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 static struct hugetlb_cgroup *root_h_cgroup __read_mostly;
34
35 static inline
hugetlb_cgroup_from_css(struct cgroup_subsys_state * s)36 struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s)
37 {
38 return s ? container_of(s, struct hugetlb_cgroup, css) : NULL;
39 }
40
41 static inline
hugetlb_cgroup_from_task(struct task_struct * task)42 struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
43 {
44 return hugetlb_cgroup_from_css(task_css(task, hugetlb_cgrp_id));
45 }
46
hugetlb_cgroup_is_root(struct hugetlb_cgroup * h_cg)47 static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
48 {
49 return (h_cg == root_h_cgroup);
50 }
51
52 static inline struct hugetlb_cgroup *
parent_hugetlb_cgroup(struct hugetlb_cgroup * h_cg)53 parent_hugetlb_cgroup(struct hugetlb_cgroup *h_cg)
54 {
55 return hugetlb_cgroup_from_css(h_cg->css.parent);
56 }
57
hugetlb_cgroup_have_usage(struct hugetlb_cgroup * h_cg)58 static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg)
59 {
60 int idx;
61
62 for (idx = 0; idx < hugetlb_max_hstate; idx++) {
63 if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE)) > 0)
64 return true;
65 }
66 return false;
67 }
68
69 static struct cgroup_subsys_state *
hugetlb_cgroup_css_alloc(struct cgroup_subsys_state * parent_css)70 hugetlb_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
71 {
72 struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css);
73 struct hugetlb_cgroup *h_cgroup;
74 int idx;
75
76 h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
77 if (!h_cgroup)
78 return ERR_PTR(-ENOMEM);
79
80 if (parent_h_cgroup) {
81 for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
82 res_counter_init(&h_cgroup->hugepage[idx],
83 &parent_h_cgroup->hugepage[idx]);
84 } else {
85 root_h_cgroup = h_cgroup;
86 for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
87 res_counter_init(&h_cgroup->hugepage[idx], NULL);
88 }
89 return &h_cgroup->css;
90 }
91
hugetlb_cgroup_css_free(struct cgroup_subsys_state * css)92 static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css)
93 {
94 struct hugetlb_cgroup *h_cgroup;
95
96 h_cgroup = hugetlb_cgroup_from_css(css);
97 kfree(h_cgroup);
98 }
99
100
101 /*
102 * Should be called with hugetlb_lock held.
103 * Since we are holding hugetlb_lock, pages cannot get moved from
104 * active list or uncharged from the cgroup, So no need to get
105 * page reference and test for page active here. This function
106 * cannot fail.
107 */
hugetlb_cgroup_move_parent(int idx,struct hugetlb_cgroup * h_cg,struct page * page)108 static void hugetlb_cgroup_move_parent(int idx, struct hugetlb_cgroup *h_cg,
109 struct page *page)
110 {
111 int csize;
112 struct res_counter *counter;
113 struct res_counter *fail_res;
114 struct hugetlb_cgroup *page_hcg;
115 struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg);
116
117 page_hcg = hugetlb_cgroup_from_page(page);
118 /*
119 * We can have pages in active list without any cgroup
120 * ie, hugepage with less than 3 pages. We can safely
121 * ignore those pages.
122 */
123 if (!page_hcg || page_hcg != h_cg)
124 goto out;
125
126 csize = PAGE_SIZE << compound_order(page);
127 if (!parent) {
128 parent = root_h_cgroup;
129 /* root has no limit */
130 res_counter_charge_nofail(&parent->hugepage[idx],
131 csize, &fail_res);
132 }
133 counter = &h_cg->hugepage[idx];
134 res_counter_uncharge_until(counter, counter->parent, csize);
135
136 set_hugetlb_cgroup(page, parent);
137 out:
138 return;
139 }
140
141 /*
142 * Force the hugetlb cgroup to empty the hugetlb resources by moving them to
143 * the parent cgroup.
