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  * Cgroup v2
   7  * Copyright (C) 2019 Red Hat, Inc.
   8  * Author: Giuseppe Scrivano <gscrivan@redhat.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of version 2.1 of the GNU Lesser General Public License
  12  * as published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it would be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  17  *
  18  */
  19
  20 #include <linux/cgroup.h>
  21 #include <linux/page_counter.h>
  22 #include <linux/slab.h>
  23 #include <linux/hugetlb.h>
  24 #include <linux/hugetlb_cgroup.h>
  25
  26 #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
  27 #define MEMFILE_IDX(val)        (((val) >> 16) & 0xffff)
  28 #define MEMFILE_ATTR(val)       ((val) & 0xffff)
  29
  30 static struct hugetlb_cgroup *root_h_cgroup __read_mostly;
  31
  32 static inline struct page_counter *
  33 __hugetlb_cgroup_counter_from_cgroup(struct hugetlb_cgroup *h_cg, int idx,
  34                                      bool rsvd)
  35 {
  36         if (rsvd)
  37                 return &h_cg->rsvd_hugepage[idx];
  38         return &h_cg->hugepage[idx];
  39 }
  40
  41 static inline struct page_counter *
  42 hugetlb_cgroup_counter_from_cgroup(struct hugetlb_cgroup *h_cg, int idx)
  43 {
  44         return __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, false);
  45 }
  46
  47 static inline struct page_counter *
  48 hugetlb_cgroup_counter_from_cgroup_rsvd(struct hugetlb_cgroup *h_cg, int idx)
  49 {
  50         return __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, true);
  51 }
  52
  53 static inline
  54 struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s)
  55 {
  56         return s ? container_of(s, struct hugetlb_cgroup, css) : NULL;
  57 }
  58
  59 static inline
  60 struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
  61 {
  62         return hugetlb_cgroup_from_css(task_css(task, hugetlb_cgrp_id));
  63 }
  64
  65 static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
  66 {
  67         return (h_cg == root_h_cgroup);
  68 }
  69
  70 static inline struct hugetlb_cgroup *
  71 parent_hugetlb_cgroup(struct hugetlb_cgroup *h_cg)
  72 {
  73         return hugetlb_cgroup_from_css(h_cg->css.parent);
  74 }
  75
  76 static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg)
  77 {
  78         struct hstate *h;
  79
  80         for_each_hstate(h) {
  81                 if (page_counter_read(
  82                     hugetlb_cgroup_counter_from_cgroup(h_cg, hstate_index(h))))
  83                         return true;
  84         }
  85         return false;
  86 }
  87
  88 static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup,
  89                                 struct hugetlb_cgroup *parent_h_cgroup)
  90 {
  91         int idx;
  92
  93         for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) {
  94                 struct page_counter *fault_parent = NULL;
  95                 struct page_counter *rsvd_parent = NULL;
  96                 unsigned long limit;
  97                 int ret;
  98
  99                 if (parent_h_cgroup) {
 100                         fault_parent = hugetlb_cgroup_counter_from_cgroup(
 101                                 parent_h_cgroup, idx);
 102                         rsvd_parent = hugetlb_cgroup_counter_from_cgroup_rsvd(
 103                                 parent_h_cgroup, idx);
 104                 }
 105                 page_counter_init(hugetlb_cgroup_counter_from_cgroup(h_cgroup,
 106                                                                      idx),
 107                                   fault_parent);
 108                 page_counter_init(
 109                         hugetlb_cgroup_counter_from_cgroup_rsvd(h_cgroup, idx),
 110                         rsvd_parent);
 111
 112                 limit = round_down(PAGE_COUNTER_MAX,
 113                                    pages_per_huge_page(&hstates[idx]));
 114
 115                 ret = page_counter_set_max(
 116                         hugetlb_cgroup_counter_from_cgroup(h_cgroup, idx),
 117                         limit);
 118                 VM_BUG_ON(ret);
 119                 ret = page_counter_set_max(
 120                         hugetlb_cgroup_counter_from_cgroup_rsvd(h_cgroup, idx),
 121                         limit);
 122                 VM_BUG_ON(ret);
 123         }
 124 }
 125
 126 static void hugetlb_cgroup_free(struct hugetlb_cgroup *h_cgroup)
 127 {
 128         int node;
 129
 130         for_each_node(node)
 131                 kfree(h_cgroup->nodeinfo[node]);
 132         kfree(h_cgroup);
 133 }
 134
 135 static struct cgroup_subsys_state *
 136 hugetlb_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
 137 {
 138         struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css);
 139         struct hugetlb_cgroup *h_cgroup;
 140         int node;
 141
 142         h_cgroup = kzalloc(struct_size(h_cgroup, nodeinfo, nr_node_ids),
 143                            GFP_KERNEL);
 144
 145         if (!h_cgroup)
 146                 return ERR_PTR(-ENOMEM);
 147
 148         if (!parent_h_cgroup)
 149                 root_h_cgroup = h_cgroup;
 150
 151         /*
 152          * TODO: this routine can waste much memory for nodes which will
 153          * never be onlined. It's better to use memory hotplug callback
 154          * function.
