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_eal.h>
  50 #include <rte_launch.h>
  51 #include <rte_per_lcore.h>
  52 #include <rte_lcore.h>
  53 #include <rte_debug.h>
  54 #include <rte_log.h>
  55 #include <rte_common.h>
  56 #include "rte_string_fns.h"
  57 #include "eal_internal_cfg.h"
  58 #include "eal_hugepages.h"
  59 #include "eal_filesystem.h"
  60
  61 static const char sys_dir_path[] = "/sys/kernel/mm/hugepages";
  62
  63 /* this function is only called from eal_hugepage_info_init which itself
  64  * is only called from a primary process */
  65 static uint32_t
  66 get_num_hugepages(const char *subdir)
  67 {
  68         char path[PATH_MAX];
  69         long unsigned resv_pages, num_pages = 0;
  70         const char *nr_hp_file = "free_hugepages";
  71         const char *nr_rsvd_file = "resv_hugepages";
  72
  73         /* first, check how many reserved pages kernel reports */
  74         snprintf(path, sizeof(path), "%s/%s/%s",
  75                         sys_dir_path, subdir, nr_rsvd_file);
  76         if (eal_parse_sysfs_value(path, &resv_pages) < 0)
  77                 return 0;
  78
  79         snprintf(path, sizeof(path), "%s/%s/%s",
  80                         sys_dir_path, subdir, nr_hp_file);
  81         if (eal_parse_sysfs_value(path, &num_pages) < 0)
  82                 return 0;
  83
  84         if (num_pages == 0)
  85                 RTE_LOG(WARNING, EAL, "No free hugepages reported in %s\n",
  86                                 subdir);
  87
  88         /* adjust num_pages */
  89         if (num_pages >= resv_pages)
  90                 num_pages -= resv_pages;
  91         else if (resv_pages)
  92                 num_pages = 0;
  93
  94         /* we want to return a uint32_t and more than this looks suspicious
  95          * anyway ... */
  96         if (num_pages > UINT32_MAX)
  97                 num_pages = UINT32_MAX;
  98
  99         return num_pages;
 100 }
 101
 102 static uint64_t
 103 get_default_hp_size(void)
 104 {
 105         const char proc_meminfo[] = "/proc/meminfo";
 106         const char str_hugepagesz[] = "Hugepagesize:";
 107         unsigned hugepagesz_len = sizeof(str_hugepagesz) - 1;
 108         char buffer[256];
 109         unsigned long long size = 0;
 110
 111         FILE *fd = fopen(proc_meminfo, "r");
 112         if (fd == NULL)
 113                 rte_panic("Cannot open %s\n", proc_meminfo);
 114         while(fgets(buffer, sizeof(buffer), fd)){
 115                 if (strncmp(buffer, str_hugepagesz, hugepagesz_len) == 0){
 116                         size = rte_str_to_size(&buffer[hugepagesz_len]);
 117                         break;
 118                 }
 119         }
 120         fclose(fd);
 121         if (size == 0)
 122                 rte_panic("Cannot get default hugepage size from %s\n", proc_meminfo);
 123         return size;
 124 }
 125
 126 static const char *
 127 get_hugepage_dir(uint64_t hugepage_sz)
 128 {
 129         enum proc_mount_fieldnames {
 130                 DEVICE = 0,
 131                 MOUNTPT,
 132                 FSTYPE,
 133                 OPTIONS,
 134                 _FIELDNAME_MAX
 135         };
 136         static uint64_t default_size = 0;
 137         const char proc_mounts[] = "/proc/mounts";
 138         const char hugetlbfs_str[] = "hugetlbfs";
 139         const size_t htlbfs_str_len = sizeof(hugetlbfs_str) - 1;
 140         const char pagesize_opt[] = "pagesize=";
 141         const size_t pagesize_opt_len = sizeof(pagesize_opt) - 1;
 142         const char split_tok = ' ';
 143         char *splitstr[_FIELDNAME_MAX];
 144         char buf[BUFSIZ];
 145         char *retval = NULL;
 146
 147         FILE *fd = fopen(proc_mounts, "r");
 148         if (fd == NULL)
 149                 rte_panic("Cannot open %s\n", proc_mounts);
 150
 151         if (default_size == 0)
 152                 default_size = get_default_hp_size();
 153
 154         while (fgets(buf, sizeof(buf), fd)){
 155                 if (rte_strsplit(buf, sizeof(buf), splitstr, _FIELDNAME_MAX,
 156                                 split_tok) != _FIELDNAME_MAX) {
 157                         RTE_LOG(ERR, EAL, "Error parsing %s\n", proc_mounts);
 158                         break; /* return NULL */
 159                 }
 160
