From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754098Ab1HHOmE (ORCPT ); Mon, 8 Aug 2011 10:42:04 -0400 Received: from merlin.infradead.org ([205.233.59.134]:38715 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753981Ab1HHOmC convert rfc822-to-8bit (ORCPT ); Mon, 8 Aug 2011 10:42:02 -0400 Subject: Re: [PATCH 2/5] writeback: dirty position control From: Peter Zijlstra To: Wu Fengguang Cc: "linux-fsdevel@vger.kernel.org" , Andrew Morton , Jan Kara , Christoph Hellwig , Dave Chinner , Greg Thelen , Minchan Kim , Vivek Goyal , Andrea Righi , linux-mm , LKML Date: Mon, 08 Aug 2011 16:41:41 +0200 In-Reply-To: <20110808141128.GA22080@localhost> References: <20110806084447.388624428@intel.com> <20110806094526.733282037@intel.com> <1312811193.10488.33.camel@twins> <20110808141128.GA22080@localhost> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.0.2- Message-ID: <1312814501.10488.41.camel@twins> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2011-08-08 at 22:11 +0800, Wu Fengguang wrote: > @@ -538,11 +538,6 @@ static unsigned long bdi_position_ratio( > goal = thresh - thresh / DIRTY_SCOPE; > origin = 4 * thresh; > > - if (unlikely(origin < limit && dirty > (goal + origin) / 2)) { > - origin = limit; /* auxiliary control line */ > - goal = (goal + origin) / 2; > - pos_ratio >>= 1; > - } > pos_ratio = origin - dirty; > pos_ratio <<= BANDWIDTH_CALC_SHIFT; > do_div(pos_ratio, origin - goal + 1); So basically, pos_ratio = (4t - d) / (25/8)t, which if I'm not mistaken comes out at 32/25 - 8d/25t. Which simply doesn't make sense at all. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 2/5] writeback: dirty position control Date: Mon, 08 Aug 2011 16:41:41 +0200 Message-ID: <1312814501.10488.41.camel@twins> References: <20110806084447.388624428@intel.com> <20110806094526.733282037@intel.com> <1312811193.10488.33.camel@twins> <20110808141128.GA22080@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Cc: "linux-fsdevel@vger.kernel.org" , Andrew Morton , Jan Kara , Christoph Hellwig , Dave Chinner , Greg Thelen , Minchan Kim , Vivek Goyal , Andrea Righi , linux-mm , LKML To: Wu Fengguang Return-path: In-Reply-To: <20110808141128.GA22080@localhost> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Mon, 2011-08-08 at 22:11 +0800, Wu Fengguang wrote: > @@ -538,11 +538,6 @@ static unsigned long bdi_position_ratio( > goal =3D thresh - thresh / DIRTY_SCOPE; > origin =3D 4 * thresh; > =20 > - if (unlikely(origin < limit && dirty > (goal + origin) / 2)) { > - origin =3D limit; /* auxiliary control li= ne */ > - goal =3D (goal + origin) / 2; > - pos_ratio >>=3D 1; > - } > pos_ratio =3D origin - dirty; > pos_ratio <<=3D BANDWIDTH_CALC_SHIFT; > do_div(pos_ratio, origin - goal + 1);=20 So basically, pos_ratio =3D (4t - d) / (25/8)t, which if I'm not mistaken comes out at 32/25 - 8d/25t. Which simply doesn't make sense at all.=20 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id C64236B0169 for ; Mon, 8 Aug 2011 10:42:00 -0400 (EDT) Subject: Re: [PATCH 2/5] writeback: dirty position control From: Peter Zijlstra Date: Mon, 08 Aug 2011 16:41:41 +0200 In-Reply-To: <20110808141128.GA22080@localhost> References: <20110806084447.388624428@intel.com> <20110806094526.733282037@intel.com> <1312811193.10488.33.camel@twins> <20110808141128.GA22080@localhost> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Message-ID: <1312814501.10488.41.camel@twins> Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Wu Fengguang Cc: "linux-fsdevel@vger.kernel.org" , Andrew Morton , Jan Kara , Christoph Hellwig , Dave Chinner , Greg Thelen , Minchan Kim , Vivek Goyal , Andrea Righi , linux-mm , LKML On Mon, 2011-08-08 at 22:11 +0800, Wu Fengguang wrote: > @@ -538,11 +538,6 @@ static unsigned long bdi_position_ratio( > goal =3D thresh - thresh / DIRTY_SCOPE; > origin =3D 4 * thresh; > =20 > - if (unlikely(origin < limit && dirty > (goal + origin) / 2)) { > - origin =3D limit; /* auxiliary control li= ne */ > - goal =3D (goal + origin) / 2; > - pos_ratio >>=3D 1; > - } > pos_ratio =3D origin - dirty; > pos_ratio <<=3D BANDWIDTH_CALC_SHIFT; > do_div(pos_ratio, origin - goal + 1);=20 So basically, pos_ratio =3D (4t - d) / (25/8)t, which if I'm not mistaken comes out at 32/25 - 8d/25t. Which simply doesn't make sense at all.=20 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org