From mboxrd@z Thu Jan  1 00:00:00 1970
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Subject: Re: performance: memcpy vs. __copy_tofrom_user
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Scott Wood <scottwood@freescale.com>
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Date: Tue, 14 Oct 2008 07:50:27 +1100
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Cc: Dominik Bozek <domino@mikroswiat.pl>, linuxppc-embedded@ozlabs.org,
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> It doesn't need to be done in non-preemptible sections, if you have a
> separate per-thread save area for kernel fp/altivec use (and appropriate
> flags so an FP unavailable handler knows which regs to restore), and you
> can avoid using it in a preempting context.

Yuck.

Ben.