Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 6 Feb 2001 15:28:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 6 Feb 2001 15:28:04 -0500 Received: from ns.caldera.de ([212.34.180.1]:45325 "EHLO ns.caldera.de") by vger.kernel.org with ESMTP id ; Tue, 6 Feb 2001 15:27:48 -0500 Date: Tue, 6 Feb 2001 21:25:03 +0100 From: Christoph Hellwig To: Linus Torvalds Cc: Ben LaHaise , Ingo Molnar , "Stephen C. Tweedie" , Alan Cox , Manfred Spraul , Steve Lord , Linux Kernel List , kiobuf-io-devel@lists.sourceforge.net, Ingo Molnar Subject: Re: [Kiobuf-io-devel] RFC: Kernel mechanism: Compound event wait Message-ID: <20010206212503.A5426@caldera.de> Mail-Followup-To: Linus Torvalds , Ben LaHaise , Ingo Molnar , "Stephen C. Tweedie" , Alan Cox , Manfred Spraul , Steve Lord , Linux Kernel List , kiobuf-io-devel@lists.sourceforge.net, Ingo Molnar In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: ; from torvalds@transmeta.com on Tue, Feb 06, 2001 at 11:32:43AM -0800 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 06, 2001 at 11:32:43AM -0800, Linus Torvalds wrote: > Traditionally, a "bh" is only _used_ for small areas, but that's not a > "bh" issue, that's a memory management issue. The code should pretty much > handle the issue of a single 64kB bh pretty much as-is, but nothing > creates them: the VM layer only creates bh's in sizes ranging from 512 > bytes to a single page. > > The IO layer could do more, but there has yet to be anybody who needed > more (becase once you hit a page-size, you tend to get into > scatter-gather, so you want to have one bh per area - and let the > low-level IO level handle the actual merging etc). Yes. That's one disadvantage blown away. The second is that bh's are two things: - a cacheing object - an io buffer This is not really an clean appropeach, and I would really like to get away from it. Christoph -- Whip me. Beat me. Make me maintain AIX. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/