mempoc for singularity-cgroups issue

mempoc.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/wait.h>

#define G 1073741824L

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

    if(argc!=3) {
        printf("Syntax ./mempoc SIZE_IN_GB NUM_CHILDREN\n");
        exit(1);
    }

    for(j=0; j<atoi(argv[2]); j++) {
        if(fork()==0) {
            long size;
            char *res;

            size=atoi(argv[1])*G;
            printf("Calling mmap %s from child %d with %ld bytes...\n", argv[1], j, size);

            res=(char *) mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_SHARED, -1, 0);
            if(res == MAP_FAILED) {
                perror("mmap failed");
                return 1;
            }

            printf("Waiting 10 seconds...\n");
            sleep(10);

            while(1) {
                printf("Filling pages with memset...\n");
                memset(res, 1, size);

                // printf("Filling pages neanderthal way...\n");
                // for(long i=0; i<size-1; i++) {
                //    res[i]='\0';
                // }
                sleep(5);
            }

            munmap(res, size);
            exit(0);
        }
    }
    while(wait(NULL)>0);

    return 0;
}