144 */
hugetlb_cgroup_css_offline(struct cgroup_subsys_state * css)145 static void hugetlb_cgroup_css_offline(struct cgroup_subsys_state *css)
146 {
147 struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
148 struct hstate *h;
149 struct page *page;
150 int idx = 0;
151
152 do {
153 for_each_hstate(h) {
154 spin_lock(&hugetlb_lock);
155 list_for_each_entry(page, &h->hugepage_activelist, lru)
156 hugetlb_cgroup_move_parent(idx, h_cg, page);
157
158 spin_unlock(&hugetlb_lock);
159 idx++;
160 }
161 cond_resched();
162 } while (hugetlb_cgroup_have_usage(h_cg));
163 }
164
hugetlb_cgroup_charge_cgroup(int idx,unsigned long nr_pages,struct hugetlb_cgroup ** ptr)165 int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
166 struct hugetlb_cgroup **ptr)
167 {
168 int ret = 0;
169 struct res_counter *fail_res;
170 struct hugetlb_cgroup *h_cg = NULL;
171 unsigned long csize = nr_pages * PAGE_SIZE;
172
173 if (hugetlb_cgroup_disabled())
174 goto done;
175 /*
176 * We don't charge any cgroup if the compound page have less
177 * than 3 pages.
178 */
179 if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
180 goto done;
181 again:
182 rcu_read_lock();
183 h_cg = hugetlb_cgroup_from_task(current);
184 if (!css_tryget_online(&h_cg->css)) {
185 rcu_read_unlock();
186 goto again;
187 }
188 rcu_read_unlock();
189
190 ret = res_counter_charge(&h_cg->hugepage[idx], csize, &fail_res);
191 css_put(&h_cg->css);
192 done:
193 *ptr = h_cg;
194 return ret;
195 }
196
197 /* Should be called with hugetlb_lock held */
hugetlb_cgroup_commit_charge(int idx,unsigned long nr_pages,struct hugetlb_cgroup * h_cg,struct page * page)198 void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
199 struct hugetlb_cgroup *h_cg,
200 struct page *page)
201 {
202 if (hugetlb_cgroup_disabled() || !h_cg)
203 return;
204
205 set_hugetlb_cgroup(page, h_cg);
206 return;
207 }
208
209 /*
210 * Should be called with hugetlb_lock held
211 */
hugetlb_cgroup_uncharge_page(int idx,unsigned long nr_pages,struct page * page)212 void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
213 struct page *page)
214 {
215 struct hugetlb_cgroup *h_cg;
216 unsigned long csize = nr_pages * PAGE_SIZE;
217
218 if (hugetlb_cgroup_disabled())
219 return;
220 lockdep_assert_held(&hugetlb_lock);
221 h_cg = hugetlb_cgroup_from_page(page);
222 if (unlikely(!h_cg))
223 return;
224 set_hugetlb_cgroup(page, NULL);
225 res_counter_uncharge(&h_cg->hugepage[idx], csize);
226 return;
227 }
228
hugetlb_cgroup_uncharge_cgroup(int idx,unsigned long nr_pages,struct hugetlb_cgroup * h_cg)229 void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
230 struct hugetlb_cgroup *h_cg)
231 {
232 unsigned long csize = nr_pages * PAGE_SIZE;
233
234 if (hugetlb_cgroup_disabled() || !h_cg)
235 return;
236
237 if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
238 return;
239
240 res_counter_uncharge(&h_cg->hugepage[idx], csize);
241 return;
242 }
243
hugetlb_cgroup_read_u64(struct cgroup_subsys_state * css,struct cftype * cft)244 static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css,
245 struct cftype *cft)
246 {
247 int idx, name;
248 struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
249
250 idx = MEMFILE_IDX(cft->private);
251 name = MEMFILE_ATTR(cft->private);
252
253 return res_counter_read_u64(&h_cg->hugepage[idx], name);
254 }
255
hugetlb_cgroup_write(struct kernfs_open_file * of,char * buf,size_t nbytes,loff_t off)256 static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
257 char *buf, size_t nbytes, loff_t off)
258 {
259 int idx, name, ret;
260 unsigned long long val;
261 struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
262
263 buf = strstrip(buf);
264 idx = MEMFILE_IDX(of_cft(of)->private);
265 name = MEMFILE_ATTR(of_cft(of)->private);
266
267 switch (name) {
268 case RES_LIMIT:
269 if (hugetlb_cgroup_is_root(h_cg)) {
270 /* Can't set limit on root */
271 ret = -EINVAL;
272 break;
273 }
274 /* This function does all necessary parse...reuse it */
275 ret = res_counter_memparse_write_strategy(buf, &val);
276 if (ret)
277 break;
