Messages in this thread |  | | Date | Tue, 8 Dec 2020 06:58:10 -0800 | | From | "Paul E. McKenney" <> | | Subject | One potential issue with concurrent execution of RCU callbacks... |
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Hello, Frederic,
Boqun just asked if RCU callbacks ran in BH-disabled context to avoid concurrent execution of the same callback. Of course, this raises the question of whether a self-posting callback can have two instances of itself running concurrently while a CPU is in the process of transitioning between softirq and rcuo invocation of callbacks.
I believe that the answer is "no" because BH-disabled context is an implicit RCU read-side critical section. Therefore, the initial invocation of the RCU callback must complete in order for a new grace period to complete, and a new grace period must complete before the second invocation of that same callback to start.
Does that make sense, or am I missing something?
Thanx, Paul
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