From: Eric Dumazet <eric.dumazet@gmail.com>
To: Florian Fainelli <f.fainelli@gmail.com>,
ahs3@redhat.com, "Lendacky, Thomas" <Thomas.Lendacky@amd.com>,
David Miller <davem@davemloft.net>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"isubramanian@apm.com" <isubramanian@apm.com>,
"kchudgar@apm.com" <kchudgar@apm.com>,
"qnguyen@apm.com" <qnguyen@apm.com>
Subject: Re: [PATCH] net: apm: xgene: force XGene enet driver to re-balance IRQ usage
Date: Tue, 18 Sep 2018 19:32:54 -0700 [thread overview]
Message-ID: <95391269-73b7-933f-27ee-2c4a17c8c6b1@gmail.com> (raw)
In-Reply-To: <0e0f3aa6-9b6e-edd5-226f-2e23de9b5a0f@gmail.com>
On 09/18/2018 05:03 PM, Florian Fainelli wrote:
> On 09/18/2018 04:56 PM, Eric Dumazet wrote:
>>
>>
>> On 09/18/2018 04:27 PM, Eric Dumazet wrote:
>>>
>>
>>> I remember one of the napi_complete_done() change had to be reverted,
>>> for some obscure reason.
>>
>>
>>
>> That was not exactly a revert, :
>
> This is what I have so far for the drivers that both use
> napi_complete_done() without checking the return value and implement a
> ndo_poll_controller() callback:
>
> https://github.com/ffainelli/linux/commits/napi-check
In fact, there is still to explain what the bug is.
napi_complete_done() return value can be ignored, unless drivers
have to disable IRQ in their interrupt handler, using the following
construct :
if (napi_schedule_prep(napi)) {
.... disable interrupt ....
__napi_schedule_irqoff(napi);
}
It _can_ be used by other drivers to not rearm interrupts needlessly.
The bug discussed in this thread (re-balance IRQ usage) is of the same kind than
the one fixed in commit d7aba644ffdebf756e51e26a2229055211838e89 ("amd-xgbe: Enable IRQs only if napi_complete_done() is true")
next prev parent reply other threads:[~2018-09-19 2:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-17 23:35 [PATCH] net: apm: xgene: force XGene enet driver to re-balance IRQ usage Al Stone
2018-09-18 2:35 ` David Miller
2018-09-18 20:21 ` Al Stone
2018-09-18 23:09 ` Lendacky, Thomas
2018-09-18 23:15 ` Al Stone
2018-09-18 23:21 ` Florian Fainelli
2018-09-18 23:27 ` Eric Dumazet
2018-09-18 23:56 ` Eric Dumazet
2018-09-19 0:03 ` Florian Fainelli
2018-09-19 2:32 ` Eric Dumazet [this message]
2018-09-18 23:25 ` Eric Dumazet
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