mm: Account for a THP NUMA hinting update as one PTE update
[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_css_alloc(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_css_free(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 void hugetlb_cgroup_css_offline(struct cgroup *cgroup)
159 {
160         struct hstate *h;
161         struct page *page;
162         int idx = 0;
163
164         do {
165                 for_each_hstate(h) {
166                         spin_lock(&hugetlb_lock);
167                         list_for_each_entry(page, &h->hugepage_activelist, lru)
168                                 hugetlb_cgroup_move_parent(idx, cgroup, page);
169
170                         spin_unlock(&hugetlb_lock);
171                         idx++;
172                 }
173                 cond_resched();
174         } while (hugetlb_cgroup_have_usage(cgroup));
175 }
176
177 int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
178                                  struct hugetlb_cgroup **ptr)
179 {
180         int ret = 0;
181         struct res_counter *fail_res;
182         struct hugetlb_cgroup *h_cg = NULL;
183         unsigned long csize = nr_pages * PAGE_SIZE;
184
185         if (hugetlb_cgroup_disabled())
186                 goto done;
187         /*
188          * We don't charge any cgroup if the compound page have less
189          * than 3 pages.
190          */
191         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
192                 goto done;
193 again:
194         rcu_read_lock();
195         h_cg = hugetlb_cgroup_from_task(current);
196         if (!css_tryget(&h_cg->css)) {
197                 rcu_read_unlock();
198                 goto again;
199         }
200         rcu_read_unlock();
201
202         ret = res_counter_charge(&h_cg->hugepage[idx], csize, &fail_res);
203         css_put(&h_cg->css);
204 done:
205         *ptr = h_cg;
206         return ret;
207 }
208
209 /* Should be called with hugetlb_lock held */
210 void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
211                                   struct hugetlb_cgroup *h_cg,
212                                   struct page *page)
213 {
214         if (hugetlb_cgroup_disabled() || !h_cg)
215                 return;
216
217         set_hugetlb_cgroup(page, h_cg);
218         return;
219 }
220
221 /*
222  * Should be called with hugetlb_lock held
223  */
224 void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
225                                   struct page *page)
226 {
227         struct hugetlb_cgroup *h_cg;
228         unsigned long csize = nr_pages * PAGE_SIZE;
229
230         if (hugetlb_cgroup_disabled())
231                 return;
232         VM_BUG_ON(!spin_is_locked(&hugetlb_lock));
233         h_cg = hugetlb_cgroup_from_page(page);
234         if (unlikely(!h_cg))
235                 return;
236         set_hugetlb_cgroup(page, NULL);
237         res_counter_uncharge(&h_cg->hugepage[idx], csize);
238         return;
239 }
240
241 void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
242                                     struct hugetlb_cgroup *h_cg)
243 {
244         unsigned long csize = nr_pages * PAGE_SIZE;
245
246         if (hugetlb_cgroup_disabled() || !h_cg)
247                 return;
248
249         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
250                 return;
251
252         res_counter_uncharge(&h_cg->hugepage[idx], csize);
253         return;
254 }
255
256 static ssize_t hugetlb_cgroup_read(struct cgroup *cgroup, struct cftype *cft,
257                                    struct file *file, char __user *buf,
258                                    size_t nbytes, loff_t *ppos)
259 {
260         u64 val;
261         char str[64];
262         int idx, name, len;
263         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
264
265         idx = MEMFILE_IDX(cft->private);
266         name = MEMFILE_ATTR(cft->private);
267
268         val = res_counter_read_u64(&h_cg->hugepage[idx], name);
269         len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
270         return simple_read_from_buffer(buf, nbytes, ppos, str, len);
271 }
272
273 static int hugetlb_cgroup_write(struct cgroup *cgroup, struct cftype *cft,
274                                 const char *buffer)
275 {
276         int idx, name, ret;
277         unsigned long long val;
278         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
279
280         idx = MEMFILE_IDX(cft->private);
281         name = MEMFILE_ATTR(cft->private);
282
283         switch (name) {
284         case RES_LIMIT:
285                 if (hugetlb_cgroup_is_root(h_cg)) {
286                         /* Can't set limit on root */
287                         ret = -EINVAL;
288                         break;
289                 }
