lib/librte_eal/linuxapp/eal/eal_hugepage_info.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4
   5 #include <string.h>
   6 #include <sys/types.h>
   7 #include <sys/file.h>
   8 #include <dirent.h>
   9 #include <stdint.h>
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <fnmatch.h>
  13 #include <inttypes.h>
  14 #include <stdarg.h>
  15 #include <unistd.h>
  16 #include <errno.h>
  17 #include <sys/queue.h>
  18 #include <sys/stat.h>
  19
  20 #include <rte_memory.h>
  21 #include <rte_eal.h>
  22 #include <rte_launch.h>
  23 #include <rte_per_lcore.h>
  24 #include <rte_lcore.h>
  25 #include <rte_debug.h>
  26 #include <rte_log.h>
  27 #include <rte_common.h>
  28 #include "rte_string_fns.h"
  29 #include "eal_internal_cfg.h"
  30 #include "eal_hugepages.h"
  31 #include "eal_filesystem.h"
  32
  33 static const char sys_dir_path[] = "/sys/kernel/mm/hugepages";
  34 static const char sys_pages_numa_dir_path[] = "/sys/devices/system/node";
  35
  36 /* this function is only called from eal_hugepage_info_init which itself
  37  * is only called from a primary process */
  38 static uint32_t
  39 get_num_hugepages(const char *subdir)
  40 {
  41         char path[PATH_MAX];
  42         long unsigned resv_pages, num_pages = 0;
  43         const char *nr_hp_file = "free_hugepages";
  44         const char *nr_rsvd_file = "resv_hugepages";
  45
  46         /* first, check how many reserved pages kernel reports */
  47         snprintf(path, sizeof(path), "%s/%s/%s",
  48                         sys_dir_path, subdir, nr_rsvd_file);
  49         if (eal_parse_sysfs_value(path, &resv_pages) < 0)
  50                 return 0;
  51
  52         snprintf(path, sizeof(path), "%s/%s/%s",
  53                         sys_dir_path, subdir, nr_hp_file);
  54         if (eal_parse_sysfs_value(path, &num_pages) < 0)
  55                 return 0;
  56
  57         if (num_pages == 0)
  58                 RTE_LOG(WARNING, EAL, "No free hugepages reported in %s\n",
  59                                 subdir);
  60
  61         /* adjust num_pages */
  62         if (num_pages >= resv_pages)
  63                 num_pages -= resv_pages;
  64         else if (resv_pages)
  65                 num_pages = 0;
  66
  67         /* we want to return a uint32_t and more than this looks suspicious
  68          * anyway ... */
  69         if (num_pages > UINT32_MAX)
  70                 num_pages = UINT32_MAX;
  71
  72         return num_pages;
  73 }
  74
  75 static uint32_t
  76 get_num_hugepages_on_node(const char *subdir, unsigned int socket)
  77 {
  78         char path[PATH_MAX], socketpath[PATH_MAX];
  79         DIR *socketdir;
  80         unsigned long num_pages = 0;
  81         const char *nr_hp_file = "free_hugepages";
  82
  83         snprintf(socketpath, sizeof(socketpath), "%s/node%u/hugepages",
  84                 sys_pages_numa_dir_path, socket);
  85
  86         socketdir = opendir(socketpath);
  87         if (socketdir) {
  88                 /* Keep calm and carry on */
  89                 closedir(socketdir);
  90         } else {
  91                 /* Can't find socket dir, so ignore it */
  92                 return 0;
  93         }
  94
  95         snprintf(path, sizeof(path), "%s/%s/%s",
  96                         socketpath, subdir, nr_hp_file);
  97         if (eal_parse_sysfs_value(path, &num_pages) < 0)
  98                 return 0;
  99
 100         if (num_pages == 0)
 101                 RTE_LOG(WARNING, EAL, "No free hugepages reported in %s\n",
 102                                 subdir);
 103
 104         /*
 105          * we want to return a uint32_t and more than this looks suspicious
 106          * anyway ...
