tools/testing/selftests/vm/thuge-gen.c

   1 /* Test selecting other page sizes for mmap/shmget.
   2
   3    Before running this huge pages for each huge page size must have been
   4    reserved.
   5    For large pages beyond MAX_ORDER (like 1GB on x86) boot options must be used.
   6    Also shmmax must be increased.
   7    And you need to run as root to work around some weird permissions in shm.
   8    And nothing using huge pages should run in parallel.
   9    When the program aborts you may need to clean up the shm segments with
  10    ipcrm -m by hand, like this
  11    sudo ipcs | awk '$1 == "0x00000000" {print $2}' | xargs -n1 sudo ipcrm -m
  12    (warning this will remove all if someone else uses them) */
  13
  14 #define _GNU_SOURCE 1
  15 #include <sys/mman.h>
  16 #include <stdlib.h>
  17 #include <stdio.h>
  18 #include <sys/ipc.h>
  19 #include <sys/shm.h>
  20 #include <sys/stat.h>
  21 #include <glob.h>
  22 #include <assert.h>
  23 #include <unistd.h>
  24 #include <stdarg.h>
  25 #include <string.h>
  26
  27 #define err(x) perror(x), exit(1)
  28
  29 #define MAP_HUGE_2MB    (21 << MAP_HUGE_SHIFT)
  30 #define MAP_HUGE_1GB    (30 << MAP_HUGE_SHIFT)
  31 #define MAP_HUGE_SHIFT  26
  32 #define MAP_HUGE_MASK   0x3f
  33 #define MAP_HUGETLB     0x40000
  34
  35 #define SHM_HUGETLB     04000   /* segment will use huge TLB pages */
  36 #define SHM_HUGE_SHIFT  26
  37 #define SHM_HUGE_MASK   0x3f
  38 #define SHM_HUGE_2MB    (21 << SHM_HUGE_SHIFT)
  39 #define SHM_HUGE_1GB    (30 << SHM_HUGE_SHIFT)
  40
  41 #define NUM_PAGESIZES   5
  42
  43 #define NUM_PAGES 4
  44
  45 #define Dprintf(fmt...) // printf(fmt)
  46
  47 unsigned long page_sizes[NUM_PAGESIZES];
  48 int num_page_sizes;
  49
  50 int ilog2(unsigned long v)
  51 {
  52         int l = 0;
  53         while ((1UL << l) < v)
  54                 l++;
  55         return l;
  56 }
  57
  58 void find_pagesizes(void)
  59 {
  60         glob_t g;
  61         int i;
  62         glob("/sys/kernel/mm/hugepages/hugepages-*kB", 0, NULL, &g);
  63         assert(g.gl_pathc <= NUM_PAGESIZES);
  64         for (i = 0; i < g.gl_pathc; i++) {
  65                 sscanf(g.gl_pathv[i], "/sys/kernel/mm/hugepages/hugepages-%lukB",
  66                                 &page_sizes[i]);
  67                 page_sizes[i] <<= 10;
  68                 printf("Found %luMB\n", page_sizes[i] >> 20);
  69         }
  70         num_page_sizes = g.gl_pathc;
  71         globfree(&g);
  72 }
  73
  74 unsigned long default_huge_page_size(void)
  75 {
  76         unsigned long hps = 0;
  77         char *line = NULL;
  78         size_t linelen = 0;
  79         FILE *f = fopen("/proc/meminfo", "r");
  80         if (!f)
  81                 return 0;
  82         while (getline(&line, &linelen, f) > 0) {
  83                 if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
  84                         hps <<= 10;
  85                         break;
  86                 }
  87         }
  88         free(line);
  89         return hps;
  90 }
  91
  92 void show(unsigned long ps)
  93 {
  94         char buf[100];
  95         if (ps == getpagesize())
  96                 return;
  97         printf("%luMB: ", ps >> 20);
  98         fflush(stdout);
  99         snprintf(buf, sizeof buf,
 100                 "cat /sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages",
 101                 ps >> 10);
 102         system(buf);
 103 }
 104
 105 unsigned long read_sysfs(int warn, char *fmt, ...)
