lib/librte_eal/linuxapp/eal/eal_hugepage_info.c

   1 /*-
   2  *   BSD LICENSE
   3  *
   4  *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
   5  *   All rights reserved.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following conditions
   9  *   are met:
  10  *
  11  *     * Redistributions of source code must retain the above copyright
  12  *       notice, this list of conditions and the following disclaimer.
  13  *     * Redistributions in binary form must reproduce the above copyright
  14  *       notice, this list of conditions and the following disclaimer in
  15  *       the documentation and/or other materials provided with the
  16  *       distribution.
  17  *     * Neither the name of Intel Corporation nor the names of its
  18  *       contributors may be used to endorse or promote products derived
  19  *       from this software without specific prior written permission.
  20  *
  21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <string.h>
  35 #include <sys/types.h>
  36 #include <sys/file.h>
  37 #include <dirent.h>
  38 #include <stdint.h>
  39 #include <stdlib.h>
  40 #include <stdio.h>
  41 #include <fnmatch.h>
  42 #include <inttypes.h>
  43 #include <stdarg.h>
  44 #include <unistd.h>
  45 #include <errno.h>
  46 #include <sys/queue.h>
  47
  48 #include <rte_memory.h>
  49 #include <rte_memzone.h>
  50 #include <rte_eal.h>
  51 #include <rte_launch.h>
  52 #include <rte_per_lcore.h>
  53 #include <rte_lcore.h>
  54 #include <rte_debug.h>
  55 #include <rte_log.h>
  56 #include <rte_common.h>
  57 #include "rte_string_fns.h"
  58 #include "eal_internal_cfg.h"
  59 #include "eal_hugepages.h"
  60 #include "eal_filesystem.h"
  61
  62 static const char sys_dir_path[] = "/sys/kernel/mm/hugepages";
  63
  64 /* this function is only called from eal_hugepage_info_init which itself
  65  * is only called from a primary process */
  66 static uint32_t
  67 get_num_hugepages(const char *subdir)
  68 {
  69         char path[PATH_MAX];
  70         long unsigned resv_pages, num_pages = 0;
  71         const char *nr_hp_file = "free_hugepages";
  72         const char *nr_rsvd_file = "resv_hugepages";
  73
  74         /* first, check how many reserved pages kernel reports */
  75         snprintf(path, sizeof(path), "%s/%s/%s",
  76                         sys_dir_path, subdir, nr_rsvd_file);
  77         if (eal_parse_sysfs_value(path, &resv_pages) < 0)
  78                 return 0;
  79
  80         snprintf(path, sizeof(path), "%s/%s/%s",
  81                         sys_dir_path, subdir, nr_hp_file);
  82         if (eal_parse_sysfs_value(path, &num_pages) < 0)
  83                 return 0;
  84
  85         if (num_pages == 0)
  86                 RTE_LOG(WARNING, EAL, "No free hugepages reported in %s\n",
  87                                 subdir);
  88
  89         /* adjust num_pages */
  90         if (num_pages >= resv_pages)
  91                 num_pages -= resv_pages;
  92         else if (resv_pages)
  93                 num_pages = 0;
  94
  95         /* we want to return a uint32_t and more than this looks suspicious
  96          * anyway ... */
  97         if (num_pages > UINT32_MAX)
  98                 num_pages = UINT32_MAX;
  99
 100         return num_pages;
 101 }
 102
 103 static uint64_t
 104 get_default_hp_size(void)
 105 {
 106         const char proc_meminfo[] = "/proc/meminfo";
 107         const char str_hugepagesz[] = "Hugepagesize:";
 108         unsigned hugepagesz_len = sizeof(str_hugepagesz) - 1;
 109         char buffer[256];
 110         unsigned long long size = 0;
 111
 112         FILE *fd = fopen(proc_meminfo, "r");
 113         if (fd == NULL)
 114                 rte_panic("Cannot open %s\n", proc_meminfo);
 115         while(fgets(buffer, sizeof(buffer), fd)){
 116                 if (strncmp(buffer, str_hugepagesz, hugepagesz_len) == 0){
 117                         size = rte_str_to_size(&buffer[hugepagesz_len]);
 118                         break;
 119                 }
 120         }
 121         fclose(fd);
 122         if (size == 0)
 123                 rte_panic("Cannot get default hugepage size from %s\n", proc_meminfo);
 124         return size;
 125 }
 126
 127 static const char *
 128 get_hugepage_dir(uint64_t hugepage_sz)
 129 {
 130         enum proc_mount_fieldnames {
 131                 DEVICE = 0,
 132                 MOUNTPT,
 133                 FSTYPE,
 134                 OPTIONS,
 135                 _FIELDNAME_MAX
 136         };
 137         static uint64_t default_size = 0;
 138         const char proc_mounts[] = "/proc/mounts";
 139         const char hugetlbfs_str[] = "hugetlbfs";
 140         const size_t htlbfs_str_len = sizeof(hugetlbfs_str) - 1;
 141         const char pagesize_opt[] = "pagesize=";
 142         const size_t pagesize_opt_len = sizeof(pagesize_opt) - 1;
 143         const char split_tok = ' ';
 144         char *splitstr[_FIELDNAME_MAX];
 145         char buf[BUFSIZ];
