Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262360AbVBLAYl (ORCPT ); Fri, 11 Feb 2005 19:24:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262366AbVBLAYl (ORCPT ); Fri, 11 Feb 2005 19:24:41 -0500 Received: from waste.org ([216.27.176.166]:12489 "EHLO waste.org") by vger.kernel.org with ESMTP id S262360AbVBLAYf (ORCPT ); Fri, 11 Feb 2005 19:24:35 -0500 Date: Fri, 11 Feb 2005 16:24:02 -0800 From: Matt Mackall To: Fruhwirth Clemens Cc: Andrew Morton , James Morris , linux-kernel@vger.kernel.org, michal@logix.cz, davem@davemloft.net, adam@yggdrasil.com Subject: Re: [PATCH 01/04] Adding cipher mode context information to crypto_tfm Message-ID: <20050212002402.GD2474@waste.org> References: <1107997358.7645.24.camel@ghanima> <20050209171943.05e9816e.akpm@osdl.org> <1108028923.14335.44.camel@ghanima> <20050210023344.390fb358.akpm@osdl.org> <1108034244.14335.59.camel@ghanima> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1108034244.14335.59.camel@ghanima> User-Agent: Mutt/1.5.6+20040907i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1377 Lines: 33 On Thu, Feb 10, 2005 at 12:17:24PM +0100, Fruhwirth Clemens wrote: > On Thu, 2005-02-10 at 02:33 -0800, Andrew Morton wrote: > > Fruhwirth Clemens wrote: > > > > > > On Wed, 2005-02-09 at 17:19 -0800, Andrew Morton wrote: > > > > Fruhwirth Clemens wrote: > > > > Adding a few more fixmap slots wouldn't hurt anyone. But if you want an > > > > arbitrarily large number of them then no, we cannot do that. > > > > > > What magnitude is "few more"? 2, 10, 100? > > > > Not 100. 10 would seem excessive. > > Out of curiosity: Where does this limitation even come from? What > prevents kmap_atomic from adding slots dynamically? There's a single page of PTEs for mapping high memory and the atomic slots are a small subset of that. They're fixed in number for complexity reasons - we don't want to have an allocator here: /* * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because * no global lock is needed and because the kmap code must perform a global TLB * invalidation when the kmap pool wraps. * -- Mathematics is the supreme nostalgia of our time. - 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/