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
  19 #include <rte_memory.h>
  20 #include <rte_eal.h>
  21 #include <rte_launch.h>
  22 #include <rte_per_lcore.h>
  23 #include <rte_lcore.h>
  24 #include <rte_debug.h>
  25 #include <rte_log.h>
  26 #include <rte_common.h>
  27 #include "rte_string_fns.h"
  28 #include "eal_internal_cfg.h"
  29 #include "eal_hugepages.h"
  30 #include "eal_filesystem.h"
  31
  32 static const char sys_dir_path[] = "/sys/kernel/mm/hugepages";
  33
  34 /* this function is only called from eal_hugepage_info_init which itself
  35  * is only called from a primary process */
  36 static uint32_t
  37 get_num_hugepages(const char *subdir)
  38 {
  39         char path[PATH_MAX];
  40         long unsigned resv_pages, num_pages = 0;
  41         const char *nr_hp_file = "free_hugepages";
  42         const char *nr_rsvd_file = "resv_hugepages";
  43
  44         /* first, check how many reserved pages kernel reports */
  45         snprintf(path, sizeof(path), "%s/%s/%s",
  46                         sys_dir_path, subdir, nr_rsvd_file);
  47         if (eal_parse_sysfs_value(path, &resv_pages) < 0)
  48                 return 0;
  49
  50         snprintf(path, sizeof(path), "%s/%s/%s",
  51                         sys_dir_path, subdir, nr_hp_file);
  52         if (eal_parse_sysfs_value(path, &num_pages) < 0)
  53                 return 0;
  54
  55         if (num_pages == 0)
  56                 RTE_LOG(WARNING, EAL, "No free hugepages reported in %s\n",
  57                                 subdir);
  58
  59         /* adjust num_pages */
  60         if (num_pages >= resv_pages)
  61                 num_pages -= resv_pages;
  62         else if (resv_pages)
  63                 num_pages = 0;
  64
  65         /* we want to return a uint32_t and more than this looks suspicious
  66          * anyway ... */
  67         if (num_pages > UINT32_MAX)
  68                 num_pages = UINT32_MAX;
  69
  70         return num_pages;
  71 }
  72
  73 static uint64_t
  74 get_default_hp_size(void)
  75 {
  76         const char proc_meminfo[] = "/proc/meminfo";
  77         const char str_hugepagesz[] = "Hugepagesize:";
  78         unsigned hugepagesz_len = sizeof(str_hugepagesz) - 1;
  79         char buffer[256];
  80         unsigned long long size = 0;
  81
  82         FILE *fd = fopen(proc_meminfo, "r");
  83         if (fd == NULL)
  84                 rte_panic("Cannot open %s\n", proc_meminfo);
  85         while(fgets(buffer, sizeof(buffer), fd)){
  86                 if (strncmp(buffer, str_hugepagesz, hugepagesz_len) == 0){
  87                         size = rte_str_to_size(&buffer[hugepagesz_len]);
  88                         break;
  89                 }
  90         }
  91         fclose(fd);
  92         if (size == 0)
  93                 rte_panic("Cannot get default hugepage size from %s\n", proc_meminfo);
  94         return size;
  95 }
  96
  97 static const char *
  98 get_hugepage_dir(uint64_t hugepage_sz)
  99 {
 100         enum proc_mount_fieldnames {
 101                 DEVICE = 0,
 102                 MOUNTPT,
 103                 FSTYPE,
 104                 OPTIONS,
 105                 _FIELDNAME_MAX
 106         };
 107         static uint64_t default_size = 0;
 108         const char proc_mounts[] = "/proc/mounts";
 109         const char hugetlbfs_str[] = "hugetlbfs";
 110         const size_t htlbfs_str_len = sizeof(hugetlbfs_str) - 1;
 111         const char pagesize_opt[] = "pagesize=";
 112         const size_t pagesize_opt_len = sizeof(pagesize_opt) - 1;
 113         const char split_tok = ' ';
 114         char *splitstr[_FIELDNAME_MAX];
 115         char buf[BUFSIZ];
 116         char *retval = NULL;
 117
 118         FILE *fd = fopen(proc_mounts, "r");
 119         if (fd == NULL)
 120                 rte_panic("Cannot open %s\n", proc_mounts);
 121
 122         if (default_size == 0)
 123                 default_size = get_default_hp_size();
 124
 125         while (fgets(buf, sizeof(buf), fd)){
 126                 if (rte_strsplit(buf, sizeof(buf), splitstr, _FIELDNAME_MAX,
 127                                 split_tok) != _FIELDNAME_MAX) {
 128                         RTE_LOG(ERR, EAL, "Error parsing %s\n", proc_mounts);
 129                         break; /* return NULL */
 130                 }
