Messages in this thread | | | From | Hubertus Franke <> | Subject | Re: Fwd: [Lse-tech] get_pid() performance fix | Date | Tue, 5 Mar 2002 14:53:15 -0500 |
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On Tuesday 05 March 2002 12:57 pm, OGAWA Hirofumi wrote: > "Rajan Ravindran" <rajancr@us.ibm.com> writes: > > Yes, pid's are guaranteed to be unique. > > Here the problem we focused is the time taken in finding the next > > available free pid. > > I really don't mean by your task->xxx. > > I'm confused. >
yes you are .....
> 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.
-- -- Hubertus Franke (frankeh@watson.ibm.com) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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