From: Eric Dumazet <eric.dumazet@gmail.com>
To: Song Liu <songliubraving@fb.com>, Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
netdev <netdev@vger.kernel.org>,
"intel-wired-lan@lists.osuosl.org"
<intel-wired-lan@lists.osuosl.org>,
Kernel Team <Kernel-team@fb.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>
Subject: Re: [PATCH net] ixgbe: check return value of napi_complete_done()
Date: Fri, 21 Sep 2018 06:33:18 -0700 [thread overview]
Message-ID: <74672b30-1627-efcd-383f-adda6cdf486f@gmail.com> (raw)
In-Reply-To: <ACD41205-3FDD-4FD2-BF36-897DD98D63EC@fb.com>
On 09/21/2018 12:17 AM, Song Liu wrote:
>
>
>> On Sep 20, 2018, at 4:49 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
>>
>>
>>
>> On 09/20/2018 04:43 PM, Song Liu wrote:
>>>
>>
>>> I tried to totally skip ndo_poll_controller() here. It did avoid hitting
>>> the issue. However, netpoll will drop (fail to send) more packets.
>>>
>>
>> Why is it failing ?
>>
>> If you are under high memory pressure, then maybe if you absolutely want memory to send
>> netpoll packets, you want to grab all NAPI contexts as a way to prevent other cpus
>> from feeding incoming packets to the host and add more memory pressure ;)
>>
>
> I did the test with Eric's latest patch (and disable ndo_poll_controller
> in driver). The result didn't show significant increase in drop packets.
> I guess packet drops in my earlier test was caused by some other changes
> I mixed there.
>
> So I think this patch does fix the issue. Thanks Eric!
Great, this is awesome.
I will prepare a patch series for net tree.
The core infrastructure is just better at being able to drain TX completions
without risking stealing the NAPI context forever.
>
> For ixgbe, I think we need to check napi_complete_done() return value
> anyway. Otherwise, the driver will enable IRQ in polling mode.
>
Sure, let's prepare such optimizations for net-next.
next prev parent reply other threads:[~2018-09-21 19:22 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-20 19:01 [PATCH net] ixgbe: check return value of napi_complete_done() Song Liu
2018-09-20 20:35 ` Eric Dumazet
2018-09-20 21:01 ` Jeff Kirsher
2018-09-20 22:42 ` Song Liu
2018-09-20 23:22 ` Eric Dumazet
2018-09-20 23:43 ` Song Liu
2018-09-20 23:49 ` Eric Dumazet
2018-09-21 7:17 ` Song Liu
2018-09-21 13:33 ` Eric Dumazet [this message]
2018-09-21 14:55 ` Alexei Starovoitov
2018-09-21 14:59 ` Eric Dumazet
2018-09-21 15:14 ` Alexei Starovoitov
2018-09-21 15:43 ` Eric Dumazet
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