From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031566Ab0B1IQL (ORCPT ); Sun, 28 Feb 2010 03:16:11 -0500 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:36234 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031512Ab0B1IQK (ORCPT ); Sun, 28 Feb 2010 03:16:10 -0500 Date: Sun, 28 Feb 2010 00:16:28 -0800 (PST) Message-Id: <20100228.001628.48507956.davem@davemloft.net> To: fujita.tomonori@lab.ntt.co.jp Cc: hancockrwd@gmail.com, bzolnier@gmail.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org Subject: Re: [RFC PATCH] fix problems with NETIF_F_HIGHDMA in networking drivers From: David Miller In-Reply-To: <20100228033706G.fujita.tomonori@lab.ntt.co.jp> References: <20100227.040502.182574085.davem@davemloft.net> <51f3faa71002271015i7c9ec45j18381b1269bfd799@mail.gmail.com> <20100228033706G.fujita.tomonori@lab.ntt.co.jp> X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: FUJITA Tomonori Date: Sun, 28 Feb 2010 03:38:19 +0900 > When I proposed such approach (always use swiotlb) before, IIRC, > the objections were: > > - better to make allocation respect dma_mask. (I don't think that this > approach is possible since we don't know which device handles data > later when we allocate memory). And such objects might end up being processed by multiple devices with different DMA restrictions. > - swiotlb is not good for small systems since it allocates too much > memory (we can fix this though). Indeed. From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [RFC PATCH] fix problems with NETIF_F_HIGHDMA in networking drivers Date: Sun, 28 Feb 2010 00:16:28 -0800 (PST) Message-ID: <20100228.001628.48507956.davem@davemloft.net> References: <20100227.040502.182574085.davem@davemloft.net> <51f3faa71002271015i7c9ec45j18381b1269bfd799@mail.gmail.com> <20100228033706G.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: hancockrwd-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, bzolnier-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: fujita.tomonori-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org Return-path: In-Reply-To: <20100228033706G.fujita.tomonori-Zyj7fXuS5i5L9jVzuh4AOg@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org From: FUJITA Tomonori Date: Sun, 28 Feb 2010 03:38:19 +0900 > When I proposed such approach (always use swiotlb) before, IIRC, > the objections were: > > - better to make allocation respect dma_mask. (I don't think that this > approach is possible since we don't know which device handles data > later when we allocate memory). And such objects might end up being processed by multiple devices with different DMA restrictions. > - swiotlb is not good for small systems since it allocates too much > memory (we can fix this though). Indeed. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html