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 }; 427