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-rw-r--r--kernel/rcutree_plugin.h33
1 files changed, 23 insertions, 10 deletions
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index d084ae3f281..170814dc418 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -28,6 +28,7 @@
#include <linux/gfp.h>
#include <linux/oom.h>
#include <linux/smpboot.h>
+#include <linux/tick.h>
#define RCU_KTHREAD_PRIO 1
@@ -1705,7 +1706,7 @@ static void rcu_prepare_for_idle(int cpu)
return;
/* If this is a no-CBs CPU, no callbacks, just return. */
- if (is_nocb_cpu(cpu))
+ if (rcu_is_nocb_cpu(cpu))
return;
/*
@@ -1747,7 +1748,7 @@ static void rcu_cleanup_after_idle(int cpu)
struct rcu_data *rdp;
struct rcu_state *rsp;
- if (is_nocb_cpu(cpu))
+ if (rcu_is_nocb_cpu(cpu))
return;
rcu_try_advance_all_cbs();
for_each_rcu_flavor(rsp) {
@@ -2052,7 +2053,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
}
/* Is the specified CPU a no-CPUs CPU? */
-static bool is_nocb_cpu(int cpu)
+bool rcu_is_nocb_cpu(int cpu)
{
if (have_rcu_nocb_mask)
return cpumask_test_cpu(cpu, rcu_nocb_mask);
@@ -2110,7 +2111,7 @@ static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp,
bool lazy)
{
- if (!is_nocb_cpu(rdp->cpu))
+ if (!rcu_is_nocb_cpu(rdp->cpu))
return 0;
__call_rcu_nocb_enqueue(rdp, rhp, &rhp->next, 1, lazy);
if (__is_kfree_rcu_offset((unsigned long)rhp->func))
@@ -2134,7 +2135,7 @@ static bool __maybe_unused rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp,
long qll = rsp->qlen_lazy;
/* If this is not a no-CBs CPU, tell the caller to do it the old way. */
- if (!is_nocb_cpu(smp_processor_id()))
+ if (!rcu_is_nocb_cpu(smp_processor_id()))
return 0;
rsp->qlen = 0;
rsp->qlen_lazy = 0;
@@ -2306,11 +2307,6 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
{
}
-static bool is_nocb_cpu(int cpu)
-{
- return false;
-}
-
static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp,
bool lazy)
{
@@ -2337,3 +2333,20 @@ static bool init_nocb_callback_list(struct rcu_data *rdp)
}
#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
+
+/*
+ * An adaptive-ticks CPU can potentially execute in kernel mode for an
+ * arbitrarily long period of time with the scheduling-clock tick turned
+ * off. RCU will be paying attention to this CPU because it is in the
+ * kernel, but the CPU cannot be guaranteed to be executing the RCU state
+ * machine because the scheduling-clock tick has been disabled. Therefore,
+ * if an adaptive-ticks CPU is failing to respond to the current grace
+ * period and has not be idle from an RCU perspective, kick it.
+ */
+static void rcu_kick_nohz_cpu(int cpu)
+{
+#ifdef CONFIG_NO_HZ_FULL
+ if (tick_nohz_full_cpu(cpu))
+ smp_send_reschedule(cpu);
+#endif /* #ifdef CONFIG_NO_HZ_FULL */
+}