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From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: frankeh@watson.ibm.com
Cc: "Rajan Ravindran" <rajancr@us.ibm.com>,
	linux-kernel@vger.kernel.org, lse-tech@lists.sourceforge.net
Subject: Re: Fwd: [Lse-tech] get_pid() performance fix
Date: Wed, 06 Mar 2002 05:10:46 +0900	[thread overview]
Message-ID: <87g03e3hdl.fsf@devron.myhome.or.jp> (raw)
In-Reply-To: <OF810580E6.8672B341-ON85256B73.005AF9B8@pok.ibm.com> <873czeaodr.fsf@devron.myhome.or.jp> <20020305195211.144FC3FE0C@smtp.linux.ibm.com>
In-Reply-To: <20020305195211.144FC3FE0C@smtp.linux.ibm.com>

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>

  reply	other threads:[~2002-03-05 20:11 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-03-05 16:43 Fwd: [Lse-tech] get_pid() performance fix Rajan Ravindran
2002-03-05 17:57 ` OGAWA Hirofumi
2002-03-05 19:53   ` Hubertus Franke
2002-03-05 20:10     ` OGAWA Hirofumi [this message]
2002-03-05 21:59       ` Hubertus Franke
2002-03-05 22:48         ` OGAWA Hirofumi
2002-03-05 23:40           ` Hubertus Franke
2002-03-14 23:18 ` [PATCH] " Hubertus Franke
2002-03-15 14:57   ` OGAWA Hirofumi
2002-03-15 15:16   ` OGAWA Hirofumi
2002-03-15 18:37     ` Hubertus Franke
2002-03-16  5:12       ` OGAWA Hirofumi
2002-03-18 21:44         ` Hubertus Franke
2002-03-22 22:14         ` Hubertus Franke
2002-03-22 22:28           ` Davide Libenzi
2002-03-22 22:26             ` Hubertus Franke
  -- strict thread matches above, loose matches on Subject: below --
2002-03-07 22:37 Fwd: [Lse-tech] " Manfred Spraul
2002-03-05  1:57 Hubertus Franke
2002-03-05 16:26 ` OGAWA Hirofumi
2002-03-05 16:43   ` Hubertus Franke
2002-03-07  3:56 ` Rusty Russell
2002-03-07 14:35   ` Hubertus Franke
2002-03-07 14:54     ` Guest section DW
2002-03-07 19:07       ` Hubertus Franke
2002-03-07 19:44         ` Richard B. Johnson
2002-03-07 19:46         ` Guest section DW
2002-03-07 23:14           ` Hubertus Franke
2002-03-07 15:21     ` Dave McCracken

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