From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shirley Ma Subject: Re: [PATCH V7 4/4 net-next] vhost: vhost TX zero-copy support Date: Wed, 06 Jul 2011 12:28:16 -0700 Message-ID: <1309980496.10209.2.camel@localhost.localdomain> References: <1306611267.5180.97.camel@localhost.localdomain> <20110629091300.GC14627@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , Eric Dumazet , Avi Kivity , Arnd Bergmann , netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: "Michael S. Tsirkin" Return-path: In-Reply-To: <20110629091300.GC14627@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Wed, 2011-06-29 at 12:13 +0300, Michael S. Tsirkin wrote: > On Sat, May 28, 2011 at 12:34:27PM -0700, Shirley Ma wrote: > > Hello Michael, > > > > In order to use wait for completion in shutting down, seems to me > > another work thread is needed to call vhost_zerocopy_add_used, > > Hmm I don't see vhost_zerocopy_add_used here. I put the call in vhost_set_vring. > > > it seems > > too much work to address a minor issue here. Do we really need it? > > Assuming you mean vhost_zerocopy_signal_used, here's how I would do > it: > add a kref and a completion, signal completion in kref_put > callback, when backend is set - kref_get, on cleanup, > kref_put and then wait_for_completion_interruptible. > Where's the need for another thread coming from? > > If you like, post a patch with busywait + a FIXME comment, > and I can write up a patch on top. I might not have time to finish this during my vacation, so I am putting busywait + a FIXME comment. > (BTW, ideally the function that does the signalling should be > in core networking bits so that it's still around > even if the vhost module gets removed). Thanks Shirley