278 val = ALIGN(val, 1ULL << huge_page_shift(&hstates[idx]));
279 ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
280 break;
281 default:
282 ret = -EINVAL;
283 break;
284 }
285 return ret ?: nbytes;
286 }
287
hugetlb_cgroup_reset(struct kernfs_open_file * of,char * buf,size_t nbytes,loff_t off)288 static ssize_t hugetlb_cgroup_reset(struct kernfs_open_file *of,
289 char *buf, size_t nbytes, loff_t off)
290 {
291 int idx, name, ret = 0;
292 struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
293
294 idx = MEMFILE_IDX(of_cft(of)->private);
295 name = MEMFILE_ATTR(of_cft(of)->private);
296
297 switch (name) {
298 case RES_MAX_USAGE:
299 res_counter_reset_max(&h_cg->hugepage[idx]);
300 break;
301 case RES_FAILCNT:
302 res_counter_reset_failcnt(&h_cg->hugepage[idx]);
303 break;
304 default:
305 ret = -EINVAL;
306 break;
307 }
308 return ret ?: nbytes;
309 }
310
mem_fmt(char * buf,int size,unsigned long hsize)311 static char *mem_fmt(char *buf, int size, unsigned long hsize)
312 {
313 if (hsize >= (1UL << 30))
314 snprintf(buf, size, "%luGB", hsize >> 30);
315 else if (hsize >= (1UL << 20))
316 snprintf(buf, size, "%luMB", hsize >> 20);
317 else
318 snprintf(buf, size, "%luKB", hsize >> 10);
319 return buf;
320 }
321
__hugetlb_cgroup_file_init(int idx)322 static void __init __hugetlb_cgroup_file_init(int idx)
323 {
324 char buf[32];
325 struct cftype *cft;
326 struct hstate *h = &hstates[idx];
327
328 /* format the size */
329 mem_fmt(buf, 32, huge_page_size(h));
330
331 /* Add the limit file */
332 cft = &h->cgroup_files[0];
333 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
334 cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
335 cft->read_u64 = hugetlb_cgroup_read_u64;
336 cft->write = hugetlb_cgroup_write;
337
338 /* Add the usage file */
339 cft = &h->cgroup_files[1];
340 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
341 cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
342 cft->read_u64 = hugetlb_cgroup_read_u64;
343
344 /* Add the MAX usage file */
345 cft = &h->cgroup_files[2];
346 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
347 cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
348 cft->write = hugetlb_cgroup_reset;
349 cft->read_u64 = hugetlb_cgroup_read_u64;
350
351 /* Add the failcntfile */
352 cft = &h->cgroup_files[3];
353 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
354 cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT);
355 cft->write = hugetlb_cgroup_reset;
356 cft->read_u64 = hugetlb_cgroup_read_u64;
357
358 /* NULL terminate the last cft */
359 cft = &h->cgroup_files[4];
360 memset(cft, 0, sizeof(*cft));
361
362 WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
363 h->cgroup_files));
364 }
365
hugetlb_cgroup_file_init(void)366 void __init hugetlb_cgroup_file_init(void)
367 {
368 struct hstate *h;
369
370 for_each_hstate(h) {
371 /*
372 * Add cgroup control files only if the huge page consists
373 * of more than two normal pages. This is because we use
374 * page[2].lru.next for storing cgroup details.
375 */
376 if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
377 __hugetlb_cgroup_file_init(hstate_index(h));
378 }
379 }
380
381 /*
382 * hugetlb_lock will make sure a parallel cgroup rmdir won't happen
383 * when we migrate hugepages
384 */
hugetlb_cgroup_migrate(struct page * oldhpage,struct page * newhpage)385 void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
386 {
387 struct hugetlb_cgroup *h_cg;
388 struct hstate *h = page_hstate(oldhpage);
389
390 if (hugetlb_cgroup_disabled())
391 return;
392
393 VM_BUG_ON_PAGE(!PageHuge(oldhpage), oldhpage);
394 spin_lock(&hugetlb_lock);
395 h_cg = hugetlb_cgroup_from_page(oldhpage);
396 set_hugetlb_cgroup(oldhpage, NULL);
397
398 /* move the h_cg details to new cgroup */
399 set_hugetlb_cgroup(newhpage, h_cg);
400 list_move(&newhpage->lru, &h->hugepage_activelist);
401 spin_unlock(&hugetlb_lock);
402 return;
403 }
404
405 struct cgroup_subsys hugetlb_cgrp_subsys = {
406 .css_alloc = hugetlb_cgroup_css_alloc,
407 .css_offline = hugetlb_cgroup_css_offline,
408 .css_free = hugetlb_cgroup_css_free,
409 };
410