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
  35 /* this function is only called from eal_hugepage_info_init which itself
  36  * is only called from a primary process */
  37 static uint32_t
  38 get_num_hugepages(const char *subdir)
  39 {
  40         char path[PATH_MAX];
  41         long unsigned resv_pages, num_pages = 0;
  42         const char *nr_hp_file = "free_hugepages";
  43         const char *nr_rsvd_file = "resv_hugepages";
  44
  45         /* first, check how many reserved pages kernel reports */
  46         snprintf(path, sizeof(path), "%s/%s/%s",
  47                         sys_dir_path, subdir, nr_rsvd_file);
  48         if (eal_parse_sysfs_value(path, &resv_pages) < 0)
  49                 return 0;
  50
  51         snprintf(path, sizeof(path), "%s/%s/%s",
  52                         sys_dir_path, subdir, nr_hp_file);
  53         if (eal_parse_sysfs_value(path, &num_pages) < 0)
  54                 return 0;
  55
  56         if (num_pages == 0)
  57                 RTE_LOG(WARNING, EAL, "No free hugepages reported in %s\n",
  58                                 subdir);
  59
  60         /* adjust num_pages */
  61         if (num_pages >= resv_pages)
  62                 num_pages -= resv_pages;
  63         else if (resv_pages)
  64                 num_pages = 0;
  65
  66         /* we want to return a uint32_t and more than this looks suspicious
  67          * anyway ... */
  68         if (num_pages > UINT32_MAX)
  69                 num_pages = UINT32_MAX;
  70
  71         return num_pages;
  72 }
  73
  74 static uint64_t
  75 get_default_hp_size(void)
  76 {
  77         const char proc_meminfo[] = "/proc/meminfo";
  78         const char str_hugepagesz[] = "Hugepagesize:";
  79         unsigned hugepagesz_len = sizeof(str_hugepagesz) - 1;
  80         char buffer[256];
  81         unsigned long long size = 0;
  82
  83         FILE *fd = fopen(proc_meminfo, "r");
  84         if (fd == NULL)
  85                 rte_panic("Cannot open %s\n", proc_meminfo);
  86         while(fgets(buffer, sizeof(buffer), fd)){
  87                 if (strncmp(buffer, str_hugepagesz, hugepagesz_len) == 0){
  88                         size = rte_str_to_size(&buffer[hugepagesz_len]);
  89                         break;
  90                 }
  91         }
  92         fclose(fd);
  93         if (size == 0)
  94                 rte_panic("Cannot get default hugepage size from %s\n", proc_meminfo);
  95         return size;
  96 }
  97
  98 static const char *
  99 get_hugepage_dir(uint64_t hugepage_sz)
 100 {
 101         enum proc_mount_fieldnames {
 102                 DEVICE = 0,
 103                 MOUNTPT,
 104                 FSTYPE,
 105                 OPTIONS,
 106                 _FIELDNAME_MAX
 107         };
 108         static uint64_t default_size = 0;
 109         const char proc_mounts[] = "/proc/mounts";
 110         const char hugetlbfs_str[] = "hugetlbfs";
 111         const size_t htlbfs_str_len = sizeof(hugetlbfs_str) - 1;
 112         const char pagesize_opt[] = "pagesize=";
 113         const size_t pagesize_opt_len = sizeof(pagesize_opt) - 1;
 114         const char split_tok = ' ';
 115         char *splitstr[_FIELDNAME_MAX];
 116         char buf[BUFSIZ];
 117         char *retval = NULL;
 118
 119         FILE *fd = fopen(proc_mounts, "r");
 120         if (fd == NULL)
 121                 rte_panic("Cannot open %s\n", proc_mounts);
 122
 123         if (default_size == 0)
 124                 default_size = get_default_hp_size();
 125
 126         while (fgets(buf, sizeof(buf), fd)){
 127                 if (rte_strsplit(buf, sizeof(buf), splitstr, _FIELDNAME_MAX,
 128                                 split_tok) != _FIELDNAME_MAX) {
 129                         RTE_LOG(ERR, EAL, "Error parsing %s\n", proc_mounts);
 130                         break; /* return NULL */
 131                 }
 132
 133                 /* we have a specified --huge-dir option, only examine that dir */
 134                 if (internal_config.hugepage_dir != NULL &&
 135                                 strcmp(splitstr[MOUNTPT], internal_config.hugepage_dir) != 0)
 136                         continue;
 137
 138                 if (strncmp(splitstr[FSTYPE], hugetlbfs_str, htlbfs_str_len) == 0){
 139                         const char *pagesz_str = strstr(splitstr[OPTIONS], pagesize_opt);
