From patchwork Sun Nov 20 07:22:40 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 126640 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 69CC9B7230 for ; Sun, 20 Nov 2011 18:24:15 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751215Ab1KTHWo (ORCPT ); Sun, 20 Nov 2011 02:22:44 -0500 Received: from www262.sakura.ne.jp ([202.181.97.72]:60829 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751187Ab1KTHWn (ORCPT ); Sun, 20 Nov 2011 02:22:43 -0500 Received: from www262.sakura.ne.jp (ksav32.sakura.ne.jp [210.224.165.212]) by www262.sakura.ne.jp (8.14.3/8.14.3) with ESMTP id pAK7Me5O061999; Sun, 20 Nov 2011 16:22:41 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) X-Nat-Received: from [202.181.97.72]:52983 [ident-empty] by smtp-proxy.isp with TPROXY id 1321773760.2575 Received: from CLAMP (KD175108057186.ppp-bb.dion.ne.jp [175.108.57.186]) by www262.sakura.ne.jp (8.14.3/8.14.3) with ESMTP id pAK7Meq7061995; Sun, 20 Nov 2011 16:22:40 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) To: ebiederm@xmission.com Cc: netdev@vger.kernel.org Subject: [PATCH for 2.6.32 (untested)] netns: Add quota for number of NET_NS instances. From: Tetsuo Handa Message-Id: <201111201622.FDJ51567.VLFHQFMFOOSOtJ@I-love.SAKURA.ne.jp> X-Mailer: Winbiff [Version 2.51 PL2] X-Accept-Language: ja,en,zh Date: Sun, 20 Nov 2011 16:22:40 +0900 Mime-Version: 1.0 X-Anti-Virus: Kaspersky Anti-Virus for Linux Mail Server 5.6.44/RELEASE, bases: 17102011 #5502725, status: clean Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In order to solve below problems, can we add sysctl variable for restricting number of NET_NS instances? -------------------------------------------------- [PATCH for 2.6.32 (untested)] netns: Add quota for number of NET_NS instances. CONFIG_NET_NS support in 2.6.32 has a problem that leads to OOM killer when clone(CLONE_NEWNET) is called instantly. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/720095 But disabling CONFIG_NET_NS broke lxc containers. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/790863 This patch introduces /proc/sys/net/core/netns_max interface that limits max number of network namespace instances. Signed-off-by: Tetsuo Handa --- include/net/sock.h | 4 ++++ net/core/net_namespace.c | 9 +++++++++ net/core/sysctl_net_core.c | 10 ++++++++++ 3 files changed, 23 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- linux-2.6.32.48.orig/include/net/sock.h +++ linux-2.6.32.48/include/net/sock.h @@ -1598,4 +1598,8 @@ extern int sysctl_optmem_max; extern __u32 sysctl_wmem_default; extern __u32 sysctl_rmem_default; +#ifdef CONFIG_NET_NS +extern int max_netns_count; +#endif + #endif /* _SOCK_H */ --- linux-2.6.32.48.orig/net/core/net_namespace.c +++ linux-2.6.32.48/net/core/net_namespace.c @@ -81,12 +81,18 @@ static struct net_generic *net_alloc_gen #ifdef CONFIG_NET_NS static struct kmem_cache *net_cachep; static struct workqueue_struct *netns_wq; +static atomic_t used_netns_count = ATOMIC_INIT(0); +unsigned int max_netns_count; static struct net *net_alloc(void) { struct net *net = NULL; struct net_generic *ng; + atomic_inc(&used_netns_count); + if (atomic_read(&used_netns_count) > max_netns_count) + goto out; + ng = net_alloc_generic(); if (!ng) goto out; @@ -96,7 +102,9 @@ static struct net *net_alloc(void) goto out_free; rcu_assign_pointer(net->gen, ng); + return net; out: + atomic_dec(&used_netns_count); return net; out_free: @@ -115,6 +123,7 @@ static void net_free(struct net *net) #endif kfree(net->gen); kmem_cache_free(net_cachep, net); + atomic_dec(&used_netns_count); } static struct net *net_create(void) --- linux-2.6.32.48.orig/net/core/sysctl_net_core.c +++ linux-2.6.32.48/net/core/sysctl_net_core.c @@ -89,6 +89,16 @@ static struct ctl_table net_core_table[] .mode = 0644, .proc_handler = proc_dointvec }, +#ifdef CONFIG_NET_NS + { + .ctl_name = CTL_UNNUMBERED, + .procname = "netns_max", + .data = &max_netns_count, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, +#endif #endif /* CONFIG_NET */ { .ctl_name = NET_CORE_BUDGET,