Merge tag 'v3.12'
[platform/adaptation/renesas_rcar/renesas_kernel.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 s ? container_of(s, struct hugetlb_cgroup, css) : NULL;
40 }
41
42 static inline
43 struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
44 {
45         return hugetlb_cgroup_from_css(task_css(task, hugetlb_subsys_id));
46 }
47
48 static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
49 {
50         return (h_cg == root_h_cgroup);
51 }
52
53 static inline struct hugetlb_cgroup *
54 parent_hugetlb_cgroup(struct hugetlb_cgroup *h_cg)
55 {
56         return hugetlb_cgroup_from_css(css_parent(&h_cg->css));
57 }
58
59 static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg)
60 {
61         int idx;
62
63         for (idx = 0; idx < hugetlb_max_hstate; idx++) {
64                 if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE)) > 0)
65                         return true;
66         }
67         return false;
68 }
69
70 static struct cgroup_subsys_state *
71 hugetlb_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
72 {
73         struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css);
74         struct hugetlb_cgroup *h_cgroup;
75         int idx;
76
77         h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
78         if (!h_cgroup)
79                 return ERR_PTR(-ENOMEM);
80
81         if (parent_h_cgroup) {
82                 for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
83                         res_counter_init(&h_cgroup->hugepage[idx],
84                                          &parent_h_cgroup->hugepage[idx]);
85         } else {
86                 root_h_cgroup = h_cgroup;
87                 for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
88                         res_counter_init(&h_cgroup->hugepage[idx], NULL);
89         }
90         return &h_cgroup->css;
91 }
92
93 static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css)
94 {
95         struct hugetlb_cgroup *h_cgroup;
96
97         h_cgroup = hugetlb_cgroup_from_css(css);
98         kfree(h_cgroup);
99 }
100
101
102 /*
103  * Should be called with hugetlb_lock held.
104  * Since we are holding hugetlb_lock, pages cannot get moved from
105  * active list or uncharged from the cgroup, So no need to get
106  * page reference and test for page active here. This function
107  * cannot fail.
108  */
109 static void hugetlb_cgroup_move_parent(int idx, struct hugetlb_cgroup *h_cg,
110                                        struct page *page)
111 {
112         int csize;
113         struct res_counter *counter;
114         struct res_counter *fail_res;
115         struct hugetlb_cgroup *page_hcg;
116         struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg);
117
118         page_hcg = hugetlb_cgroup_from_page(page);
119         /*
120          * We can have pages in active list without any cgroup
121          * ie, hugepage with less than 3 pages. We can safely
122          * ignore those pages.
123          */
124         if (!page_hcg || page_hcg != h_cg)
125                 goto out;
126
127         csize = PAGE_SIZE << compound_order(page);
128         if (!parent) {
129                 parent = root_h_cgroup;
130                 /* root has no limit */
131                 res_counter_charge_nofail(&parent->hugepage[idx],
132                                           csize, &fail_res);
133         }
134         counter = &h_cg->hugepage[idx];
135         res_counter_uncharge_until(counter, counter->parent, csize);
136
137         set_hugetlb_cgroup(page, parent);
138 out:
139         return;
140 }
141
142 /*
143  * Force the hugetlb cgroup to empty the hugetlb resources by moving them to
144  * the parent cgroup.
145  */
146 static void hugetlb_cgroup_css_offline(struct cgroup_subsys_state *css)
147 {
148         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
149         struct hstate *h;
150         struct page *page;
151         int idx = 0;
152
153         do {
154                 for_each_hstate(h) {
155                         spin_lock(&hugetlb_lock);
156                         list_for_each_entry(page, &h->hugepage_activelist, lru)
157                                 hugetlb_cgroup_move_parent(idx, h_cg, page);
158
159                         spin_unlock(&hugetlb_lock);
160                         idx++;
161                 }
162                 cond_resched();
163         } while (hugetlb_cgroup_have_usage(h_cg));
164 }
165
166 int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
167                                  struct hugetlb_cgroup **ptr)
168 {
169         int ret = 0;
170         struct res_counter *fail_res;
171         struct hugetlb_cgroup *h_cg = NULL;
172         unsigned long csize = nr_pages * PAGE_SIZE;
173
174         if (hugetlb_cgroup_disabled())
175                 goto done;
176         /*
177          * We don't charge any cgroup if the compound page have less
178          * than 3 pages.
