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Date: Fri, 15 Mar 2002 00:51:55 -0800 (PST)
Message-Id: <20020315.005155.93361168.davem@redhat.com>
To: ian@ianduggan.net
Cc: alan@lxorguk.ukuu.org.uk, rml@tech9.net, linux-kernel@vger.kernel.org
Subject: Re: 2.4.18 Preempt Freezeups
From: "David S. Miller" <davem@redhat.com>
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   From: Ian Duggan <ian@ianduggan.net>
   Date: Fri, 15 Mar 2002 00:38:37 -0800
   
   What is required for preempt beyond "SMP safe" code? I thought the whole
   idea was to make the preemptions transparent to other code by utilizing
   the SMP critical regions?

Pre-empt makes things like per-cpu data structures require
preemption disables around cpu-local critical regions.

Code that works before just because it knows the data structure is
only even accessed by the current cpu doesn't work because preemption
can cause a context switch at any time.
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