From: Jeremy Fitzhardinge Subject: Re: [PATCH 03 of 38] swiotlb: allow architectures tooverride swiotlb pool allocation Date: Fri, 14 Nov 2008 11:33:14 -0800 Message-ID: <491DD27A.30707@goop.org> References: <491D4C89.76E4.0078.0@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <491D4C89.76E4.0078.0@novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Xen-devel , the arch/x86 maintainers , Ian Campbell List-Id: xen-devel@lists.xenproject.org Jan Beulich wrote: > Not directly related to this patch alone, but to the combined set of changes > to swiotlb: I don't see any handling of CONFIG_HIGHMEM here (or at least > a note that this a known limitation needing work). I mention this because > this was the largest part of the changes I had posted long ago to make > lib/swiotlb.c Xen-ready, and which got rejected due to their ugliness. > Was that Andi's objection on the grounds that he didn't think that Xen should need swiotlb at all? I have to admit I didn't follow that thread very closely (or threads, as I seem to remember). Do you have a pointer to the pertinent bits? > While perhaps less intrusive to take care of, I also didn't see an equivalent > of the range_straddles_page_boundary() logic, without which I can't see > how this would work in the common case. > Could you be more specific? The swiotlb allocation should be machine contiguous and so there's no stradding required, but I think I'm missing your point. J