netdev - Re: WARN_ON_ONCE(work > weight) in napi

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Date:   Mon, 24 Jul 2017 12:30:44 +0300
From:   Andrey Ryabinin <aryabinin@...tuozzo.com>
To:     Ryan Hsu <ryanhsu@....qualcomm.com>,
        Igor Mitsyanko <igor.mitsyanko.os@...ntenna.com>,
        Kalle Valo <kvalo@....qualcomm.com>
Cc:     Networking <netdev@...r.kernel.org>,
        linux-wireless <linux-wireless@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "ath10k@...ts.infradead.org" <ath10k@...ts.infradead.org>
Subject: Re: WARN_ON_ONCE(work > weight) in napi_poll()

On 07/18/2017 09:47 AM, Ryan Hsu wrote:
> On 07/11/2017 06:19 PM, Igor Mitsyanko wrote:
> 
>> On 07/11/2017 10:28 AM, Andrey Ryabinin wrote:
>>>
>>> It gave me this:
>>>
>>> [118648.825347] #1 quota too big 72 64 16
>>> [118648.825351] #2 quota too big 72 64 16
>>> [118648.825471] ------------[ cut here ]------------
>>> [118648.825484] WARNING: CPU: 0 PID: 0 at ../net/core/dev.c:5274 net_rx_action+0x258/0x360
>>>
>>> So this means that we didn't met the condition bellow, i.e. skb_queue_empty() returned true.
>>>
>>>          ath10k_htt_txrx_compl_task():
>>>
>>>                  if ((quota > ATH10K_NAPI_QUOTA_LIMIT) &&
>>>                      !skb_queue_empty(&htt->rx_in_ord_compl_q)) {
>>>                          resched_napi = true;
>>>                          goto exit;
>>>                  }
>>>
>>>> Also WLAN.RM.2.0-00180-QCARMSWPZ-1 firmware is a bit old, could you also update firmware to give it a try?
>>>> https://github.com/kvalo/ath10k-firmware/tree/master/QCA6174/hw3.0/4.4
>>>>
>>>
>>> Will try.
>>>
>>
>> Maybe ath10k_htt_rx_in_ord_ind() has to accept "budget_left" parameter and use it to limit number of processed MSDUs in queued AMSDU and saving rest for later (NAPI has to be rescheduled in this case).
>> It seems natural that this problem happens with current logic, in case AMSDU in Rx queue has more elements then left in budget.
> 
> Thanks, likely in current logic, it does have chance to exceed the budget while dequeuing from the last list.
> 
> Can you give it a try this one? for QCA6174 reorder is offload, so this should be good enough for your case to test, will have to check non-offload reorder case... but let me know if you're seeing something different....
> 

I've been running with this patch almost a week and haven't seen the WARNING. One week is usually enough to trigger it several times.
I guess we can assume that the patch fixed the problem.