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From: Thomas Graf <tgraf-H+wXaHxf7aLQT0dZR+AlfA@public•gmane.org>
To: Zoltan Kiss <zoltan.kiss-Sxgqhf6Nn4DQT0dZR+AlfA@public•gmane.org>,
	Jesse Gross <jesse-l0M0P4e3n4LQT0dZR+AlfA@public•gmane.org>,
	pshelar-l0M0P4e3n4LQT0dZR+AlfA@public•gmane.org,
	dev-yBygre7rU0TnMu66kgdUjQ@public•gmane.org
Cc: xen-devel-GuqFBffKawtpuQazS67q72D2FQJk+8+b@public•gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org
Subject: Re: [PATCH] openvswitch: Orphan frags before sending to userspace via Netlink to avoid guest stall
Date: Fri, 07 Mar 2014 17:23:14 +0100	[thread overview]
Message-ID: <5319F272.1070101@redhat.com> (raw)
In-Reply-To: <1393615016-9187-1-git-send-email-zoltan.kiss-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org>

On 02/28/2014 08:16 PM, Zoltan Kiss wrote:
> The kernel datapath now switched to zerocopy Netlink messages, but that also
> means that the pages on frags array are sent straight to userspace. If those
> pages came outside the kernel, we have to swap them out with local copies.
>
> Signed-off-by: Zoltan Kiss <zoltan.kiss-Sxgqhf6Nn4DQT0dZR+AlfA@public•gmane.org>
> ---
>   net/openvswitch/datapath.c |    6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
> index 36f8872..ffb563c 100644
> --- a/net/openvswitch/datapath.c
> +++ b/net/openvswitch/datapath.c
> @@ -464,6 +464,12 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
>   	}
>   	nla->nla_len = nla_attr_size(skb->len);
>
> +	if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) {
> +		err = -ENOMEM;
> +		skb_tx_error(skb);
> +		goto out;
> +	}
> +
>   	skb_zerocopy(user_skb, skb, skb->len, hlen);
>
>   	/* Pad OVS_PACKET_ATTR_PACKET if linear copy was performed */

How about we move the call to skb_orphan_frags() into skb_zerocopy()
itself and call it before we actually reference the frags?

It's not just OVS affected but nfqueue as well.

  parent reply	other threads:[~2014-03-07 16:23 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-28 19:16 [PATCH] openvswitch: Orphan frags before sending to userspace via Netlink to avoid guest stall Zoltan Kiss
2014-03-06 17:09 ` Zoltan Kiss
2014-03-07  4:46   ` Pravin Shelar
2014-03-07 12:29     ` Zoltan Kiss
     [not found]       ` <5319BBAE.7030109-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org>
2014-03-07 17:38         ` Pravin Shelar
     [not found]     ` <CALnjE+rWc=n_F+1jSLQtPrgKSvvxONEkkYxWEHon2_KVNG9z3Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-03-07 15:58       ` Thomas Graf
     [not found]         ` <5319EC8E.2010606-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-03-07 17:19           ` Pravin Shelar
     [not found]             ` <CALnjE+oDM=ga_C6T_-9i2UNwv=K4g-+y-LJA04nh+=WmoeuNXw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-03-07 18:05               ` Thomas Graf
     [not found]                 ` <531A0A5B.2000104-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-03-07 18:43                   ` Pravin Shelar
     [not found] ` <1393615016-9187-1-git-send-email-zoltan.kiss-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org>
2014-03-07 16:23   ` Thomas Graf [this message]
     [not found]     ` <5319F272.1070101-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-03-07 17:28       ` Pravin Shelar
     [not found]         ` <CALnjE+q=fejHPsjVj9+jnypJCUHfCDFc553U48WR48Tjcf3FZw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-03-07 17:59           ` Thomas Graf
     [not found]             ` <531A0911.4040304-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-03-07 18:41               ` Pravin Shelar
2014-03-11 19:41               ` Zoltan Kiss
     [not found]                 ` <531F66D0.1050000-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org>
2014-03-14 22:26                   ` Zoltan Kiss

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