Hi, there is the second version of patchset introducing net_sem instead of net_mutex. The patchset adds net_sem in addition to net_mutex and allows pernet_operations to be async. This flag means, the pernet_operations methods are safe to be executed with any othor pernet_operations (un)initializing another net.
If there are only async pernet_operations in the system, net_mutex is not used either for setup_net() or for cleanup_net(). The flag is little easier, then (un)register_pernet_sys(), as it changes one line only. Also, it requires less changes in code. In future, when all pernet_operations are async, we'll just remove this struct field. The pernet_operations converted in this patchset allow to create minimal .config to have network working, and the changes improve the performance like you may see below: %for i in {1..10000}; do unshare -n bash -c exit; done *before* real 1m40,377s user 0m9,672s sys 0m19,928s *after* real 0m17,007s user 0m5,311s sys 0m11,779 (5.8 times faster) --- Kirill Tkhai (31): net: Assign net to net_namespace_list in setup_net() net: Cleanup copy_net_ns() net: Introduce net_sem for protection of pernet_list net: Move mutex_unlock() in cleanup_net() up net: Allow pernet_operations to be executed in parallel net: Convert proc_net_ns_ops net: Convert net_ns_ops methods net: Convert sysctl_pernet_ops net: Convert netfilter_net_ops net: Convert nf_log_net_ops net: Convert net_inuse_ops net: Convert net_defaults_ops net: Convert netlink_net_ops net: Convert rtnetlink_net_ops net: Convert audit_net_ops net: Convert uevent_net_ops net: Convert proto_net_ops net: Convert pernet_subsys ops, registered via net_dev_init() net: Convert fib_* pernet_operations, registered via subsys_initcall net: Convert subsys_initcall() registered pernet_operations from net/sched net: Convert genl_pernet_ops net: Convert wext_pernet_ops net: Convert sysctl_core_ops net: Convert pernet_subsys, registered from inet_init() net: Convert unix_net_ops net: Convert packet_net_ops net: Convert ipv4_sysctl_ops net: Convert addrconf_ops net: Convert loopback_net_ops net: Convert default_device_ops net: Convert diag_net_ops drivers/net/loopback.c | 1 fs/proc/proc_net.c | 1 include/linux/rtnetlink.h | 1 include/net/net_namespace.h | 6 +++ kernel/audit.c | 1 lib/kobject_uevent.c | 1 net/core/dev.c | 2 + net/core/fib_notifier.c | 1 net/core/fib_rules.c | 1 net/core/net-procfs.c | 2 + net/core/net_namespace.c | 94 +++++++++++++++++++++++++------------------ net/core/rtnetlink.c | 5 +- net/core/sock.c | 2 + net/core/sock_diag.c | 1 net/core/sysctl_net_core.c | 1 net/ipv4/af_inet.c | 2 + net/ipv4/arp.c | 1 net/ipv4/devinet.c | 1 net/ipv4/fib_frontend.c | 1 net/ipv4/icmp.c | 1 net/ipv4/igmp.c | 1 net/ipv4/ip_fragment.c | 1 net/ipv4/ipmr.c | 1 net/ipv4/ping.c | 1 net/ipv4/proc.c | 1 net/ipv4/raw.c | 1 net/ipv4/route.c | 4 ++ net/ipv4/sysctl_net_ipv4.c | 1 net/ipv4/tcp_ipv4.c | 2 + net/ipv4/tcp_metrics.c | 1 net/ipv4/udp.c | 1 net/ipv4/udplite.c | 1 net/ipv4/xfrm4_policy.c | 1 net/ipv6/addrconf.c | 1 net/netfilter/core.c | 1 net/netfilter/nf_log.c | 1 net/netlink/af_netlink.c | 1 net/netlink/genetlink.c | 1 net/packet/af_packet.c | 1 net/sched/act_api.c | 1 net/sched/sch_api.c | 1 net/sysctl_net.c | 1 net/unix/af_unix.c | 1 net/wireless/wext-core.c | 1 net/xfrm/xfrm_policy.c | 1 45 files changed, 114 insertions(+), 41 deletions(-) -- Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>