Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6-microblaze.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/page_counter.h>
18 #include <linux/slab.h>
19 #include <linux/hugetlb.h>
20 #include <linux/hugetlb_cgroup.h>
21
22 struct hugetlb_cgroup {
23         struct cgroup_subsys_state css;
24         /*
25          * the counter to account for hugepages from hugetlb.
26          */
27         struct page_counter hugepage[HUGE_MAX_HSTATE];
28 };
29
30 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
31 #define MEMFILE_IDX(val)        (((val) >> 16) & 0xffff)
32 #define MEMFILE_ATTR(val)       ((val) & 0xffff)
33
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_cgrp_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(h_cg->css.parent);
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 (page_counter_read(&h_cg->hugepage[idx]))
65                         return true;
66         }
67         return false;
68 }
69
70 static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup,
71                                 struct hugetlb_cgroup *parent_h_cgroup)
72 {
73         int idx;
74
75         for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) {
76                 struct page_counter *counter = &h_cgroup->hugepage[idx];
77                 struct page_counter *parent = NULL;
78                 unsigned long limit;
79                 int ret;
80
81                 if (parent_h_cgroup)
82                         parent = &parent_h_cgroup->hugepage[idx];
83                 page_counter_init(counter, parent);
84
85                 limit = round_down(PAGE_COUNTER_MAX,
86                                    1 << huge_page_order(&hstates[idx]));
87                 ret = page_counter_set_max(counter, limit);
88                 VM_BUG_ON(ret);
89         }
90 }
91
92 static struct cgroup_subsys_state *
93 hugetlb_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
94 {
95         struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css);
96         struct hugetlb_cgroup *h_cgroup;
97
98         h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
99         if (!h_cgroup)
100                 return ERR_PTR(-ENOMEM);
101
102         if (!parent_h_cgroup)
103                 root_h_cgroup = h_cgroup;
104
105         hugetlb_cgroup_init(h_cgroup, parent_h_cgroup);
106         return &h_cgroup->css;
107 }
108
109 static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css)
110 {
111         struct hugetlb_cgroup *h_cgroup;
112
113         h_cgroup = hugetlb_cgroup_from_css(css);
114         kfree(h_cgroup);
115 }
116
117
118 /*
119  * Should be called with hugetlb_lock held.
120  * Since we are holding hugetlb_lock, pages cannot get moved from
121  * active list or uncharged from the cgroup, So no need to get
122  * page reference and test for page active here. This function
123  * cannot fail.
124  */
125 static void hugetlb_cgroup_move_parent(int idx, struct hugetlb_cgroup *h_cg,
126                                        struct page *page)
127 {
128         unsigned int nr_pages;
129         struct page_counter *counter;
130         struct hugetlb_cgroup *page_hcg;
131         struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg);
132
133         page_hcg = hugetlb_cgroup_from_page(page);
134         /*
135          * We can have pages in active list without any cgroup
136          * ie, hugepage with less than 3 pages. We can safely
137          * ignore those pages.
138          */
139         if (!page_hcg || page_hcg != h_cg)
140                 goto out;
141
142         nr_pages = compound_nr(page);
143         if (!parent) {
144                 parent = root_h_cgroup;
145                 /* root has no limit */
146                 page_counter_charge(&parent->hugepage[idx], nr_pages);
147         }
148         counter = &h_cg->hugepage[idx];
149         /* Take the pages off the local counter */
150         page_counter_cancel(counter, nr_pages);
151
152         set_hugetlb_cgroup(page, parent);
153 out:
154         return;
155 }
156
157 /*
158  * Force the hugetlb cgroup to empty the hugetlb resources by moving them to
159  * the parent cgroup.
160  */
161 static void hugetlb_cgroup_css_offline(struct cgroup_subsys_state *css)
162 {
163         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
164         struct hstate *h;
165         struct page *page;
166         int idx = 0;
167
168         do {
169                 for_each_hstate(h) {
170                         spin_lock(&hugetlb_lock);
171                         list_for_each_entry(page, &h->hugepage_activelist, lru)
172                                 hugetlb_cgroup_move_parent(idx, h_cg, page);
173
174                         spin_unlock(&hugetlb_lock);
175                         idx++;
176                 }
177                 cond_resched();
178         } while (hugetlb_cgroup_have_usage(h_cg));
179 }
180
181 int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
182                                  struct hugetlb_cgroup **ptr)
183 {
184         int ret = 0;
185         struct page_counter *counter;
186         struct hugetlb_cgroup *h_cg = NULL;
187
188         if (hugetlb_cgroup_disabled())
189                 goto done;
190         /*
191          * We don't charge any cgroup if the compound page have less
192          * than 3 pages.
