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Subject: Re: irq-disabled vs vmap vs text_poke
From: Peter Zijlstra <peterz@infradead.org>
To: Nick Piggin <npiggin@suse.de>
Cc: Masami Hiramatsu <mhiramat@redhat.com>,
       Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
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       linux-kernel <linux-kernel@vger.kernel.org>,
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       Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
       Jim Keniston <jkenisto@us.ibm.com>
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Date: Tue, 17 Feb 2009 09:31:56 +0100
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On Tue, 2009-02-17 at 04:03 +0100, Nick Piggin wrote:

> It is not a bad idea, but I don't think it quite goes far enough.
> IMO we should reserve 2 pages of virtual memory for each CPU, and
> then do the mapping/unmapping without locking, and with another
> variant of unmap_kernel_range that does not do the global TLB
> flush.

A bit like kmap_atomic() except for 2 pages and !highmem. Should work.