 140
 141                         /* if no explicit page size, the default page size is compared */
 142                         if (pagesz_str == NULL){
 143                                 if (hugepage_sz == default_size){
 144                                         retval = strdup(splitstr[MOUNTPT]);
 145                                         break;
 146                                 }
 147                         }
 148                         /* there is an explicit page size, so check it */
 149                         else {
 150                                 uint64_t pagesz = rte_str_to_size(&pagesz_str[pagesize_opt_len]);
 151                                 if (pagesz == hugepage_sz) {
 152                                         retval = strdup(splitstr[MOUNTPT]);
 153                                         break;
 154                                 }
 155                         }
 156                 } /* end if strncmp hugetlbfs */
 157         } /* end while fgets */
 158
 159         fclose(fd);
 160         return retval;
 161 }
 162
 163 /*
 164  * uses fstat to report the size of a file on disk
 165  */
 166 static off_t
 167 get_file_size(int fd)
 168 {
 169         struct stat st;
 170         if (fstat(fd, &st) < 0)
 171                 return 0;
 172         return st.st_size;
 173 }
 174
 175 /*
 176  * Clear the hugepage directory of whatever hugepage files
 177  * there are. Checks if the file is locked (i.e.
 178  * if it's in use by another DPDK process).
 179  */
 180 static int
 181 clear_hugedir(const char * hugedir)
 182 {
 183         DIR *dir;
 184         struct dirent *dirent;
 185         int dir_fd, fd, lck_result;
 186         const char filter[] = "*map_*"; /* matches hugepage files */
 187
 188         /* open directory */
 189         dir = opendir(hugedir);
 190         if (!dir) {
 191                 RTE_LOG(ERR, EAL, "Unable to open hugepage directory %s\n",
 192                                 hugedir);
 193                 goto error;
 194         }
 195         dir_fd = dirfd(dir);
 196
 197         dirent = readdir(dir);
 198         if (!dirent) {
 199                 RTE_LOG(ERR, EAL, "Unable to read hugepage directory %s\n",
 200                                 hugedir);
 201                 goto error;
 202         }
 203
 204         while(dirent != NULL){
 205                 struct flock lck = {0};
 206
 207                 /* skip files that don't match the hugepage pattern */
 208                 if (fnmatch(filter, dirent->d_name, 0) > 0) {
 209                         dirent = readdir(dir);
 210                         continue;
 211                 }
 212
 213                 /* try and lock the file */
 214                 fd = openat(dir_fd, dirent->d_name, O_RDONLY);
 215
 216                 /* skip to next file */
 217                 if (fd == -1) {
 218                         dirent = readdir(dir);
 219                         continue;
 220                 }
 221
 222                 /* non-blocking lock */
 223                 lck.l_type = F_RDLCK;
 224                 lck.l_whence = SEEK_SET;
 225                 lck.l_start = 0;
 226                 lck.l_len = get_file_size(fd);
 227
 228                 lck_result = fcntl(fd, F_SETLK, &lck);
 229
 230                 /* if lock succeeds, unlock and remove the file */
 231                 if (lck_result != -1) {
 232                         lck.l_type = F_UNLCK;
 233                         fcntl(fd, F_SETLK, &lck);
 234                         unlinkat(dir_fd, dirent->d_name, 0);
 235                 }
 236                 close (fd);
 237                 dirent = readdir(dir);
 238         }
 239
 240         closedir(dir);
 241         return 0;
 242
 243 error:
 244         if (dir)
 245                 closedir(dir);
 246
 247         RTE_LOG(ERR, EAL, "Error while clearing hugepage dir: %s\n",
 248                 strerror(errno));
 249
 250         return -1;
 251 }
 252
 253 static int
 254 compare_hpi(const void *a, const void *b)
 255 {
 256         const struct hugepage_info *hpi_a = a;
 257         const struct hugepage_info *hpi_b = b;
 258
 259         return hpi_b->hugepage_sz - hpi_a->hugepage_sz;
 260 }
 261
 262 /*
 263  * when we initialize the hugepage info, everything goes
 264  * to socket 0 by default. it will later get sorted by memory
 265  * initialization procedure.
