mm: swap: implement generic handler for swap_activate
[linux-3.10.git] / mm / hugetlb_cgroup.c
1 /*
2  *
3  * Copyright IBM Corporation, 2012
4  * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of version 2.1 of the GNU Lesser General Public License
8  * as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it would be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
13  *
14  */
15
16 #include <linux/cgroup.h>
17 #include <linux/slab.h>
18 #include <linux/hugetlb.h>
19 #include <linux/hugetlb_cgroup.h>
20
21 struct hugetlb_cgroup {
22         struct cgroup_subsys_state css;
23         /*
24          * the counter to account for hugepages from hugetlb.
25          */
26         struct res_counter hugepage[HUGE_MAX_HSTATE];
27 };
28
29 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
30 #define MEMFILE_IDX(val)        (((val) >> 16) & 0xffff)
31 #define MEMFILE_ATTR(val)       ((val) & 0xffff)
32
33 struct cgroup_subsys hugetlb_subsys __read_mostly;
34 static struct hugetlb_cgroup *root_h_cgroup __read_mostly;
35
36 static inline
37 struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s)
38 {
39         return container_of(s, struct hugetlb_cgroup, css);
40 }
41
42 static inline
43 struct hugetlb_cgroup *hugetlb_cgroup_from_cgroup(struct cgroup *cgroup)
44 {
45         return hugetlb_cgroup_from_css(cgroup_subsys_state(cgroup,
46                                                            hugetlb_subsys_id));
47 }
48
49 static inline
50 struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
51 {
52         return hugetlb_cgroup_from_css(task_subsys_state(task,
53                                                          hugetlb_subsys_id));
54 }
55
56 static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
57 {
58         return (h_cg == root_h_cgroup);
59 }
60
61 static inline struct hugetlb_cgroup *parent_hugetlb_cgroup(struct cgroup *cg)
62 {
63         if (!cg->parent)
64                 return NULL;
65         return hugetlb_cgroup_from_cgroup(cg->parent);
66 }
67
68 static inline bool hugetlb_cgroup_have_usage(struct cgroup *cg)
69 {
70         int idx;
71         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cg);
72
73         for (idx = 0; idx < hugetlb_max_hstate; idx++) {
74                 if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE)) > 0)
75                         return true;
76         }
77         return false;
78 }
79
80 static struct cgroup_subsys_state *hugetlb_cgroup_create(struct cgroup *cgroup)
81 {
82         int idx;
83         struct cgroup *parent_cgroup;
84         struct hugetlb_cgroup *h_cgroup, *parent_h_cgroup;
85
86         h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
87         if (!h_cgroup)
88                 return ERR_PTR(-ENOMEM);
89
90         parent_cgroup = cgroup->parent;
91         if (parent_cgroup) {
92                 parent_h_cgroup = hugetlb_cgroup_from_cgroup(parent_cgroup);
93                 for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
94                         res_counter_init(&h_cgroup->hugepage[idx],
95                                          &parent_h_cgroup->hugepage[idx]);
96         } else {
97                 root_h_cgroup = h_cgroup;
98                 for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
99                         res_counter_init(&h_cgroup->hugepage[idx], NULL);
100         }
101         return &h_cgroup->css;
102 }
103
104 static void hugetlb_cgroup_destroy(struct cgroup *cgroup)
105 {
106         struct hugetlb_cgroup *h_cgroup;
107
108         h_cgroup = hugetlb_cgroup_from_cgroup(cgroup);
109         kfree(h_cgroup);
110 }
111
112
113 /*
114  * Should be called with hugetlb_lock held.
115  * Since we are holding hugetlb_lock, pages cannot get moved from
116  * active list or uncharged from the cgroup, So no need to get
117  * page reference and test for page active here. This function
118  * cannot fail.
119  */
120 static void hugetlb_cgroup_move_parent(int idx, struct cgroup *cgroup,
121                                        struct page *page)
122 {
123         int csize;
124         struct res_counter *counter;
125         struct res_counter *fail_res;
126         struct hugetlb_cgroup *page_hcg;
127         struct hugetlb_cgroup *h_cg   = hugetlb_cgroup_from_cgroup(cgroup);
128         struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(cgroup);
129
130         page_hcg = hugetlb_cgroup_from_page(page);
131         /*
132          * We can have pages in active list without any cgroup
133          * ie, hugepage with less than 3 pages. We can safely
134          * ignore those pages.