 161                 /* we have a specified --huge-dir option, only examine that dir */
 162                 if (internal_config.hugepage_dir != NULL &&
 163                                 strcmp(splitstr[MOUNTPT], internal_config.hugepage_dir) != 0)
 164                         continue;
 165
 166                 if (strncmp(splitstr[FSTYPE], hugetlbfs_str, htlbfs_str_len) == 0){
 167                         const char *pagesz_str = strstr(splitstr[OPTIONS], pagesize_opt);
 168
 169                         /* if no explicit page size, the default page size is compared */
 170                         if (pagesz_str == NULL){
 171                                 if (hugepage_sz == default_size){
 172                                         retval = strdup(splitstr[MOUNTPT]);
 173                                         break;
 174                                 }
 175                         }
 176                         /* there is an explicit page size, so check it */
 177                         else {
 178                                 uint64_t pagesz = rte_str_to_size(&pagesz_str[pagesize_opt_len]);
 179                                 if (pagesz == hugepage_sz) {
 180                                         retval = strdup(splitstr[MOUNTPT]);
 181                                         break;
 182                                 }
 183                         }
 184                 } /* end if strncmp hugetlbfs */
 185         } /* end while fgets */
 186
 187         fclose(fd);
 188         return retval;
 189 }
 190
 191 /*
 192  * Clear the hugepage directory of whatever hugepage files
 193  * there are. Checks if the file is locked (i.e.
 194  * if it's in use by another DPDK process).
 195  */
 196 static int
 197 clear_hugedir(const char * hugedir)
 198 {
 199         DIR *dir;
 200         struct dirent *dirent;
 201         int dir_fd, fd, lck_result;
 202         const char filter[] = "*map_*"; /* matches hugepage files */
 203
 204         /* open directory */
 205         dir = opendir(hugedir);
 206         if (!dir) {
 207                 RTE_LOG(ERR, EAL, "Unable to open hugepage directory %s\n",
 208                                 hugedir);
 209                 goto error;
 210         }
 211         dir_fd = dirfd(dir);
 212
 213         dirent = readdir(dir);
 214         if (!dirent) {
 215                 RTE_LOG(ERR, EAL, "Unable to read hugepage directory %s\n",
 216                                 hugedir);
 217                 goto error;
 218         }
 219
 220         while(dirent != NULL){
 221                 /* skip files that don't match the hugepage pattern */
 222                 if (fnmatch(filter, dirent->d_name, 0) > 0) {
 223                         dirent = readdir(dir);
 224                         continue;
 225                 }
 226
 227                 /* try and lock the file */
 228                 fd = openat(dir_fd, dirent->d_name, O_RDONLY);
 229
 230                 /* skip to next file */
 231                 if (fd == -1) {
 232                         dirent = readdir(dir);
 233                         continue;
 234                 }
 235
 236                 /* non-blocking lock */
 237                 lck_result = flock(fd, LOCK_EX | LOCK_NB);
 238
 239                 /* if lock succeeds, unlock and remove the file */
 240                 if (lck_result != -1) {
 241                         flock(fd, LOCK_UN);
 242                         unlinkat(dir_fd, dirent->d_name, 0);
 243                 }
 244                 close (fd);
 245                 dirent = readdir(dir);
 246         }
 247
 248         closedir(dir);
 249         return 0;
 250
 251 error:
 252         if (dir)
 253                 closedir(dir);
 254
 255         RTE_LOG(ERR, EAL, "Error while clearing hugepage dir: %s\n",
 256                 strerror(errno));
 257
 258         return -1;
 259 }
 260
 261 static int
 262 compare_hpi(const void *a, const void *b)
 263 {
 264         const struct hugepage_info *hpi_a = a;
 265         const struct hugepage_info *hpi_b = b;
 266
 267         return hpi_b->hugepage_sz - hpi_a->hugepage_sz;
 268 }
 269
 270 /*
 271  * when we initialize the hugepage info, everything goes
 272  * to socket 0 by default. it will later get sorted by memory
 273  * initialization procedure.
