netdev - Re: [PATCH net] ixgbe: check return value of napi_complete

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Message-ID: <028b4cea-0e3f-fab5-7a74-cf003bbd1134@gmail.com>
Date:   Thu, 20 Sep 2018 16:49:06 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Song Liu <songliubraving@...com>,
        Eric Dumazet <eric.dumazet@...il.com>
Cc:     Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
        netdev <netdev@...r.kernel.org>,
        "intel-wired-lan@...ts.osuosl.org" <intel-wired-lan@...ts.osuosl.org>,
        Kernel Team <Kernel-team@...com>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Alexei Starovoitov <ast@...nel.org>
Subject: Re: [PATCH net] ixgbe: check return value of napi_complete_done()



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 ;)