 155          */
 156         for_each_node(node) {
 157                 /* Set node_to_alloc to NUMA_NO_NODE for offline nodes. */
 158                 int node_to_alloc =
 159                         node_state(node, N_NORMAL_MEMORY) ? node : NUMA_NO_NODE;
 160                 h_cgroup->nodeinfo[node] =
 161                         kzalloc_node(sizeof(struct hugetlb_cgroup_per_node),
 162                                      GFP_KERNEL, node_to_alloc);
 163                 if (!h_cgroup->nodeinfo[node])
 164                         goto fail_alloc_nodeinfo;
 165         }
 166
 167         hugetlb_cgroup_init(h_cgroup, parent_h_cgroup);
 168         return &h_cgroup->css;
 169
 170 fail_alloc_nodeinfo:
 171         hugetlb_cgroup_free(h_cgroup);
 172         return ERR_PTR(-ENOMEM);
 173 }
 174
 175 static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css)
 176 {
 177         hugetlb_cgroup_free(hugetlb_cgroup_from_css(css));
 178 }
 179
 180 /*
 181  * Should be called with hugetlb_lock held.
 182  * Since we are holding hugetlb_lock, pages cannot get moved from
 183  * active list or uncharged from the cgroup, So no need to get
 184  * page reference and test for page active here. This function
 185  * cannot fail.
 186  */
 187 static void hugetlb_cgroup_move_parent(int idx, struct hugetlb_cgroup *h_cg,
 188                                        struct page *page)
 189 {
 190         unsigned int nr_pages;
 191         struct page_counter *counter;
 192         struct hugetlb_cgroup *page_hcg;
 193         struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg);
 194         struct folio *folio = page_folio(page);
 195
 196         page_hcg = hugetlb_cgroup_from_folio(folio);
 197         /*
 198          * We can have pages in active list without any cgroup
 199          * ie, hugepage with less than 3 pages. We can safely
 200          * ignore those pages.
 201          */
 202         if (!page_hcg || page_hcg != h_cg)
 203                 goto out;
 204
 205         nr_pages = compound_nr(page);
 206         if (!parent) {
 207                 parent = root_h_cgroup;
 208                 /* root has no limit */
 209                 page_counter_charge(&parent->hugepage[idx], nr_pages);
 210         }
 211         counter = &h_cg->hugepage[idx];
 212         /* Take the pages off the local counter */
 213         page_counter_cancel(counter, nr_pages);
 214
 215         set_hugetlb_cgroup(folio, parent);
 216 out:
 217         return;
 218 }
 219
 220 /*
 221  * Force the hugetlb cgroup to empty the hugetlb resources by moving them to
 222  * the parent cgroup.
 223  */
 224 static void hugetlb_cgroup_css_offline(struct cgroup_subsys_state *css)
 225 {
 226         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
 227         struct hstate *h;
 228         struct page *page;
 229
 230         do {
 231                 for_each_hstate(h) {
 232                         spin_lock_irq(&hugetlb_lock);
 233                         list_for_each_entry(page, &h->hugepage_activelist, lru)
 234                                 hugetlb_cgroup_move_parent(hstate_index(h), h_cg, page);
 235
 236                         spin_unlock_irq(&hugetlb_lock);
 237                 }
 238                 cond_resched();
 239         } while (hugetlb_cgroup_have_usage(h_cg));
 240 }
 241
 242 static inline void hugetlb_event(struct hugetlb_cgroup *hugetlb, int idx,
 243                                  enum hugetlb_memory_event event)
 244 {
 245         atomic_long_inc(&hugetlb->events_local[idx][event]);
 246         cgroup_file_notify(&hugetlb->events_local_file[idx]);
 247
 248         do {
 249                 atomic_long_inc(&hugetlb->events[idx][event]);
 250                 cgroup_file_notify(&hugetlb->events_file[idx]);
 251         } while ((hugetlb = parent_hugetlb_cgroup(hugetlb)) &&
 252                  !hugetlb_cgroup_is_root(hugetlb));
 253 }
 254
 255 static int __hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
 256                                           struct hugetlb_cgroup **ptr,
 257                                           bool rsvd)
 258 {
 259         int ret = 0;
 260         struct page_counter *counter;
 261         struct hugetlb_cgroup *h_cg = NULL;
 262
 263         if (hugetlb_cgroup_disabled())
 264                 goto done;
 265         /*
 266          * We don't charge any cgroup if the compound page have less
 267          * than 3 pages.