179          */
180         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
181                 goto done;
182 again:
183         rcu_read_lock();
184         h_cg = hugetlb_cgroup_from_task(current);
185         if (!css_tryget(&h_cg->css)) {
186                 rcu_read_unlock();
187                 goto again;
188         }
189         rcu_read_unlock();
190
191         ret = res_counter_charge(&h_cg->hugepage[idx], csize, &fail_res);
192         css_put(&h_cg->css);
193 done:
194         *ptr = h_cg;
195         return ret;
196 }
197
198 /* Should be called with hugetlb_lock held */
199 void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
200                                   struct hugetlb_cgroup *h_cg,
201                                   struct page *page)
202 {
203         if (hugetlb_cgroup_disabled() || !h_cg)
204                 return;
205
206         set_hugetlb_cgroup(page, h_cg);
207         return;
208 }
209
210 /*
211  * Should be called with hugetlb_lock held
212  */
213 void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
214                                   struct page *page)
215 {
216         struct hugetlb_cgroup *h_cg;
217         unsigned long csize = nr_pages * PAGE_SIZE;
218
219         if (hugetlb_cgroup_disabled())
220                 return;
221         VM_BUG_ON(!spin_is_locked(&hugetlb_lock));
222         h_cg = hugetlb_cgroup_from_page(page);
223         if (unlikely(!h_cg))
224                 return;
225         set_hugetlb_cgroup(page, NULL);
226         res_counter_uncharge(&h_cg->hugepage[idx], csize);
227         return;
228 }
229
230 void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
231                                     struct hugetlb_cgroup *h_cg)
232 {
233         unsigned long csize = nr_pages * PAGE_SIZE;
234
235         if (hugetlb_cgroup_disabled() || !h_cg)
236                 return;
237
238         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
239                 return;
240
241         res_counter_uncharge(&h_cg->hugepage[idx], csize);
242         return;
243 }
244
245 static ssize_t hugetlb_cgroup_read(struct cgroup_subsys_state *css,
246                                    struct cftype *cft, struct file *file,
247                                    char __user *buf, size_t nbytes,
248                                    loff_t *ppos)
249 {
250         u64 val;
251         char str[64];
252         int idx, name, len;
253         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
254
255         idx = MEMFILE_IDX(cft->private);
256         name = MEMFILE_ATTR(cft->private);
257
258         val = res_counter_read_u64(&h_cg->hugepage[idx], name);
259         len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
260         return simple_read_from_buffer(buf, nbytes, ppos, str, len);
261 }
262
263 static int hugetlb_cgroup_write(struct cgroup_subsys_state *css,
264                                 struct cftype *cft, const char *buffer)
265 {
266         int idx, name, ret;
267         unsigned long long val;
268         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
269
270         idx = MEMFILE_IDX(cft->private);
271         name = MEMFILE_ATTR(cft->private);
272
273         switch (name) {
274         case RES_LIMIT:
275                 if (hugetlb_cgroup_is_root(h_cg)) {
276                         /* Can't set limit on root */
277                         ret = -EINVAL;
278                         break;
279                 }
280                 /* This function does all necessary parse...reuse it */
281                 ret = res_counter_memparse_write_strategy(buffer, &val);
282                 if (ret)
283                         break;
284                 ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
285                 break;
286         default:
287                 ret = -EINVAL;
288                 break;
289         }
290         return ret;
291 }
292
293 static int hugetlb_cgroup_reset(struct cgroup_subsys_state *css,
294                                 unsigned int event)
295 {
296         int idx, name, ret = 0;
297         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
298
299         idx = MEMFILE_IDX(event);
