netdev - RE: [PATCH] hv_netvsc: remove ndo_poll

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Message-ID: <BN6PR21MB01614C78F46274A97AD5BD9BCAED0@BN6PR21MB0161.namprd21.prod.outlook.com>
Date:   Sat, 29 Sep 2018 14:12:49 +0000
From:   Haiyang Zhang <haiyangz@...rosoft.com>
To:     Stephen Hemminger <stephen@...workplumber.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     Stephen Hemminger <sthemmin@...rosoft.com>,
        Eric Dumazet <edumazet@...gle.com>
Subject: RE: [PATCH] hv_netvsc: remove ndo_poll_controller



> -----Original Message-----
> From: Stephen Hemminger <stephen@...workplumber.org>
> Sent: Saturday, September 29, 2018 8:53 AM
> To: netdev@...r.kernel.org
> Cc: Stephen Hemminger <sthemmin@...rosoft.com>; Haiyang Zhang
> <haiyangz@...rosoft.com>; Eric Dumazet <edumazet@...gle.com>
> Subject: [PATCH] hv_netvsc: remove ndo_poll_controller
> 
> Similar to other patches from ERic.
> 
> 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 can last for unlimited
> amount of time, since one cpu is generally not able to drain all the queues
> under load.
> 
> In netvsc driver it uses NAPI for TX completions. The default poll_napi will do
> this for us now and avoid the capture.
> 
> Signed-off-by: Stephen Hemminger <sthemmin@...rosoft.com>
> Cc: Haiyang Zhang <haiyangz@...rosoft.com>
> Cc: Eric Dumazet <edumazet@...gle.com>
> ---

Thank you.
Reviewed-by: Haiyang Zhang <haiyangz@...rosoft.com>