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Diffstat (limited to 'Documentation/RCU/whatisRCU.rst')
| -rw-r--r-- | Documentation/RCU/whatisRCU.rst | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst index fb3ff76c3e73..17e95ab2a201 100644 --- a/Documentation/RCU/whatisRCU.rst +++ b/Documentation/RCU/whatisRCU.rst @@ -497,8 +497,7 @@ long -- there might be other high-priority work to be done. In such cases, one uses call_rcu() rather than synchronize_rcu(). The call_rcu() API is as follows:: - void call_rcu(struct rcu_head * head, - void (*func)(struct rcu_head *head)); + void call_rcu(struct rcu_head *head, rcu_callback_t func); This function invokes func(head) after a grace period has elapsed. This invocation might happen from either softirq or process context, @@ -684,7 +683,7 @@ Quick Quiz #1: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This section presents a "toy" RCU implementation that is based on "classic RCU". It is also short on performance (but only for updates) and -on features such as hotplug CPU and the ability to run in CONFIG_PREEMPT +on features such as hotplug CPU and the ability to run in CONFIG_PREEMPTION kernels. The definitions of rcu_dereference() and rcu_assign_pointer() are the same as those shown in the preceding section, so they are omitted. :: @@ -740,7 +739,7 @@ Quick Quiz #2: Quick Quiz #3: If it is illegal to block in an RCU read-side critical section, what the heck do you do in - PREEMPT_RT, where normal spinlocks can block??? + CONFIG_PREEMPT_RT, where normal spinlocks can block??? :ref:`Answers to Quick Quiz <8_whatisRCU>` @@ -1094,7 +1093,7 @@ Quick Quiz #2: overhead is **negative**. Answer: - Imagine a single-CPU system with a non-CONFIG_PREEMPT + Imagine a single-CPU system with a non-CONFIG_PREEMPTION kernel where a routing table is used by process-context code, but can be updated by irq-context code (for example, by an "ICMP REDIRECT" packet). The usual way of handling @@ -1121,10 +1120,10 @@ Answer: Quick Quiz #3: If it is illegal to block in an RCU read-side critical section, what the heck do you do in - PREEMPT_RT, where normal spinlocks can block??? + CONFIG_PREEMPT_RT, where normal spinlocks can block??? Answer: - Just as PREEMPT_RT permits preemption of spinlock + Just as CONFIG_PREEMPT_RT permits preemption of spinlock critical sections, it permits preemption of RCU read-side critical sections. It also permits spinlocks blocking while in RCU read-side critical |