From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH net-next 04/11] tuntap: simplify error handling in tun_build_skb()
Date: Fri, 7 Sep 2018 10:17:35 -0400 [thread overview]
Message-ID: <20180907101645-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <e1f17f51-5f99-df18-4185-6c6e4dfaba89@redhat.com>
On Fri, Sep 07, 2018 at 11:22:00AM +0800, Jason Wang wrote:
> > > @@ -1668,6 +1668,9 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
> > > if (copied != len)
> > > return ERR_PTR(-EFAULT);
> > > + get_page(alloc_frag->page);
> > > + alloc_frag->offset += buflen;
> > > +
> > This adds an atomic op on XDP_DROP which is a data path
> > operation for some workloads.
>
> Yes, I have patch on top to amortize this, the idea is to have a very big
> refcount once after the frag was allocated and maintain a bias and decrease
> them all when allocating new frags.'
Why bother with refcounting for a drop though? It should be simple.
--
MST
next prev parent reply other threads:[~2018-09-07 14:17 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-06 4:05 [PATCH net-next 00/11] Vhost_net TX batching Jason Wang
2018-09-06 4:05 ` [PATCH net-next 01/11] net: sock: introduce SOCK_XDP Jason Wang
2018-09-06 16:56 ` Michael S. Tsirkin
2018-09-07 3:07 ` Jason Wang
2018-09-06 4:05 ` [PATCH net-next 02/11] tuntap: switch to use XDP_PACKET_HEADROOM Jason Wang
2018-09-06 16:57 ` Michael S. Tsirkin
2018-09-07 3:12 ` Jason Wang
2018-09-06 4:05 ` [PATCH net-next 03/11] tuntap: enable bh early during processing XDP Jason Wang
2018-09-06 17:02 ` Michael S. Tsirkin
2018-09-06 4:05 ` [PATCH net-next 04/11] tuntap: simplify error handling in tun_build_skb() Jason Wang
2018-09-06 17:14 ` Michael S. Tsirkin
2018-09-07 3:22 ` Jason Wang
2018-09-07 14:17 ` Michael S. Tsirkin [this message]
2018-09-10 3:44 ` Jason Wang
2018-09-06 4:05 ` [PATCH net-next 05/11] tuntap: tweak on the path of non-xdp case " Jason Wang
2018-09-06 17:16 ` Michael S. Tsirkin
2018-09-07 3:24 ` Jason Wang
2018-09-06 4:05 ` [PATCH net-next 06/11] tuntap: split out XDP logic Jason Wang
2018-09-06 17:21 ` Michael S. Tsirkin
2018-09-07 3:29 ` Jason Wang
2018-09-07 14:16 ` Michael S. Tsirkin
2018-09-10 3:43 ` Jason Wang
2018-09-06 4:05 ` [PATCH net-next 07/11] tuntap: move XDP flushing out of tun_do_xdp() Jason Wang
2018-09-06 17:48 ` Michael S. Tsirkin
2018-09-07 3:31 ` Jason Wang
2018-09-06 4:05 ` [PATCH net-next 08/11] tun: switch to new type of msg_control Jason Wang
2018-09-06 16:54 ` Michael S. Tsirkin
2018-09-07 3:35 ` Jason Wang
2018-09-06 4:05 ` [PATCH net-next 09/11] tuntap: accept an array of XDP buffs through sendmsg() Jason Wang
2018-09-06 17:51 ` Michael S. Tsirkin
2018-09-07 7:33 ` Jason Wang
2018-09-06 4:05 ` [PATCH net-next 10/11] tap: " Jason Wang
2018-09-06 18:00 ` Michael S. Tsirkin
2018-09-07 3:41 ` Jason Wang
2018-09-06 4:05 ` [PATCH net-next 11/11] vhost_net: batch submitting XDP buffers to underlayer sockets Jason Wang
2018-09-06 16:46 ` Michael S. Tsirkin
2018-09-07 7:41 ` Jason Wang
2018-09-07 16:13 ` Michael S. Tsirkin
2018-09-10 3:47 ` Jason Wang
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