[PATCH] ptrace: document the locking rules

[linux-2.6-omap-h63xx.git] / include / linux / rcupdate.h

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 981f9aa433538a8ec2e8b0142da769b2e5a4dd87..970284f571a6d522f60362c0f585ba7d837b1cb2 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -98,19 +98,21 @@ struct rcu_data {
        long            batch;           /* Batch # for current RCU batch */
        struct rcu_head *nxtlist;
        struct rcu_head **nxttail;
-       long            count; /* # of queued items */
+       long            qlen;            /* # of queued callbacks */
        struct rcu_head *curlist;
        struct rcu_head **curtail;
        struct rcu_head *donelist;
        struct rcu_head **donetail;
+       long            blimit;          /* Upper limit on a processed batch */
        int cpu;
        struct rcu_head barrier;
+#ifdef CONFIG_SMP
+       long            last_rs_qlen;    /* qlen during the last resched */
+#endif
 };
 
 DECLARE_PER_CPU(struct rcu_data, rcu_data);
 DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
-extern struct rcu_ctrlblk rcu_ctrlblk;
-extern struct rcu_ctrlblk rcu_bh_ctrlblk;
 
 /*
  * Increment the quiescent state counter.
@@ -130,6 +132,7 @@ static inline void rcu_bh_qsctr_inc(int cpu)
 }
 
 extern int rcu_pending(int cpu);
+extern int rcu_needs_cpu(int cpu);
 
 /**
  * rcu_read_lock - mark the beginning of an RCU read-side critical section.
@@ -240,11 +243,14 @@ extern int rcu_pending(int cpu);
  * This means that all preempt_disable code sequences, including NMI and
  * hardware-interrupt handlers, in progress on entry will have completed
  * before this primitive returns.  However, this does not guarantee that
- * softirq handlers will have completed, since in some kernels
+ * softirq handlers will have completed, since in some kernels, these
+ * handlers can run in process context, and can block.
  *
  * This primitive provides the guarantees made by the (deprecated)
  * synchronize_kernel() API.  In contrast, synchronize_rcu() only
  * guarantees that rcu_read_lock() sections will have completed.
+ * In "classic RCU", these two guarantees happen to be one and
+ * the same, but can differ in realtime RCU implementations.
  */
 #define synchronize_sched() synchronize_rcu()