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From: Ingo Molnar <mingo@elte.hu>
To: Jens Maurer <Jens.Maurer@gmx.net>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@osdl.org>,
	Arjan van de Ven <arjanv@redhat.com>
Subject: Re: [PATCH] Use x86 SSE instructions for clear_page, copy_page
Date: Wed, 18 Aug 2004 09:00:13 +0200	[thread overview]
Message-ID: <20040818070013.GA11048@elte.hu> (raw)
In-Reply-To: <4121A211.8080902@gmx.net>


* Jens Maurer <Jens.Maurer@gmx.net> wrote:

> The attached patch (against kernel 2.6.8.1) enables using SSE
> instructions for copy_page and clear_page.

besides the cache arguments Arjan raised, you are also corrupting SSE
registers big way. You are saving/clearing/restoring the TS but that's
not enough - what if e.g. a pagefault happened while userspace code
executed SSE code? You are corrupting those registers.

check out raid6_before_sse()/raid6_after_sse() how to write proper SSE
code for the kernel.

	Ingo

  parent reply	other threads:[~2004-08-18  6:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-08-17  6:13 [PATCH] Use x86 SSE instructions for clear_page, copy_page Jens Maurer
2004-08-17  7:27 ` Arjan van de Ven
2004-08-17  8:10   ` Andrey Panin
2004-08-17  8:11     ` Arjan van de Ven
2004-08-17 22:40   ` Jens Maurer
2004-08-18  2:33     ` David S. Miller
2004-08-22 20:49       ` Jens Maurer
2004-08-18  7:00 ` Ingo Molnar [this message]
2004-08-18  7:11   ` Ingo Molnar

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