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From:   Tung Quang Nguyen <tung.q.nguyen@dektech.com.au>
To:     xu <xu.xin.sc@gmail.com>
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Subject: RE: [RFC PATCH] net/tipc: reduce tipc_node lock holding time in
 tipc_rcv
Thread-Topic: [RFC PATCH] net/tipc: reduce tipc_node lock holding time in
 tipc_rcv
Thread-Index: AQHaHbcmsQ7KURUzRkaicoeZO+zrDrCHRXnwgAAp2oCAAAQK0IABobQAgAAL9yCAABqGgIAAB5KQ
Date:   Fri, 24 Nov 2023 10:22:28 +0000
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>Why can't use le->lock instead of node's lock to protect it in tipc_link_r=
cv.
>
I have already explained:
__tipc_node_link_down()
{
    ...
   if (!l || tipc_link_is_reset(l)) <-- read link status
    ...
}
>>What I showed you were just 2 use cases (link reset/delete). There are mo=
re use cases (netlink, transmit path etc) that need proper
>locks.
>
>The same. We can also add spin_lock_bh(&le->lock) to protect the link in o=
ther places where it changes the link status in addition to
>'reset/delete'. Because using node lock to protect the link in tipc_link_r=
cv is really wasting CPU performance.
>
If you want to change current lock policy, you need to submit a complete/co=
rrect patch. I will acknowledge this patch if I can see a significant impro=
vement in my test.