From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [net-next RFC PATCH 5/5] virtio-net: flow director support Date: Tue, 6 Dec 2011 17:36:16 +0000 Message-ID: <1323192976.2772.3.camel@bwh-desktop> References: <20111205085603.6116.65101.stgit@dhcp-8-146.nay.redhat.com> <20111205085925.6116.94352.stgit@dhcp-8-146.nay.redhat.com> <1323117745.2887.31.camel@bwh-desktop> <4EDDC35C.2070100@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: krkumar2@in.ibm.com, kvm@vger.kernel.org, mst@redhat.com, netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, levinsasha928@gmail.com To: Jason Wang Return-path: In-Reply-To: <4EDDC35C.2070100@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: netdev.vger.kernel.org On Tue, 2011-12-06 at 15:25 +0800, Jason Wang wrote: > On 12/06/2011 04:42 AM, Ben Hutchings wrote: [...] > > This is not a proper implementation of ndo_rx_flow_steer. If you steer > > a flow by changing the RSS table this can easily cause packet reordering > > in other flows. The filtering should be more precise, ideally matching > > exactly a single flow by e.g. VID and IP 5-tuple. > > > > I think you need to add a second hash table which records exactly which > > flow is supposed to be steered. Also, you must call > > rps_may_expire_flow() to check whether an entry in this table may be > > replaced; otherwise you can cause packet reordering in the flow that was > > previously being steered. > > > > Finally, this function must return the table index it assigned, so that > > rps_may_expire_flow() works. > > Thanks for the explanation, how about document this briefly in scaling.txt? [...] I believe scaling.txt is intended for users/administrators, not developers. The documentation for implementers of accelerated RFS is in the comment for struct net_device_ops and the commit message adding it. But I really should improve that comment. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.