Preemptible variants of RCU (CONFIG_TREE_PREEMPT_RCU) get the
same effect, but require that the readers manipulate CPU-local
- counters. These counters allow limited types of blocking
- within RCU read-side critical sections. SRCU also uses
- CPU-local counters, and permits general blocking within
- RCU read-side critical sections. These two variants of
- RCU detect grace periods by sampling these counters.
+ counters. These counters allow limited types of blocking within
+ RCU read-side critical sections. SRCU also uses CPU-local
+ counters, and permits general blocking within RCU read-side
+ critical sections. These variants of RCU detect grace periods
+ by sampling these counters.
o If I am running on a uniprocessor kernel, which can only do one
thing at a time, why should I wait for a grace period?