From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 09 Feb 2005 18:11:04 +0000 (GMT) Received: from p3EE07C4A.dip.t-dialin.net ([IPv6:::ffff:62.224.124.74]:285 "EHLO mail.linux-mips.net") by linux-mips.org with ESMTP id ; Wed, 9 Feb 2005 18:10:45 +0000 Received: from fluff.linux-mips.net (localhost.localdomain [127.0.0.1]) by mail.linux-mips.net (8.13.1/8.13.1) with ESMTP id j19IAinD005862; Wed, 9 Feb 2005 19:10:44 +0100 Received: (from ralf@localhost) by fluff.linux-mips.net (8.13.1/8.13.1/Submit) id j19IAiW8005861; Wed, 9 Feb 2005 19:10:44 +0100 Date: Wed, 9 Feb 2005 19:10:44 +0100 From: Ralf Baechle To: Atsushi Nemoto Cc: linux-mips@linux-mips.org Subject: Re: copy_from_user_page/copy_to_user_page fix Message-ID: <20050209181044.GA5740@linux-mips.org> References: <20050209.184947.30439119.nemoto@toshiba-tops.co.jp> <20050209125105.GA27875@linux-mips.org> <20050209.225256.92587183.anemo@mba.ocn.ne.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050209.225256.92587183.anemo@mba.ocn.ne.jp> User-Agent: Mutt/1.4.1i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 7216 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Wed, Feb 09, 2005 at 10:52:56PM +0900, Atsushi Nemoto wrote: > ralf> I'm going to apply this because it's a correct fix; the > ralf> temporary mapping strategy as we've discussed for the dup_mmap > ralf> problem would be preferable. > > Thank you. I agree that the temporary mapping will be more efficient > though I chose a simple fix. I suppose a performance requirement for > ptrace() would be less than the dup_mmap (fork()). People have come up with creative abuses for ptrace which actually make it a performance critical path. Especially UML should be mentioned in this cathegory. And we're talkign about a few thousand cycles differences per ptrace invocation. Ralf