 268          */
 269         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
 270                 goto done;
 271 again:
 272         rcu_read_lock();
 273         h_cg = hugetlb_cgroup_from_task(current);
 274         if (!css_tryget(&h_cg->css)) {
 275                 rcu_read_unlock();
 276                 goto again;
 277         }
 278         rcu_read_unlock();
 279
 280         if (!page_counter_try_charge(
 281                     __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd),
 282                     nr_pages, &counter)) {
 283                 ret = -ENOMEM;
 284                 hugetlb_event(h_cg, idx, HUGETLB_MAX);
 285                 css_put(&h_cg->css);
 286                 goto done;
 287         }
 288         /* Reservations take a reference to the css because they do not get
 289          * reparented.
 290          */
 291         if (!rsvd)
 292                 css_put(&h_cg->css);
 293 done:
 294         *ptr = h_cg;
 295         return ret;
 296 }
 297
 298 int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
 299                                  struct hugetlb_cgroup **ptr)
 300 {
 301         return __hugetlb_cgroup_charge_cgroup(idx, nr_pages, ptr, false);
 302 }
 303
 304 int hugetlb_cgroup_charge_cgroup_rsvd(int idx, unsigned long nr_pages,
 305                                       struct hugetlb_cgroup **ptr)
 306 {
 307         return __hugetlb_cgroup_charge_cgroup(idx, nr_pages, ptr, true);
 308 }
 309
 310 /* Should be called with hugetlb_lock held */
 311 static void __hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
 312                                            struct hugetlb_cgroup *h_cg,
 313                                            struct folio *folio, bool rsvd)
 314 {
 315         if (hugetlb_cgroup_disabled() || !h_cg)
 316                 return;
 317
 318         __set_hugetlb_cgroup(folio, h_cg, rsvd);
 319         if (!rsvd) {
 320                 unsigned long usage =
 321                         h_cg->nodeinfo[folio_nid(folio)]->usage[idx];
 322                 /*
 323                  * This write is not atomic due to fetching usage and writing
 324                  * to it, but that's fine because we call this with
 325                  * hugetlb_lock held anyway.
 326                  */
 327                 WRITE_ONCE(h_cg->nodeinfo[folio_nid(folio)]->usage[idx],
 328                            usage + nr_pages);
 329         }
 330 }
 331
 332 void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
 333                                   struct hugetlb_cgroup *h_cg,
 334                                   struct page *page)
 335 {
 336         struct folio *folio = page_folio(page);
 337
 338         __hugetlb_cgroup_commit_charge(idx, nr_pages, h_cg, folio, false);
 339 }
 340
 341 void hugetlb_cgroup_commit_charge_rsvd(int idx, unsigned long nr_pages,
 342                                        struct hugetlb_cgroup *h_cg,
 343                                        struct page *page)
 344 {
 345         struct folio *folio = page_folio(page);
 346
 347         __hugetlb_cgroup_commit_charge(idx, nr_pages, h_cg, folio, true);
 348 }
 349
 350 /*
 351  * Should be called with hugetlb_lock held
 352  */
 353 static void __hugetlb_cgroup_uncharge_folio(int idx, unsigned long nr_pages,
 354                                            struct folio *folio, bool rsvd)
 355 {
 356         struct hugetlb_cgroup *h_cg;
 357
 358         if (hugetlb_cgroup_disabled())
 359                 return;
 360         lockdep_assert_held(&hugetlb_lock);
 361         h_cg = __hugetlb_cgroup_from_folio(folio, rsvd);
 362         if (unlikely(!h_cg))
 363                 return;
 364         __set_hugetlb_cgroup(folio, NULL, rsvd);
 365
 366         page_counter_uncharge(__hugetlb_cgroup_counter_from_cgroup(h_cg, idx,
 367                                                                    rsvd),
 368                               nr_pages);
 369
 370         if (rsvd)
 371                 css_put(&h_cg->css);
 372         else {
 373                 unsigned long usage =
 374                         h_cg->nodeinfo[folio_nid(folio)]->usage[idx];
 375                 /*
 376                  * This write is not atomic due to fetching usage and writing
 377                  * to it, but that's fine because we call this with
 378                  * hugetlb_lock held anyway.
