doc: Emphasize that "toy" RCU requires recursive rwlock

Reported-by: "yangzc@uit.com.cn" <yangzc@uit.com.cn>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2017-03-28 19:57:45 -07:00
parent 93728af0a1
commit d3d3a3ccc4

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@ -562,7 +562,9 @@ This section presents a "toy" RCU implementation that is based on
familiar locking primitives. Its overhead makes it a non-starter for
real-life use, as does its lack of scalability. It is also unsuitable
for realtime use, since it allows scheduling latency to "bleed" from
one read-side critical section to another.
one read-side critical section to another. It also assumes recursive
reader-writer locks: If you try this with non-recursive locks, and
you allow nested rcu_read_lock() calls, you can deadlock.
However, it is probably the easiest implementation to relate to, so is
a good starting point.