 107          */
 108         if (num_pages > UINT32_MAX)
 109                 num_pages = UINT32_MAX;
 110
 111         return num_pages;
 112 }
 113
 114 static uint64_t
 115 get_default_hp_size(void)
 116 {
 117         const char proc_meminfo[] = "/proc/meminfo";
 118         const char str_hugepagesz[] = "Hugepagesize:";
 119         unsigned hugepagesz_len = sizeof(str_hugepagesz) - 1;
 120         char buffer[256];
 121         unsigned long long size = 0;
 122
 123         FILE *fd = fopen(proc_meminfo, "r");
 124         if (fd == NULL)
 125                 rte_panic("Cannot open %s\n", proc_meminfo);
 126         while(fgets(buffer, sizeof(buffer), fd)){
 127                 if (strncmp(buffer, str_hugepagesz, hugepagesz_len) == 0){
 128                         size = rte_str_to_size(&buffer[hugepagesz_len]);
 129                         break;
 130                 }
 131         }
 132         fclose(fd);
 133         if (size == 0)
 134                 rte_panic("Cannot get default hugepage size from %s\n", proc_meminfo);
 135         return size;
 136 }
 137
 138 static const char *
 139 get_hugepage_dir(uint64_t hugepage_sz)
 140 {
 141         enum proc_mount_fieldnames {
 142                 DEVICE = 0,
 143                 MOUNTPT,
 144                 FSTYPE,
 145                 OPTIONS,
 146                 _FIELDNAME_MAX
 147         };
 148         static uint64_t default_size = 0;
 149         const char proc_mounts[] = "/proc/mounts";
 150         const char hugetlbfs_str[] = "hugetlbfs";
 151         const size_t htlbfs_str_len = sizeof(hugetlbfs_str) - 1;
 152         const char pagesize_opt[] = "pagesize=";
 153         const size_t pagesize_opt_len = sizeof(pagesize_opt) - 1;
 154         const char split_tok = ' ';
 155         char *splitstr[_FIELDNAME_MAX];
 156         char buf[BUFSIZ];
 157         char *retval = NULL;
 158
 159         FILE *fd = fopen(proc_mounts, "r");
 160         if (fd == NULL)
 161                 rte_panic("Cannot open %s\n", proc_mounts);
 162
 163         if (default_size == 0)
 164                 default_size = get_default_hp_size();
 165
 166         while (fgets(buf, sizeof(buf), fd)){
 167                 if (rte_strsplit(buf, sizeof(buf), splitstr, _FIELDNAME_MAX,
 168                                 split_tok) != _FIELDNAME_MAX) {
 169                         RTE_LOG(ERR, EAL, "Error parsing %s\n", proc_mounts);
 170                         break; /* return NULL */
 171                 }
 172
 173                 /* we have a specified --huge-dir option, only examine that dir */
 174                 if (internal_config.hugepage_dir != NULL &&
 175                                 strcmp(splitstr[MOUNTPT], internal_config.hugepage_dir) != 0)
 176                         continue;
 177
 178                 if (strncmp(splitstr[FSTYPE], hugetlbfs_str, htlbfs_str_len) == 0){
 179                         const char *pagesz_str = strstr(splitstr[OPTIONS], pagesize_opt);
 180
 181                         /* if no explicit page size, the default page size is compared */
 182                         if (pagesz_str == NULL){
 183                                 if (hugepage_sz == default_size){
 184                                         retval = strdup(splitstr[MOUNTPT]);
 185                                         break;
 186                                 }
 187                         }
 188                         /* there is an explicit page size, so check it */
 189                         else {
 190                                 uint64_t pagesz = rte_str_to_size(&pagesz_str[pagesize_opt_len]);
 191                                 if (pagesz == hugepage_sz) {
 192                                         retval = strdup(splitstr[MOUNTPT]);
 193                                         break;
 194                                 }
 195                         }
 196                 } /* end if strncmp hugetlbfs */
 197         } /* end while fgets */
 198
 199         fclose(fd);
 200         return retval;
 201 }
 202
 203 /*
 204  * uses fstat to report the size of a file on disk
 205  */
 206 static off_t
 207 get_file_size(int fd)
 208 {
 209         struct stat st;
 210         if (fstat(fd, &st) < 0)
 211                 return 0;
 212         return st.st_size;
 213 }
 214
 215 /*
 216  * Clear the hugepage directory of whatever hugepage files
 217  * there are. Checks if the file is locked (i.e.