 379                  */
 380                 WRITE_ONCE(h_cg->nodeinfo[folio_nid(folio)]->usage[idx],
 381                            usage - nr_pages);
 382         }
 383 }
 384
 385 void hugetlb_cgroup_uncharge_folio(int idx, unsigned long nr_pages,
 386                                   struct folio *folio)
 387 {
 388         __hugetlb_cgroup_uncharge_folio(idx, nr_pages, folio, false);
 389 }
 390
 391 void hugetlb_cgroup_uncharge_folio_rsvd(int idx, unsigned long nr_pages,
 392                                        struct folio *folio)
 393 {
 394         __hugetlb_cgroup_uncharge_folio(idx, nr_pages, folio, true);
 395 }
 396
 397 static void __hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
 398                                              struct hugetlb_cgroup *h_cg,
 399                                              bool rsvd)
 400 {
 401         if (hugetlb_cgroup_disabled() || !h_cg)
 402                 return;
 403
 404         if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
 405                 return;
 406
 407         page_counter_uncharge(__hugetlb_cgroup_counter_from_cgroup(h_cg, idx,
 408                                                                    rsvd),
 409                               nr_pages);
 410
 411         if (rsvd)
 412                 css_put(&h_cg->css);
 413 }
 414
 415 void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
 416                                     struct hugetlb_cgroup *h_cg)
 417 {
 418         __hugetlb_cgroup_uncharge_cgroup(idx, nr_pages, h_cg, false);
 419 }
 420
 421 void hugetlb_cgroup_uncharge_cgroup_rsvd(int idx, unsigned long nr_pages,
 422                                          struct hugetlb_cgroup *h_cg)
 423 {
 424         __hugetlb_cgroup_uncharge_cgroup(idx, nr_pages, h_cg, true);
 425 }
 426
 427 void hugetlb_cgroup_uncharge_counter(struct resv_map *resv, unsigned long start,
 428                                      unsigned long end)
 429 {
 430         if (hugetlb_cgroup_disabled() || !resv || !resv->reservation_counter ||
 431             !resv->css)
 432                 return;
 433
 434         page_counter_uncharge(resv->reservation_counter,
 435                               (end - start) * resv->pages_per_hpage);
 436         css_put(resv->css);
 437 }
 438
 439 void hugetlb_cgroup_uncharge_file_region(struct resv_map *resv,
 440                                          struct file_region *rg,
 441                                          unsigned long nr_pages,
 442                                          bool region_del)
 443 {
 444         if (hugetlb_cgroup_disabled() || !resv || !rg || !nr_pages)
 445                 return;
 446
 447         if (rg->reservation_counter && resv->pages_per_hpage &&
 448             !resv->reservation_counter) {
 449                 page_counter_uncharge(rg->reservation_counter,
 450                                       nr_pages * resv->pages_per_hpage);
 451                 /*
 452                  * Only do css_put(rg->css) when we delete the entire region
 453                  * because one file_region must hold exactly one css reference.
 454                  */
 455                 if (region_del)
 456                         css_put(rg->css);
 457         }
 458 }
 459
 460 enum {
 461         RES_USAGE,
 462         RES_RSVD_USAGE,
 463         RES_LIMIT,
 464         RES_RSVD_LIMIT,
 465         RES_MAX_USAGE,
 466         RES_RSVD_MAX_USAGE,
 467         RES_FAILCNT,
 468         RES_RSVD_FAILCNT,
 469 };
 470
 471 static int hugetlb_cgroup_read_numa_stat(struct seq_file *seq, void *dummy)
 472 {
 473         int nid;
 474         struct cftype *cft = seq_cft(seq);
 475         int idx = MEMFILE_IDX(cft->private);
 476         bool legacy = MEMFILE_ATTR(cft->private);
 477         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(seq_css(seq));
 478         struct cgroup_subsys_state *css;
 479         unsigned long usage;
 480
 481         if (legacy) {
 482                 /* Add up usage across all nodes for the non-hierarchical total. */
 483                 usage = 0;
 484                 for_each_node_state(nid, N_MEMORY)
 485                         usage += READ_ONCE(h_cg->nodeinfo[nid]->usage[idx]);
 486                 seq_printf(seq, "total=%lu", usage * PAGE_SIZE);
 487
 488                 /* Simply print the per-node usage for the non-hierarchical total. */
 489                 for_each_node_state(nid, N_MEMORY)
 490                         seq_printf(seq, " N%d=%lu", nid,
 491                                    READ_ONCE(h_cg->nodeinfo[nid]->usage[idx]) *
 492                                            PAGE_SIZE);
 493                 seq_putc(seq, '\n');
 494         }
 495
 496         /*
 497          * The hierarchical total is pretty much the value recorded by the
 498          * counter, so use that.