 274  */
 275 int
 276 eal_hugepage_info_init(void)
 277 {
 278         const char dirent_start_text[] = "hugepages-";
 279         const size_t dirent_start_len = sizeof(dirent_start_text) - 1;
 280         unsigned i, num_sizes = 0;
 281         DIR *dir;
 282         struct dirent *dirent;
 283
 284         dir = opendir(sys_dir_path);
 285         if (dir == NULL) {
 286                 RTE_LOG(ERR, EAL,
 287                         "Cannot open directory %s to read system hugepage info\n",
 288                         sys_dir_path);
 289                 return -1;
 290         }
 291
 292         for (dirent = readdir(dir); dirent != NULL; dirent = readdir(dir)) {
 293                 struct hugepage_info *hpi;
 294
 295                 if (strncmp(dirent->d_name, dirent_start_text,
 296                             dirent_start_len) != 0)
 297                         continue;
 298
 299                 if (num_sizes >= MAX_HUGEPAGE_SIZES)
 300                         break;
 301
 302                 hpi = &internal_config.hugepage_info[num_sizes];
 303                 hpi->hugepage_sz =
 304                         rte_str_to_size(&dirent->d_name[dirent_start_len]);
 305                 hpi->hugedir = get_hugepage_dir(hpi->hugepage_sz);
 306
 307                 /* first, check if we have a mountpoint */
 308                 if (hpi->hugedir == NULL) {
 309                         uint32_t num_pages;
 310
 311                         num_pages = get_num_hugepages(dirent->d_name);
 312                         if (num_pages > 0)
 313                                 RTE_LOG(NOTICE, EAL,
 314                                         "%" PRIu32 " hugepages of size "
 315                                         "%" PRIu64 " reserved, but no mounted "
 316                                         "hugetlbfs found for that size\n",
 317                                         num_pages, hpi->hugepage_sz);
 318                         continue;
 319                 }
 320
 321                 /* try to obtain a writelock */
 322                 hpi->lock_descriptor = open(hpi->hugedir, O_RDONLY);
 323
 324                 /* if blocking lock failed */
 325                 if (flock(hpi->lock_descriptor, LOCK_EX) == -1) {
 326                         RTE_LOG(CRIT, EAL,
 327                                 "Failed to lock hugepage directory!\n");
 328                         break;
 329                 }
 330                 /* clear out the hugepages dir from unused pages */
 331                 if (clear_hugedir(hpi->hugedir) == -1)
 332                         break;
 333
 334                 /* for now, put all pages into socket 0,
 335                  * later they will be sorted */
 336                 hpi->num_pages[0] = get_num_hugepages(dirent->d_name);
 337
 338 #ifndef RTE_ARCH_64
 339                 /* for 32-bit systems, limit number of hugepages to
 340                  * 1GB per page size */
 341                 hpi->num_pages[0] = RTE_MIN(hpi->num_pages[0],
 342                                             RTE_PGSIZE_1G / hpi->hugepage_sz);
 343 #endif
 344
 345                 num_sizes++;
 346         }
 347         closedir(dir);
 348
 349         /* something went wrong, and we broke from the for loop above */
 350         if (dirent != NULL)
 351                 return -1;
 352
 353         internal_config.num_hugepage_sizes = num_sizes;
 354
 355         /* sort the page directory entries by size, largest to smallest */
 356         qsort(&internal_config.hugepage_info[0], num_sizes,
 357               sizeof(internal_config.hugepage_info[0]), compare_hpi);
 358
 359         /* now we have all info, check we have at least one valid size */
 360         for (i = 0; i < num_sizes; i++)
 361                 if (internal_config.hugepage_info[i].hugedir != NULL &&
 362                     internal_config.hugepage_info[i].num_pages[0] > 0)
 363                         return 0;
 364
 365         /* no valid hugepage mounts available, return error */
 366         return -1;
 367 }