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From: Ingo Molnar <mingo@elte.hu>
To: Ricky Beam <jfbeam@bluetronic.net>
Cc: Linux Kernel Mail List <linux-kernel@vger.kernel.org>
Subject: Re: [patch] remove the BKL (Big Kernel Lock), this time for real
Date: Wed, 15 Sep 2004 21:39:11 +0200	[thread overview]
Message-ID: <20040915193911.GA17052@elte.hu> (raw)
In-Reply-To: <Pine.GSO.4.33.0409151300280.10693-100000@sweetums.bluetronic.net>


* Ricky Beam <jfbeam@bluetronic.net> wrote:

> On Wed, 15 Sep 2004, Ingo Molnar wrote:
> >yes, but progress in this area seems to have slowed down, and people are
> >hurting from the latencies introduced by the BKL meanwhile. Who cares if
> >some rare big chunk of code runs under a semaphore, as long as it's
> >preemptable?
> 
> "as long as it's preemptable" is the key there.  Not all arch's can
> run with PREEMPT enabled (yet) -- sparc/sparc64 for but one.  And at
> the moment, PREEMPT is a bit on the hosed side.

there's no problem at all - with my patch you'll still get the other
advantage:

- there is no time wasted spinning on the BKL if there's BKL contention

so if a platform doesnt support PREEMPT (or a user doesnt enable it)
then BKS-holding kernel code wont be preempted of course.

	Ingo

  reply	other threads:[~2004-09-15 19:38 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-15 15:18 [patch] remove the BKL (Big Kernel Lock), this time for real Ingo Molnar
2004-09-15 15:40 ` Linus Torvalds
2004-09-15 15:55   ` Ingo Molnar
2004-09-15 17:04     ` Ricky Beam
2004-09-15 19:39       ` Ingo Molnar [this message]
2004-09-15 18:28     ` Chris Wedgwood
2004-09-15 21:25   ` William Lee Irwin III
2004-09-17 10:39 ` Ingo Molnar
2004-09-17 12:53   ` Ingo Molnar
2004-09-17 20:56     ` Andrea Arcangeli
2004-09-18  8:02       ` Ingo Molnar
2004-09-18 23:36         ` Andrea Arcangeli
2004-09-17 13:26   ` Andrea Arcangeli
2004-09-17 13:47     ` William Lee Irwin III
2004-09-17 13:56       ` Andrea Arcangeli
2004-09-17 14:18         ` William Lee Irwin III
2004-09-17 15:16   ` Linus Torvalds
     [not found] <2EJTp-7bx-1@gated-at.bofh.it>
2004-09-15 15:46 ` Andi Kleen
2004-09-15 15:58   ` Ingo Molnar
2004-09-15 20:11   ` Ingo Molnar
2004-09-16  1:17     ` Nick Piggin
2004-09-16 14:28   ` Bill Davidsen
2004-09-16 22:29     ` Bill Huey
2004-09-16 22:40       ` David S. Miller
2004-09-16 22:51         ` Bill Huey
2004-09-16 22:54           ` David S. Miller
2004-09-16 23:01             ` Bill Huey
2004-09-16 23:33             ` William Lee Irwin III
2004-09-17  6:43           ` Ingo Molnar
2004-09-17  7:21             ` Tony Lee
  -- strict thread matches above, loose matches on Subject: below --
2004-09-18  5:44 Manfred Spraul
2004-09-18 13:09 ` Ingo Molnar

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