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Diffstat (limited to 'Documentation/RCU/Design/Data-Structures/Data-Structures.html')
| -rw-r--r-- | Documentation/RCU/Design/Data-Structures/Data-Structures.html | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/RCU/Design/Data-Structures/Data-Structures.html b/Documentation/RCU/Design/Data-Structures/Data-Structures.html index bf7f266e8888..3d0311657533 100644 --- a/Documentation/RCU/Design/Data-Structures/Data-Structures.html +++ b/Documentation/RCU/Design/Data-Structures/Data-Structures.html @@ -1105,6 +1105,7 @@ Its fields are as follows: 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 @@ -1123,12 +1124,19 @@ CPU's transitions to and from dyntick-idle mode, so that this counter 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> |