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 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

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