGE];
389    sc = page_address(mappage);
390    return sc + offset % SC_PER_PAGE;
391}
392
393/**
394 * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
395 * @ent: 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 */
402unsigned 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 * @id: mem_cgroup to be recorded
426 *
427 * Returns old value at success, 0 at failure.
428 * (Of course, old value can be 0.)
429 */
430unsigned 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 */
453unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
454{
455    return lookup_swap_cgroup(ent, NULL)->id;
456}
457
458int 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;
491nomem:
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
498void 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
526

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