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 static struct hugetlb_cgroup *root_h_cgroup __read_mostly;
  34
  35 static inline
  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
  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
  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 *
  53 parent_hugetlb_cgroup(struct hugetlb_cgroup *h_cg)
  54 {
  55         return hugetlb_cgroup_from_css(css_parent(&h_cg->css));
  56 }
  57
  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 *
  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
  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  */
 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  */
 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
 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(&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 */
 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  */
 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         VM_BUG_ON(!spin_is_locked(&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
 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
 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
 256 static int hugetlb_cgroup_write(struct cgroup_subsys_state *css,
 257                                 struct cftype *cft, char *buffer)
 258 {
 259         int idx, name, ret;
 260         unsigned long long val;
 261         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
 262
 263         idx = MEMFILE_IDX(cft->private);
 264         name = MEMFILE_ATTR(cft->private);
 265
 266         switch (name) {
 267         case RES_LIMIT:
 268                 if (hugetlb_cgroup_is_root(h_cg)) {
 269                         /* Can't set limit on root */
 270                         ret = -EINVAL;
 271                         break;
 272                 }
 273                 /* This function does all necessary parse...reuse it */
 274                 ret = res_counter_memparse_write_strategy(buffer, &val);
 275                 if (ret)
 276                         break;
 277                 ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
 278                 break;
 279         default:
 280                 ret = -EINVAL;
 281                 break;
 282         }
 283         return ret;
 284 }
 285
 286 static int hugetlb_cgroup_reset(struct cgroup_subsys_state *css,
 287                                 unsigned int event)
 288 {
 289         int idx, name, ret = 0;
 290         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
 291
 292         idx = MEMFILE_IDX(event);
 293         name = MEMFILE_ATTR(event);
 294
 295         switch (name) {
 296         case RES_MAX_USAGE:
 297                 res_counter_reset_max(&h_cg->hugepage[idx]);
 298                 break;
 299         case RES_FAILCNT:
 300                 res_counter_reset_failcnt(&h_cg->hugepage[idx]);
 301                 break;
 302         default:
 303                 ret = -EINVAL;
 304                 break;
 305         }
 306         return ret;
 307 }
 308
 309 static char *mem_fmt(char *buf, int size, unsigned long hsize)
 310 {
 311         if (hsize >= (1UL << 30))
 312                 snprintf(buf, size, "%luGB", hsize >> 30);
 313         else if (hsize >= (1UL << 20))
 314                 snprintf(buf, size, "%luMB", hsize >> 20);
 315         else
 316                 snprintf(buf, size, "%luKB", hsize >> 10);
 317         return buf;
 318 }
 319
 320 static void __init __hugetlb_cgroup_file_init(int idx)
 321 {
 322         char buf[32];
 323         struct cftype *cft;
 324         struct hstate *h = &hstates[idx];
 325
 326         /* format the size */
 327         mem_fmt(buf, 32, huge_page_size(h));
 328
 329         /* Add the limit file */
 330         cft = &h->cgroup_files[0];
 331         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
 332         cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
 333         cft->read_u64 = hugetlb_cgroup_read_u64;
 334         cft->write_string = hugetlb_cgroup_write;
 335
 336         /* Add the usage file */
 337         cft = &h->cgroup_files[1];
 338         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
 339         cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
 340         cft->read_u64 = hugetlb_cgroup_read_u64;
 341
 342         /* Add the MAX usage file */
 343         cft = &h->cgroup_files[2];
 344         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
 345         cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
 346         cft->trigger = hugetlb_cgroup_reset;
 347         cft->read_u64 = hugetlb_cgroup_read_u64;
 348
 349         /* Add the failcntfile */
 350         cft = &h->cgroup_files[3];
 351         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
 352         cft->private  = MEMFILE_PRIVATE(idx, RES_FAILCNT);
 353         cft->trigger  = hugetlb_cgroup_reset;
 354         cft->read_u64 = hugetlb_cgroup_read_u64;
 355
 356         /* NULL terminate the last cft */
 357         cft = &h->cgroup_files[4];
 358         memset(cft, 0, sizeof(*cft));
 359
 360         WARN_ON(cgroup_add_cftypes(&hugetlb_cgrp_subsys, h->cgroup_files));
 361
 362         return;
 363 }
 364
 365 void __init hugetlb_cgroup_file_init(void)
 366 {
 367         struct hstate *h;
 368
 369         for_each_hstate(h) {
 370                 /*
 371                  * Add cgroup control files only if the huge page consists
 372                  * of more than two normal pages. This is because we use
 373                  * page[2].lru.next for storing cgroup details.
 374                  */
 375                 if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
 376                         __hugetlb_cgroup_file_init(hstate_index(h));
 377         }
 378 }
 379
 380 /*
 381  * hugetlb_lock will make sure a parallel cgroup rmdir won't happen
 382  * when we migrate hugepages
 383  */
 384 void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
 385 {
 386         struct hugetlb_cgroup *h_cg;
 387         struct hstate *h = page_hstate(oldhpage);
 388
 389         if (hugetlb_cgroup_disabled())
 390                 return;
 391
 392         VM_BUG_ON_PAGE(!PageHuge(oldhpage), oldhpage);
 393         spin_lock(&hugetlb_lock);
 394         h_cg = hugetlb_cgroup_from_page(oldhpage);
 395         set_hugetlb_cgroup(oldhpage, NULL);
 396
 397         /* move the h_cg details to new cgroup */
 398         set_hugetlb_cgroup(newhpage, h_cg);
 399         list_move(&newhpage->lru, &h->hugepage_activelist);
 400         spin_unlock(&hugetlb_lock);
 401         return;
 402 }
 403
 404 struct cgroup_subsys hugetlb_cgrp_subsys = {
 405         .css_alloc      = hugetlb_cgroup_css_alloc,
 406         .css_offline    = hugetlb_cgroup_css_offline,
 407         .css_free       = hugetlb_cgroup_css_free,
 408 };