Script to test memory usage conditions using mlock and mmap.

memory-test.c

#include <stdlib.h>     
#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
#include <fcntl.h>

void main(int argc, char *argv[])
{

    if( argc != 2 ) {
        printf("Pass correct number of arguments");
        return;
    }

    if ( mlockall(MCL_CURRENT|MCL_FUTURE) == -1 )
        perror("mlockall failed");


    const char *filepath = "file";
    int fd = open(filepath, O_RDONLY);
    if (fd == -1)
    {
        perror("Error opening file");
        return;
    }        
    struct stat info = {0};
    
    if (fstat(fd, &info) == -1)
    {
        perror("Error getting file size");
        return;
    }
    char *map = mmap(0, info.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
    if (map == MAP_FAILED)
    {
        perror("Error mmapping the file");
        return;
    }
  
    char *data;
    long int i=0;
    long int one_giga_byte = (1024*1024*1024);
    int gb_multipler = atoi(argv[1]) ;
    
    data = (char *) malloc(one_giga_byte*gb_multipler);
    
    for(;i<one_giga_byte*gb_multipler;i++){
      data[i] = (char) rand();
    }
      
    sleep(1000);
}