On Mon, Nov 14, 2016 at 4:28 PM, Eric Dumazet <[email protected]> wrote: > From: Eric Dumazet <[email protected]> > > Rolf Neugebauer reported very long delays at netns dismantle. > > Eric W. Biederman was kind enough to look at this problem > and noticed synchronize_net() occurring from netif_napi_del() that was > added in linux-4.5 > > Busy polling makes no sense for tunnels NAPI. > If busy poll is used for sessions over tunnels, the poller will need to > poll the physical device queue anyway. > > netif_tx_napi_add() could be used here, but function name is misleading, > and renaming it is not stable material, so set NAPI_STATE_NO_BUSY_POLL > bit directly. > > This will avoid inserting gro_cells napi structures in napi_hash[] > and avoid the problematic synchronize_net() (per possible cpu) that > Rolf reported. > > Fixes: 93d05d4a320c ("net: provide generic busy polling to all NAPI drivers") > Signed-off-by: Eric Dumazet <[email protected]> > Reported-by: Rolf Neugebauer <[email protected]> > Reported-by: Eric W. Biederman <[email protected]>
Acked-by: Cong Wang <[email protected]>
