From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zoltan Kiss Subject: Re: [PATCH net-next v5 0/9] xen-netback: TX grant mapping with SKBTX_DEV_ZEROCOPY instead of copy Date: Thu, 23 Jan 2014 13:13:07 +0000 Message-ID: <52E11563.1090707@citrix.com> References: <1390253069-25507-1-git-send-email-zoltan.kiss@citrix.com> <20140122.175031.873909526743971037.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Cc: , , , , , , "xen-devel@lists.xenproject.org" To: David Miller Return-path: In-Reply-To: <20140122.175031.873909526743971037.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 23/01/14 01:50, David Miller wrote: > From: Zoltan Kiss > Date: Mon, 20 Jan 2014 21:24:20 +0000 > >> A long known problem of the upstream netback implementation that on the TX >> path (from guest to Dom0) it copies the whole packet from guest memory into >> Dom0. That simply became a bottleneck with 10Gb NICs, and generally it's a >> huge perfomance penalty. The classic kernel version of netback used grant >> mapping, and to get notified when the page can be unmapped, it used page >> destructors. Unfortunately that destructor is not an upstreamable solution. >> Ian Campbell's skb fragment destructor patch series [1] tried to solve this >> problem, however it seems to be very invasive on the network stack's code, >> and therefore haven't progressed very well. >> This patch series use SKBTX_DEV_ZEROCOPY flags to tell the stack it needs to >> know when the skb is freed up. > > This series does not apply to net-next due to some other recent changes. > > Please respin, thanks. It is already based on two predecessor patches, one which is already accepted but not applied yet: [PATCH net-next v2] xen-netback: Rework rx_work_todo And the other one is hopefully will be accepted very soon: [PATCH v5] xen/grant-table: Avoid m2p_override during mapping Zoli