Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755300AbcJUCqg (ORCPT ); Thu, 20 Oct 2016 22:46:36 -0400 Received: from mail-pf0-f196.google.com ([209.85.192.196]:33484 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755205AbcJUCqa (ORCPT ); Thu, 20 Oct 2016 22:46:30 -0400 From: Andrei Vagin To: "David S. Miller" Cc: "Eric W . Biederman" , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Andrei Vagin Subject: [PATCH] net: skip genenerating uevents for network namespaces that are exiting Date: Thu, 20 Oct 2016 19:46:26 -0700 Message-Id: <1477017986-18889-1-git-send-email-avagin@openvz.org> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2800 Lines: 82 No one can see these events, because a network namespace can not be destroyed, if it has sockets. My experiments shows that net namespaces are destroyed more 30% faster with this optimization. Here is a perf output for destroying network namespaces without this patch. - 94.76% 0.02% kworker/u48:1 [kernel.kallsyms] [k] cleanup_net - 94.74% cleanup_net - 94.64% ops_exit_list.isra.4 - 41.61% default_device_exit_batch - 41.47% unregister_netdevice_many - rollback_registered_many - 40.36% netdev_unregister_kobject - 14.55% device_del + 13.71% kobject_uevent - 13.04% netdev_queue_update_kobjects + 12.96% kobject_put - 12.72% net_rx_queue_update_kobjects kobject_put - kobject_release + 12.69% kobject_uevent + 0.80% call_netdevice_notifiers_info + 19.57% nfsd_exit_net + 11.15% tcp_net_metrics_exit + 8.25% rpcsec_gss_exit_net It's very critical to optimize the exit path for network namespaces, because they are destroyed under net_mutex and many namespaces can be destroyed for one iteration. Cc: "David S. Miller" Cc: Eric W. Biederman Signed-off-by: Andrei Vagin --- net/core/net-sysfs.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 6e4f347..c02515e 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -950,10 +950,13 @@ net_rx_queue_update_kobjects(struct net_device *dev, int old_num, int new_num) } while (--i >= new_num) { + struct kobject *kobj = &dev->_rx[i].kobj; + + if (!list_empty(&dev_net(dev)->exit_list)) + kobj->uevent_suppress = 1; if (dev->sysfs_rx_queue_group) - sysfs_remove_group(&dev->_rx[i].kobj, - dev->sysfs_rx_queue_group); - kobject_put(&dev->_rx[i].kobj); + sysfs_remove_group(kobj, dev->sysfs_rx_queue_group); + kobject_put(kobj); } return error; @@ -1340,6 +1343,8 @@ netdev_queue_update_kobjects(struct net_device *dev, int old_num, int new_num) while (--i >= new_num) { struct netdev_queue *queue = dev->_tx + i; + if (!list_empty(&dev_net(dev)->exit_list)) + queue->kobj.uevent_suppress = 1; #ifdef CONFIG_BQL sysfs_remove_group(&queue->kobj, &dql_group); #endif @@ -1525,6 +1530,9 @@ void netdev_unregister_kobject(struct net_device *ndev) { struct device *dev = &(ndev->dev); + if (!list_empty(&dev_net(ndev)->exit_list)) + dev->kobj.uevent_suppress = 1; + kobject_get(&dev->kobj); remove_queue_kobjects(ndev); -- 2.7.4