C Program on Linux to exhaust memory

Question

I would like to write a program to consume all the memory available to understand the outcome. I\'ve heard that linux starts killing the processes once it is unable to alloc

Answer 1

You should write to the allocated blocks. If you just ask for memory, linux might just hand out a reservation for memory, but nothing will be allocated until the memory is accessed.

int main()
{
        while(1)
        {
                void *m = malloc(1024*1024);
                memset(m,0,1024*1024);
        }
        return 0;
}

You really only need to write 1 byte on every page (4096 bytes on x86 normally) though.