Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761707AbXHaVnz (ORCPT ); Fri, 31 Aug 2007 17:43:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757185AbXHaVne (ORCPT ); Fri, 31 Aug 2007 17:43:34 -0400 Received: from mx1.redhat.com ([66.187.233.31]:37832 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756717AbXHaVnc (ORCPT ); Fri, 31 Aug 2007 17:43:32 -0400 Date: Fri, 31 Aug 2007 22:41:37 +0100 From: Alasdair G Kergon To: Daniel Phillips Cc: Evgeniy Polyakov , Jens Axboe , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Peter Zijlstra , Neil Brown Subject: Re: [1/1] Block device throttling [Re: Distributed storage.] Message-ID: <20070831214137.GD30122@agk.fab.redhat.com> Mail-Followup-To: Daniel Phillips , Evgeniy Polyakov , Jens Axboe , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Peter Zijlstra , Neil Brown References: <20070731171347.GA14267@2ka.mipt.ru> <200708281408.06618.phillips@phunq.net> <20070829085331.GA16607@2ka.mipt.ru> <200708301620.37965.phillips@phunq.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200708301620.37965.phillips@phunq.net> User-Agent: Mutt/1.4.1i Organization: Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 762 Lines: 18 On Thu, Aug 30, 2007 at 04:20:35PM -0700, Daniel Phillips wrote: > Resubmitting a bio or submitting a dependent bio from > inside a block driver does not need to be throttled because all > resources required to guarantee completion must have been obtained > _before_ the bio was allowed to proceed into the block layer. I'm toying with the idea of keeping track of the maximum device stack depth for each stacked device, and only permitting it to increase in controlled circumstances. Alasdair -- agk@redhat.com - 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/