 499          */
 500         seq_printf(seq, "%stotal=%lu", legacy ? "hierarchical_" : "",
 501                    page_counter_read(&h_cg->hugepage[idx]) * PAGE_SIZE);
 502
 503         /*
 504          * For each node, transverse the css tree to obtain the hierarchical
 505          * node usage.
 506          */
 507         for_each_node_state(nid, N_MEMORY) {
 508                 usage = 0;
 509                 rcu_read_lock();
 510                 css_for_each_descendant_pre(css, &h_cg->css) {
 511                         usage += READ_ONCE(hugetlb_cgroup_from_css(css)
 512                                                    ->nodeinfo[nid]
 513                                                    ->usage[idx]);
 514                 }
 515                 rcu_read_unlock();
 516                 seq_printf(seq, " N%d=%lu", nid, usage * PAGE_SIZE);
 517         }
 518
 519         seq_putc(seq, '\n');
 520
 521         return 0;
 522 }
 523
 524 static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css,
 525                                    struct cftype *cft)
 526 {
 527         struct page_counter *counter;
 528         struct page_counter *rsvd_counter;
 529         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
 530
 531         counter = &h_cg->hugepage[MEMFILE_IDX(cft->private)];
 532         rsvd_counter = &h_cg->rsvd_hugepage[MEMFILE_IDX(cft->private)];
 533
 534         switch (MEMFILE_ATTR(cft->private)) {
 535         case RES_USAGE:
 536                 return (u64)page_counter_read(counter) * PAGE_SIZE;
 537         case RES_RSVD_USAGE:
 538                 return (u64)page_counter_read(rsvd_counter) * PAGE_SIZE;
 539         case RES_LIMIT:
 540                 return (u64)counter->max * PAGE_SIZE;
 541         case RES_RSVD_LIMIT:
 542                 return (u64)rsvd_counter->max * PAGE_SIZE;
 543         case RES_MAX_USAGE:
 544                 return (u64)counter->watermark * PAGE_SIZE;
 545         case RES_RSVD_MAX_USAGE:
 546                 return (u64)rsvd_counter->watermark * PAGE_SIZE;
 547         case RES_FAILCNT:
 548                 return counter->failcnt;
 549         case RES_RSVD_FAILCNT:
 550                 return rsvd_counter->failcnt;
 551         default:
 552                 BUG();
 553         }
 554 }
 555
 556 static int hugetlb_cgroup_read_u64_max(struct seq_file *seq, void *v)
 557 {
 558         int idx;
 559         u64 val;
 560         struct cftype *cft = seq_cft(seq);
 561         unsigned long limit;
 562         struct page_counter *counter;
 563         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(seq_css(seq));
 564
 565         idx = MEMFILE_IDX(cft->private);
 566         counter = &h_cg->hugepage[idx];
 567
 568         limit = round_down(PAGE_COUNTER_MAX,
 569                            pages_per_huge_page(&hstates[idx]));
 570
 571         switch (MEMFILE_ATTR(cft->private)) {
 572         case RES_RSVD_USAGE:
 573                 counter = &h_cg->rsvd_hugepage[idx];
 574                 fallthrough;
 575         case RES_USAGE:
 576                 val = (u64)page_counter_read(counter);
 577                 seq_printf(seq, "%llu\n", val * PAGE_SIZE);
 578                 break;
 579         case RES_RSVD_LIMIT:
 580                 counter = &h_cg->rsvd_hugepage[idx];
 581                 fallthrough;
 582         case RES_LIMIT:
 583                 val = (u64)counter->max;
 584                 if (val == limit)
 585                         seq_puts(seq, "max\n");
 586                 else
 587                         seq_printf(seq, "%llu\n", val * PAGE_SIZE);
 588                 break;
 589         default:
 590                 BUG();
 591         }
 592
 593         return 0;
 594 }
 595
 596 static DEFINE_MUTEX(hugetlb_limit_mutex);
 597
 598 static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
 599                                     char *buf, size_t nbytes, loff_t off,
 600                                     const char *max)
 601 {
 602         int ret, idx;
 603         unsigned long nr_pages;
 604         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
 605         bool rsvd = false;
 606
 607         if (hugetlb_cgroup_is_root(h_cg)) /* Can't set limit on root */
 608                 return -EINVAL;
 609
