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 s ? container_of(s, struct hugetlb_cgroup, css) : NULL; 40 } 41 42 static inline 43 struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task) 44 { 45 return hugetlb_cgroup_from_css(task_css(task, hugetlb_subsys_id)); 46 } 47 48 static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg) 49 { 50 return (h_cg == root_h_cgroup); 51 } 52 53 static inline struct hugetlb_cgroup * 54 parent_hugetlb_cgroup(struct hugetlb_cgroup *h_cg) 55 { 56 return hugetlb_cgroup_from_css(css_parent(&h_cg->css)); 57 } 58 59 static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg) 60 { 61 int idx; 62 63 for (idx = 0; idx < hugetlb_max_hstate; idx++) { 64 if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE)) > 0) 65 return true; 66 } 67 return false; 68 } 69 70 static struct cgroup_subsys_state * 71 hugetlb_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 72 { 73 struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css); 74 struct hugetlb_cgroup *h_cgroup; 75 int idx; 76 77 h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL); 78 if (!h_cgroup) 79 return ERR_PTR(-ENOMEM); 80 81 if (parent_h_cgroup) { 82 for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) 83 res_counter_init(&h_cgroup->hugepage[idx], 84 &parent_h_cgroup->hugepage[idx]); 85 } else { 86 root_h_cgroup = h_cgroup; 87 for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) 88 res_counter_init(&h_cgroup->hugepage[idx], NULL); 89 } 90 return &h_cgroup->css; 91 } 92 93 static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css) 94 { 95 struct hugetlb_cgroup *h_cgroup; 96 97 h_cgroup = hugetlb_cgroup_from_css(css); 98 kfree(h_cgroup); 99 } 100 101 102 /* 103 * Should be called with hugetlb_lock held. 104 * Since we are holding hugetlb_lock, pages cannot get moved from 105 * active list or uncharged from the cgroup, So no need to get 106 * page reference and test for page active here. This function 107 * cannot fail. 108 */ 109 static void hugetlb_cgroup_move_parent(int idx, struct hugetlb_cgroup *h_cg, 110 struct page *page) 111 { 112 int csize; 113 struct res_counter *counter; 114 struct res_counter *fail_res; 115 struct hugetlb_cgroup *page_hcg; 116 struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg); 117 118 page_hcg = hugetlb_cgroup_from_page(page); 119 /* 120 * We can have pages in active list without any cgroup 121 * ie, hugepage with less than 3 pages. We can safely 122 * ignore those pages. 123 */ 124 if (!page_hcg || page_hcg != h_cg) 125 goto out; 126 127 csize = PAGE_SIZE << compound_order(page); 128 if (!parent) { 129 parent = root_h_cgroup; 130 /* root has no limit */ 131 res_counter_charge_nofail(&parent->hugepage[idx], 132 csize, &fail_res); 133 } 134 counter = &h_cg->hugepage[idx]; 135 res_counter_uncharge_until(counter, counter->parent, csize); 136 137 set_hugetlb_cgroup(page, parent); 138 out: 139 return; 140 } 141 142 /* 143 * Force the hugetlb cgroup to empty the hugetlb resources by moving them to 144 * the parent cgroup. 145 */ 146 static void hugetlb_cgroup_css_offline(struct cgroup_subsys_state *css) 147 { 148 struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); 149 struct hstate *h; 150 struct page *page; 151 int idx = 0; 152 153 do { 154 for_each_hstate(h) { 155 spin_lock(&hugetlb_lock); 156 list_for_each_entry(page, &h->hugepage_activelist, lru) 157 hugetlb_cgroup_move_parent(idx, h_cg, page); 158 159 spin_unlock(&hugetlb_lock); 160 idx++; 161 } 162 cond_resched(); 163 } while (hugetlb_cgroup_have_usage(h_cg)); 164 } 165 166 int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, 167 struct hugetlb_cgroup **ptr) 168 { 169 int ret = 0; 170 struct res_counter *fail_res; 171 struct hugetlb_cgroup *h_cg = NULL; 172 unsigned long csize = nr_pages * PAGE_SIZE; 173 174 if (hugetlb_cgroup_disabled()) 175 goto done; 176 /* 177 * We don't charge any cgroup if the compound page have less 178 * than 3 pages. 