 146         char *retval = NULL;
 147
 148         FILE *fd = fopen(proc_mounts, "r");
 149         if (fd == NULL)
 150                 rte_panic("Cannot open %s\n", proc_mounts);
 151
 152         if (default_size == 0)
 153                 default_size = get_default_hp_size();
 154
 155         while (fgets(buf, sizeof(buf), fd)){
 156                 if (rte_strsplit(buf, sizeof(buf), splitstr, _FIELDNAME_MAX,
 157                                 split_tok) != _FIELDNAME_MAX) {
 158                         RTE_LOG(ERR, EAL, "Error parsing %s\n", proc_mounts);
 159                         break; /* return NULL */
 160                 }
 161
 162                 /* we have a specified --huge-dir option, only examine that dir */
 163                 if (internal_config.hugepage_dir != NULL &&
 164                                 strcmp(splitstr[MOUNTPT], internal_config.hugepage_dir) != 0)
 165                         continue;
 166
 167                 if (strncmp(splitstr[FSTYPE], hugetlbfs_str, htlbfs_str_len) == 0){
 168                         const char *pagesz_str = strstr(splitstr[OPTIONS], pagesize_opt);
 169
 170                         /* if no explicit page size, the default page size is compared */
 171                         if (pagesz_str == NULL){
 172                                 if (hugepage_sz == default_size){
 173                                         retval = strdup(splitstr[MOUNTPT]);
 174                                         break;
 175                                 }
 176                         }
 177                         /* there is an explicit page size, so check it */
 178                         else {
 179                                 uint64_t pagesz = rte_str_to_size(&pagesz_str[pagesize_opt_len]);
 180                                 if (pagesz == hugepage_sz) {
 181                                         retval = strdup(splitstr[MOUNTPT]);
 182                                         break;
 183                                 }
 184                         }
 185                 } /* end if strncmp hugetlbfs */
 186         } /* end while fgets */
 187
 188         fclose(fd);
 189         return retval;
 190 }
 191
 192 /*
 193  * Clear the hugepage directory of whatever hugepage files
 194  * there are. Checks if the file is locked (i.e.
 195  * if it's in use by another DPDK process).
 196  */
 197 static int
 198 clear_hugedir(const char * hugedir)
 199 {
 200         DIR *dir;
 201         struct dirent *dirent;
 202         int dir_fd, fd, lck_result;
 203         const char filter[] = "*map_*"; /* matches hugepage files */
 204
 205         /* open directory */
 206         dir = opendir(hugedir);
 207         if (!dir) {
 208                 RTE_LOG(ERR, EAL, "Unable to open hugepage directory %s\n",
 209                                 hugedir);
 210                 goto error;
 211         }
 212         dir_fd = dirfd(dir);
 213
 214         dirent = readdir(dir);
 215         if (!dirent) {
 216                 RTE_LOG(ERR, EAL, "Unable to read hugepage directory %s\n",
 217                                 hugedir);
 218                 goto error;
 219         }
 220
 221         while(dirent != NULL){
 222                 /* skip files that don't match the hugepage pattern */
 223                 if (fnmatch(filter, dirent->d_name, 0) > 0) {
 224                         dirent = readdir(dir);
 225                         continue;
 226                 }
 227
 228                 /* try and lock the file */
 229                 fd = openat(dir_fd, dirent->d_name, O_RDONLY);
 230
 231                 /* skip to next file */
 232                 if (fd == -1) {
 233                         dirent = readdir(dir);
 234                         continue;
 235                 }
 236
 237                 /* non-blocking lock */
 238                 lck_result = flock(fd, LOCK_EX | LOCK_NB);
 239
 240                 /* if lock succeeds, unlock and remove the file */
 241                 if (lck_result != -1) {
 242                         flock(fd, LOCK_UN);
 243                         unlinkat(dir_fd, dirent->d_name, 0);
 244                 }
 245                 close (fd);
 246                 dirent = readdir(dir);
 247         }
 248
 249         closedir(dir);
 250         return 0;
 251
 252 error:
 253         if (dir)
 254                 closedir(dir);
 255
 256         RTE_LOG(ERR, EAL, "Error while clearing hugepage dir: %s\n",
 257                 strerror(errno));
 258
 259         return -1;
 260 }
 261
 262 static int
 263 compare_hpi(const void *a, const void *b)
 264 {
 265         const struct hugepage_info *hpi_a = a;
 266         const struct hugepage_info *hpi_b = b;
 267
 268         return hpi_b->hugepage_sz - hpi_a->hugepage_sz;
 269 }
 270
 271 /*
 272  * when we initialize the hugepage info, everything goes
 273  * to socket 0 by default. it will later get sorted by memory
 274  * initialization procedure.
