From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: brouer@redhat.com, Saeed Mahameed <saeedm@mellanox.com>,
"stephen@networkplumber.org" <stephen@networkplumber.org>,
"jiri@resnulli.us" <jiri@resnulli.us>,
"sthemmin@microsoft.com" <sthemmin@microsoft.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH v3 2/2] net: core: support XDP generic on stacked devices.
Date: Fri, 24 May 2019 12:07:15 +0200 [thread overview]
Message-ID: <20190524120715.6f1c13bd@carbon> (raw)
In-Reply-To: <ebf12468-504c-fae7-b62d-2b6db47391f9@redhat.com>
On Fri, 24 May 2019 12:17:27 +0800
Jason Wang <jasowang@redhat.com> wrote:
> > Maybe this is acceptable, but it should be documented, as the current
> > assumption dictates: XDP program runs on the core where the XDP
> > frame/SKB was first seen.
>
>
> At lest for TUN, this is not true. XDP frames were built by vhost_net
> and passed to TUN. There's no guarantee that vhost_net kthread won't
> move to another core.
This sound a little scary, as we depend on per-CPU variables (e.g.
bpf_redirect_info). Can the vhost_net kthread move between CPUs
within/during the NAPI-poll?
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2019-05-24 10:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 17:54 [PATCH v3 0/2] XDP generic fixes Stephen Hemminger
2019-05-23 17:54 ` [PATCH v3 1/2] netvsc: unshare skb in VF rx handler Stephen Hemminger
2019-05-23 17:54 ` [PATCH v3 2/2] net: core: support XDP generic on stacked devices Stephen Hemminger
2019-05-23 19:19 ` Saeed Mahameed
2019-05-23 20:15 ` Stephen Hemminger
2019-05-24 9:33 ` Jesper Dangaard Brouer
2019-05-24 13:25 ` Jason Wang
2019-05-24 4:17 ` Jason Wang
2019-05-24 10:07 ` Jesper Dangaard Brouer [this message]
2019-05-24 13:06 ` Jason Wang
2019-05-27 4:29 ` David Miller
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