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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , netdev@vger.kernel.org Subject: Re: [PATCH v2 net-next 0/2] ip: Batch flushing uncached routes per batched device unregistration. Message-ID: References: <20260929201546.1533268-1-kuniyu@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260929201546.1533268-1-kuniyu@google.com> On 2026-09-29 20:15:06, Kuniyuki Iwashima wrote: > Chris J Arges reported high RTNL contention during cleanup_net() > caused by rt_flush_dev() and rt6_uncached_list_flush_dev() iterating > over the global per-cpu uncached route lists for every netdev in > dying netns [0]. > > This series resolves the issue by batching the uncached route > cleanup after __rtnl_unlock() in netdev_run_todo(). > > [0]: https://lore.kernel.org/netdev/20260917-hash-bucket-route-lists-v3-0-30493a37b6eb@cloudflare.com/ > > > Changelog: > v2: > * Drop ->pre_exit_batch() > * Do batching after setting NETDEV_UNREGISTERED in netdev_run_todo() > > v1: https://lore.kernel.org/netdev/20260927202429.2452589-1-kuniyu@google.com/ > > > Kuniyuki Iwashima (2): > ipv4: Batch rt_flush_dev() in netdev_run_todo(). > ipv6: Batch rt6_uncached_list_flush_dev() in netdev_run_todo(). > > include/net/ip6_route.h | 7 +++++++ > include/net/route.h | 6 ++++++ > net/core/dev.c | 5 +++++ > net/ipv4/route.c | 11 +++++++++-- > net/ipv6/route.c | 18 ++++++++++++++---- > 5 files changed, 41 insertions(+), 6 deletions(-) > > -- > 2.56.0.rc1.315.gc6ed9934b7-goog > I was able to test and confirm that this patchset reduces RTNL lock contention with my test case. Please add: Tested-by: Chris J Arges Also for "ipv4: Batch rt_flush_dev() in netdev_run_todo()" please include: Reported-by: Chris J Arges . Thanks, --chris