Re: [PATCH] net: rps: fix data stall after hotplug

[subashab@codeaurora.org]

> On Thu, 2015-03-19 at 14:50 -0700, Eric Dumazet wrote:
>
>> Are you seeing this race on x86 ?
>>
>> If IPI are not reliable on your arch, I am guessing you should fix them.
>>
>> Otherwise, even without hotplug you'll have hangs.
>
> Please try instead this patch :
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index
> 5d43e010ef870a6ab92895297fe18d6e6a03593a..baa4bff9a6fbe0d77d7921865c038060cb5efffd
> 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -4320,9 +4320,8 @@ static void net_rps_action_and_irq_enable(struct
> softnet_data *sd)
>  		while (remsd) {
>  			struct softnet_data *next = remsd->rps_ipi_next;
>
> -			if (cpu_online(remsd->cpu))
> -				smp_call_function_single_async(remsd->cpu,
> -							   &remsd->csd);
> +			smp_call_function_single_async(remsd->cpu,
> +						       &remsd->csd);
>  			remsd = next;
>  		}
>  	} else
>
>
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>
Thanks for the patch Eric. We are seeing this race on ARM.
I will try this and update.

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