Commit-ID: 319362c90f7af92d03714759bea5d2ba7c88e388
Gitweb: http://git.kernel.org/tip/319362c90f7af92d03714759bea5d2ba7c88e388
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Tue, 19 May 2015 14:16:52 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Wed, 15 Jul 2015 14:45:10 -0700
rcu: Provide more diagnostics for stalled GP kthread
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 10 ++++++++--
kernel/rcu/tree.h | 6 +++++-
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 65137bc..1c58cbd 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1178,9 +1178,11 @@ static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp)
j = jiffies;
gpa = READ_ONCE(rsp->gp_activity);
if (j - gpa > 2 * HZ)
- pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x\n",
+ pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x s%d ->state=%#lx\n",
rsp->name, j - gpa,
- rsp->gpnum, rsp->completed, rsp->gp_flags);
+ rsp->gpnum, rsp->completed,
+ rsp->gp_flags, rsp->gp_state,
+ rsp->gp_kthread ? rsp->gp_kthread->state : 0);
}
/*
@@ -2041,6 +2043,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
wait_event_interruptible(rsp->gp_wq,
READ_ONCE(rsp->gp_flags) &
RCU_GP_FLAG_INIT);
+ rsp->gp_state = RCU_GP_DONE_GPS;
/* Locking provides needed memory barrier. */
if (rcu_gp_init(rsp))
break;
@@ -2073,6 +2076,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
(!READ_ONCE(rnp->qsmask) &&
!rcu_preempt_blocked_readers_cgp(rnp)),
j);
+ rsp->gp_state = RCU_GP_DONE_FQS;
/* Locking provides needed memory barriers. */
/* If grace period done, leave loop. */
if (!READ_ONCE(rnp->qsmask) &&
@@ -2110,7 +2114,9 @@ static int __noreturn rcu_gp_kthread(void *arg)
}
/* Handle grace-period end. */
+ rsp->gp_state = RCU_GP_CLEANUP;
rcu_gp_cleanup(rsp);
+ rsp->gp_state = RCU_GP_CLEANED;
}
}
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 4adb7ca..f1f4784 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -527,7 +527,11 @@ struct rcu_state {
/* Values for rcu_state structure's gp_flags field. */
#define RCU_GP_WAIT_INIT 0 /* Initial state. */
#define RCU_GP_WAIT_GPS 1 /* Wait for grace-period start. */
-#define RCU_GP_WAIT_FQS 2 /* Wait for force-quiescent-state time. */
+#define RCU_GP_DONE_GPS 2 /* Wait done for grace-period start. */
+#define RCU_GP_WAIT_FQS 3 /* Wait for force-quiescent-state time. */
+#define RCU_GP_DONE_FQS 4 /* Wait done for force-quiescent-state time. */
+#define RCU_GP_CLEANUP 5 /* Grace-period cleanup started. */
+#define RCU_GP_CLEANED 6 /* Grace-period cleanup complete. */
extern struct list_head rcu_struct_flavors;
--
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