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
22struct 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
34static struct hugetlb_cgroup *root_h_cgroup __read_mostly;
35
36static inline
37struct 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
42static inline
43struct 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
48static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
49{
50 return (h_cg == root_h_cgroup);
51}
52
53static inline struct hugetlb_cgroup *
54parent_hugetlb_cgroup(struct hugetlb_cgroup *h_cg)
55{
56 return hugetlb_cgroup_from_css(h_cg->css.parent);
57}
58
59static 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
70static 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
92static struct cgroup_subsys_state *
93hugetlb_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
109static 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 */
125static 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 = 1 << compound_order(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);
153out:
154 return;
155}
156
157/*
158 * Force the hugetlb cgroup to empty the hugetlb resources by moving them to
159 * the parent cgroup.
160 */
161static 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
181int 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;
196again:
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);
208done:
209 *ptr = h_cg;
210 return ret;
211}
212
213/* Should be called with hugetlb_lock held */
214void 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 */
228void 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
244void 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
257enum {
258 RES_USAGE,
259 RES_LIMIT,
260 RES_MAX_USAGE,
261 RES_FAILCNT,
262};
263
264static 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
286static DEFINE_MUTEX(hugetlb_limit_mutex);
287
288static 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
319static 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
342static 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
353static 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
397void __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 */
416void 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
436struct 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};
441