From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH v2 1/4] Defer skb allocation -- add destroy buffers function for virtio Date: Mon, 14 Dec 2009 22:22:53 +0200 Message-ID: <20091214202253.GG6150@redhat.com> References: <1258697359.7416.14.camel@localhost.localdomain> <200911231123.18898.rusty@rustcorp.com.au> <20091208122134.GA17286@redhat.com> <1260534506.30371.6.camel@localhost.localdomain> <1260534805.30371.10.camel@localhost.localdomain> <20091213102632.GB6789@redhat.com> <1260821285.8716.7.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Rusty Russell , Avi Kivity , netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Anthony Liguori To: Shirley Ma Return-path: Content-Disposition: inline In-Reply-To: <1260821285.8716.7.camel@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, Dec 14, 2009 at 12:08:05PM -0800, Shirley Ma wrote: > Hello Michael, > > I agree with the comments (will have two patches instead of 4 based on > Rusty's comments) except below one. > > On Sun, 2009-12-13 at 12:26 +0200, Michael S. Tsirkin wrote: > > That said - do we have to use a callback? > > I think destroy_buf which returns data pointer, > > and which we call repeatedly until we get NULL > > or error, would be an a better, more flexible API. > > This is not critical though. > > The reason to use this is because in virtio_net remove, it has > BUG_ON(vi->num != 0), which will be consistent with small skb packet. If > we use NULL, error then we lose the track for vi->num, since we don't > know how many buffers have been passed to ULPs or still unused. > > Thanks > Shirley I dont insist, but my idea was for (;;) { b = vq->destroy(vq); if (!b) break; --vi->num; put_page(b); } so we do not have to lose track of the counter. -- MST