193          */
194         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
195                 goto done;
196 again:
197         rcu_read_lock();
198         h_cg = hugetlb_cgroup_from_task(current);
199         if (!css_tryget_online(&h_cg->css)) {
200                 rcu_read_unlock();
201                 goto again;
202         }
203         rcu_read_unlock();
204
205         if (!page_counter_try_charge(&h_cg->hugepage[idx], nr_pages, &counter))
206                 ret = -ENOMEM;
207         css_put(&h_cg->css);
208 done:
209         *ptr = h_cg;
210         return ret;
211 }
212
213 /* Should be called with hugetlb_lock held */
214 void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
215                                   struct hugetlb_cgroup *h_cg,
216                                   struct page *page)
217 {
218         if (hugetlb_cgroup_disabled() || !h_cg)
219                 return;
220
221         set_hugetlb_cgroup(page, h_cg);
222         return;
223 }
224
225 /*
226  * Should be called with hugetlb_lock held
227  */
228 void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
229                                   struct page *page)
230 {
231         struct hugetlb_cgroup *h_cg;
232
233         if (hugetlb_cgroup_disabled())
234                 return;
235         lockdep_assert_held(&hugetlb_lock);
236         h_cg = hugetlb_cgroup_from_page(page);
237         if (unlikely(!h_cg))
238                 return;
239         set_hugetlb_cgroup(page, NULL);
240         page_counter_uncharge(&h_cg->hugepage[idx], nr_pages);
241         return;
242 }
243
244 void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
245                                     struct hugetlb_cgroup *h_cg)
246 {
247         if (hugetlb_cgroup_disabled() || !h_cg)
248                 return;
249
250         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
251                 return;
252
253         page_counter_uncharge(&h_cg->hugepage[idx], nr_pages);
254         return;
255 }
256
257 enum {
258         RES_USAGE,
259         RES_LIMIT,
260         RES_MAX_USAGE,
261         RES_FAILCNT,
262 };
263
264 static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css,
265                                    struct cftype *cft)
266 {
267         struct page_counter *counter;
268         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
269
270         counter = &h_cg->hugepage[MEMFILE_IDX(cft->private)];
271
272         switch (MEMFILE_ATTR(cft->private)) {
273         case RES_USAGE:
274                 return (u64)page_counter_read(counter) * PAGE_SIZE;
275         case RES_LIMIT:
276                 return (u64)counter->max * PAGE_SIZE;
277         case RES_MAX_USAGE:
278                 return (u64)counter->watermark * PAGE_SIZE;
279         case RES_FAILCNT:
280                 return counter->failcnt;
281         default:
282                 BUG();
283         }
284 }
285
286 static DEFINE_MUTEX(hugetlb_limit_mutex);
287
288 static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
289                                     char *buf, size_t nbytes, loff_t off)
290 {
291         int ret, idx;
292         unsigned long nr_pages;
293         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
294
295         if (hugetlb_cgroup_is_root(h_cg)) /* Can't set limit on root */
296                 return -EINVAL;
297
298         buf = strstrip(buf);
299         ret = page_counter_memparse(buf, "-1", &nr_pages);
300         if (ret)
301                 return ret;
302
303         idx = MEMFILE_IDX(of_cft(of)->private);
304         nr_pages = round_down(nr_pages, 1 << huge_page_order(&hstates[idx]));
305
306         switch (MEMFILE_ATTR(of_cft(of)->private)) {
307         case RES_LIMIT:
308                 mutex_lock(&hugetlb_limit_mutex);
309                 ret = page_counter_set_max(&h_cg->hugepage[idx], nr_pages);
310                 mutex_unlock(&hugetlb_limit_mutex);
311                 break;
312         default:
313                 ret = -EINVAL;
314                 break;
315         }
316         return ret ?: nbytes;
317 }
318
319 static ssize_t hugetlb_cgroup_reset(struct kernfs_open_file *of,
320                                     char *buf, size_t nbytes, loff_t off)
321 {
322         int ret = 0;