 131
 132                 /* we have a specified --huge-dir option, only examine that dir */
 133                 if (internal_config.hugepage_dir != NULL &&
 134                                 strcmp(splitstr[MOUNTPT], internal_config.hugepage_dir) != 0)
 135                         continue;
 136
 137                 if (strncmp(splitstr[FSTYPE], hugetlbfs_str, htlbfs_str_len) == 0){
 138                         const char *pagesz_str = strstr(splitstr[OPTIONS], pagesize_opt);
 139
 140                         /* if no explicit page size, the default page size is compared */
 141                         if (pagesz_str == NULL){
 142                                 if (hugepage_sz == default_size){
 143                                         retval = strdup(splitstr[MOUNTPT]);
 144                                         break;
 145                                 }
 146                         }
 147                         /* there is an explicit page size, so check it */
 148                         else {
 149                                 uint64_t pagesz = rte_str_to_size(&pagesz_str[pagesize_opt_len]);
 150                                 if (pagesz == hugepage_sz) {
 151                                         retval = strdup(splitstr[MOUNTPT]);
 152                                         break;
 153                                 }
 154                         }
 155                 } /* end if strncmp hugetlbfs */
 156         } /* end while fgets */
 157
 158         fclose(fd);
 159         return retval;
 160 }
 161
 162 /*
 163  * Clear the hugepage directory of whatever hugepage files
 164  * there are. Checks if the file is locked (i.e.
 165  * if it's in use by another DPDK process).
 166  */
 167 static int
 168 clear_hugedir(const char * hugedir)
 169 {
 170         DIR *dir;
 171         struct dirent *dirent;
 172         int dir_fd, fd, lck_result;
 173         const char filter[] = "*map_*"; /* matches hugepage files */
 174
 175         /* open directory */
 176         dir = opendir(hugedir);
 177         if (!dir) {
 178                 RTE_LOG(ERR, EAL, "Unable to open hugepage directory %s\n",
 179                                 hugedir);
 180                 goto error;
 181         }
 182         dir_fd = dirfd(dir);
 183
 184         dirent = readdir(dir);
 185         if (!dirent) {
 186                 RTE_LOG(ERR, EAL, "Unable to read hugepage directory %s\n",
 187                                 hugedir);
 188                 goto error;
 189         }
 190
 191         while(dirent != NULL){
 192                 /* skip files that don't match the hugepage pattern */
 193                 if (fnmatch(filter, dirent->d_name, 0) > 0) {
 194                         dirent = readdir(dir);
 195                         continue;
 196                 }
 197
 198                 /* try and lock the file */
 199                 fd = openat(dir_fd, dirent->d_name, O_RDONLY);
 200
 201                 /* skip to next file */
 202                 if (fd == -1) {
 203                         dirent = readdir(dir);
 204                         continue;
 205                 }
 206
 207                 /* non-blocking lock */
 208                 lck_result = flock(fd, LOCK_EX | LOCK_NB);
 209
 210                 /* if lock succeeds, unlock and remove the file */
 211                 if (lck_result != -1) {
 212                         flock(fd, LOCK_UN);
 213                         unlinkat(dir_fd, dirent->d_name, 0);
 214                 }
 215                 close (fd);
 216                 dirent = readdir(dir);
 217         }
 218
 219         closedir(dir);
 220         return 0;
 221
 222 error:
 223         if (dir)
 224                 closedir(dir);
 225
 226         RTE_LOG(ERR, EAL, "Error while clearing hugepage dir: %s\n",
 227                 strerror(errno));
 228
 229         return -1;
 230 }
 231
 232 static int
 233 compare_hpi(const void *a, const void *b)
 234 {
 235         const struct hugepage_info *hpi_a = a;
 236         const struct hugepage_info *hpi_b = b;
 237
 238         return hpi_b->hugepage_sz - hpi_a->hugepage_sz;
 239 }
 240
 241 /*
 242  * when we initialize the hugepage info, everything goes
 243  * to socket 0 by default. it will later get sorted by memory
 244  * initialization procedure.
