Re: [PATCH v2 00/31] Replacing net_mutex with rw_semaphore

[Kirill Tkhai]

Still no comments :(

Ping, ping, ping.

Here is the second version of big patch set with Eric's commentaries accounted.

What will we do next?

On 20.11.2017 21:32, Kirill Tkhai wrote:
> 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 <ktkhai@xxxxxxxxxxxxx>
>