 610         buf = strstrip(buf);
 611         ret = page_counter_memparse(buf, max, &nr_pages);
 612         if (ret)
 613                 return ret;
 614
 615         idx = MEMFILE_IDX(of_cft(of)->private);
 616         nr_pages = round_down(nr_pages, pages_per_huge_page(&hstates[idx]));
 617
 618         switch (MEMFILE_ATTR(of_cft(of)->private)) {
 619         case RES_RSVD_LIMIT:
 620                 rsvd = true;
 621                 fallthrough;
 622         case RES_LIMIT:
 623                 mutex_lock(&hugetlb_limit_mutex);
 624                 ret = page_counter_set_max(
 625                         __hugetlb_cgroup_counter_from_cgroup(h_cg, idx, rsvd),
 626                         nr_pages);
 627                 mutex_unlock(&hugetlb_limit_mutex);
 628                 break;
 629         default:
 630                 ret = -EINVAL;
 631                 break;
 632         }
 633         return ret ?: nbytes;
 634 }
 635
 636 static ssize_t hugetlb_cgroup_write_legacy(struct kernfs_open_file *of,
 637                                            char *buf, size_t nbytes, loff_t off)
 638 {
 639         return hugetlb_cgroup_write(of, buf, nbytes, off, "-1");
 640 }
 641
 642 static ssize_t hugetlb_cgroup_write_dfl(struct kernfs_open_file *of,
 643                                         char *buf, size_t nbytes, loff_t off)
 644 {
 645         return hugetlb_cgroup_write(of, buf, nbytes, off, "max");
 646 }
 647
 648 static ssize_t hugetlb_cgroup_reset(struct kernfs_open_file *of,
 649                                     char *buf, size_t nbytes, loff_t off)
 650 {
 651         int ret = 0;
 652         struct page_counter *counter, *rsvd_counter;
 653         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
 654
 655         counter = &h_cg->hugepage[MEMFILE_IDX(of_cft(of)->private)];
 656         rsvd_counter = &h_cg->rsvd_hugepage[MEMFILE_IDX(of_cft(of)->private)];
 657
 658         switch (MEMFILE_ATTR(of_cft(of)->private)) {
 659         case RES_MAX_USAGE:
 660                 page_counter_reset_watermark(counter);
 661                 break;
 662         case RES_RSVD_MAX_USAGE:
 663                 page_counter_reset_watermark(rsvd_counter);
 664                 break;
 665         case RES_FAILCNT:
 666                 counter->failcnt = 0;
 667                 break;
 668         case RES_RSVD_FAILCNT:
 669                 rsvd_counter->failcnt = 0;
 670                 break;
 671         default:
 672                 ret = -EINVAL;
 673                 break;
 674         }
 675         return ret ?: nbytes;
 676 }
 677
 678 static char *mem_fmt(char *buf, int size, unsigned long hsize)
 679 {
 680         if (hsize >= SZ_1G)
 681                 snprintf(buf, size, "%luGB", hsize / SZ_1G);
 682         else if (hsize >= SZ_1M)
 683                 snprintf(buf, size, "%luMB", hsize / SZ_1M);
 684         else
 685                 snprintf(buf, size, "%luKB", hsize / SZ_1K);
 686         return buf;
 687 }
 688
 689 static int __hugetlb_events_show(struct seq_file *seq, bool local)
 690 {
 691         int idx;
 692         long max;
 693         struct cftype *cft = seq_cft(seq);
 694         struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(seq_css(seq));
 695
 696         idx = MEMFILE_IDX(cft->private);
 697
 698         if (local)
 699                 max = atomic_long_read(&h_cg->events_local[idx][HUGETLB_MAX]);
 700         else
 701                 max = atomic_long_read(&h_cg->events[idx][HUGETLB_MAX]);
 702
 703         seq_printf(seq, "max %lu\n", max);
 704
 705         return 0;
 706 }
 707
 708 static int hugetlb_events_show(struct seq_file *seq, void *v)
 709 {
 710         return __hugetlb_events_show(seq, false);
 711 }
 712
 713 static int hugetlb_events_local_show(struct seq_file *seq, void *v)
 714 {
 715         return __hugetlb_events_show(seq, true);
 716 }
 717
 718 static void __init __hugetlb_cgroup_file_dfl_init(int idx)
 719 {
 720         char buf[32];
 721         struct cftype *cft;
 722         struct hstate *h = &hstates[idx];
 723
 724         /* format the size */
 725         mem_fmt(buf, sizeof(buf), huge_page_size(h));
 726
 727         /* Add the limit file */
 728         cft = &h->cgroup_files_dfl[0];
 729         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max", buf);
