tools/testing/selftests/vm/gup_test.c

   1 #include <fcntl.h>
   2 #include <errno.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <unistd.h>
   6 #include <dirent.h>
   7 #include <sys/ioctl.h>
   8 #include <sys/mman.h>
   9 #include <sys/stat.h>
  10 #include <sys/types.h>
  11 #include <pthread.h>
  12 #include <assert.h>
  13 #include <mm/gup_test.h>
  14 #include "../kselftest.h"
  15
  16 #include "util.h"
  17
  18 #define MB (1UL << 20)
  19
  20 /* Just the flags we need, copied from mm.h: */
  21 #define FOLL_WRITE      0x01    /* check pte is writable */
  22 #define FOLL_TOUCH      0x02    /* mark page accessed */
  23
  24 #define GUP_TEST_FILE "/sys/kernel/debug/gup_test"
  25
  26 static unsigned long cmd = GUP_FAST_BENCHMARK;
  27 static int gup_fd, repeats = 1;
  28 static unsigned long size = 128 * MB;
  29 /* Serialize prints */
  30 static pthread_mutex_t print_mutex = PTHREAD_MUTEX_INITIALIZER;
  31
  32 static char *cmd_to_str(unsigned long cmd)
  33 {
  34         switch (cmd) {
  35         case GUP_FAST_BENCHMARK:
  36                 return "GUP_FAST_BENCHMARK";
  37         case PIN_FAST_BENCHMARK:
  38                 return "PIN_FAST_BENCHMARK";
  39         case PIN_LONGTERM_BENCHMARK:
  40                 return "PIN_LONGTERM_BENCHMARK";
  41         case GUP_BASIC_TEST:
  42                 return "GUP_BASIC_TEST";
  43         case PIN_BASIC_TEST:
  44                 return "PIN_BASIC_TEST";
  45         case DUMP_USER_PAGES_TEST:
  46                 return "DUMP_USER_PAGES_TEST";
  47         }
  48         return "Unknown command";
  49 }
  50
  51 void *gup_thread(void *data)
  52 {
  53         struct gup_test gup = *(struct gup_test *)data;
  54         int i;
  55
  56         /* Only report timing information on the *_BENCHMARK commands: */
  57         if ((cmd == PIN_FAST_BENCHMARK) || (cmd == GUP_FAST_BENCHMARK) ||
  58              (cmd == PIN_LONGTERM_BENCHMARK)) {
  59                 for (i = 0; i < repeats; i++) {
  60                         gup.size = size;
  61                         if (ioctl(gup_fd, cmd, &gup))
  62                                 perror("ioctl"), exit(1);
  63
  64                         pthread_mutex_lock(&print_mutex);
  65                         printf("%s: Time: get:%lld put:%lld us",
  66                                cmd_to_str(cmd), gup.get_delta_usec,
  67                                gup.put_delta_usec);
  68                         if (gup.size != size)
  69                                 printf(", truncated (size: %lld)", gup.size);
  70                         printf("\n");
  71                         pthread_mutex_unlock(&print_mutex);
  72                 }
  73         } else {
  74                 gup.size = size;
  75                 if (ioctl(gup_fd, cmd, &gup)) {
  76                         perror("ioctl");
  77                         exit(1);
  78                 }
  79
  80                 pthread_mutex_lock(&print_mutex);
  81                 printf("%s: done\n", cmd_to_str(cmd));
  82                 if (gup.size != size)
  83                         printf("Truncated (size: %lld)\n", gup.size);
  84                 pthread_mutex_unlock(&print_mutex);
  85         }
  86
  87         return NULL;
  88 }
  89
  90 int main(int argc, char **argv)
  91 {
  92         struct gup_test gup = { 0 };
  93         int filed, i, opt, nr_pages = 1, thp = -1, write = 1, nthreads = 1, ret;
  94         int flags = MAP_PRIVATE, touch = 0;
  95         char *file = "/dev/zero";
  96         pthread_t *tid;
  97         char *p;
  98
  99         while ((opt = getopt(argc, argv, "m:r:n:F:f:abcj:tTLUuwWSHpz")) != -1) {
 100                 switch (opt) {
 101                 case 'a':
 102                         cmd = PIN_FAST_BENCHMARK;
 103                         break;
 104                 case 'b':
 105                         cmd = PIN_BASIC_TEST;
 106                         break;
 107                 case 'L':
 108                         cmd = PIN_LONGTERM_BENCHMARK;
 109                         break;
 110                 case 'c':
 111                         cmd = DUMP_USER_PAGES_TEST;
 112                         /*
 113                          * Dump page 0 (index 1). May be overridden later, by
 114                          * user's non-option arguments.
 115                          *
 116                          * .which_pages is zero-based, so that zero can mean "do
 117                          * nothing".
