Commit-ID: 1a682754c7ed9df213069d5a0d3981f8360a32c2
Gitweb: https://git.kernel.org/tip/1a682754c7ed9df213069d5a0d3981f8360a32c2
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
AuthorDate: Wed, 3 Oct 2018 12:33:41 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
CommitDate: Sat, 1 Dec 2018 12:45:39 -0800
rcutorture: Print histogram of CB invocation at OOM time
One reason why a forward-progress test might fail would be if something
prevented or delayed callback invocation. This commit therefore adds a
callback-invocation histogram printout when OOM is reported to rcutorture.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
---
kernel/rcu/rcutorture.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index f28b88ecb47a..329f4fb13125 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1631,6 +1631,20 @@ static bool rcu_fwd_emergency_stop;
#define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
static long n_launders_hist[2 * MAX_FWD_CB_JIFFIES / HZ];
+static void rcu_torture_fwd_cb_hist(void)
+{
+ int i;
+ int j;
+
+ for (i = ARRAY_SIZE(n_launders_hist) - 1; i > 0; i--)
+ if (n_launders_hist[i] > 0)
+ break;
+ pr_alert("%s: Callback-invocation histogram:", __func__);
+ for (j = 0; j <= i; j++)
+ pr_cont(" %ds: %ld", j + 1, n_launders_hist[j]);
+ pr_cont("\n");
+}
+
/* Callback function for continuous-flood RCU callbacks. */
static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
{
@@ -1718,7 +1732,6 @@ static void rcu_torture_fwd_prog_cr(void)
unsigned long cver;
unsigned long gps;
int i;
- int j;
long n_launders;
long n_launders_cb_snap;
long n_launders_sa;
@@ -1791,13 +1804,7 @@ static void rcu_torture_fwd_prog_cr(void)
n_launders + n_max_cbs - n_launders_cb_snap,
n_launders, n_launders_sa,
n_max_gps, n_max_cbs, cver, gps);
- for (i = ARRAY_SIZE(n_launders_hist) - 1; i > 0; i--)
- if (n_launders_hist[i] > 0)
- break;
- pr_alert("Callback-invocation histogram:");
- for (j = 0; j <= i; j++)
- pr_cont(" %ds: %ld", j + 1, n_launders_hist[j]);
- pr_cont("\n");
+ rcu_torture_fwd_cb_hist();
}
}
@@ -1809,6 +1816,7 @@ static void rcu_torture_fwd_prog_cr(void)
static int rcutorture_oom_notify(struct notifier_block *self,
unsigned long notused, void *nfreed)
{
+ rcu_torture_fwd_cb_hist();
rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwd_startat) / 2));
WRITE_ONCE(rcu_fwd_emergency_stop, true);
return NOTIFY_OK;
|