Re: [PATCH] Linux-2.5 fix/improve get_pid()

[Linus Torvalds]

On Thu, 8 Aug 2002, Linus Torvalds wrote:
> 
> So let's just try Andries approach, suggested patch as follows..

"ps" seems to do ok from a visual standpoint at least up to 99 million. 
Maybe it won't look that good after that, I'm too lazy to test.

The following trivial program is useful for efficiently allocating pid
numbers without blowing chunks on the VM subsystem and spending all the
time on page table updates - for people who want to test (look out: I've
got dual 2.4GHz CPU's with HT, so getting up to 10+ million was easy, your
milage may wary and at some point you should just compile a kernel that
starts higher ;).

		Linus

---
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

int main()
{
        int i;
        for (i = 1; i < 250000; i++) {
                if (!vfork())
                        exit(1);
                if (waitpid(-1, NULL, WNOHANG) < 0)
                        perror("waitpid");
        }
        return 0;
}