Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755392AbYHTSrq (ORCPT ); Wed, 20 Aug 2008 14:47:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752818AbYHTSri (ORCPT ); Wed, 20 Aug 2008 14:47:38 -0400 Received: from gw.goop.org ([64.81.55.164]:35765 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751020AbYHTSrh (ORCPT ); Wed, 20 Aug 2008 14:47:37 -0400 Message-ID: <48AC66C6.1080406@goop.org> Date: Wed, 20 Aug 2008 11:47:34 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.16 (X11/20080723) MIME-Version: 1.0 To: Jaya Kumar CC: Andrew Morton , Ian Campbell , Linus Torvalds , Linux Kernel Mailing List , stable@vger.kernel.org, Nick Piggin , Peter Zijlstra , Hugh Dickins , Johannes Weiner , Kel Modderman , Markus Armbruster Subject: Re: [PATCH] fbdefio: add set_page_dirty handler to deferred IO FB References: <1219125765-31833-1-git-send-email-ijc@hellion.org.uk> <20080818233824.5d219105.akpm@linux-foundation.org> <45a44e480808200146m1167b8e6o74d68324ad138dc5@mail.gmail.com> In-Reply-To: <45a44e480808200146m1167b8e6o74d68324ad138dc5@mail.gmail.com> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1024 Lines: 22 Jaya Kumar wrote: > I hope I have understood your question. You are right that PG_dirty > isn't used directly in defio. The defio portion does use each > page_mkwrite callback to build a list of the pages of the framebuffer > that were written to and then passes that list to pvfb (in this case). > pvfb then optimizes writeback by interpreting that list according to > its framebuffer and sending it to its actual destination. I think > Markus's code in xenfb_deferred_io() and xenfb_send* is doing the > latter. > The original Xen-specific implementation of this did use PG_dirty, which has the nice property of using the hardware feature without invoking any pagefaults. It would be nice if defio could be extended to allow this on platforms where it makes sense. J -- 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/