179 */ 180 if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER) 181 goto done; 182 again: 183 rcu_read_lock(); 184 h_cg = hugetlb_cgroup_from_task(current); 185 if (!css_tryget(&h_cg->css)) { 186 rcu_read_unlock(); 187 goto again; 188 } 189 rcu_read_unlock(); 190 191 ret = res_counter_charge(&h_cg->hugepage[idx], csize, &fail_res); 192 css_put(&h_cg->css); 193 done: 194 *ptr = h_cg; 195 return ret; 196 } 197 198 /* Should be called with hugetlb_lock held */ 199 void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages, 200 struct hugetlb_cgroup *h_cg, 201 struct page *page) 202 { 203 if (hugetlb_cgroup_disabled() || !h_cg) 204 return; 205 206 set_hugetlb_cgroup(page, h_cg); 207 return; 208 } 209 210 /* 211 * Should be called with hugetlb_lock held 212 */ 213 void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, 214 struct page *page) 215 { 216 struct hugetlb_cgroup *h_cg; 217 unsigned long csize = nr_pages * PAGE_SIZE; 218 219 if (hugetlb_cgroup_disabled()) 220 return; 221 VM_BUG_ON(!spin_is_locked(&hugetlb_lock)); 222 h_cg = hugetlb_cgroup_from_page(page); 223 if (unlikely(!h_cg)) 224 return; 225 set_hugetlb_cgroup(page, NULL); 226 res_counter_uncharge(&h_cg->hugepage[idx], csize); 227 return; 228 } 229 230 void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, 231 struct hugetlb_cgroup *h_cg) 232 { 233 unsigned long csize = nr_pages * PAGE_SIZE; 234 235 if (hugetlb_cgroup_disabled() || !h_cg) 236 return; 237 238 if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER) 239 return; 240 241 res_counter_uncharge(&h_cg->hugepage[idx], csize); 242 return; 243 } 244 245 static ssize_t hugetlb_cgroup_read(struct cgroup_subsys_state *css, 246 struct cftype *cft, struct file *file, 247 char __user *buf, size_t nbytes, 248 loff_t *ppos) 249 { 250 u64 val; 251 char str[64]; 252 int idx, name, len; 253 struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); 254 255 idx = MEMFILE_IDX(cft->private); 256 name = MEMFILE_ATTR(cft->private); 257 258 val = res_counter_read_u64(&h_cg->hugepage[idx], name); 259 len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val); 260 return simple_read_from_buffer(buf, nbytes, ppos, str, len); 261 } 262 263 static int hugetlb_cgroup_write(struct cgroup_subsys_state *css, 264 struct cftype *cft, const char *buffer) 265 { 266 int idx, name, ret; 267 unsigned long long val; 268 struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); 269 270 idx = MEMFILE_IDX(cft->private); 271 name = MEMFILE_ATTR(cft->private); 272 273 switch (name) { 274 case RES_LIMIT: 275 if (hugetlb_cgroup_is_root(h_cg)) { 276 /* Can't set limit on root */ 277 ret = -EINVAL; 278 break; 279 } 280 /* This function does all necessary parse...reuse it */ 281 ret = res_counter_memparse_write_strategy(buffer, &val); 282 if (ret) 283 break; 284 ret = res_counter_set_limit(&h_cg->hugepage[idx], val); 285 break; 286 default: 287 ret = -EINVAL; 288 break; 289 } 290 return ret; 291 } 292 293 static int hugetlb_cgroup_reset(struct cgroup_subsys_state *css, 294 unsigned int event) 295 { 296 int idx, name, ret = 0; 297 struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); 298 299 idx = MEMFILE_IDX(event); 300 name = MEMFILE_ATTR(event); 301 302 switch (name) { 303 case RES_MAX_USAGE: 304 res_counter_reset_max(&h_cg->hugepage[idx]); 305 break; 306 case RES_FAILCNT: 307 res_counter_reset_failcnt(&h_cg->hugepage[idx]); 308 break; 309 default: 310 ret = -EINVAL; 311 break; 312 } 313 return ret; 314 } 315 316 static char *mem_fmt(char *buf, int size, unsigned long hsize) 317 { 318 if (hsize >= (1UL << 30)) 319 snprintf(buf, size, "%luGB", hsize >> 30); 320 else if (hsize >= (1UL << 20)) 321 snprintf(buf, size, "%luMB", hsize >> 20); 322 else 323 snprintf(buf, size, "%luKB", hsize >> 10); 324 return buf; 325 } 326 327 static void __init __hugetlb_cgroup_file_init(int idx) 328 { 329 char buf[32]; 330 struct cftype *cft; 331 struct hstate *h = &hstates[idx]; 332 333 /* format the size */ 334 mem_fmt(buf, 32, huge_page_size(h)); 335 336 /* Add the limit file */ 337 cft = &h->cgroup_files[0]; 338 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf); 339 cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT); 340 cft->read = hugetlb_cgroup_read; 341 cft->write_string = hugetlb_cgroup_write; 342 343 /* Add the usage file */ 344 cft = &h->cgroup_files[1]; 345 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf); 346 cft->private = MEMFILE_PRIVATE(idx, RES_USAGE); 347 cft->read = hugetlb_cgroup_read; 348 349 /* Add the MAX usage file */ 350 cft = &h->cgroup_files[2]; 351 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf); 352 cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE); 353 cft->trigger = hugetlb_cgroup_reset; 354 cft->read = hugetlb_cgroup_read; 355 356 /* Add the failcntfile */ 357 cft = &h->cgroup_files[3]; 358 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf); 359 cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT); 360 cft->trigger = hugetlb_cgroup_reset; 361 cft->read = hugetlb_cgroup_read; 362 363 /* NULL terminate the last cft */ 364 cft = &h->cgroup_files[4]; 365 memset(cft, 0, sizeof(*cft)); 366 367 WARN_ON(cgroup_add_cftypes(&hugetlb_subsys, h->cgroup_files)); 368 369 return; 370 } 371 372 void __init hugetlb_cgroup_file_init(void) 373 { 374 struct hstate *h; 375 376 for_each_hstate(h) { 377 /* 378 * Add cgroup control files only if the huge page consists 379 * of more than two normal pages. This is because we use 380 * page[2].lru.next for storing cgroup details. 381 */ 382 if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER) 383 __hugetlb_cgroup_file_init(hstate_index(h)); 384 } 385 } 386 387 /* 388 * hugetlb_lock will make sure a parallel cgroup rmdir won't happen 389 * when we migrate hugepages 390 */ 391 void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage) 392 { 393 struct hugetlb_cgroup *h_cg; 394 struct hstate *h = page_hstate(oldhpage); 395 396 if (hugetlb_cgroup_disabled()) 397 return; 398 399 VM_BUG_ON(!PageHuge(oldhpage)); 400 spin_lock(&hugetlb_lock); 401 h_cg = hugetlb_cgroup_from_page(oldhpage); 402 set_hugetlb_cgroup(oldhpage, NULL); 403 404 /* move the h_cg details to new cgroup */ 405 set_hugetlb_cgroup(newhpage, h_cg); 406 list_move(&newhpage->lru, &h->hugepage_activelist); 407 spin_unlock(&hugetlb_lock); 408 return; 409 } 410 411 struct cgroup_subsys hugetlb_subsys = { 412 .name = "hugetlb", 413 .css_alloc = hugetlb_cgroup_css_alloc, 414 .css_offline = hugetlb_cgroup_css_offline, 415 .css_free = hugetlb_cgroup_css_free, 416 .subsys_id = hugetlb_subsys_id, 417 }; 418