在 2023/6/22 5:09, Bob Pearson 写道:
On 5/8/23 02:56, Zhu Yanjun wrote:
From: Zhu Yanjun <yanjun.zhu@xxxxxxxxx>
When run "ip link add" command to add a rxe rdma link in a net
namespace, normally this rxe rdma link can not work in a net
name space.
The root cause is that a sock listening on udp port 4791 is created
in init_net when the rdma_rxe module is loaded into kernel. That is,
the sock listening on udp port 4791 is created in init_net. Other net
namespace is difficult to use this sock.
The following commits will solve this problem.
In the first commit, move the creating sock listening on udp port 4791
from module_init function to rdma link creating functions. That is,
after the module rdma_rxe is loaded, the sock will not be created.
When run "rdma link add ..." command, the sock will be created. So
when creating a rdma link in the net namespace, the sock will be
created in this net namespace.
In the second commit, the functions udp4_lib_lookup and udp6_lib_lookup
will check the sock exists in the net namespace or not. If yes, rdma
link will increase the reference count of this sock, then continue other
jobs instead of creating a new sock to listen on udp port 4791. Since the
network notifier is global, when the module rdma_rxe is loaded, this
notifier will be registered.
After the rdma link is created, the command "rdma link del" is to
delete rdma link at the same time the sock is checked. If the reference
count of this sock is greater than the sock reference count needed by
udp tunnel, the sock reference count is decreased by one. If equal, it
indicates that this rdma link is the last one. As such, the udp tunnel
is shut down and the sock is closed. The above work should be
implemented in linkdel function. But currently no dellink function in
rxe. So the 3rd commit addes dellink function pointer. And the 4th
commit implements the dellink function in rxe.
To now, it is not necessary to keep a global variable to store the sock
listening udp port 4791. This global variable can be replaced by the
functions udp4_lib_lookup and udp6_lib_lookup totally. Because the
function udp6_lib_lookup is in the fast path, a member variable l_sk6
is added to store the sock. If l_sk6 is NULL, udp6_lib_lookup is called
to lookup the sock, then the sock is stored in l_sk6, in the future,it
can be used directly.
All the above work has been done in init_net. And it can also work in
the net namespace. So the init_net is replaced by the individual net
namespace. This is what the 6th commit does. Because rxe device is
dependent on the net device and the sock listening on udp port 4791,
every rxe device is in exclusive mode in the individual net namespace.
Other rdma netns operations will be considerred in the future.
In the 7th commit, the register_pernet_subsys/unregister_pernet_subsys
functions are added. When a new net namespace is created, the init
function will initialize the sk4 and sk6 socks. Then the 2 socks will
be released when the net namespace is destroyed. The functions
rxe_ns_pernet_sk4/rxe_ns_pernet_set_sk4 will get and set sk4 in the net
namespace. The functions rxe_ns_pernet_sk6/rxe_ns_pernet_set_sk6 will
handle sk6. Then sk4 and sk6 are used in the previous commits.
As the sk4 and sk6 in pernet namespace can be accessed, it is not
necessary to add a new l_sk6. As such, in the 8th commit, the l_sk6 is
replaced with the sk6 in pernet namespace.
Test steps:
1) Suppose that 2 NICs are in 2 different net namespaces.
# ip netns exec net0 ip link
3: eno2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP
link/ether 00:1e:67:a0:22:3f brd ff:ff:ff:ff:ff:ff
altname enp5s0
# ip netns exec net1 ip link
4: eno3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel
link/ether f8:e4:3b:3b:e4:10 brd ff:ff:ff:ff:ff:ff
2) Add rdma link in the different net namespace
net0:
# ip netns exec net0 rdma link add rxe0 type rxe netdev eno2
net1:
# ip netns exec net1 rdma link add rxe1 type rxe netdev eno3
3) Run rping test.
net0
# ip netns exec net0 rping -s -a 192.168.2.1 -C 1&
[1] 1737
# ip netns exec net1 rping -c -a 192.168.2.1 -d -v -C 1
verbose
count 1
...
ping data: rdma-ping-0: ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqr
...
4) Remove the rdma links from the net namespaces.
net0:
# ip netns exec net0 ss -lu
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
UNCONN 0 0 0.0.0.0:4791 0.0.0.0:*
UNCONN 0 0 [::]:4791 [::]:*
# ip netns exec net0 rdma link del rxe0
# ip netns exec net0 ss -lu
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
net1:
# ip netns exec net0 ss -lu
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
UNCONN 0 0 0.0.0.0:4791 0.0.0.0:*
UNCONN 0 0 [::]:4791 [::]:*
# ip netns exec net1 rdma link del rxe1
# ip netns exec net0 ss -lu
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
V4->V5: Rebase the commits to V6.4-rc1
V3->V4: Rebase the commits to rdma-next;
V2->V3: 1) Add "rdma link del" example in the cover letter, and use "ss -lu" to
verify rdma link is removed.