 275  */
 276 int
 277 eal_hugepage_info_init(void)
 278 {
 279         const char dirent_start_text[] = "hugepages-";
 280         const size_t dirent_start_len = sizeof(dirent_start_text) - 1;
 281         unsigned i, num_sizes = 0;
 282         DIR *dir;
 283         struct dirent *dirent;
 284
 285         dir = opendir(sys_dir_path);
 286         if (dir == NULL) {
 287                 RTE_LOG(ERR, EAL,
 288                         "Cannot open directory %s to read system hugepage info\n",
 289                         sys_dir_path);
 290                 return -1;
 291         }
 292
 293         for (dirent = readdir(dir); dirent != NULL; dirent = readdir(dir)) {
 294                 struct hugepage_info *hpi;
 295
 296                 if (strncmp(dirent->d_name, dirent_start_text,
 297                             dirent_start_len) != 0)
 298                         continue;
 299
 300                 if (num_sizes >= MAX_HUGEPAGE_SIZES)
 301                         break;
 302
 303                 hpi = &internal_config.hugepage_info[num_sizes];
 304                 hpi->hugepage_sz =
 305                         rte_str_to_size(&dirent->d_name[dirent_start_len]);
 306                 hpi->hugedir = get_hugepage_dir(hpi->hugepage_sz);
 307
 308                 /* first, check if we have a mountpoint */
 309                 if (hpi->hugedir == NULL) {
 310                         uint32_t num_pages;
 311
 312                         num_pages = get_num_hugepages(dirent->d_name);
 313                         if (num_pages > 0)
 314                                 RTE_LOG(NOTICE, EAL,
 315                                         "%" PRIu32 " hugepages of size "
 316                                         "%" PRIu64 " reserved, but no mounted "
 317                                         "hugetlbfs found for that size\n",
 318                                         num_pages, hpi->hugepage_sz);
 319                         continue;
 320                 }
 321
 322                 /* try to obtain a writelock */
 323                 hpi->lock_descriptor = open(hpi->hugedir, O_RDONLY);
 324
 325                 /* if blocking lock failed */
 326                 if (flock(hpi->lock_descriptor, LOCK_EX) == -1) {
 327                         RTE_LOG(CRIT, EAL,
 328                                 "Failed to lock hugepage directory!\n");
 329                         break;
 330                 }
 331                 /* clear out the hugepages dir from unused pages */
 332                 if (clear_hugedir(hpi->hugedir) == -1)
 333                         break;
 334
 335                 /* for now, put all pages into socket 0,
 336                  * later they will be sorted */
 337                 hpi->num_pages[0] = get_num_hugepages(dirent->d_name);
 338
 339 #ifndef RTE_ARCH_64
 340                 /* for 32-bit systems, limit number of hugepages to
 341                  * 1GB per page size */
 342                 hpi->num_pages[0] = RTE_MIN(hpi->num_pages[0],
 343                                             RTE_PGSIZE_1G / hpi->hugepage_sz);
 344 #endif
 345
 346                 num_sizes++;
 347         }
 348         closedir(dir);
 349
 350         /* something went wrong, and we broke from the for loop above */
 351         if (dirent != NULL)
 352                 return -1;
 353
 354         internal_config.num_hugepage_sizes = num_sizes;
 355
 356         /* sort the page directory entries by size, largest to smallest */
 357         qsort(&internal_config.hugepage_info[0], num_sizes,
 358               sizeof(internal_config.hugepage_info[0]), compare_hpi);
 359
 360         /* now we have all info, check we have at least one valid size */
 361         for (i = 0; i < num_sizes; i++)
 362                 if (internal_config.hugepage_info[i].hugedir != NULL &&
 363                     internal_config.hugepage_info[i].num_pages[0] > 0)
 364                         return 0;
 365
 366         /* no valid hugepage mounts available, return error */
 367         return -1;
 368 }