From: Pavel Machek <pavel@suse.cz>
To: Martin Mares <mj@ucw.cz>
Cc: Ingo Molnar <mingo@elte.hu>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [patch] lockless, scalable get_pid(), for_each_process() elimination, 2.5.35-BK
Date: Tue, 17 Sep 2002 15:31:14 +0000 [thread overview]
Message-ID: <20020917153114.A35@toy.ucw.cz> (raw)
In-Reply-To: <20020919192758.GA430@ucw.cz>; from mj@ucw.cz on Thu, Sep 19, 2002 at 09:27:58PM +0200
Hi!
> > nevertheless we do lock up for 32 seconds if there are 32K PIDs allocated
> > in a row and last_pid hits that range - regardless of pid_max. (Depending
> > on the cache architecture it could take significantly more.)
>
> What about randomizing the PID selection a bit? I.e., allocate PIDs
> consecutively as long as they are free; if you hit an already used
> PID, roll dice to find a new position where the search should be
> continued. As long as the allocated fraction of PID space is reasonably
> small, this algorithm should be very quick in average case.
Problem is it may take infinite time if you are unlucky...
Pavel
--
Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt,
details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.
next prev parent reply other threads:[~2002-09-22 20:48 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-17 23:06 [patch] lockless, scalable get_pid(), for_each_process() elimination, 2.5.35-BK Ingo Molnar
2002-09-18 0:22 ` William Lee Irwin III
2002-09-18 1:27 ` David S. Miller
2002-09-18 2:22 ` William Lee Irwin III
2002-09-18 10:11 ` Ingo Molnar
2002-09-18 14:28 ` William Lee Irwin III
2002-09-18 12:32 ` Andries Brouwer
2002-09-18 12:56 ` Ingo Molnar
2002-09-18 16:17 ` Linus Torvalds
2002-09-18 16:46 ` Ingo Molnar
2002-09-18 16:57 ` Ingo Molnar
2002-09-18 18:28 ` Andries Brouwer
2002-09-18 18:27 ` William Lee Irwin III
2002-09-18 19:00 ` Ingo Molnar
2002-09-18 20:11 ` Andries Brouwer
2002-09-18 20:29 ` William Lee Irwin III
2002-09-18 21:15 ` Andries Brouwer
2002-09-19 3:05 ` Ingo Molnar
2002-09-19 13:11 ` Andries Brouwer
2002-09-21 12:56 ` quadratic behaviour Andries Brouwer
2002-09-21 17:06 ` Linus Torvalds
2002-09-21 17:35 ` William Lee Irwin III
2002-09-21 17:49 ` Ingo Molnar
2002-09-21 17:46 ` William Lee Irwin III
2002-09-18 14:49 ` [patch] lockless, scalable get_pid(), for_each_process() elimination, 2.5.35-BK William Lee Irwin III
2002-09-18 15:01 ` Cort Dougan
2002-09-18 15:33 ` Ingo Molnar
2002-09-18 15:31 ` yodaiken
2002-09-18 15:35 ` Cort Dougan
2002-09-18 15:37 ` Rik van Riel
2002-09-18 15:50 ` Alan Cox
2002-09-18 18:31 ` Andries Brouwer
2002-09-18 18:32 ` William Lee Irwin III
2002-09-18 16:15 ` Linus Torvalds
2002-09-18 16:32 ` Rik van Riel
2002-09-18 16:48 ` Linus Torvalds
2002-09-18 17:31 ` Ingo Molnar
2002-09-18 21:46 ` Rogier Wolff
2002-09-18 16:41 ` Ingo Molnar
2002-09-18 16:45 ` William Lee Irwin III
2002-09-18 16:59 ` Linus Torvalds
2002-09-18 17:36 ` Ingo Molnar
2002-09-18 17:36 ` William Lee Irwin III
2002-09-18 17:46 ` Linus Torvalds
2002-09-18 17:47 ` William Lee Irwin III
2002-09-18 17:59 ` Ingo Molnar
2002-09-18 17:50 ` William Lee Irwin III
2002-09-18 18:07 ` Ingo Molnar
2002-09-19 19:27 ` Martin Mares
2002-09-17 15:31 ` Pavel Machek [this message]
2002-09-19 20:07 ` Richard B. Johnson
2002-09-18 16:46 ` Rik van Riel
2002-09-18 16:53 ` Linus Torvalds
2002-09-18 17:00 ` Rik van Riel
2002-09-18 17:16 ` Linus Torvalds
2002-09-18 17:28 ` Ingo Molnar
2002-09-18 17:38 ` Ingo Molnar
2002-09-18 17:24 ` Ingo Molnar
2002-09-18 17:30 ` Linus Torvalds
2002-09-18 17:35 ` Cort Dougan
2002-09-18 17:43 ` Rik van Riel
2002-09-18 17:48 ` Martin J. Bligh
2002-09-18 17:57 ` Cort Dougan
2002-09-18 18:08 ` Martin J. Bligh
2002-09-18 18:28 ` Ingo Molnar
2002-09-18 18:33 ` Linus Torvalds
2002-09-18 18:51 ` Ingo Molnar
2002-09-18 18:56 ` interruptible_sleep_on_timeout() and signals Imran Badr
2002-09-19 7:16 ` David Woodhouse
2002-09-18 19:53 ` [patch] lockless, scalable get_pid(), for_each_process() elimination, 2.5.35-BK Martin J. Bligh
2002-09-22 0:34 ` Andrea Arcangeli
2002-09-22 10:02 ` Ingo Molnar
2002-09-22 15:27 ` Andrea Arcangeli
2002-09-18 18:02 ` Ingo Molnar
2002-09-18 17:58 ` Cort Dougan
2002-09-18 18:14 ` Ingo Molnar
2002-09-18 17:54 ` Alan Cox
2002-09-18 17:54 ` Ingo Molnar
2002-09-18 18:00 ` yodaiken
2002-09-18 18:21 ` Ingo Molnar
2002-09-18 18:33 ` yodaiken
2002-09-18 16:55 ` Alan Cox
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