huge page

[root@localhost ~]# free -g
total used free shared buff/cache available
Mem: 510 129 377 0 3 339
Swap: 0 0 0
[root@localhost ~]# cat /proc/meminfo | grep -i huge
AnonHugePages: 0 kB
ShmemHugePages: 0 kB
HugePages_Total: 256
HugePages_Free: 255
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 524288 kB

#include <sys/mman.h>
#include <stdio.h>
#include <memory.h>

int main(int argc, char *argv[]) {
  char *m;
  size_t s = (8UL * 1024 * 1024);

  m = mmap(NULL, s, PROT_READ | PROT_WRITE,
                    MAP_PRIVATE | MAP_ANONYMOUS | 0x40000 /*MAP_HUGETLB*/, -1, 0);
  if (m == MAP_FAILED) {
    perror("map mem");
    m = NULL;
    return 1;
  }

  memset(m, 0, s);

  printf("map_hugetlb ok, press ENTER to quit!
");
  getchar();

  munmap(m, s);
  return 0;
}

[root@localhost ~]# cat /proc/meminfo  | grep -i huge
AnonHugePages:         0 kB
ShmemHugePages:        0 kB
HugePages_Total:     256
HugePages_Free:      254
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:     524288 kB
[root@localhost ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:            510         129         377           0           3         339
Swap: 

[root@localhost ~]# ps -elf | grep map
0 S root     115112 114967  0  80   0 -  8231 wait_w 07:26 pts/0    00:00:00 ./map
0 S root     115141 115051  0  80   0 -  1729 pipe_w 07:26 pts/1    00:00:00 grep --color=auto map
[root@localhost ~]# cat /proc/115112/map
map_files/ maps       
[root@localhost ~]# cat /proc/115112/maps
00400000-00410000 r-xp 00000000 08:10 22155957                           /data1/dpdk-19.11/demo/huge/map
00410000-00420000 r--p 00000000 08:10 22155957                           /data1/dpdk-19.11/demo/huge/map
00420000-00430000 rw-p 00010000 08:10 22155957                           /data1/dpdk-19.11/demo/huge/map
400000000000-400020000000 rw-p 00000000 00:0f 293434                     /anon_hugepage (deleted)
ffff9c9e0000-ffff9c9f0000 rw-p 00000000 00:00 0 
ffff9c9f0000-ffff9cb60000 r-xp 00000000 08:03 247                        /usr/lib64/libc-2.17.so
ffff9cb60000-ffff9cb70000 r--p 00160000 08:03 247                        /usr/lib64/libc-2.17.so
ffff9cb70000-ffff9cb80000 rw-p 00170000 08:03 247                        /usr/lib64/libc-2.17.so
ffff9cb80000-ffff9cb90000 rw-p 00000000 00:00 0 
ffff9cb90000-ffff9cba0000 r--p 00000000 00:00 0                          [vvar]
ffff9cba0000-ffff9cbb0000 r-xp 00000000 00:00 0                          [vdso]
ffff9cbb0000-ffff9cbd0000 r-xp 00000000 08:03 240                        /usr/lib64/ld-2.17.so
ffff9cbd0000-ffff9cbe0000 r--p 00010000 08:03 240                        /usr/lib64/ld-2.17.so
ffff9cbe0000-ffff9cbf0000 rw-p 00020000 08:03 240                        /usr/lib64/ld-2.17.so
fffff7cf0000-fffff7d20000 rw-p 00000000 00:00 0                          [stack]
[root@localhost ~]# 

#include <sys/mman.h>
#include <stdio.h>
#include <memory.h>

int main(int argc, char *argv[]) {
  char *m;
  size_t s = (16UL * 1024 * 1024*1024); //改大

  m = mmap(NULL, s, PROT_READ | PROT_WRITE,
                    MAP_PRIVATE | MAP_ANONYMOUS | 0x40000 /*MAP_HUGETLB*/, -1, 0);
  if (m == MAP_FAILED) {
    perror("map mem");
    m = NULL;
    return 1;
  }

  memset(m, 0, s);

  printf("map_hugetlb ok, press ENTER to quit!
");
  getchar();

  munmap(m, s);
  return 0;
}

[root@localhost ~]# ps -elf | grep map
0 S root     115761 114967 21  80   0 - 262183 wait_w 07:39 pts/0   00:00:01 ./map
0 S root     115769 115051  0  80   0 -  1729 pipe_w 07:39 pts/1    00:00:00 grep --color=auto map
[root@localhost ~]# cat /proc/meminfo  | grep -i huge
AnonHugePages:         0 kB
ShmemHugePages:        0 kB
HugePages_Total:     256
HugePages_Free:      223
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:     524288 kB
[root@localhost ~]# cat /proc/115761/maps
00400000-00410000 r-xp 00000000 08:10 22155957                           /data1/dpdk-19.11/demo/huge/map
00410000-00420000 r--p 00000000 08:10 22155957                           /data1/dpdk-19.11/demo/huge/map
00420000-00430000 rw-p 00010000 08:10 22155957                           /data1/dpdk-19.11/demo/huge/map
400000000000-400400000000 rw-p 00000000 00:0f 292814                     /anon_hugepage (deleted)
ffffb1060000-ffffb1070000 rw-p 00000000 00:00 0 
ffffb1070000-ffffb11e0000 r-xp 00000000 08:03 247                        /usr/lib64/libc-2.17.so
ffffb11e0000-ffffb11f0000 r--p 00160000 08:03 247                        /usr/lib64/libc-2.17.so
ffffb11f0000-ffffb1200000 rw-p 00170000 08:03 247                        /usr/lib64/libc-2.17.so
ffffb1200000-ffffb1210000 rw-p 00000000 00:00 0 
ffffb1210000-ffffb1220000 r--p 00000000 00:00 0                          [vvar]
ffffb1220000-ffffb1230000 r-xp 00000000 00:00 0                          [vdso]
ffffb1230000-ffffb1250000 r-xp 00000000 08:03 240                        /usr/lib64/ld-2.17.so
ffffb1250000-ffffb1260000 r--p 00010000 08:03 240                        /usr/lib64/ld-2.17.so
ffffb1260000-ffffb1270000 rw-p 00020000 08:03 240                        /usr/lib64/ld-2.17.so
ffffffc30000-ffffffc60000 rw-p 00000000 00:00 0                          [stack]
[root@localhost ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:            510         129         377           0           3         339
Swap:             0           0           0
[root@localhost ~]#