[lttng-dev] QSBR urcu read lock question
mathieu.desnoyers at efficios.com
Thu Apr 15 12:00:28 EDT 2021
----- On Apr 15, 2021, at 10:54 AM, lbj lbj137 at yahoo.com wrote:
> Thanks so much for your wealth if information and timely responses, they are
> greatly appreciated. Final question: is there any harm in explicitly calling
> rcu_thread_online/rcu_thread_offline from within my call_rcu callback function?
> From what you described it sounds like it would be redundant, but presumably
> would be harmless. Correct? Thanks again.
You could indeed invoke pairs of:
rcu_thread_offline(); <--- emphasis on _offline_ here.
[ long wait ... ]
in that specific order within the call-rcu worker thread. Note that the qsbr state
of the call-rcu worker thread is "online" when it invokes the callbacks, so each callback
should make sure that state is back to "online" before it returns control back
to its caller.
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