 730         cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
 731         cft->seq_show = hugetlb_cgroup_read_u64_max;
 732         cft->write = hugetlb_cgroup_write_dfl;
 733         cft->flags = CFTYPE_NOT_ON_ROOT;
 734
 735         /* Add the reservation limit file */
 736         cft = &h->cgroup_files_dfl[1];
 737         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.max", buf);
 738         cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_LIMIT);
 739         cft->seq_show = hugetlb_cgroup_read_u64_max;
 740         cft->write = hugetlb_cgroup_write_dfl;
 741         cft->flags = CFTYPE_NOT_ON_ROOT;
 742
 743         /* Add the current usage file */
 744         cft = &h->cgroup_files_dfl[2];
 745         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.current", buf);
 746         cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
 747         cft->seq_show = hugetlb_cgroup_read_u64_max;
 748         cft->flags = CFTYPE_NOT_ON_ROOT;
 749
 750         /* Add the current reservation usage file */
 751         cft = &h->cgroup_files_dfl[3];
 752         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.current", buf);
 753         cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_USAGE);
 754         cft->seq_show = hugetlb_cgroup_read_u64_max;
 755         cft->flags = CFTYPE_NOT_ON_ROOT;
 756
 757         /* Add the events file */
 758         cft = &h->cgroup_files_dfl[4];
 759         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events", buf);
 760         cft->private = MEMFILE_PRIVATE(idx, 0);
 761         cft->seq_show = hugetlb_events_show;
 762         cft->file_offset = offsetof(struct hugetlb_cgroup, events_file[idx]);
 763         cft->flags = CFTYPE_NOT_ON_ROOT;
 764
 765         /* Add the events.local file */
 766         cft = &h->cgroup_files_dfl[5];
 767         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events.local", buf);
 768         cft->private = MEMFILE_PRIVATE(idx, 0);
 769         cft->seq_show = hugetlb_events_local_show;
 770         cft->file_offset = offsetof(struct hugetlb_cgroup,
 771                                     events_local_file[idx]);
 772         cft->flags = CFTYPE_NOT_ON_ROOT;
 773
 774         /* Add the numa stat file */
 775         cft = &h->cgroup_files_dfl[6];
 776         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
 777         cft->private = MEMFILE_PRIVATE(idx, 0);
 778         cft->seq_show = hugetlb_cgroup_read_numa_stat;
 779         cft->flags = CFTYPE_NOT_ON_ROOT;
 780
 781         /* NULL terminate the last cft */
 782         cft = &h->cgroup_files_dfl[7];
 783         memset(cft, 0, sizeof(*cft));
 784
 785         WARN_ON(cgroup_add_dfl_cftypes(&hugetlb_cgrp_subsys,
 786                                        h->cgroup_files_dfl));
 787 }
 788
 789 static void __init __hugetlb_cgroup_file_legacy_init(int idx)
 790 {
 791         char buf[32];
 792         struct cftype *cft;
 793         struct hstate *h = &hstates[idx];
 794
 795         /* format the size */
 796         mem_fmt(buf, sizeof(buf), huge_page_size(h));
 797
 798         /* Add the limit file */
 799         cft = &h->cgroup_files_legacy[0];
 800         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
 801         cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
 802         cft->read_u64 = hugetlb_cgroup_read_u64;
 803         cft->write = hugetlb_cgroup_write_legacy;
 804
 805         /* Add the reservation limit file */
 806         cft = &h->cgroup_files_legacy[1];
 807         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.limit_in_bytes", buf);
 808         cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_LIMIT);
 809         cft->read_u64 = hugetlb_cgroup_read_u64;
 810         cft->write = hugetlb_cgroup_write_legacy;
 811
 812         /* Add the usage file */
 813         cft = &h->cgroup_files_legacy[2];
 814         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
 815         cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
 816         cft->read_u64 = hugetlb_cgroup_read_u64;
 817
 818         /* Add the reservation usage file */
 819         cft = &h->cgroup_files_legacy[3];
 820         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.usage_in_bytes", buf);
