Subject: Re: [RFC] virtio_net: add local_bh_disable() around u64_stats_update_begin

From: Stephen Hemminger <[email-masked]>
Date: Tue, 16 Oct 2018 11:01:14 -0700

On Tue, 16 Oct 2018 18:55:45 +0200
Sebastian Andrzej Siewior <[email-masked]> wrote:

> Also, ptr->var++ is not an atomic operation even on 64bit CPUs. Which
> means if try_fill_recv() runs on CPU0 (via virtnet_receive()) then the
> worker might run on CPU1.

On modern CPU's increment of native types is atomic but not locked.
u64_stats_update_begin is a no-op on UP and also if BIT_PER_LONG != 32