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