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Miller" , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, eric.dumazet@gmail.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, Mar 29, 2024 at 4:21=E2=80=AFAM Jason Xing wrote: > > On Fri, Mar 29, 2024 at 1:07=E2=80=AFAM Eric Dumazet wrote: > > > > If the device attached to the packet given to enqueue_to_backlog() > > is not running, we drop the packet. > > > > But we accidentally increase sd->dropped, giving false signals > > to admins: sd->dropped should be reserved to cpu backlog pressure, > > not to temporary glitches at device dismantles. > > It seems that drop action happening is intended in this case (see > commit e9e4dd3267d0c ("net: do not process device backlog during > unregistration")). We can see the strange/unexpected behaviour at > least through simply taking a look at /proc/net/softnet_stat file. I disagree. We are dismantling a device, temporary drops are expected, and this patch adds a more precise drop_reason. I have seen admins being worried about this counter being not zero on carefully tuned hosts. If you think we have to carry these drops forever in /proc/net/softnet_stat, you will have give a more precise reason than "This was intentionally added in 2015" e9e4dd3267d0c5234c changelog was very long, but said nothing about why sd->dropped _had_ to be updated.