 118                          */
 119                         gup.which_pages[0] = 1;
 120                         break;
 121                 case 'p':
 122                         /* works only with DUMP_USER_PAGES_TEST */
 123                         gup.test_flags |= GUP_TEST_FLAG_DUMP_PAGES_USE_PIN;
 124                         break;
 125                 case 'F':
 126                         /* strtol, so you can pass flags in hex form */
 127                         gup.gup_flags = strtol(optarg, 0, 0);
 128                         break;
 129                 case 'j':
 130                         nthreads = atoi(optarg);
 131                         break;
 132                 case 'm':
 133                         size = atoi(optarg) * MB;
 134                         break;
 135                 case 'r':
 136                         repeats = atoi(optarg);
 137                         break;
 138                 case 'n':
 139                         nr_pages = atoi(optarg);
 140                         break;
 141                 case 't':
 142                         thp = 1;
 143                         break;
 144                 case 'T':
 145                         thp = 0;
 146                         break;
 147                 case 'U':
 148                         cmd = GUP_BASIC_TEST;
 149                         break;
 150                 case 'u':
 151                         cmd = GUP_FAST_BENCHMARK;
 152                         break;
 153                 case 'w':
 154                         write = 1;
 155                         break;
 156                 case 'W':
 157                         write = 0;
 158                         break;
 159                 case 'f':
 160                         file = optarg;
 161                         break;
 162                 case 'S':
 163                         flags &= ~MAP_PRIVATE;
 164                         flags |= MAP_SHARED;
 165                         break;
 166                 case 'H':
 167                         flags |= (MAP_HUGETLB | MAP_ANONYMOUS);
 168                         break;
 169                 case 'z':
 170                         /* fault pages in gup, do not fault in userland */
 171                         touch = 1;
 172                         break;
 173                 default:
 174                         return -1;
 175                 }
 176         }
 177
 178         if (optind < argc) {
 179                 int extra_arg_count = 0;
 180                 /*
 181                  * For example:
 182                  *
 183                  *   ./gup_test -c 0 1 0x1001
 184                  *
 185                  * ...to dump pages 0, 1, and 4097
 186                  */
 187
 188                 while ((optind < argc) &&
 189                        (extra_arg_count < GUP_TEST_MAX_PAGES_TO_DUMP)) {
 190                         /*
 191                          * Do the 1-based indexing here, so that the user can
 192                          * use normal 0-based indexing on the command line.
 193                          */
 194                         long page_index = strtol(argv[optind], 0, 0) + 1;
 195
 196                         gup.which_pages[extra_arg_count] = page_index;
 197                         extra_arg_count++;
 198                         optind++;
 199                 }
 200         }
 201
 202         filed = open(file, O_RDWR|O_CREAT);
 203         if (filed < 0) {
 204                 perror("open");
 205                 exit(filed);
 206         }
 207
 208         gup.nr_pages_per_call = nr_pages;
 209         if (write)
 210                 gup.gup_flags |= FOLL_WRITE;
 211
 212         gup_fd = open(GUP_TEST_FILE, O_RDWR);
 213         if (gup_fd == -1) {
 214                 switch (errno) {
 215                 case EACCES:
 216                         if (getuid())
 217                                 printf("Please run this test as root\n");
 218                         break;
 219                 case ENOENT:
 220                         if (opendir("/sys/kernel/debug") == NULL) {
 221                                 printf("mount debugfs at /sys/kernel/debug\n");
 222                                 break;
 223                         }
 224                         printf("check if CONFIG_GUP_TEST is enabled in kernel config\n");
 225                         break;
 226                 default:
 227                         perror("failed to open " GUP_TEST_FILE);
 228                         break;
 229                 }
 230                 exit(KSFT_SKIP);
 231         }
 232
 233         p = mmap(NULL, size, PROT_READ | PROT_WRITE, flags, filed, 0);
 234         if (p == MAP_FAILED) {
 235                 perror("mmap");
 236                 exit(1);
 237         }
 238         gup.addr = (unsigned long)p;
 239
 240         if (thp == 1)
 241                 madvise(p, size, MADV_HUGEPAGE);
 242         else if (thp == 0)
 243                 madvise(p, size, MADV_NOHUGEPAGE);
 244
 245         /*
 246          * FOLL_TOUCH, in gup_test, is used as an either/or case: either
 247          * fault pages in from the kernel via FOLL_TOUCH, or fault them
 248          * in here, from user space. This allows comparison of performance
 249          * between those two cases.
 250          */
 251         if (touch) {
 252                 gup.gup_flags |= FOLL_TOUCH;
 253         } else {
 254                 for (; (unsigned long)p < gup.addr + size; p += PAGE_SIZE)
 255                         p[0] = 0;
 256         }
 257
 258         tid = malloc(sizeof(pthread_t) * nthreads);
 259         assert(tid);
 260         for (i = 0; i < nthreads; i++) {
 261                 ret = pthread_create(&tid[i], NULL, gup_thread, &gup);
 262                 assert(ret == 0);
 263         }
 264         for (i = 0; i < nthreads; i++) {
 265                 ret = pthread_join(tid[i], NULL);
 266                 assert(ret == 0);
 267         }
 268         free(tid);
 269
 270         return 0;
 271 }