From: Jason Wang <jasowang@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: davem@davemloft.net, mst@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 1/6] net: skbuff: don't use union for napi_id and sender_cpu
Date: Fri, 1 Apr 2016 12:49:31 +0800 [thread overview]
Message-ID: <56FDFDDB.7090606@redhat.com> (raw)
In-Reply-To: <1459479325.6473.260.camel@edumazet-glaptop3.roam.corp.google.com>
On 04/01/2016 10:55 AM, Eric Dumazet wrote:
> On Fri, 2016-04-01 at 10:13 +0800, Jason Wang wrote:
>
>
>> The problem is we want to support busy polling for tun. This needs
>> napi_id to be passed to tun socket by sk_mark_napi_id() during
>> tun_net_xmit(). But before reaching this, XPS will set sender_cpu will
>> make us can't see correct napi_id.
>>
> Looks like napi_id should have precedence then ?
But then when busy polling is enabled, we may still hit the issue before
commit 2bd82484bb4c5db1d5dc983ac7c409b2782e0154? So looks like sometimes
(e.g for tun), we need both two fields.
>
> Only forwarding should allow the field to be cleared to allow XPS to do
> its job.
>
> Maybe skb_sender_cpu_clear() was removed too early (commit
> 64d4e3431e686dc37ce388ba531c4c4e866fb141)
Not sure I get you, but this will clear napi_id too.
> Look, it is 8pm here, I am pretty sure a solution can be found,
> but I am also need to take a break, I started at 3am today...
>
>
>
next prev parent reply other threads:[~2016-04-01 4:49 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-31 5:50 [PATCH net-next 0/6] net device rx busy polling support in vhost_net Jason Wang
2016-03-31 5:50 ` [PATCH net-next 1/6] net: skbuff: don't use union for napi_id and sender_cpu Jason Wang
2016-03-31 10:32 ` Eric Dumazet
2016-03-31 20:01 ` David Miller
2016-04-01 2:46 ` Jason Wang
2016-04-01 2:13 ` Jason Wang
2016-04-01 2:55 ` Eric Dumazet
2016-04-01 4:49 ` Jason Wang [this message]
2016-04-01 13:04 ` Eric Dumazet
2016-04-05 15:05 ` Michael S. Tsirkin
2016-04-06 6:22 ` Jason Wang
2016-03-31 5:50 ` [PATCH net-next 2/6] tuntap: socket rx busy polling support Jason Wang
2016-03-31 5:50 ` [PATCH net-next 3/6] macvtap: " Jason Wang
2016-03-31 5:50 ` [PATCH net-next 4/6] net: core: factor out core busy polling logic to sk_busy_loop_once() Jason Wang
2016-03-31 5:50 ` [PATCH net-next 5/6] net: export napi_by_id() Jason Wang
2016-03-31 5:50 ` [PATCH net-next 6/6] vhost_net: net device rx busy polling support Jason Wang
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