From: William Lee Irwin III <wli@holomorphy.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@transmeta.com>, linux-kernel@vger.kernel.org
Subject: Re: [patch] lockless, scalable get_pid(), for_each_process() elimination, 2.5.35-BK
Date: Wed, 18 Sep 2002 07:28:23 -0700 [thread overview]
Message-ID: <20020918142823.GT3530@holomorphy.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0209181136180.2750-100000@localhost.localdomain>
On Wed, Sep 18, 2002 at 12:11:30PM +0200, Ingo Molnar wrote:
> so i think the most we could get is to actually eliminate the pidhash and
> use the idtag hash for it. This would concentrate all the performance
> efforts on the idtag hash.
I eventually had special-case handling of IDTAG_PID so that it did not
use idtags, but chained tasks directly, and removing the pidhash as goals.
On Wed, Sep 18, 2002 at 12:11:30PM +0200, Ingo Molnar wrote:
> another, locking improvement is possible as well:
> - the idtag spinlock should be eliminated, we can reuse the tasklist lock
> for it - in the exit and fork path we hold it already. This also means
> we can walk an ID list by read-locking the tasklist lock.
> the idtag spinlock is already superfluous i think, because the idtag task
> list is only safely walked if we read-lock the task list. So it's not like
> anyone could hash in a new idtag while we walk the list.
> What do you think?
ISTR the idtag_lock was for cases where the hashtable was modified
while the tasklist_lock was only held for reading. Basically, once
those are resolved, the idtag_lock goes away.
Cheers,
Bill
next prev parent reply other threads:[~2002-09-18 14:28 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 [this message]
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
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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