300         name = MEMFILE_ATTR(event);
301
302         switch (name) {
303         case RES_MAX_USAGE:
304                 res_counter_reset_max(&h_cg->hugepage[idx]);
305                 break;
306         case RES_FAILCNT:
307                 res_counter_reset_failcnt(&h_cg->hugepage[idx]);
308                 break;
309         default:
310                 ret = -EINVAL;
311                 break;
312         }
313         return ret;
314 }
315
316 static char *mem_fmt(char *buf, int size, unsigned long hsize)
317 {
318         if (hsize >= (1UL << 30))
319                 snprintf(buf, size, "%luGB", hsize >> 30);
320         else if (hsize >= (1UL << 20))
321                 snprintf(buf, size, "%luMB", hsize >> 20);
322         else
323                 snprintf(buf, size, "%luKB", hsize >> 10);
324         return buf;
325 }
326
327 static void __init __hugetlb_cgroup_file_init(int idx)
328 {
329         char buf[32];
330         struct cftype *cft;
331         struct hstate *h = &hstates[idx];
332
333         /* format the size */
334         mem_fmt(buf, 32, huge_page_size(h));
335
336         /* Add the limit file */
337         cft = &h->cgroup_files[0];
338         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
339         cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
340         cft->read = hugetlb_cgroup_read;
341         cft->write_string = hugetlb_cgroup_write;
342
343         /* Add the usage file */
344         cft = &h->cgroup_files[1];
345         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
346         cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
347         cft->read = hugetlb_cgroup_read;
348
349         /* Add the MAX usage file */
350         cft = &h->cgroup_files[2];
351         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
352         cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
353         cft->trigger = hugetlb_cgroup_reset;
354         cft->read = hugetlb_cgroup_read;
355
356         /* Add the failcntfile */
357         cft = &h->cgroup_files[3];
358         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
359         cft->private  = MEMFILE_PRIVATE(idx, RES_FAILCNT);
360         cft->trigger  = hugetlb_cgroup_reset;
361         cft->read = hugetlb_cgroup_read;
362
363         /* NULL terminate the last cft */
364         cft = &h->cgroup_files[4];
365         memset(cft, 0, sizeof(*cft));
366
367         WARN_ON(cgroup_add_cftypes(&hugetlb_subsys, h->cgroup_files));
368
369         return;
370 }
371
372 void __init hugetlb_cgroup_file_init(void)
373 {
374         struct hstate *h;
375
376         for_each_hstate(h) {
377                 /*
378                  * Add cgroup control files only if the huge page consists
379                  * of more than two normal pages. This is because we use
380                  * page[2].lru.next for storing cgroup details.
381                  */
382                 if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
383                         __hugetlb_cgroup_file_init(hstate_index(h));
384         }
385 }
386
387 /*
388  * hugetlb_lock will make sure a parallel cgroup rmdir won't happen
389  * when we migrate hugepages
390  */
391 void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
392 {
393         struct hugetlb_cgroup *h_cg;
394         struct hstate *h = page_hstate(oldhpage);
395
396         if (hugetlb_cgroup_disabled())
397                 return;
398
399         VM_BUG_ON(!PageHuge(oldhpage));
400         spin_lock(&hugetlb_lock);
401         h_cg = hugetlb_cgroup_from_page(oldhpage);
402         set_hugetlb_cgroup(oldhpage, NULL);
403
404         /* move the h_cg details to new cgroup */
405         set_hugetlb_cgroup(newhpage, h_cg);
406         list_move(&newhpage->lru, &h->hugepage_activelist);
407         spin_unlock(&hugetlb_lock);
408         return;
409 }
410
411 struct cgroup_subsys hugetlb_subsys = {
412         .name = "hugetlb",
413         .css_alloc      = hugetlb_cgroup_css_alloc,
414         .css_offline    = hugetlb_cgroup_css_offline,
415         .css_free       = hugetlb_cgroup_css_free,
416         .subsys_id      = hugetlb_subsys_id,
417 };