From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pogo.mtv1.steeleye.com (host194.steeleye.com [66.206.164.34]) by dsl2.external.hp.com (Postfix) with ESMTP id F1DA84829 for ; Sat, 9 Nov 2002 19:01:46 -0700 (MST) Received: (from root@localhost) by pogo.mtv1.steeleye.com (8.9.3/8.9.3) id SAA21845 for ; Sat, 9 Nov 2002 18:01:37 -0800 Received: from mulgrave (jejb@localhost) by localhost.localdomain (8.11.6/linuxconf) with ESMTP id gAA21Uv04824; Sat, 9 Nov 2002 21:01:30 -0500 Message-Id: <200211100201.gAA21Uv04824@localhost.localdomain> To: "Adam J. Richter" Cc: James.Bottomley@SteelEye.com, andmike@us.ibm.com, greg@kroah.com, hch@lst.de, linux-kernel@vger.kernel.org, mochel@osdl.org, parisc-linux@lists.parisc-linux.org, willy@debian.org Subject: Re: [parisc-linux] Untested port of parisc_device to generic device interface In-Reply-To: Message from "Adam J. Richter" of "Sat, 09 Nov 2002 16:23:59 PST." <200211100023.QAA27139@baldur.yggdrasil.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sat, 09 Nov 2002 21:01:29 -0500 From: "J.E.J. Bottomley" Sender: parisc-linux-admin@lists.parisc-linux.org Errors-To: parisc-linux-admin@lists.parisc-linux.org List-Help: List-Post: List-Subscribe: , List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: adam@yggdrasil.com said: > > I'd like to know more about what these machines look like in the real > world. Specifically, I am interested in the trade-off of having a > parameter to wback_fake_consistent so that it could be enabled or > disabled on an individual basis. Actually, so would I. I can suspect why there might exist machines like this (say the consistent attribute is settable at the pgd level) > I suspect that the parameter is not worth the clutter because these > "partially consistent" machines either have a large amount of > consistent memory, so the case of the allocation failing in the is not > worth supporting, or it is easy to check for consistent memory on them > with something like "if ((unsigned long) vaddr < 0xwhatever)", but I'm > just guessing. Well, if it has to be done, it can be done by making alloc_consistent return a handle rather than an address and making wback/invalidate take the handle (but it's certainly not ideal). James