netdev - Re: [PATCH net 00/11] netpoll: second round of fixes.

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Date:   Fri, 28 Sep 2018 11:14:18 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     edumazet@...gle.com
Cc:     netdev@...r.kernel.org, michael.chan@...adcom.com,
        aviad.krawczyk@...wei.com, songliubraving@...com,
        dougmill@...ux.vnet.ibm.com, yisen.zhuang@...wei.com,
        mst@...hat.com, jasowang@...hat.com, harish.patil@...ium.com,
        manish.chopra@...ium.com, netanel@...zon.com,
        linux-net-drivers@...arflare.com, tlfalcon@...ux.vnet.ibm.com
Subject: Re: [PATCH net 00/11] netpoll: second round of fixes.

From: Eric Dumazet <edumazet@...gle.com>
Date: Thu, 27 Sep 2018 09:31:50 -0700

> As diagnosed by Song Liu, ndo_poll_controller() can
> be very dangerous on loaded hosts, since the cpu
> calling ndo_poll_controller() might steal all NAPI
> contexts (for all RX/TX queues of the NIC).
> 
> This capture, showing one ksoftirqd eating all cycles
> can last for unlimited amount of time, since one
> cpu is generally not able to drain all the queues under load.
> 
> It seems that all networking drivers that do use NAPI
> for their TX completions, should not provide a ndo_poll_controller() :
> 
> Most NAPI drivers have netpoll support already handled
> in core networking stack, since netpoll_poll_dev()
> uses poll_napi(dev) to iterate through registered
> NAPI contexts for a device.
> 
> First patch is a fix in poll_one_napi().
> 
> Then following patches take care of ten drivers.

Series applied, thanks Eric.