290                 /* This function does all necessary parse...reuse it */
291                 ret = res_counter_memparse_write_strategy(buffer, &val);
292                 if (ret)
293                         break;
294                 ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
295                 break;
296         default:
297                 ret = -EINVAL;
298                 break;
299         }
300         return ret;
301 }
302
303 static int hugetlb_cgroup_reset(struct cgroup *cgroup, unsigned int event)
304 {
305         int idx, name, ret = 0;
306         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
307
308         idx = MEMFILE_IDX(event);
309         name = MEMFILE_ATTR(event);
310
311         switch (name) {
312         case RES_MAX_USAGE:
313                 res_counter_reset_max(&h_cg->hugepage[idx]);
314                 break;
315         case RES_FAILCNT:
316                 res_counter_reset_failcnt(&h_cg->hugepage[idx]);
317                 break;
318         default:
319                 ret = -EINVAL;
320                 break;
321         }
322         return ret;
323 }
324
325 static char *mem_fmt(char *buf, int size, unsigned long hsize)
326 {
327         if (hsize >= (1UL << 30))
328                 snprintf(buf, size, "%luGB", hsize >> 30);
329         else if (hsize >= (1UL << 20))
330                 snprintf(buf, size, "%luMB", hsize >> 20);
331         else
332                 snprintf(buf, size, "%luKB", hsize >> 10);
333         return buf;
334 }
335
336 static void __init __hugetlb_cgroup_file_init(int idx)
337 {
338         char buf[32];
339         struct cftype *cft;
340         struct hstate *h = &hstates[idx];
341
342         /* format the size */
343         mem_fmt(buf, 32, huge_page_size(h));
344
345         /* Add the limit file */
346         cft = &h->cgroup_files[0];
347         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
348         cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
349         cft->read = hugetlb_cgroup_read;
350         cft->write_string = hugetlb_cgroup_write;
351
352         /* Add the usage file */
353         cft = &h->cgroup_files[1];
354         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
355         cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
356         cft->read = hugetlb_cgroup_read;
357
358         /* Add the MAX usage file */
359         cft = &h->cgroup_files[2];
360         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
361         cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
362         cft->trigger = hugetlb_cgroup_reset;
363         cft->read = hugetlb_cgroup_read;
364
365         /* Add the failcntfile */
366         cft = &h->cgroup_files[3];
367         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
368         cft->private  = MEMFILE_PRIVATE(idx, RES_FAILCNT);
369         cft->trigger  = hugetlb_cgroup_reset;
370         cft->read = hugetlb_cgroup_read;
371
372         /* NULL terminate the last cft */
373         cft = &h->cgroup_files[4];
374         memset(cft, 0, sizeof(*cft));
375
376         WARN_ON(cgroup_add_cftypes(&hugetlb_subsys, h->cgroup_files));
377
378         return;
379 }
380
381 void __init hugetlb_cgroup_file_init(void)
382 {
383         struct hstate *h;
384
385         for_each_hstate(h) {
386                 /*
387                  * Add cgroup control files only if the huge page consists
388                  * of more than two normal pages. This is because we use
389                  * page[2].lru.next for storing cgroup details.
390                  */
391                 if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
392                         __hugetlb_cgroup_file_init(hstate_index(h));
393         }
394 }
395
396 /*
397  * hugetlb_lock will make sure a parallel cgroup rmdir won't happen
398  * when we migrate hugepages
399  */
400 void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
401 {
402         struct hugetlb_cgroup *h_cg;
403         struct hstate *h = page_hstate(oldhpage);
404
405         if (hugetlb_cgroup_disabled())
406                 return;
407
408         VM_BUG_ON(!PageHuge(oldhpage));
409         spin_lock(&hugetlb_lock);
410         h_cg = hugetlb_cgroup_from_page(oldhpage);
411         set_hugetlb_cgroup(oldhpage, NULL);
412
413         /* move the h_cg details to new cgroup */
414         set_hugetlb_cgroup(newhpage, h_cg);
415         list_move(&newhpage->lru, &h->hugepage_activelist);
416         spin_unlock(&hugetlb_lock);
417         return;
418 }
419
420 struct cgroup_subsys hugetlb_subsys = {
421         .name = "hugetlb",
422         .css_alloc      = hugetlb_cgroup_css_alloc,
423         .css_offline    = hugetlb_cgroup_css_offline,
424         .css_free       = hugetlb_cgroup_css_free,
425         .subsys_id      = hugetlb_subsys_id,
426 };