jrcu: show #passes affected by NMIs.
If one has a system that generates lots of NMIs, they
may disturb jrcu significantly. It is good to see that
happening in the rcudata file stats.
Signed-off-by: Joe Korty <[email protected]>
Index: b/kernel/jrcu.c
===================================================================
--- a/kernel/jrcu.c
+++ b/kernel/jrcu.c
@@ -122,6 +122,7 @@ static struct rcu_stats {
unsigned npasses; /* #passes made */
unsigned nlast; /* #passes since last end-of-batch */
unsigned nbatches; /* #end-of-batches (eobs) seen */
+ unsigned nmis; /* #passes discarded due to NMI */
atomic_t nbarriers; /* #rcu barriers processed */
atomic_t nsyncs; /* #rcu syncs processed */
u64 ninvoked; /* #invoked (ie, finished) callbacks */
@@ -302,17 +303,20 @@ static void __rcu_delimit_batches(struct
struct rcu_list *plist;
int cpu, eob, prev;
+ if (!rcu_scheduler_active)
+ return;
+
+ rcu_stats.nlast++;
+
/* If an NMI occured then the previous batch may not yet be
* quiescent. Let's wait till it is.
*/
if (rcu_nmi_seen) {
rcu_nmi_seen = 0;
+ rcu_stats.nmis++;
return;
}
- if (!rcu_scheduler_active)
- return;
-
/*
* Find out if the current batch has ended
* (end-of-batch).
@@ -329,8 +333,6 @@ static void __rcu_delimit_batches(struct
}
}
- rcu_stats.nlast++;
-
/*
* Exit if batch has not ended. But first, tickle all non-cooperating
* CPUs if enough time has passed.
@@ -345,7 +347,7 @@ static void __rcu_delimit_batches(struct
}
}
rcu_wdog_ctr += rcu_hz_period_us;
- return eob;
+ return;
}
/*
@@ -603,10 +605,12 @@ static int rcu_debugfs_show(struct seq_f
seq_printf(m, "\n");
seq_printf(m, "%14u: #passes\n",
rcu_stats.npasses);
+ seq_printf(m, "%14u: #passes discarded due to NMI\n",
+ rcu_stats.nmis);
seq_printf(m, "%14u: #passes resulting in end-of-batch\n",
rcu_stats.nbatches);
seq_printf(m, "%14u: #passes not resulting in end-of-batch\n",
- rcu_stats.npasses - rcu_stats.nbatches);
+ rcu_stats.npasses - rcu_stats.nbatches - rcu_stats.nmis);
seq_printf(m, "%14u: #passes since last end-of-batch\n",
rcu_stats.nlast);
seq_printf(m, "%14u: #passes forced (0 is best)\n",