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authorIngo Molnar <mingo@kernel.org>2013-11-06 07:50:37 +0100
committerIngo Molnar <mingo@kernel.org>2013-11-06 07:50:37 +0100
commitc90423d1de12fbeaf0c898e1db0e962de347302b (patch)
tree8c7a32b37e74155324ae2b556fcc42718ccf29a3 /kernel/rcu
parentecf1f014325ba60f4df35edae1a357c67c5d4eb1 (diff)
parentb8a216269ec0ce2e961d32e6d640d7010b8a818e (diff)
Merge branch 'sched/core' into core/locking, to prepare the kernel/locking/ file move
Conflicts: kernel/Makefile There are conflicts in kernel/Makefile due to file moving in the scheduler tree - resolve them. Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8a2c81e86dda..4c06ddfea7cd 100644
--- 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)