Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756166AbYLERcT (ORCPT ); Fri, 5 Dec 2008 12:32:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752523AbYLERcJ (ORCPT ); Fri, 5 Dec 2008 12:32:09 -0500 Received: from qw-out-2122.google.com ([74.125.92.27]:11110 "EHLO qw-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751382AbYLERcG (ORCPT ); Fri, 5 Dec 2008 12:32:06 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references:x-google-sender-auth; b=kWU+oTF2vPFSc8BmwUihtaHxCjUwnUC4+LYFh6kNGysbsg64kBi+9+Q1b27NRhjIFs dX3xgKdO3zIOOuD7Zz4OFAlZnSjgaSg9RoyTYUTqhltPgOExsihcqFQV8pSmHbEu64li ZXTgqbKTb75+JgNxltfi1FIkFsqXXBYmc/q58= Message-ID: <119aab440812050932h9173a4bm79273b7ea8fe9a3a@mail.gmail.com> Date: Fri, 5 Dec 2008 12:32:04 -0500 From: "Carlos O'Donell" To: "Dave Airlie" Subject: Re: IO space memcpy support for userspace. Cc: "linux-kernel@vger.kernel.org" , libc-alpha@sources.redhat.com In-Reply-To: <21d7e9970812041940h29994c60w3e7bcf20b96efe04@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <21d7e9970812041940h29994c60w3e7bcf20b96efe04@mail.gmail.com> X-Google-Sender-Auth: cd1df5cae69b2c8f Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 954 Lines: 24 On Thu, Dec 4, 2008 at 10:40 PM, Dave Airlie wrote: > I'm sure this has come up before and I'm sure I'll either wish I never > posted this or someone will show me the crisp corpse of the last guy > who suggested it. Do you plan to prevent the compiler from issuing the same sorts of instructions that might appear in an optimized memcpy? Isn't it dangerous to have memory that doesn't behave like normal memory, and yet try to treat it like normal memory? This mismatch of abstractions is a warning that must not be ignored. IMHO you need a thin library with a new API (adding support for HAL would be a clever way to check for PCI devices and perhaps even mappings). Cheers, Carlos. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/