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doc: Update checklist.rst discussion of callback execution

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This commit completes the list of call_rcu*() functions that are not
guaranteed to have their callbacks executing on the same CPU.  While in
the area, fix an unrelated typo.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
This commit is contained in:
Paul E. McKenney 2023-12-13 09:49:20 -08:00 committed by Boqun Feng
parent 56823e9f60
commit e15aed426a
1 changed files with 11 additions and 10 deletions
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21
Documentation/RCU/checklist.rst
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@ -383,16 +383,17 @@ over a rather long period of time, but improvements are always welcome!
must use whatever locking or other synchronization is required
to safely access and/or modify that data structure.
Do not assume that RCU callbacks will be executed on the same
CPU that executed the corresponding call_rcu() or call_srcu().
For example, if a given CPU goes offline while having an RCU
callback pending, then that RCU callback will execute on some
surviving CPU. (If this was not the case, a self-spawning RCU
callback would prevent the victim CPU from ever going offline.)
Furthermore, CPUs designated by rcu_nocbs= might well *always*
have their RCU callbacks executed on some other CPUs, in fact,
for some real-time workloads, this is the whole point of using
the rcu_nocbs= kernel boot parameter.
Do not assume that RCU callbacks will be executed on
the same CPU that executed the corresponding call_rcu(),
call_srcu(), call_rcu_tasks(), call_rcu_tasks_rude(), or
call_rcu_tasks_trace(). For example, if a given CPU goes offline
while having an RCU callback pending, then that RCU callback
will execute on some surviving CPU. (If this was not the case,
a self-spawning RCU callback would prevent the victim CPU from
ever going offline.) Furthermore, CPUs designated by rcu_nocbs=
might well *always* have their RCU callbacks executed on some
other CPUs, in fact, for some real-time workloads, this is the
whole point of using the rcu_nocbs= kernel boot parameter.
In addition, do not assume that callbacks queued in a given order
will be invoked in that order, even if they all are queued on the