Kirill Tkhai <ktk...@virtuozzo.com> writes: > Hi, > > this is continuation of discussion from here: > > https://lkml.org/lkml/2017/11/14/298 > > The plan has changed a little bit, so I'd be happy to hear > people's comments, before I dived into all 400+ pernet subsys > and devices. > > The patch set adds pernet sys list ahead of subsys and device, > and it's used for pernet_operations, which may be executed > in parallel with any other pernet_operations methods. Also, > some high-priority ops converted (up to registered using > postcore_initcall(), and some subsys_initcall()) in order > of appearance. The sequence in setup_net() is following: > > 1)execute all the callbacks from pernet_sys list > 2)lock net_mutex > 3)execute all the callbacks from pernet_subsys list > 4)execute all the callbacks from pernet_device list > 5)unlock net_mutex > > There was not pernet_operations, requiring additional > synchronization, yet, but I've bumped in another problem. > The problem is that some drivers may be compiled as modules > and as kernel-image part. They register pernet_operations > from device_initcall() for example. This initcall executes > in different time comparing to in-kernel built-in only > drivers. > > Imagine, we have three state driverA, and boolean driverB. > driverA registers pernet_subsys from subsys_initcall(). > driverB registers pernet_subsys from fs_initcall(). > So, here we have two cases: > > driverA is module driverA is built-in > -------------------- ------------------- > register driverB ops register driverA ops > register driverA ops register driverB ops > > So, the order is different. When converting driver one-by-one, > it's impossible to make the order true for all .config > states, because of the above. So, the bisect won't work. > > And it seems, it's just the same as to convert pernet_operations > from all the files in file alphabetical order. What do you > think about this? (Note, the patches has no such a problem > at the moment, as there are all in-kernel early core drivers). > > Maybe there are another comments on the code.
I think there is an solution in the center. Just have a count (protected by down_write net_sem) of the number of modules that still need net_mutex. If the count is non-zero we take net_mutex in setup_net and cleanup_net. That way limited network stacks can see the benefit and actively test the parallism, while other configurations can be safe in still having the same behavior. Eric > --- > > Kirill Tkhai (25): > 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: Add primitives to update heads of pernet_list sublists > net: Add pernet sys and registration functions > net: Make sys sublist pernet_operations executed out of net_mutex > net: Move proc_net_ns_ops to pernet_sys list > net: Move net_ns_ops to pernet_sys list > net: Move sysctl_pernet_ops to pernet_sys list > net: Move netfilter_net_ops to pernet_sys list > net: Move nf_log_net_ops to pernet_sys list > net: Move net_inuse_ops to pernet_sys list > net: Move net_defaults_ops to pernet_sys list > net: Move netlink_net_ops to pernet_sys list > net: Move rtnetlink_net_ops to pernet_sys list > net: Move audit_net_ops to pernet_sys list > net: Move uevent_net_ops to pernet_sys list > net: Move proto_net_ops to pernet_sys list > net: Move pernet_subsys, registered via net_dev_init(), to pernet_sys > list > net: Move fib_* pernet_operations, registered via subsys_initcall(), to > pernet_sys list > net: Move subsys_initcall() registered pernet_operations from net/sched > to pernet_sys list > net: Move genl_pernet_ops to pernet_sys list > net: Move wext_pernet_ops to pernet_sys list > net: Move sysctl_core_ops to pernet_sys list > > > fs/proc/proc_net.c | 2 > include/linux/rtnetlink.h | 1 > include/net/net_namespace.h | 2 > kernel/audit.c | 2 > lib/kobject_uevent.c | 2 > net/core/dev.c | 2 > net/core/fib_notifier.c | 2 > net/core/fib_rules.c | 2 > net/core/net-procfs.c | 4 - > net/core/net_namespace.c | 203 > +++++++++++++++++++++++++++++++++---------- > net/core/rtnetlink.c | 6 + > net/core/sock.c | 4 - > net/core/sysctl_net_core.c | 2 > net/netfilter/core.c | 2 > net/netfilter/nf_log.c | 2 > net/netlink/af_netlink.c | 2 > net/netlink/genetlink.c | 2 > net/sched/act_api.c | 2 > net/sched/sch_api.c | 2 > net/sysctl_net.c | 2 > net/wireless/wext-core.c | 2 > 21 files changed, 183 insertions(+), 67 deletions(-) > > -- > Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>
