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From: Dave Jones <davej@redhat.com>
To: Lee Revell <rlrevell@joe-job.com>
Cc: Jeff Garzik <jgarzik@pobox.com>,
	Ricky Beam <jfbeam@bluetronic.net>,
	Zilvinas Valinskas <zilvinas@gemtek.lt>,
	Erik Tews <erik@debian.franken.de>,
	linux-kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.9 rc2 freezing
Date: Wed, 15 Sep 2004 17:59:33 +0100	[thread overview]
Message-ID: <20040915165933.GD24892@redhat.com> (raw)
In-Reply-To: <1095264408.2406.148.camel@krustophenia.net>

On Wed, Sep 15, 2004 at 12:06:48PM -0400, Lee Revell wrote:

 > Anyway, if you are running anything on your server that breaks under
 > PREEMPT, it will break anyway as soon as you add another processor.

Wrong. Code can be SMP safe but not preempt safe.
This is why we have get_cpu()/put_cpu(), and
preempt_disable()/preempt_enable() pairs around certain parts of code.

Anything using per-CPU data like MSRs for example needs explicit
protection against preemption.

		Dave


  parent reply	other threads:[~2004-09-15 17:06 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-13 16:55 2.6.9 rc2 freezing Zilvinas Valinskas
2004-09-13 17:12 ` Jeff Garzik
2004-09-13 17:16   ` Zilvinas Valinskas
2004-09-15  8:25     ` Erik Tews
2004-09-15  9:58       ` Zilvinas Valinskas
2004-09-15 14:55         ` Ricky Beam
2004-09-15 15:48           ` Lee Revell
2004-09-15 15:58             ` Jeff Garzik
2004-09-15 16:06               ` Lee Revell
2004-09-15 16:11                 ` Jeff Garzik
2004-09-15 16:58                   ` Ricky Beam
2004-09-15 17:49                     ` Lee Revell
2004-09-15 17:52                       ` Jeff Garzik
2004-09-15 17:59                         ` Lee Revell
2004-09-16  8:39                         ` Helge Hafting
2004-09-17  8:05                           ` Zilvinas Valinskas
2004-09-17 13:21                             ` Zilvinas Valinskas
2004-09-15 16:59                 ` Dave Jones [this message]
2004-09-13 17:19   ` Zilvinas Valinskas

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