2. cat /proc/sys/vm/swappiness
  3. cat /proc/sys/vm/overcommit_memory
  4. cat /proc/sys/vm/overcommit_ratio
  6. # LOWER SWAPS LESS
  7. echo 0 > /proc/sys/vm/swappiness
  9. # DISABLES OVERCOMMITING MEMORY
  10. # overcommit_memory — Configures the conditions under which a large memory request is accepted or denied.
  11. # 2 — The kernel fails requests for memory that add up to all of swap plus the percent of physical RAM specified in /proc/sys/vm/overcommit_ratio. This setting is best for those who desire less risk of memory overcommitment.
  12. echo 2 > /proc/sys/vm/overcommit_memory
  14. # USE UP ALL PHYSICAL RAM
  15. # Specifies the percentage of physical RAM considered when /proc/sys/vm/overcommit_memory is set to 2. The default value is 50.
  16. echo 80 > /proc/sys/vm/overcommit_ratio
  19. ### TO SYSCTL.CONF
  20. vm.swapiness = 0
  21. vm.overcommit_memory = 2
  22. vm.overcommit_ratio = 80
  24. ### C code to use all memory
  25. ### https://stackoverflow.com/questions/1865501/c-program-on-linux-to-exhaust-memory/6617363#6617363
  26. #include <stdio.h>
  27. #include <stdlib.h>
  28. #include <string.h>
  30. #define PAGE_SZ (1<<12)
  32. int main() {
  33.     int i;
  34.     int gb = 2; // memory to consume in GB
  36.     for (i = 0; i < ((unsigned long)gb<<30)/PAGE_SZ ; ++i) {
  37.         void *m = malloc(PAGE_SZ);
  38.         if (!m)
  39.             break;
  40.         memset(m, 0, 1);
  41.     }
  42.     printf("allocated %lu MB\n", ((unsigned long)i*PAGE_SZ)>>20);
  43.     getchar();
  44.     return 0;
  45. }