 821         cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_USAGE);
 822         cft->read_u64 = hugetlb_cgroup_read_u64;
 823
 824         /* Add the MAX usage file */
 825         cft = &h->cgroup_files_legacy[4];
 826         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
 827         cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
 828         cft->write = hugetlb_cgroup_reset;
 829         cft->read_u64 = hugetlb_cgroup_read_u64;
 830
 831         /* Add the MAX reservation usage file */
 832         cft = &h->cgroup_files_legacy[5];
 833         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.max_usage_in_bytes", buf);
 834         cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_MAX_USAGE);
 835         cft->write = hugetlb_cgroup_reset;
 836         cft->read_u64 = hugetlb_cgroup_read_u64;
 837
 838         /* Add the failcntfile */
 839         cft = &h->cgroup_files_legacy[6];
 840         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
 841         cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT);
 842         cft->write = hugetlb_cgroup_reset;
 843         cft->read_u64 = hugetlb_cgroup_read_u64;
 844
 845         /* Add the reservation failcntfile */
 846         cft = &h->cgroup_files_legacy[7];
 847         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.rsvd.failcnt", buf);
 848         cft->private = MEMFILE_PRIVATE(idx, RES_RSVD_FAILCNT);
 849         cft->write = hugetlb_cgroup_reset;
 850         cft->read_u64 = hugetlb_cgroup_read_u64;
 851
 852         /* Add the numa stat file */
 853         cft = &h->cgroup_files_legacy[8];
 854         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
 855         cft->private = MEMFILE_PRIVATE(idx, 1);
 856         cft->seq_show = hugetlb_cgroup_read_numa_stat;
 857
 858         /* NULL terminate the last cft */
 859         cft = &h->cgroup_files_legacy[9];
 860         memset(cft, 0, sizeof(*cft));
 861
 862         WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
 863                                           h->cgroup_files_legacy));
 864 }
 865
 866 static void __init __hugetlb_cgroup_file_init(int idx)
 867 {
 868         __hugetlb_cgroup_file_dfl_init(idx);
 869         __hugetlb_cgroup_file_legacy_init(idx);
 870 }
 871
 872 void __init hugetlb_cgroup_file_init(void)
 873 {
 874         struct hstate *h;
 875
 876         for_each_hstate(h) {
 877                 /*
 878                  * Add cgroup control files only if the huge page consists
 879                  * of more than two normal pages. This is because we use
 880                  * page[2].private for storing cgroup details.
 881                  */
 882                 if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
 883                         __hugetlb_cgroup_file_init(hstate_index(h));
 884         }
 885 }
 886
 887 /*
 888  * hugetlb_lock will make sure a parallel cgroup rmdir won't happen
 889  * when we migrate hugepages
 890  */
 891 void hugetlb_cgroup_migrate(struct folio *old_folio, struct folio *new_folio)
 892 {
 893         struct hugetlb_cgroup *h_cg;
 894         struct hugetlb_cgroup *h_cg_rsvd;
 895         struct hstate *h = folio_hstate(old_folio);
 896
 897         if (hugetlb_cgroup_disabled())
 898                 return;
 899
 900         spin_lock_irq(&hugetlb_lock);
 901         h_cg = hugetlb_cgroup_from_folio(old_folio);
 902         h_cg_rsvd = hugetlb_cgroup_from_folio_rsvd(old_folio);
 903         set_hugetlb_cgroup(old_folio, NULL);
 904         set_hugetlb_cgroup_rsvd(old_folio, NULL);
 905
 906         /* move the h_cg details to new cgroup */
 907         set_hugetlb_cgroup(new_folio, h_cg);
 908         set_hugetlb_cgroup_rsvd(new_folio, h_cg_rsvd);
 909         list_move(&new_folio->lru, &h->hugepage_activelist);
 910         spin_unlock_irq(&hugetlb_lock);
 911         return;
 912 }
 913
 914 static struct cftype hugetlb_files[] = {
 915         {} /* terminate */
 916 };
 917
 918 struct cgroup_subsys hugetlb_cgrp_subsys = {
 919         .css_alloc      = hugetlb_cgroup_css_alloc,
 920         .css_offline    = hugetlb_cgroup_css_offline,
 921         .css_free       = hugetlb_cgroup_css_free,
 922         .dfl_cftypes    = hugetlb_files,
 923         .legacy_cftypes = hugetlb_files,
 924 };