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-rw-r--r--include/trace/events/rcu.h38
-rw-r--r--kernel/rcutiny.c10
-rw-r--r--kernel/rcutiny_plugin.h25
-rw-r--r--kernel/rcutree.c8
4 files changed, 68 insertions, 13 deletions
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index c75418c3ccb8..d2d88bed891b 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -461,27 +461,46 @@ TRACE_EVENT(rcu_invoke_kfree_callback,
/*
* Tracepoint for exiting rcu_do_batch after RCU callbacks have been
- * invoked. The first argument is the name of the RCU flavor and
- * the second argument is number of callbacks actually invoked.
+ * invoked. The first argument is the name of the RCU flavor,
+ * the second argument is number of callbacks actually invoked,
+ * the third argument (cb) is whether or not any of the callbacks that
+ * were ready to invoke at the beginning of this batch are still
+ * queued, the fourth argument (nr) is the return value of need_resched(),
+ * the fifth argument (iit) is 1 if the current task is the idle task,
+ * and the sixth argument (risk) is the return value from
+ * rcu_is_callbacks_kthread().
*/
TRACE_EVENT(rcu_batch_end,
- TP_PROTO(char *rcuname, int callbacks_invoked),
+ TP_PROTO(char *rcuname, int callbacks_invoked,
+ bool cb, bool nr, bool iit, bool risk),
- TP_ARGS(rcuname, callbacks_invoked),
+ TP_ARGS(rcuname, callbacks_invoked, cb, nr, iit, risk),
TP_STRUCT__entry(
__field(char *, rcuname)
__field(int, callbacks_invoked)
+ __field(bool, cb)
+ __field(bool, nr)
+ __field(bool, iit)
+ __field(bool, risk)
),
TP_fast_assign(
__entry->rcuname = rcuname;
__entry->callbacks_invoked = callbacks_invoked;
- ),
-
- TP_printk("%s CBs-invoked=%d",
- __entry->rcuname, __entry->callbacks_invoked)
+ __entry->cb = cb;
+ __entry->nr = nr;
+ __entry->iit = iit;
+ __entry->risk = risk;
+ ),
+
+ TP_printk("%s CBs-invoked=%d idle=%c%c%c%c",
+ __entry->rcuname, __entry->callbacks_invoked,
+ __entry->cb ? 'C' : '.',
+ __entry->nr ? 'S' : '.',
+ __entry->iit ? 'I' : '.',
+ __entry->risk ? 'R' : '.')
);
/*
@@ -524,7 +543,8 @@ TRACE_EVENT(rcu_torture_read,
#define trace_rcu_batch_start(rcuname, qlen, blimit) do { } while (0)
#define trace_rcu_invoke_callback(rcuname, rhp) do { } while (0)
#define trace_rcu_invoke_kfree_callback(rcuname, rhp, offset) do { } while (0)
-#define trace_rcu_batch_end(rcuname, callbacks_invoked) do { } while (0)
+#define trace_rcu_batch_end(rcuname, callbacks_invoked, cb, nr, iit, risk) \
+ do { } while (0)
#define trace_rcu_torture_read(rcutorturename, rhp) do { } while (0)
#endif /* #else #ifdef CONFIG_RCU_TRACE */
diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index e5bd94954fa3..977296dca0a4 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -259,7 +259,11 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
/* If no RCU callbacks ready to invoke, just return. */
if (&rcp->rcucblist == rcp->donetail) {
RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, -1));
- RCU_TRACE(trace_rcu_batch_end(rcp->name, 0));
+ RCU_TRACE(trace_rcu_batch_end(rcp->name, 0,
+ ACCESS_ONCE(rcp->rcucblist),
+ need_resched(),
+ is_idle_task(current),
+ rcu_is_callbacks_kthread()));
return;
}
@@ -288,7 +292,9 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
RCU_TRACE(cb_count++);
}
RCU_TRACE(rcu_trace_sub_qlen(rcp, cb_count));
- RCU_TRACE(trace_rcu_batch_end(rcp->name, cb_count));
+ RCU_TRACE(trace_rcu_batch_end(rcp->name, cb_count, 0, need_resched(),
+ is_idle_task(current),
+ rcu_is_callbacks_kthread()));
}
static void rcu_process_callbacks(struct softirq_action *unused)
diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index 2b0484a5dc28..dfa97cbb3910 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -885,6 +885,19 @@ static void invoke_rcu_callbacks(void)
wake_up(&rcu_kthread_wq);
}
+#ifdef CONFIG_RCU_TRACE
+
+/*
+ * Is the current CPU running the RCU-callbacks kthread?
+ * Caller must have preemption disabled.
+ */
+static bool rcu_is_callbacks_kthread(void)
+{
+ return rcu_kthread_task == current;
+}
+
+#endif /* #ifdef CONFIG_RCU_TRACE */
+
/*
* This kthread invokes RCU callbacks whose grace periods have
* elapsed. It is awakened as needed, and takes the place of the
@@ -938,6 +951,18 @@ void invoke_rcu_callbacks(void)
raise_softirq(RCU_SOFTIRQ);
}
+#ifdef CONFIG_RCU_TRACE
+
+/*
+ * There is no callback kthread, so this thread is never it.
+ */
+static bool rcu_is_callbacks_kthread(void)
+{
+ return false;
+}
+
+#endif /* #ifdef CONFIG_RCU_TRACE */
+
void rcu_init(void)
{
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 2b2e1a996a65..6c4a6722abfd 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1373,7 +1373,9 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
/* If no callbacks are ready, just return.*/
if (!cpu_has_callbacks_ready_to_invoke(rdp)) {
trace_rcu_batch_start(rsp->name, 0, 0);
- trace_rcu_batch_end(rsp->name, 0);
+ trace_rcu_batch_end(rsp->name, 0, !!ACCESS_ONCE(rdp->nxtlist),
+ need_resched(), is_idle_task(current),
+ rcu_is_callbacks_kthread());
return;
}
@@ -1409,7 +1411,9 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
}
local_irq_save(flags);
- trace_rcu_batch_end(rsp->name, count);
+ trace_rcu_batch_end(rsp->name, count, !!list, need_resched(),
+ is_idle_task(current),
+ rcu_is_callbacks_kthread());
/* Update count, and requeue any remaining callbacks. */
rdp->qlen -= count;