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From: Alexei Starovoitov <ast@fb.com>
To: Eric Dumazet <eric.dumazet@gmail.com>, Song Liu <songliubraving@fb.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 15:14:43 +0000	[thread overview]
Message-ID: <d15e9eec-6236-af26-0eb5-84e7dc27b4d7@fb.com> (raw)
In-Reply-To: <e6afa0d0-ba22-8205-076c-6a259a9f1b52@gmail.com>

On 9/21/18 7:59 AM, Eric Dumazet wrote:
>
>
> On 09/21/2018 07:55 AM, Alexei Starovoitov wrote:
>
>>
>> should we remove ndo_poll_controller then?
>> My understanding that the patch helps by not letting
>> drivers do napi_schedule() for all queues into this_cpu, right?
>> But most of the drivers do exactly that in their ndo_poll_controller
>> implementations. Means most of the drivers will experience
>> this nasty behavior.
>>
>
> Some legacy drivers do not use NAPI yet, but provide ndo_poll_controller()
>
> I believe users caring about system behavior with multi queue NIC are
> all using NAPI enabled drivers, so this should be fine.

I'm not following.
All modern napi enabled drivers need to _remove_ ndo_poll_controller
from the driver. This is a lot of churn.
Isn't it cleaner (less error prone) to introduce new ndo
for legacy drivers without napi?


  reply	other threads:[~2018-09-21 15:14 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
2018-09-21 14:55                 ` Alexei Starovoitov
2018-09-21 14:59                   ` Eric Dumazet
2018-09-21 15:14                     ` Alexei Starovoitov [this message]
2018-09-21 15:43                       ` Eric Dumazet

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