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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2009-08-24 09:42:01 -0700
committerIngo Molnar <mingo@elte.hu>2009-08-24 20:37:04 +0200
commit33f76148ced0e0618062e302d2a9614efdbd4a06 (patch)
tree82a5c2719301bcb9f20b0597b77e91529f9ec2df
parent7c614d6461399acca5c0ba444f5db49cb332fc08 (diff)
rcu: Add CPU-offline processing for single-node configurations
Add preemptable-RCU plugin to handle the CPU-offline processing. An additional plugin is forthcoming to handle multinode RCU trees, but this current plugin works for configurations up to 32 CPUs (64 CPUs for 64-bit kernels). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <12511321213336-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/rcutree.c2
-rw-r--r--kernel/rcutree_plugin.h24
2 files changed, 26 insertions, 0 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index cc025571407..000b0760987 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -84,6 +84,7 @@ extern long rcu_batches_completed_sched(void);
static void cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp,
struct rcu_node *rnp, unsigned long flags);
static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags);
+static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp);
static void __rcu_process_callbacks(struct rcu_state *rsp,
struct rcu_data *rdp);
static void __call_rcu(struct rcu_head *head,
@@ -920,6 +921,7 @@ static void rcu_offline_cpu(int cpu)
{
__rcu_offline_cpu(cpu, &rcu_sched_state);
__rcu_offline_cpu(cpu, &rcu_bh_state);
+ rcu_preempt_offline_cpu(cpu);
}
#else /* #ifdef CONFIG_HOTPLUG_CPU */
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index cd2ab67400c..201334cdc20 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -259,6 +259,18 @@ static int rcu_preempted_readers(struct rcu_node *rnp)
return !list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]);
}
+#ifdef CONFIG_HOTPLUG_CPU
+
+/*
+ * Do CPU-offline processing for preemptable RCU.
+ */
+static void rcu_preempt_offline_cpu(int cpu)
+{
+ __rcu_offline_cpu(cpu, &rcu_preempt_state);
+}
+
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+
/*
* Check for a quiescent state from the current CPU. When a task blocks,
* the task is recorded in the corresponding CPU's rcu_node structure,
@@ -395,6 +407,18 @@ static int rcu_preempted_readers(struct rcu_node *rnp)
return 0;
}
+#ifdef CONFIG_HOTPLUG_CPU
+
+/*
+ * Because preemptable RCU does not exist, it never needs CPU-offline
+ * processing.
+ */
+static void rcu_preempt_offline_cpu(int cpu)
+{
+}
+
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+
/*
* Because preemptable RCU does not exist, it never has any callbacks
* to check.