Re: Fwd: [Lse-tech] get_pid() performance fix

OGAWA Hirofumi
2002-03-05T20:11:30Z

Hubertus Franke <frankeh@watson.ibm.com> writes:

> > I said:
> > task { pid = 300, pgrp = 301, };
> > 301 is free;
> >
> > get_pid() returns 301.
> >
> > "task 301" can't call setsid(). pid 301 is available?
>
> The original code is/was:
>
> if(p->pid == last_pid ||
> p->pgrp == last_pid ||
> p->tgid == last_pid ||
> p->session == last_pid) {
> if(++last_pid >= next_safe) {
> if(last_pid & 0xffff8000)
> last_pid = 300;
> next_safe = PID_MAX;
> }
> goto repeat;
> }
>
> if any process holds the pgrp=301 as in your case, 301 won't be eligible due
> to (p->pgrp == last_pid) check.

I know.

> @@ -153,13 +155,18 @@
> if(last_pid & 0xffff8000)
> last_pid = 300;
> next_safe = PID_MAX;
> + goto repeat;
> }
> - goto repeat;
> + if(unlikely(last_pid == beginpid))
> + goto nomorepids;
> + continue;

You changed it. No?
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>