From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org,
John Fastabend <john.fastabend@gmail.com>,
netdev@vger.kernel.org, David Miller <davem@davemloft.net>
Subject: Re: [RFC PATCH v2] ptr_ring: linked list fallback
Date: Wed, 28 Feb 2018 14:28:21 +0800 [thread overview]
Message-ID: <11ef5721-1a4c-f216-9f46-08a0ad0ca49d@redhat.com> (raw)
In-Reply-To: <20180228060845-mutt-send-email-mst@kernel.org>
On 2018年02月28日 12:09, Michael S. Tsirkin wrote:
>>> Or we can add plist to a union:
>>>
>>>
>>> struct sk_buff {
>>> union {
>>> struct {
>>> /* These two members must be first. */
>>> struct sk_buff *next;
>>> struct sk_buff *prev;
>>> union {
>>> struct net_device *dev;
>>> /* Some protocols might use this space to store information,
>>> * while device pointer would be NULL.
>>> * UDP receive path is one user.
>>> */
>>> unsigned long dev_scratch;
>>> };
>>> };
>>> struct rb_node rbnode; /* used in netem & tcp stack */
>>> + struct plist plist; /* For use with ptr_ring */
>>> };
>>>
>> This look ok.
>>
>>>> For XDP, we need to embed plist in struct xdp_buff too,
>>> Right - that's pretty straightforward, isn't it?
>> Yes, it's not clear to me this is really needed for XDP consider the lock
>> contention it brings.
>>
>> Thanks
> The contention is only when the ring overflows into the list though.
>
Right, but there's usually a mismatch of speed between producer and
consumer. In case of a fast producer, we may get this contention very
frequently.
Thanks
next prev parent reply other threads:[~2018-02-28 6:28 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-26 1:17 [RFC PATCH v2] ptr_ring: linked list fallback Michael S. Tsirkin
2018-02-26 3:15 ` Jason Wang
2018-02-26 20:34 ` Michael S. Tsirkin
2018-02-27 2:29 ` Jason Wang
2018-02-27 17:12 ` Michael S. Tsirkin
2018-02-28 3:28 ` Jason Wang
2018-02-28 3:39 ` Jason Wang
2018-02-28 4:11 ` Michael S. Tsirkin
2018-02-28 4:09 ` Michael S. Tsirkin
2018-02-28 6:28 ` Jason Wang [this message]
2018-02-28 14:01 ` Michael S. Tsirkin
2018-02-28 14:20 ` Jason Wang
2018-02-28 15:43 ` Michael S. Tsirkin
2018-03-01 6:41 ` Jason Wang
2018-02-27 17:53 ` Eric Dumazet
2018-02-27 19:35 ` Michael S. Tsirkin
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