 266  */
 267 int
 268 eal_hugepage_info_init(void)
 269 {
 270         const char dirent_start_text[] = "hugepages-";
 271         const size_t dirent_start_len = sizeof(dirent_start_text) - 1;
 272         unsigned i, num_sizes = 0;
 273         DIR *dir;
 274         struct dirent *dirent;
 275
 276         dir = opendir(sys_dir_path);
 277         if (dir == NULL) {
 278                 RTE_LOG(ERR, EAL,
 279                         "Cannot open directory %s to read system hugepage info\n",
 280                         sys_dir_path);
 281                 return -1;
 282         }
 283
 284         for (dirent = readdir(dir); dirent != NULL; dirent = readdir(dir)) {
 285                 struct hugepage_info *hpi;
 286
 287                 if (strncmp(dirent->d_name, dirent_start_text,
 288                             dirent_start_len) != 0)
 289                         continue;
 290
 291                 if (num_sizes >= MAX_HUGEPAGE_SIZES)
 292                         break;
 293
 294                 hpi = &internal_config.hugepage_info[num_sizes];
 295                 hpi->hugepage_sz =
 296                         rte_str_to_size(&dirent->d_name[dirent_start_len]);
 297                 hpi->hugedir = get_hugepage_dir(hpi->hugepage_sz);
 298
 299                 /* first, check if we have a mountpoint */
 300                 if (hpi->hugedir == NULL) {
 301                         uint32_t num_pages;
 302
 303                         num_pages = get_num_hugepages(dirent->d_name);
 304                         if (num_pages > 0)
 305                                 RTE_LOG(NOTICE, EAL,
 306                                         "%" PRIu32 " hugepages of size "
 307                                         "%" PRIu64 " reserved, but no mounted "
 308                                         "hugetlbfs found for that size\n",
 309                                         num_pages, hpi->hugepage_sz);
 310                         continue;
 311                 }
 312
 313                 /* try to obtain a writelock */
 314                 hpi->lock_descriptor = open(hpi->hugedir, O_RDONLY);
 315
 316                 /* if blocking lock failed */
 317                 if (flock(hpi->lock_descriptor, LOCK_EX) == -1) {
 318                         RTE_LOG(CRIT, EAL,
 319                                 "Failed to lock hugepage directory!\n");
 320                         break;
 321                 }
 322                 /* clear out the hugepages dir from unused pages */
 323                 if (clear_hugedir(hpi->hugedir) == -1)
 324                         break;
 325
 326                 /* for now, put all pages into socket 0,
 327                  * later they will be sorted */
 328                 hpi->num_pages[0] = get_num_hugepages(dirent->d_name);
 329
 330 #ifndef RTE_ARCH_64
 331                 /* for 32-bit systems, limit number of hugepages to
 332                  * 1GB per page size */
 333                 hpi->num_pages[0] = RTE_MIN(hpi->num_pages[0],
 334                                             RTE_PGSIZE_1G / hpi->hugepage_sz);
 335 #endif
 336
 337                 num_sizes++;
 338         }
 339         closedir(dir);
 340
 341         /* something went wrong, and we broke from the for loop above */
 342         if (dirent != NULL)
 343                 return -1;
 344
 345         internal_config.num_hugepage_sizes = num_sizes;
 346
 347         /* sort the page directory entries by size, largest to smallest */
 348         qsort(&internal_config.hugepage_info[0], num_sizes,
 349               sizeof(internal_config.hugepage_info[0]), compare_hpi);
 350
 351         /* now we have all info, check we have at least one valid size */
 352         for (i = 0; i < num_sizes; i++)
 353                 if (internal_config.hugepage_info[i].hugedir != NULL &&
 354                     internal_config.hugepage_info[i].num_pages[0] > 0)
 355                         return 0;
 356
 357         /* no valid hugepage mounts available, return error */
 358         return -1;
 359 }