135          */
136         if (!page_hcg || page_hcg != h_cg)
137                 goto out;
138
139         csize = PAGE_SIZE << compound_order(page);
140         if (!parent) {
141                 parent = root_h_cgroup;
142                 /* root has no limit */
143                 res_counter_charge_nofail(&parent->hugepage[idx],
144                                           csize, &fail_res);
145         }
146         counter = &h_cg->hugepage[idx];
147         res_counter_uncharge_until(counter, counter->parent, csize);
148
149         set_hugetlb_cgroup(page, parent);
150 out:
151         return;
152 }
153
154 /*
155  * Force the hugetlb cgroup to empty the hugetlb resources by moving them to
156  * the parent cgroup.
157  */
158 static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)
159 {
160         struct hstate *h;
161         struct page *page;
162         int ret = 0, idx = 0;
163
164         do {
165                 if (cgroup_task_count(cgroup) ||
166                     !list_empty(&cgroup->children)) {
167                         ret = -EBUSY;
168                         goto out;
169                 }
170                 for_each_hstate(h) {
171                         spin_lock(&hugetlb_lock);
172                         list_for_each_entry(page, &h->hugepage_activelist, lru)
173                                 hugetlb_cgroup_move_parent(idx, cgroup, page);
174
175                         spin_unlock(&hugetlb_lock);
176                         idx++;
177                 }
178                 cond_resched();
179         } while (hugetlb_cgroup_have_usage(cgroup));
180 out:
181         return ret;
182 }
183
184 int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
185                                  struct hugetlb_cgroup **ptr)
186 {
187         int ret = 0;
188         struct res_counter *fail_res;
189         struct hugetlb_cgroup *h_cg = NULL;
190         unsigned long csize = nr_pages * PAGE_SIZE;
191
192         if (hugetlb_cgroup_disabled())
193                 goto done;
194         /*
195          * We don't charge any cgroup if the compound page have less
196          * than 3 pages.
197          */
198         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
199                 goto done;
200 again:
201         rcu_read_lock();
202         h_cg = hugetlb_cgroup_from_task(current);
203         if (!css_tryget(&h_cg->css)) {
204                 rcu_read_unlock();
205                 goto again;
206         }
207         rcu_read_unlock();
208
209         ret = res_counter_charge(&h_cg->hugepage[idx], csize, &fail_res);
210         css_put(&h_cg->css);
211 done:
212         *ptr = h_cg;
213         return ret;
214 }
215
216 /* Should be called with hugetlb_lock held */
217 void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
218                                   struct hugetlb_cgroup *h_cg,
219                                   struct page *page)
220 {
221         if (hugetlb_cgroup_disabled() || !h_cg)
222                 return;
223
224         set_hugetlb_cgroup(page, h_cg);
225         return;
226 }
227
228 /*
229  * Should be called with hugetlb_lock held
230  */
231 void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
232                                   struct page *page)
233 {
234         struct hugetlb_cgroup *h_cg;
235         unsigned long csize = nr_pages * PAGE_SIZE;
236
237         if (hugetlb_cgroup_disabled())
238                 return;
239         VM_BUG_ON(!spin_is_locked(&hugetlb_lock));
240         h_cg = hugetlb_cgroup_from_page(page);
241         if (unlikely(!h_cg))
242                 return;
243         set_hugetlb_cgroup(page, NULL);
244         res_counter_uncharge(&h_cg->hugepage[idx], csize);
245         return;
246 }
247
248 void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
249                                     struct hugetlb_cgroup *h_cg)
250 {
251         unsigned long csize = nr_pages * PAGE_SIZE;
252
253         if (hugetlb_cgroup_disabled() || !h_cg)
254                 return;
255
256         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
257                 return;
258
259         res_counter_uncharge(&h_cg->hugepage[idx], csize);
260         return;
261 }
262
263 static ssize_t hugetlb_cgroup_read(struct cgroup *cgroup, struct cftype *cft,
264                                    struct file *file, char __user *buf,
265                                    size_t nbytes, loff_t *ppos)
266 {
267         u64 val;
268         char str[64];
269         int idx, name, len;
270         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
271
272         idx = MEMFILE_IDX(cft->private);
273         name = MEMFILE_ATTR(cft->private);
274
275         val = res_counter_read_u64(&h_cg->hugepage[idx], name);
276         len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
277         return simple_read_from_buffer(buf, nbytes, ppos, str, len);
