From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1165502AbdEYUJD (ORCPT ); Thu, 25 May 2017 16:09:03 -0400 Received: from www.llwyncelyn.cymru ([82.70.14.225]:35544 "EHLO fuzix.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764107AbdEYUI7 (ORCPT ); Thu, 25 May 2017 16:08:59 -0400 Date: Thu, 25 May 2017 21:08:55 +0100 From: Alan Cox To: Pavel Machek Cc: Kevin McKinney , linux-kernel@vger.kernel.org Subject: Re: Change PAGE_SIZE from minimum 4k to 12k Message-ID: <20170525210855.3ca03356@alans-desktop> In-Reply-To: <20170525170526.GD3085@amd> References: <20170525170526.GD3085@amd> Organization: Intel Corporation X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 25 May 2017 19:05:26 +0200 Pavel Machek wrote: > On Tue 2017-05-16 11:27:08, Kevin McKinney wrote: > > Hi Everyone, > > > > Would it be possible to have a custom block device driver read/write > > in increments of 12k instead of reading/writing data in 4k increments? > > In other words, I would like to change the default page size on a > > x86_64 platform (4.4.0 kernel) from 4k to 12k as the minimum page > > size? I understand I may have negative performance due to > > fragmentation. Any help would be appreciated. > > > > If this is the wrong mailing list, please let me know the right one to use. > > I won't say "no" but ammount of work neccessary is likely measured in > man-years. Plus, hardware page size _is_ 4KB. Or a few other much larger sizes. Not that it actually matters. You can implement a larger software page size for a platform but it would still neeed to be a power of two, and you'd have trouble running some existing binaries for x86. What problem are you *actually* trying to solve ? Alan