From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A0371F55E4; Tue, 21 Jan 2025 18:10:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737483000; cv=none; b=Oa2GgZ3AqIkDXGo/99kY65QlBxbBCB6CwMDnXaM44//Fxncr0Ldp0wka0twONtKV7i8zjSNCPF3kOtjZvR7U7vUGTakt54b0ib8gEmB2//nvrWtJqL4Lb/XCuCd4uoxviUW6Ao8WDIHkPahn9+bRfeLuFJCufNKbCRAZPARNeXk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737483000; c=relaxed/simple; bh=wwCljFcI4a3OR/mrRavRSmr/xXazSZ0sGFj519F70ew=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GQN4nP9ezVbsYwlyZJO9688BuY7YjJxDPj0RppRDUwLY3zD8Wj8w9Bj9VEg6ZKPLMmoADj7BYiTL7MhuQ1Sz3DniT2d7pluhIbpIfx/orlEN2xbgarAndV90RZy5ILUzDiFFFS0ECRlMG2ZWrNNTE6b1wOJz7EWocrGTMFQVi+I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fWsK0/sA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="fWsK0/sA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B155C4CEDF; Tue, 21 Jan 2025 18:09:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1737482999; bh=wwCljFcI4a3OR/mrRavRSmr/xXazSZ0sGFj519F70ew=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fWsK0/sAiMVIs/3GmZxT814KElbDWo/W6i4hqd9ZxbvdFYmuB0BzGnWya2bOXibIs N5ybmMcUqnz/W6SP6JnP+H20hiqbaaRUK2eV3beOqcHRNlApZpouHg1C5+OWxRh7BI XdFqsJtYVsUB5z2pE4TD/3pkB47zbP6kvPmXqN2I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Antoine Tenart , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 082/127] net: add exit_batch_rtnl() method Date: Tue, 21 Jan 2025 18:52:34 +0100 Message-ID: <20250121174532.813984483@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250121174529.674452028@linuxfoundation.org> References: <20250121174529.674452028@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit fd4f101edbd9f99567ab2adb1f2169579ede7c13 ] Many (struct pernet_operations)->exit_batch() methods have to acquire rtnl. In presence of rtnl mutex pressure, this makes cleanup_net() very slow. This patch adds a new exit_batch_rtnl() method to reduce number of rtnl acquisitions from cleanup_net(). exit_batch_rtnl() handlers are called while rtnl is locked, and devices to be killed can be queued in a list provided as their second argument. A single unregister_netdevice_many() is called right before rtnl is released. exit_batch_rtnl() handlers are called before ->exit() and ->exit_batch() handlers. Signed-off-by: Eric Dumazet Reviewed-by: Antoine Tenart Link: https://lore.kernel.org/r/20240206144313.2050392-2-edumazet@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 46841c7053e6 ("gtp: Use for_each_netdev_rcu() in gtp_genl_dump_pdp().") Signed-off-by: Sasha Levin --- include/net/net_namespace.h | 3 +++ net/core/net_namespace.c | 31 ++++++++++++++++++++++++++++++- 2 files changed, 33 insertions(+), 1 deletion(-) diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index c47baa623ba58..d184b832166b6 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -389,6 +389,9 @@ struct pernet_operations { void (*pre_exit)(struct net *net); void (*exit)(struct net *net); void (*exit_batch)(struct list_head *net_exit_list); + /* Following method is called with RTNL held. */ + void (*exit_batch_rtnl)(struct list_head *net_exit_list, + struct list_head *dev_kill_list); unsigned int *id; size_t size; }; diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 3addbce20f8ed..1e9e76c4ff5be 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -313,8 +313,9 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) { /* Must be called with pernet_ops_rwsem held */ const struct pernet_operations *ops, *saved_ops; - int error = 0; LIST_HEAD(net_exit_list); + LIST_HEAD(dev_kill_list); + int error = 0; refcount_set(&net->ns.count, 1); refcount_set(&net->passive, 1); @@ -350,6 +351,15 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) synchronize_rcu(); + ops = saved_ops; + rtnl_lock(); + list_for_each_entry_continue_reverse(ops, &pernet_list, list) { + if (ops->exit_batch_rtnl) + ops->exit_batch_rtnl(&net_exit_list, &dev_kill_list); + } + unregister_netdevice_many(&dev_kill_list); + rtnl_unlock(); + ops = saved_ops; list_for_each_entry_continue_reverse(ops, &pernet_list, list) ops_exit_list(ops, &net_exit_list); @@ -554,6 +564,7 @@ static void cleanup_net(struct work_struct *work) struct net *net, *tmp, *last; struct llist_node *net_kill_list; LIST_HEAD(net_exit_list); + LIST_HEAD(dev_kill_list); /* Atomically snapshot the list of namespaces to cleanup */ net_kill_list = llist_del_all(&cleanup_list); @@ -594,6 +605,14 @@ static void cleanup_net(struct work_struct *work) */ synchronize_rcu(); + rtnl_lock(); + list_for_each_entry_reverse(ops, &pernet_list, list) { + if (ops->exit_batch_rtnl) + ops->exit_batch_rtnl(&net_exit_list, &dev_kill_list); + } + unregister_netdevice_many(&dev_kill_list); + rtnl_unlock(); + /* Run all of the network namespace exit methods */ list_for_each_entry_reverse(ops, &pernet_list, list) ops_exit_list(ops, &net_exit_list); @@ -1134,7 +1153,17 @@ static void free_exit_list(struct pernet_operations *ops, struct list_head *net_ { ops_pre_exit_list(ops, net_exit_list); synchronize_rcu(); + + if (ops->exit_batch_rtnl) { + LIST_HEAD(dev_kill_list); + + rtnl_lock(); + ops->exit_batch_rtnl(net_exit_list, &dev_kill_list); + unregister_netdevice_many(&dev_kill_list); + rtnl_unlock(); + } ops_exit_list(ops, net_exit_list); + ops_free_list(ops, net_exit_list); } -- 2.39.5