278 }
279
280 static int hugetlb_cgroup_write(struct cgroup *cgroup, struct cftype *cft,
281                                 const char *buffer)
282 {
283         int idx, name, ret;
284         unsigned long long val;
285         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
286
287         idx = MEMFILE_IDX(cft->private);
288         name = MEMFILE_ATTR(cft->private);
289
290         switch (name) {
291         case RES_LIMIT:
292                 if (hugetlb_cgroup_is_root(h_cg)) {
293                         /* Can't set limit on root */
294                         ret = -EINVAL;
295                         break;
296                 }
297                 /* This function does all necessary parse...reuse it */
298                 ret = res_counter_memparse_write_strategy(buffer, &val);
299                 if (ret)
300                         break;
301                 ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
302                 break;
303         default:
304                 ret = -EINVAL;
305                 break;
306         }
307         return ret;
308 }
309
310 static int hugetlb_cgroup_reset(struct cgroup *cgroup, unsigned int event)
311 {
312         int idx, name, ret = 0;
313         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
314
315         idx = MEMFILE_IDX(event);
316         name = MEMFILE_ATTR(event);
317
318         switch (name) {
319         case RES_MAX_USAGE:
320                 res_counter_reset_max(&h_cg->hugepage[idx]);
321                 break;
322         case RES_FAILCNT:
323                 res_counter_reset_failcnt(&h_cg->hugepage[idx]);
324                 break;
325         default:
326                 ret = -EINVAL;
327                 break;
328         }
329         return ret;
330 }
331
332 static char *mem_fmt(char *buf, int size, unsigned long hsize)
333 {
334         if (hsize >= (1UL << 30))
335                 snprintf(buf, size, "%luGB", hsize >> 30);
336         else if (hsize >= (1UL << 20))
337                 snprintf(buf, size, "%luMB", hsize >> 20);
338         else
339                 snprintf(buf, size, "%luKB", hsize >> 10);
340         return buf;
341 }
342
343 int __init hugetlb_cgroup_file_init(int idx)
344 {
345         char buf[32];
346         struct cftype *cft;
347         struct hstate *h = &hstates[idx];
348
349         /* format the size */
350         mem_fmt(buf, 32, huge_page_size(h));
351
352         /* Add the limit file */
353         cft = &h->cgroup_files[0];
354         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
355         cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
356         cft->read = hugetlb_cgroup_read;
357         cft->write_string = hugetlb_cgroup_write;
358
359         /* Add the usage file */
360         cft = &h->cgroup_files[1];
361         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
362         cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
363         cft->read = hugetlb_cgroup_read;
364
365         /* Add the MAX usage file */
366         cft = &h->cgroup_files[2];
367         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
368         cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
369         cft->trigger = hugetlb_cgroup_reset;
370         cft->read = hugetlb_cgroup_read;
371
372         /* Add the failcntfile */
373         cft = &h->cgroup_files[3];
374         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
375         cft->private  = MEMFILE_PRIVATE(idx, RES_FAILCNT);
376         cft->trigger  = hugetlb_cgroup_reset;
377         cft->read = hugetlb_cgroup_read;
378
379         /* NULL terminate the last cft */
380         cft = &h->cgroup_files[4];
381         memset(cft, 0, sizeof(*cft));
382
383         WARN_ON(cgroup_add_cftypes(&hugetlb_subsys, h->cgroup_files));
384
385         return 0;
386 }
387
388 /*
389  * hugetlb_lock will make sure a parallel cgroup rmdir won't happen
390  * when we migrate hugepages
391  */
392 void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
393 {
394         struct hugetlb_cgroup *h_cg;
395         struct hstate *h = page_hstate(oldhpage);
396
397         if (hugetlb_cgroup_disabled())
398                 return;
399
400         VM_BUG_ON(!PageHuge(oldhpage));
401         spin_lock(&hugetlb_lock);
402         h_cg = hugetlb_cgroup_from_page(oldhpage);
403         set_hugetlb_cgroup(oldhpage, NULL);
404
405         /* move the h_cg details to new cgroup */
406         set_hugetlb_cgroup(newhpage, h_cg);
407         list_move(&newhpage->lru, &h->hugepage_activelist);
408         spin_unlock(&hugetlb_lock);
409         return;
410 }
411
412 struct cgroup_subsys hugetlb_subsys = {
413         .name = "hugetlb",
414         .create     = hugetlb_cgroup_create,
415         .pre_destroy = hugetlb_cgroup_pre_destroy,
416         .destroy    = hugetlb_cgroup_destroy,
417         .subsys_id  = hugetlb_subsys_id,
418 };