Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

[cascardo/linux.git] / kernel / rcu / tree.c

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8a2c81e..4c06ddf 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -916,6 +916,12 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
        force_quiescent_state(rsp);  /* Kick them all. */
 }
 
+/*
+ * This function really isn't for public consumption, but RCU is special in
+ * that context switches can allow the state machine to make progress.
+ */
+extern void resched_cpu(int cpu);
+
 static void print_cpu_stall(struct rcu_state *rsp)
 {
        int cpu;
@@ -945,7 +951,14 @@ static void print_cpu_stall(struct rcu_state *rsp)
                                     3 * rcu_jiffies_till_stall_check() + 3;
        raw_spin_unlock_irqrestore(&rnp->lock, flags);
 
-       set_need_resched();  /* kick ourselves to get things going. */
+       /*
+        * Attempt to revive the RCU machinery by forcing a context switch.
+        *
+        * A context switch would normally allow the RCU state machine to make
+        * progress and it could be we're stuck in kernel space without context
+        * switches for an entirely unreasonable amount of time.
+        */
+       resched_cpu(smp_processor_id());
 }
 
 static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)