Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754666Ab0G1OVf (ORCPT ); Wed, 28 Jul 2010 10:21:35 -0400 Received: from sh.osrg.net ([192.16.179.4]:59656 "EHLO sh.osrg.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752309Ab0G1OVc (ORCPT ); Wed, 28 Jul 2010 10:21:32 -0400 Date: Wed, 28 Jul 2010 23:20:59 +0900 To: andi@firstfloor.org Cc: fujita.tomonori@lab.ntt.co.jp, ak@linux.intel.com, konrad.wilk@oracle.com, akataria@vmware.com, lenb@kernel.org, x86@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, petr@vmware.com Subject: Re: swiotlb detection should be memory hotplug aware ? From: FUJITA Tomonori In-Reply-To: <8739v3kgl6.fsf@basil.nowhere.org> References: <4C49B3F5.3030904@linux.intel.com> <20100728190939D.fujita.tomonori@lab.ntt.co.jp> <8739v3kgl6.fsf@basil.nowhere.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20100728232026V.fujita.tomonori@lab.ntt.co.jp> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (sh.osrg.net [192.16.179.4]); Wed, 28 Jul 2010 23:21:01 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1392 Lines: 35 On Wed, 28 Jul 2010 13:09:57 +0200 Andi Kleen wrote: > FUJITA Tomonori writes: > > > >> The other problem is that using only two bits for the needed address > >> space is also extremly > >> inefficient (4GB and 16MB on x86). Really want masks everywhere and > >> optimize for the > >> actual requirements. > > > > swiotlb doesn't allocate GFP_DMA memory. It handles only GFP_DMA32. > > I was lumping GFP_DMA and swiotlb together here. The > pci_alloc_consistent() function uses both interchangedly. > They really effectively are the same thing these days > and just separated by historical accident. Sorry, I meant to ZONE_DMA. You are talking about your dma mask allocation patchset, right? I meant that swiotlb doesn't need to handle ZONE_DMA. It handles only devices that can handle ZONE_DMA32. > > I have a half-baked patch for it. I'll send it later. > > The problem are still the *_map users which usually cannot sleep, > and then it's difficult to grow. Why we can't use GFP_NOWAIT? My approach is starting with small (like 4MB) and increasing io_tbl by chunk such as 4MB. -- 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/