2 int dynticks_nmi_nesting;
3 atomic_t dynticks;
4 int rcu_sched_qs_mask;
+ 5 unsigned long rcu_qs_ctr;
</pre>
<p>The <tt>->dynticks_nesting</tt> field counts the
has an even value when the CPU is in dyntick-idle mode and an odd
value otherwise.
-</p><p>Finally, the <tt>->rcu_sched_qs_mask</tt> field is used
+</p><p>The <tt>->rcu_sched_qs_mask</tt> field is used
to record the fact that the RCU core code would really like to
-see a quiescent state from the corresponding CPU.
+see a quiescent state from the corresponding CPU, so much so that
+it is willing to call for heavy-weight dyntick-counter operations.
This flag is checked by RCU's context-switch and <tt>cond_resched()</tt>
code, which provide a momentary idle sojourn in response.
+</p><p>Finally the <tt>->rcu_qs_ctr</tt> field is used to record
+quiescent states from <tt>cond_resched()</tt>.
+Because <tt>cond_resched()</tt> can execute quite frequently, this
+must be quite lightweight, as in a non-atomic increment of this
+per-CPU field.
+
<table>
<tr><th> </th></tr>
<tr><th align="left">Quick Quiz:</th></tr>