2) Add register_pernet_subsys/unregister_pernet_subsys net namespace
3) Replace l_sk6 with sk6 of pernet_name_space
V1->V2: Add the explicit initialization of sk6.
Zhu Yanjun (8):
RDMA/rxe: Creating listening sock in newlink function
RDMA/rxe: Support more rdma links in init_net
RDMA/nldev: Add dellink function pointer
RDMA/rxe: Implement dellink in rxe
RDMA/rxe: Replace global variable with sock lookup functions
RDMA/rxe: add the support of net namespace
RDMA/rxe: Add the support of net namespace notifier
RDMA/rxe: Replace l_sk6 with sk6 in net namespace
drivers/infiniband/core/nldev.c | 6 ++
drivers/infiniband/sw/rxe/Makefile | 3 +-
drivers/infiniband/sw/rxe/rxe.c | 35 +++++++-
drivers/infiniband/sw/rxe/rxe_net.c | 113 +++++++++++++++++------
drivers/infiniband/sw/rxe/rxe_net.h | 9 +-
drivers/infiniband/sw/rxe/rxe_ns.c | 134 ++++++++++++++++++++++++++++ip netns add test
drivers/infiniband/sw/rxe/rxe_ns.h | 17 ++++
include/rdma/rdma_netlink.h | 2 +
8 files changed, 279 insertions(+), 40 deletions(-)
create mode 100644 drivers/infiniband/sw/rxe/rxe_ns.c
create mode 100644 drivers/infiniband/sw/rxe/rxe_ns.hip netns add test
Zhu,
I did some simple experiments on netns functionality.
With your patch set applied and rxe0 created on enp6s0 and rxe1 created on lo in the default namespace
# sudo ip netns add test
# ip netns
test
# sudo ip netns exec test ip link
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
# sudo ip netns exec test ip link set dev lo up
# sudo ip netns exec test ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
# sudo ip netns exec test ip addr add dev lo fe80::0200:00ff:fe00:0000/64
[rxe doesn't work unless this IPV6 address is set]
# sudo ip netns exec test ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 fe80::200:ff:fe00:0/64 scope link
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
# sudo ip netns exec test ls /sys/class/infiniband
rxe0 rxe1
[These show up even though the ndevs do *not* belong to the test namespace! Probably OK.]
# sudo ip netns exec test rdma link add rxe2 type rxe netdev lo
# ls /sys/class/infiniband
rxe0 rxe1 rxe2
[The new rxe device shows up in the default namespace. At least we're consistent.]
# ib_send_bw -d rxe0 ... 192.168.0.27
[Works. Didn't break the existing rxe devices. Expected]
# ib_send_bw -d rxe1 ... 127.0.0.1
[Works. Expected]
# ib_send_bw -d rxe2 ... 127.0.0.1
IB device rxe2 not found
Unable to find the Infiniband/RoCE device
[Not work. Expected.]
# sudo ip netns exec test ib_send_bw -d rxe2 ... 127.0.0.1
IB device rxe2 not found
Unable to find the Infiniband/RoCE device
[Also not work. Turns out rxe2 device is gone after failure. Not expected.]
# sudo ip netns exec test rdma link add rxe2 type rxe netdev lo
# ls /sys/class/infiniband
rxe0 rxe1 rxe2
[Good. It's back]
# sudo ip netns exec test ib_send_bw -d rxe2 ... 127.0.0.1
[Works in test namespace! Expected.]
# sudo ip netns exec test ib_send_bw -d rxe1 ... 127.0.0.1
[Also works. Definitely not expected.]
My take, it sort of works. But there are some serious issues. You shouldn't be able to use the
rxe2 device in the default namespace. It would be nice if you couldn't see the rxe devices in each
other's namespaces (Like ip link or ip addr hide other namespace's devices.)
Thanks a lot for your testing. Bob.
There are 2 modes in rdma net namespace. One is shared mode, the other
is exclusive mode.
Share mode is the defaut mode. So what you have found is normal.
The followings are the explanations of both shared and exclusive modes.
rdma system set netns shared|exclusive, specifies the RDMA
subsystem mode. Either exclusive or shared. When user wants
to assign dedicated RDMA device to a particular network
namespace, exclusive mode should
be set before creating any network namespace. If there are
active network namespaces and
if one or more RDMA devices exist, changing mode from shared to
exclusive returns error
code EBUSY.
When RDMA subsystem is in shared mode, RDMA device is accessible
in all network namespace.
When RDMA device isolation among multiple network namespaces is
not needed, shared mode
can be used.
It is preferred to not change the subsystem mode when there is
active RDMA traffic
running, even though it is supported.
Zhu Yanjun
Bob