 218  * if it's in use by another DPDK process).
 219  */
 220 static int
 221 clear_hugedir(const char * hugedir)
 222 {
 223         DIR *dir;
 224         struct dirent *dirent;
 225         int dir_fd, fd, lck_result;
 226         const char filter[] = "*map_*"; /* matches hugepage files */
 227
 228         /* open directory */
 229         dir = opendir(hugedir);
 230         if (!dir) {
 231                 RTE_LOG(ERR, EAL, "Unable to open hugepage directory %s\n",
 232                                 hugedir);
 233                 goto error;
 234         }
 235         dir_fd = dirfd(dir);
 236
 237         dirent = readdir(dir);
 238         if (!dirent) {
 239                 RTE_LOG(ERR, EAL, "Unable to read hugepage directory %s\n",
 240                                 hugedir);
 241                 goto error;
 242         }
 243
 244         while(dirent != NULL){
 245                 struct flock lck = {0};
 246
 247                 /* skip files that don't match the hugepage pattern */
 248                 if (fnmatch(filter, dirent->d_name, 0) > 0) {
 249                         dirent = readdir(dir);
 250                         continue;
 251                 }
 252
 253                 /* try and lock the file */
 254                 fd = openat(dir_fd, dirent->d_name, O_RDONLY);
 255
 256                 /* skip to next file */
 257                 if (fd == -1) {
 258                         dirent = readdir(dir);
 259                         continue;
 260                 }
 261
 262                 /* non-blocking lock */
 263                 lck.l_type = F_RDLCK;
 264                 lck.l_whence = SEEK_SET;
 265                 lck.l_start = 0;
 266                 lck.l_len = get_file_size(fd);
 267
 268                 lck_result = fcntl(fd, F_SETLK, &lck);
 269
 270                 /* if lock succeeds, unlock and remove the file */
 271                 if (lck_result != -1) {
 272                         lck.l_type = F_UNLCK;
 273                         fcntl(fd, F_SETLK, &lck);
 274                         unlinkat(dir_fd, dirent->d_name, 0);
 275                 }
 276                 close (fd);
 277                 dirent = readdir(dir);
 278         }
 279
 280         closedir(dir);
 281         return 0;
 282
 283 error:
 284         if (dir)
 285                 closedir(dir);
 286
 287         RTE_LOG(ERR, EAL, "Error while clearing hugepage dir: %s\n",
 288                 strerror(errno));
 289
 290         return -1;
 291 }
 292
 293 static int
 294 compare_hpi(const void *a, const void *b)
 295 {
 296         const struct hugepage_info *hpi_a = a;
 297         const struct hugepage_info *hpi_b = b;
 298
 299         return hpi_b->hugepage_sz - hpi_a->hugepage_sz;
 300 }
 301
 302 /*
 303  * when we initialize the hugepage info, everything goes
 304  * to socket 0 by default. it will later get sorted by memory
 305  * initialization procedure.
