From: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
If there is a large number of torture tests running concurrently,
all of which are dumping large ftrace buffers at shutdown time, the
resulting dumping can take a very long time, particularly on systems
with rotating-rust storage. This commit therefore adds a default-off
torture.ftrace_dump_at_shutdown module parameter that enables
shutdown-time ftrace-buffer dumping.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
kernel/torture.c | 6 +++++-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a0dcc92..9f11ff8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5096,6 +5096,13 @@
Prevent the CPU-hotplug component of torturing
until after init has spawned.
+ torture.ftrace_dump_at_shutdown= [KNL]
+ Dump the ftrace buffer at torture-test shutdown,
+ even if there were no errors. This can be a
+ very costly operation when many torture tests
+ are running concurrently, especially on systems
+ with rotating-rust storage.
+
tp720= [HW,PS2]
tpm_suspend_pcr=[HW,TPM]
diff --git a/kernel/torture.c b/kernel/torture.c
index a1a4148..1061492 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -45,6 +45,9 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@xxxxxxxxxxxxx>");
static bool disable_onoff_at_boot;
module_param(disable_onoff_at_boot, bool, 0444);
+static bool ftrace_dump_at_shutdown;
+module_param(ftrace_dump_at_shutdown, bool, 0444);
+
static char *torture_type;
static int verbose;
@@ -527,7 +530,8 @@ static int torture_shutdown(void *arg)
torture_shutdown_hook();
else
VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
- rcu_ftrace_dump(DUMP_ALL);
+ if (ftrace_dump_at_shutdown)
+ rcu_ftrace_dump(DUMP_ALL);
kernel_power_off(); /* Shut down the system. */
return 0;
}
--
2.9.5