 245  */
 246 int
 247 eal_hugepage_info_init(void)
 248 {
 249         const char dirent_start_text[] = "hugepages-";
 250         const size_t dirent_start_len = sizeof(dirent_start_text) - 1;
 251         unsigned i, num_sizes = 0;
 252         DIR *dir;
 253         struct dirent *dirent;
 254
 255         dir = opendir(sys_dir_path);
 256         if (dir == NULL) {
 257                 RTE_LOG(ERR, EAL,
 258                         "Cannot open directory %s to read system hugepage info\n",
 259                         sys_dir_path);
 260                 return -1;
 261         }
 262
 263         for (dirent = readdir(dir); dirent != NULL; dirent = readdir(dir)) {
 264                 struct hugepage_info *hpi;
 265
 266                 if (strncmp(dirent->d_name, dirent_start_text,
 267                             dirent_start_len) != 0)
 268                         continue;
 269
 270                 if (num_sizes >= MAX_HUGEPAGE_SIZES)
 271                         break;
 272
 273                 hpi = &internal_config.hugepage_info[num_sizes];
 274                 hpi->hugepage_sz =
 275                         rte_str_to_size(&dirent->d_name[dirent_start_len]);
 276                 hpi->hugedir = get_hugepage_dir(hpi->hugepage_sz);
 277
 278                 /* first, check if we have a mountpoint */
 279                 if (hpi->hugedir == NULL) {
 280                         uint32_t num_pages;
 281
 282                         num_pages = get_num_hugepages(dirent->d_name);
 283                         if (num_pages > 0)
 284                                 RTE_LOG(NOTICE, EAL,
 285                                         "%" PRIu32 " hugepages of size "
 286                                         "%" PRIu64 " reserved, but no mounted "
 287                                         "hugetlbfs found for that size\n",
 288                                         num_pages, hpi->hugepage_sz);
 289                         continue;
 290                 }
 291
 292                 /* try to obtain a writelock */
 293                 hpi->lock_descriptor = open(hpi->hugedir, O_RDONLY);
 294
 295                 /* if blocking lock failed */
 296                 if (flock(hpi->lock_descriptor, LOCK_EX) == -1) {
 297                         RTE_LOG(CRIT, EAL,
 298                                 "Failed to lock hugepage directory!\n");
 299                         break;
 300                 }
 301                 /* clear out the hugepages dir from unused pages */
 302                 if (clear_hugedir(hpi->hugedir) == -1)
 303                         break;
 304
 305                 /* for now, put all pages into socket 0,
 306                  * later they will be sorted */
 307                 hpi->num_pages[0] = get_num_hugepages(dirent->d_name);
 308
 309 #ifndef RTE_ARCH_64
 310                 /* for 32-bit systems, limit number of hugepages to
 311                  * 1GB per page size */
 312                 hpi->num_pages[0] = RTE_MIN(hpi->num_pages[0],
 313                                             RTE_PGSIZE_1G / hpi->hugepage_sz);
 314 #endif
 315
 316                 num_sizes++;
 317         }
 318         closedir(dir);
 319
 320         /* something went wrong, and we broke from the for loop above */
 321         if (dirent != NULL)
 322                 return -1;
 323
 324         internal_config.num_hugepage_sizes = num_sizes;
 325
 326         /* sort the page directory entries by size, largest to smallest */
 327         qsort(&internal_config.hugepage_info[0], num_sizes,
 328               sizeof(internal_config.hugepage_info[0]), compare_hpi);
 329
 330         /* now we have all info, check we have at least one valid size */
 331         for (i = 0; i < num_sizes; i++)
 332                 if (internal_config.hugepage_info[i].hugedir != NULL &&
 333                     internal_config.hugepage_info[i].num_pages[0] > 0)
 334                         return 0;
 335
 336         /* no valid hugepage mounts available, return error */
 337         return -1;
 338 }