Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266663AbUJFBkU (ORCPT ); Tue, 5 Oct 2004 21:40:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266674AbUJFBkU (ORCPT ); Tue, 5 Oct 2004 21:40:20 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:53123 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S266663AbUJFBkQ (ORCPT ); Tue, 5 Oct 2004 21:40:16 -0400 Message-ID: <41634CF3.5040807@pobox.com> Date: Tue, 05 Oct 2004 21:40:03 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20040922 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Nick Piggin CC: Roland Dreier , linux-kernel@vger.kernel.org Subject: Re: Preempt? (was Re: Cannot enable DMA on SATA drive (SCSI-libsata, VIA SATA)) References: <4136E4660006E2F7@mail-7.tiscali.it> <41634236.1020602@pobox.com> <52is9or78f.fsf_-_@topspin.com> <4163465F.6070309@pobox.com> <41634A34.20500@yahoo.com.au> In-Reply-To: <41634A34.20500@yahoo.com.au> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 720 Lines: 22 Nick Piggin wrote: > When you say low latency, you mean small lock hold times, *and* > cond_rescheds placed everywhere - it is this second requirement > that isn't the cleanest way of doign things. > > With preempt, sure you still need small lock hold times. No big > deal. And with preempt you're still hiding stuff that needs fixing. And when it gets fixed, you don't need preempt. Therefore, preempt is just a hack that hides stuff that wants fixing anyway. Jeff - 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/