 106 {
 107         char *line = NULL;
 108         size_t linelen = 0;
 109         char buf[100];
 110         FILE *f;
 111         va_list ap;
 112         unsigned long val = 0;
 113
 114         va_start(ap, fmt);
 115         vsnprintf(buf, sizeof buf, fmt, ap);
 116         va_end(ap);
 117
 118         f = fopen(buf, "r");
 119         if (!f) {
 120                 if (warn)
 121                         printf("missing %s\n", buf);
 122                 return 0;
 123         }
 124         if (getline(&line, &linelen, f) > 0) {
 125                 sscanf(line, "%lu", &val);
 126         }
 127         fclose(f);
 128         free(line);
 129         return val;
 130 }
 131
 132 unsigned long read_free(unsigned long ps)
 133 {
 134         return read_sysfs(ps != getpagesize(),
 135                         "/sys/kernel/mm/hugepages/hugepages-%lukB/free_hugepages",
 136                         ps >> 10);
 137 }
 138
 139 void test_mmap(unsigned long size, unsigned flags)
 140 {
 141         char *map;
 142         unsigned long before, after;
 143         int err;
 144
 145         before = read_free(size);
 146         map = mmap(NULL, size*NUM_PAGES, PROT_READ|PROT_WRITE,
 147                         MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|flags, 0, 0);
 148
 149         if (map == (char *)-1) err("mmap");
 150         memset(map, 0xff, size*NUM_PAGES);
 151         after = read_free(size);
 152         Dprintf("before %lu after %lu diff %ld size %lu\n",
 153                 before, after, before - after, size);
 154         assert(size == getpagesize() || (before - after) == NUM_PAGES);
 155         show(size);
 156         err = munmap(map, size);
 157         assert(!err);
 158 }
 159
 160 void test_shmget(unsigned long size, unsigned flags)
 161 {
 162         int id;
 163         unsigned long before, after;
 164         int err;
 165
 166         before = read_free(size);
 167         id = shmget(IPC_PRIVATE, size * NUM_PAGES, IPC_CREAT|0600|flags);
 168         if (id < 0) err("shmget");
 169
 170         struct shm_info i;
 171         if (shmctl(id, SHM_INFO, (void *)&i) < 0) err("shmctl");
 172         Dprintf("alloc %lu res %lu\n", i.shm_tot, i.shm_rss);
 173
 174
 175         Dprintf("id %d\n", id);
 176         char *map = shmat(id, NULL, 0600);
 177         if (map == (char*)-1) err("shmat");
 178
 179         shmctl(id, IPC_RMID, NULL);
 180
 181         memset(map, 0xff, size*NUM_PAGES);
 182         after = read_free(size);
 183
 184         Dprintf("before %lu after %lu diff %ld size %lu\n",
 185                 before, after, before - after, size);
 186         assert(size == getpagesize() || (before - after) == NUM_PAGES);
 187         show(size);
 188         err = shmdt(map);
 189         assert(!err);
 190 }
 191
 192 void sanity_checks(void)
 193 {
 194         int i;
 195         unsigned long largest = getpagesize();
 196
 197         for (i = 0; i < num_page_sizes; i++) {
 198                 if (page_sizes[i] > largest)
 199                         largest = page_sizes[i];
 200
 201                 if (read_free(page_sizes[i]) < NUM_PAGES) {
 202                         printf("Not enough huge pages for page size %lu MB, need %u\n",
 203                                 page_sizes[i] >> 20,
 204                                 NUM_PAGES);
 205                         exit(0);
 206                 }
 207         }
 208
 209         if (read_sysfs(0, "/proc/sys/kernel/shmmax") < NUM_PAGES * largest) {
 210                 printf("Please do echo %lu > /proc/sys/kernel/shmmax", largest * NUM_PAGES);
 211                 exit(0);
 212         }
 213
 214 #if defined(__x86_64__)
 215         if (largest != 1U<<30) {
 216                 printf("No GB pages available on x86-64\n"
 217                        "Please boot with hugepagesz=1G hugepages=%d\n", NUM_PAGES);
 218                 exit(0);
 219         }
 220 #endif
 221 }
 222
 223 int main(void)
 224 {
 225         int i;
 226         unsigned default_hps = default_huge_page_size();
 227
 228         find_pagesizes();
 229
 230         sanity_checks();
 231
 232         for (i = 0; i < num_page_sizes; i++) {
 233                 unsigned long ps = page_sizes[i];
 234                 int arg = ilog2(ps) << MAP_HUGE_SHIFT;
 235                 printf("Testing %luMB mmap with shift %x\n", ps >> 20, arg);
 236                 test_mmap(ps, MAP_HUGETLB | arg);
 237         }
 238         printf("Testing default huge mmap\n");
 239         test_mmap(default_hps, SHM_HUGETLB);
 240
 241         puts("Testing non-huge shmget");
 242         test_shmget(getpagesize(), 0);
 243
 244         for (i = 0; i < num_page_sizes; i++) {
 245                 unsigned long ps = page_sizes[i];
 246                 int arg = ilog2(ps) << SHM_HUGE_SHIFT;
 247                 printf("Testing %luMB shmget with shift %x\n", ps >> 20, arg);
 248                 test_shmget(ps, SHM_HUGETLB | arg);
 249         }
 250         puts("default huge shmget");
 251         test_shmget(default_hps, SHM_HUGETLB);
 252
 253         return 0;
 254 }