Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755177AbXHaHL5 (ORCPT ); Fri, 31 Aug 2007 03:11:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752109AbXHaHLq (ORCPT ); Fri, 31 Aug 2007 03:11:46 -0400 Received: from brick.kernel.dk ([87.55.233.238]:5851 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751765AbXHaHLp (ORCPT ); Fri, 31 Aug 2007 03:11:45 -0400 Date: Fri, 31 Aug 2007 09:11:43 +0200 From: Jens Axboe To: Christoph Lameter Cc: Dmitry Monakhov , torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , Mel Gorman , William Lee Irwin III , David Chinner , Badari Pulavarty , Maxim Levitsky , Fengguang Wu , swin wang , totty.lu@gmail.com, "H. Peter Anvin" , joern@lazybastard.org, "Eric W. Biederman" Subject: Re: [11/36] Use page_cache_xxx in fs/buffer.c Message-ID: <20070831071142.GI29452@kernel.dk> References: <20070828190551.415127746@sgi.com> <20070828190730.220393749@sgi.com> <20070830092038.GD22586@dnb.sw.ru> <20070831065613.GH29452@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 924 Lines: 26 On Fri, Aug 31 2007, Christoph Lameter wrote: > On Fri, 31 Aug 2007, Jens Axboe wrote: > > > > So if we try to push a too large buffer down with submit_bh() we get a > > > failure. > > > > Only partly, you may be violating a number of other restrictions (size > > is many things, not just length of the data). > > Could you be more specific? Size of a single segment, for instance. Or if the bio crosses a dma boundary. If your block is 64kb and the maximum segment size is 32kb, then you would need to clone the bio and split it into two. Things like that. This isn't a problem with single page requests, as we based the lower possible boundaries on that. -- Jens Axboe - 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/