323         struct page_counter *counter;
324         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
325
326         counter = &h_cg->hugepage[MEMFILE_IDX(of_cft(of)->private)];
327
328         switch (MEMFILE_ATTR(of_cft(of)->private)) {
329         case RES_MAX_USAGE:
330                 page_counter_reset_watermark(counter);
331                 break;
332         case RES_FAILCNT:
333                 counter->failcnt = 0;
334                 break;
335         default:
336                 ret = -EINVAL;
337                 break;
338         }
339         return ret ?: nbytes;
340 }
341
342 static char *mem_fmt(char *buf, int size, unsigned long hsize)
343 {
344         if (hsize >= (1UL << 30))
345                 snprintf(buf, size, "%luGB", hsize >> 30);
346         else if (hsize >= (1UL << 20))
347                 snprintf(buf, size, "%luMB", hsize >> 20);
348         else
349                 snprintf(buf, size, "%luKB", hsize >> 10);
350         return buf;
351 }
352
353 static void __init __hugetlb_cgroup_file_init(int idx)
354 {
355         char buf[32];
356         struct cftype *cft;
357         struct hstate *h = &hstates[idx];
358
359         /* format the size */
360         mem_fmt(buf, 32, huge_page_size(h));
361
362         /* Add the limit file */
363         cft = &h->cgroup_files[0];
364         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
365         cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
366         cft->read_u64 = hugetlb_cgroup_read_u64;
367         cft->write = hugetlb_cgroup_write;
368
369         /* Add the usage file */
370         cft = &h->cgroup_files[1];
371         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
372         cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
373         cft->read_u64 = hugetlb_cgroup_read_u64;
374
375         /* Add the MAX usage file */
376         cft = &h->cgroup_files[2];
377         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
378         cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
379         cft->write = hugetlb_cgroup_reset;
380         cft->read_u64 = hugetlb_cgroup_read_u64;
381
382         /* Add the failcntfile */
383         cft = &h->cgroup_files[3];
384         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
385         cft->private  = MEMFILE_PRIVATE(idx, RES_FAILCNT);
386         cft->write = hugetlb_cgroup_reset;
387         cft->read_u64 = hugetlb_cgroup_read_u64;
388
389         /* NULL terminate the last cft */
390         cft = &h->cgroup_files[4];
391         memset(cft, 0, sizeof(*cft));
392
393         WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
394                                           h->cgroup_files));
395 }
396
397 void __init hugetlb_cgroup_file_init(void)
398 {
399         struct hstate *h;
400
401         for_each_hstate(h) {
402                 /*
403                  * Add cgroup control files only if the huge page consists
404                  * of more than two normal pages. This is because we use
405                  * page[2].private for storing cgroup details.
406                  */
407                 if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
408                         __hugetlb_cgroup_file_init(hstate_index(h));
409         }
410 }
411
412 /*
413  * hugetlb_lock will make sure a parallel cgroup rmdir won't happen
414  * when we migrate hugepages
415  */
416 void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
417 {
418         struct hugetlb_cgroup *h_cg;
419         struct hstate *h = page_hstate(oldhpage);
420
421         if (hugetlb_cgroup_disabled())
422                 return;
423
424         VM_BUG_ON_PAGE(!PageHuge(oldhpage), oldhpage);
425         spin_lock(&hugetlb_lock);
426         h_cg = hugetlb_cgroup_from_page(oldhpage);
427         set_hugetlb_cgroup(oldhpage, NULL);
428
429         /* move the h_cg details to new cgroup */
430         set_hugetlb_cgroup(newhpage, h_cg);
431         list_move(&newhpage->lru, &h->hugepage_activelist);
432         spin_unlock(&hugetlb_lock);
433         return;
434 }
435
436 struct cgroup_subsys hugetlb_cgrp_subsys = {
437         .css_alloc      = hugetlb_cgroup_css_alloc,
438         .css_offline    = hugetlb_cgroup_css_offline,
439         .css_free       = hugetlb_cgroup_css_free,
440 };