[PATCH tip/core/rcu 12/17] torture: Throttle VERBOSE_TOROUT_*() output

paulmck
2021-01-06T17:18:53Z

This commit adds kernel boot parameters torture.verbose_sleep_frequency
and torture.verbose_sleep_duration, which allow VERBOSE_TOROUT_*() output
to be throttled with periodic sleeps on large systems.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++
include/linux/torture.h | 15 +++++++++++++--
kernel/torture.c | 20 ++++++++++++++++++++
3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 29ea816..5ce95dd 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5337,6 +5337,14 @@
are running concurrently, especially on systems
with rotating-rust storage.

+ torture.verbose_sleep_frequency= [KNL]
+ Specifies how many verbose printk()s should be
+ emitted between each sleep. The default of zero
+ disables verbose-printk() sleeping.
+
+ torture.verbose_sleep_duration= [KNL]
+ Duration of each verbose-printk() sleep in jiffies.
+
tp720= [HW,PS2]

tpm_suspend_pcr=[HW,TPM]
diff --git a/include/linux/torture.h b/include/linux/torture.h
index 32941f8..d62d13c 100644
--- a/include/linux/torture.h
+++ b/include/linux/torture.h
@@ -32,9 +32,20 @@
#define TOROUT_STRING(s) \
pr_alert("%s" TORTURE_FLAG " %s\n", torture_type, s)
#define VERBOSE_TOROUT_STRING(s) \
- do { if (verbose) pr_alert("%s" TORTURE_FLAG " %s\n", torture_type, s); } while (0)
+do { \
+ if (verbose) { \
+ verbose_torout_sleep(); \
+ pr_alert("%s" TORTURE_FLAG " %s\n", torture_type, s); \
+ } \
+} while (0)
#define VERBOSE_TOROUT_ERRSTRING(s) \
- do { if (verbose) pr_alert("%s" TORTURE_FLAG "!!! %s\n", torture_type, s); } while (0)
+do { \
+ if (verbose) { \
+ verbose_torout_sleep(); \
+ pr_alert("%s" TORTURE_FLAG "!!! %s\n", torture_type, s); \
+ } \
+} while (0)
+void verbose_torout_sleep(void);

/* Definitions for online/offline exerciser. */
typedef void torture_ofl_func(void);
diff --git a/kernel/torture.c b/kernel/torture.c
index 7ad5c96..93eeeb2 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -48,6 +48,12 @@ module_param(disable_onoff_at_boot, bool, 0444);
static bool ftrace_dump_at_shutdown;
module_param(ftrace_dump_at_shutdown, bool, 0444);

+static int verbose_sleep_frequency;
+module_param(verbose_sleep_frequency, int, 0444);
+
+static int verbose_sleep_duration = 1;
+module_param(verbose_sleep_duration, int, 0444);
+
static char *torture_type;
static int verbose;

@@ -58,6 +64,20 @@ static int verbose;
static int fullstop = FULLSTOP_RMMOD;
static DEFINE_MUTEX(fullstop_mutex);

+static atomic_t verbose_sleep_counter;
+
+/*
+ * Sleep if needed from VERBOSE_TOROUT*().
+ */
+void verbose_torout_sleep(void)
+{
+ if (verbose_sleep_frequency > 0 &&
+ verbose_sleep_duration > 0 &&
+ !(atomic_inc_return(&verbose_sleep_counter) % verbose_sleep_frequency))
+ schedule_timeout_uninterruptible(verbose_sleep_duration);
+}
+EXPORT_SYMBOL_GPL(verbose_torout_sleep);
+
/*
* Schedule a high-resolution-timer sleep in nanoseconds, with a 32-bit
* nanosecond random fuzz. This function and its friends desynchronize
--
2.9.5