 306  */
 307 int
 308 eal_hugepage_info_init(void)
 309 {
 310         const char dirent_start_text[] = "hugepages-";
 311         const size_t dirent_start_len = sizeof(dirent_start_text) - 1;
 312         unsigned int i, total_pages, num_sizes = 0;
 313         DIR *dir;
 314         struct dirent *dirent;
 315
 316         dir = opendir(sys_dir_path);
 317         if (dir == NULL) {
 318                 RTE_LOG(ERR, EAL,
 319                         "Cannot open directory %s to read system hugepage info\n",
 320                         sys_dir_path);
 321                 return -1;
 322         }
 323
 324         for (dirent = readdir(dir); dirent != NULL; dirent = readdir(dir)) {
 325                 struct hugepage_info *hpi;
 326
 327                 if (strncmp(dirent->d_name, dirent_start_text,
 328                             dirent_start_len) != 0)
 329                         continue;
 330
 331                 if (num_sizes >= MAX_HUGEPAGE_SIZES)
 332                         break;
 333
 334                 hpi = &internal_config.hugepage_info[num_sizes];
 335                 hpi->hugepage_sz =
 336                         rte_str_to_size(&dirent->d_name[dirent_start_len]);
 337                 hpi->hugedir = get_hugepage_dir(hpi->hugepage_sz);
 338
 339                 /* first, check if we have a mountpoint */
 340                 if (hpi->hugedir == NULL) {
 341                         uint32_t num_pages;
 342
 343                         num_pages = get_num_hugepages(dirent->d_name);
 344                         if (num_pages > 0)
 345                                 RTE_LOG(NOTICE, EAL,
 346                                         "%" PRIu32 " hugepages of size "
 347                                         "%" PRIu64 " reserved, but no mounted "
 348                                         "hugetlbfs found for that size\n",
 349                                         num_pages, hpi->hugepage_sz);
 350                         continue;
 351                 }
 352
 353                 /* try to obtain a writelock */
 354                 hpi->lock_descriptor = open(hpi->hugedir, O_RDONLY);
 355
 356                 /* if blocking lock failed */
 357                 if (flock(hpi->lock_descriptor, LOCK_EX) == -1) {
 358                         RTE_LOG(CRIT, EAL,
 359                                 "Failed to lock hugepage directory!\n");
 360                         break;
 361                 }
 362                 /* clear out the hugepages dir from unused pages */
 363                 if (clear_hugedir(hpi->hugedir) == -1)
 364                         break;
 365
 366                 /*
 367                  * first, try to put all hugepages into relevant sockets, but
 368                  * if first attempts fails, fall back to collecting all pages
 369                  * in one socket and sorting them later
 370                  */
 371                 total_pages = 0;
 372                 /* we also don't want to do this for legacy init */
 373                 if (!internal_config.legacy_mem)
 374                         for (i = 0; i < rte_socket_count(); i++) {
 375                                 int socket = rte_socket_id_by_idx(i);
 376                                 unsigned int num_pages =
 377                                                 get_num_hugepages_on_node(
 378                                                         dirent->d_name, socket);
 379                                 hpi->num_pages[socket] = num_pages;
 380                                 total_pages += num_pages;
 381                         }
 382                 /*
 383                  * we failed to sort memory from the get go, so fall
 384                  * back to old way
 385                  */
 386                 if (total_pages == 0)
 387                         hpi->num_pages[0] = get_num_hugepages(dirent->d_name);
 388
 389 #ifndef RTE_ARCH_64
 390                 /* for 32-bit systems, limit number of hugepages to
 391                  * 1GB per page size */
 392                 hpi->num_pages[0] = RTE_MIN(hpi->num_pages[0],
 393                                             RTE_PGSIZE_1G / hpi->hugepage_sz);
 394 #endif
 395
 396                 num_sizes++;
 397         }
 398         closedir(dir);
 399
 400         /* something went wrong, and we broke from the for loop above */
 401         if (dirent != NULL)
 402                 return -1;
 403
 404         internal_config.num_hugepage_sizes = num_sizes;
 405
 406         /* sort the page directory entries by size, largest to smallest */
 407         qsort(&internal_config.hugepage_info[0], num_sizes,
 408               sizeof(internal_config.hugepage_info[0]), compare_hpi);
 409
 410         /* now we have all info, check we have at least one valid size */
 411         for (i = 0; i < num_sizes; i++) {
 412                 /* pages may no longer all be on socket 0, so check all */
 413                 unsigned int j, num_pages = 0;
 414
 415                 for (j = 0; j < RTE_MAX_NUMA_NODES; j++) {
 416                         struct hugepage_info *hpi =
 417                                         &internal_config.hugepage_info[i];
 418                         num_pages += hpi->num_pages[j];
 419                 }
 420                 if (internal_config.hugepage_info[i].hugedir != NULL &&
 421                                 num_pages > 0)
 422                         return 0;
 423         }
 424
 425         /* no valid hugepage mounts available, return error */
 426         return -1;
 427 }