From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Patrick McHardy <kaber@trash.net>,
Vladislav Yasevich <vyasevic@redhat.com>
Subject: Re: [PATCH net-next] macvtap/macvlan: use IFF_NO_QUEUE
Date: Tue, 25 Aug 2015 19:30:09 +0800 [thread overview]
Message-ID: <55DC51C1.5090201@redhat.com> (raw)
In-Reply-To: <20150825131608-mutt-send-email-mst@redhat.com>
On 08/25/2015 06:17 PM, Michael S. Tsirkin wrote:
> On Mon, Aug 24, 2015 at 04:33:12PM +0800, Jason Wang wrote:
>> > For macvlan, switch to use IFF_NO_QUEUE instead of tx_queue_len = 0.
>> >
>> > For macvtap, after commit 6acf54f1cf0a6747bac9fea26f34cfc5a9029523
>> > ("macvtap: Add support of packet capture on macvtap
>> > device."). Multiqueue macvtap suffers from single qdisc lock
>> > contention. This is because macvtap claims a non zero tx_queue_len and
>> > it reuses this value as it socket receive queue size.Thanks to
>> > IFF_NO_QUEUE, we can remove the lock contention without breaking
>> > existing socket receive queue length logic.
>> >
>> > Cc: Patrick McHardy <kaber@trash.net>
>> > Cc: Vladislav Yasevich <vyasevic@redhat.com>
>> > Cc: Michael S. Tsirkin <mst@redhat.com>
>> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> Seems to make sense. Give me a day or two to get over the jet lag
> (and get out from under the pile of mail accumulated while I was traveling),
> I'll review properly and ack.
>
A note on this patch: only default qdisc were removed but we don't lose
the ability to attach a qdisc to macvtap (though it may cause lock
contention on multiqueue case).
next prev parent reply other threads:[~2015-08-25 11:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-24 8:33 [PATCH net-next] macvtap/macvlan: use IFF_NO_QUEUE Jason Wang
2015-08-25 10:17 ` Michael S. Tsirkin
2015-08-25 11:30 ` Jason Wang [this message]
2015-08-25 16:32 ` Vlad Yasevich
2015-08-26 5:45 ` Jason Wang
2015-08-27 10:43 ` Michael S. Tsirkin
2015-08-28 2:42 ` Jason Wang
2015-08-28 12:25 ` Vlad Yasevich
2015-08-31 2:45 ` Jason Wang
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