Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030299AbXAaUFS (ORCPT ); Wed, 31 Jan 2007 15:05:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030211AbXAaUFR (ORCPT ); Wed, 31 Jan 2007 15:05:17 -0500 Received: from kanga.kvack.org ([66.96.29.28]:49277 "EHLO kanga.kvack.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030299AbXAaUFP (ORCPT ); Wed, 31 Jan 2007 15:05:15 -0500 Date: Wed, 31 Jan 2007 15:05:02 -0500 From: Benjamin LaHaise To: Zach Brown Cc: Benjamin Herrenschmidt , linux-kernel@vger.kernel.org, linux-aio@kvack.org, Suparna Bhattacharya , Linus Torvalds Subject: Re: [PATCH 0 of 4] Generic AIO by scheduling stacks Message-ID: <20070131200502.GO1344@kvack.org> References: <1170209044.26655.364.camel@localhost.localdomain> <6CDD5D9D-E031-499D-9A8A-5A8522C66D37@oracle.com> <20070131175118.GN1344@kvack.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1166 Lines: 28 On Wed, Jan 31, 2007 at 11:25:30AM -0800, Zach Brown wrote: > >without linking it into the system lists. The reason I don't think > >this > >approach works (and I looked at it a few times) is that many things > >end > >up requiring special handling: things like permissions, signals, > >FPU state, > >segment registers.... > > Can you share a specific example of the special handling required? Take FPU state: memory copies and RAID xor functions use MMX/SSE and require that the full task state be saved and restored. Task priority is another. POSIX AIO lets you specify request priority, and it really is needed for realtime workloads where things like keepalive must be processed at a higher priority. This is especially important on embedded systems which don't have a surplus of CPU cycles. -ben -- "Time is of no importance, Mr. President, only life is important." Don't Email: . - 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/