The current default implementation of the hardlockup detector assumes that
it is implemented using perf events. However, the hardlockup detector can
be driven by other sources of non-maskable interrupts (e.g., a properly
configured timer).
Group and wrap in #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF all the code
specific to perf: create and manage perf events, stop and start the perf-
based detector.
The generic portion of the detector (monitor the timers' thresholds, check
timestamps and detect hardlockups as well as the implementation of
arch_touch_nmi_watchdog()) is now selected with the new intermediate config
symbol CONFIG_HARDLOCKUP_DETECTOR_CORE.
The perf-based implementation of the detector selects the new intermediate
symbol. Other implementations should do the same.
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Nicholas Piggin <npig...@gmail.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Stephane Eranian <eran...@google.com>
Cc: "Ravi V. Shankar" <ravi.v.shan...@intel.com>
Cc: io...@lists.linux-foundation.org
Cc: linuxppc-dev@lists.ozlabs.org
Reviewed-by: Tony Luck <tony.l...@intel.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calde...@linux.intel.com>
---
Changes since v6:
* None
Changes since v5:
* None
Changes since v4:
* None
Changes since v3:
* Squashed into this patch a previous patch to make
arch_touch_nmi_watchdog() part of the core detector code.
Changes since v2:
* Undid split of the generic hardlockup detector into a separate file.
(Thomas Gleixner)
* Added a new intermediate symbol CONFIG_HARDLOCKUP_DETECTOR_CORE to
select generic parts of the detector (Paul E. McKenney,
Thomas Gleixner).
Changes since v1:
* Make the generic detector code with CONFIG_HARDLOCKUP_DETECTOR.
---
include/linux/nmi.h | 5 ++++-
kernel/Makefile | 2 +-
kernel/watchdog_hld.c | 32 ++++++++++++++++++++------------
lib/Kconfig.debug | 4 ++++
4 files changed, 29 insertions(+), 14 deletions(-)
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 75038cb2710e..a38c4509f9eb 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -94,8 +94,11 @@ static inline void hardlockup_detector_disable(void) {}
# define NMI_WATCHDOG_SYSCTL_PERM 0444
#endif
-#if defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
+#if defined(CONFIG_HARDLOCKUP_DETECTOR_CORE)
extern void arch_touch_nmi_watchdog(void);
+#endif
+
+#if defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
extern void hardlockup_detector_perf_stop(void);
extern void hardlockup_detector_perf_restart(void);
extern void hardlockup_detector_perf_disable(void);
diff --git a/kernel/Makefile b/kernel/Makefile
index 10ef068f598d..f35fad36cf81 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -91,7 +91,7 @@ obj-$(CONFIG_FAIL_FUNCTION) += fail_function.o
obj-$(CONFIG_KGDB) += debug/
obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
-obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR_CORE) += watchdog_hld.o
obj-$(CONFIG_SECCOMP) += seccomp.o
obj-$(CONFIG_RELAY) += relay.o
obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index b352e507b17f..bb6435978c46 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -22,12 +22,8 @@
static DEFINE_PER_CPU(bool, hard_watchdog_warn);
static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
-static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
-static DEFINE_PER_CPU(struct perf_event *, dead_event);
-static struct cpumask dead_events_mask;
static unsigned long hardlockup_allcpu_dumped;
-static atomic_t watchdog_cpus = ATOMIC_INIT(0);
notrace void arch_touch_nmi_watchdog(void)
{
@@ -98,14 +94,6 @@ static inline bool watchdog_check_timestamp(void)
}
#endif
-static struct perf_event_attr wd_hw_attr = {
- .type = PERF_TYPE_HARDWARE,
- .config = PERF_COUNT_HW_CPU_CYCLES,
- .size = sizeof(struct perf_event_attr),
- .pinned = 1,
- .disabled = 1,
-};
-
void inspect_for_hardlockups(struct pt_regs *regs)
{
if (__this_cpu_read(watchdog_nmi_touch) == true) {
@@ -157,6 +145,24 @@ void inspect_for_hardlockups(struct pt_regs *regs)
return;
}
+#ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
+#undef pr_fmt
+#define pr_fmt(fmt) "NMI perf watchdog: " fmt
+
+static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
+static DEFINE_PER_CPU(struct perf_event *, dead_event);
+static struct cpumask dead_events_mask;
+
+static atomic_t watchdog_cpus = ATOMIC_INIT(0);
+
+static struct perf_event_attr wd_hw_attr = {
+ .type = PERF_TYPE_HARDWARE,
+ .config = PERF_COUNT_HW_CPU_CYCLES,
+ .size = sizeof(struct perf_event_attr),
+ .pinned = 1,
+ .disabled = 1,
+};
+
/* Callback function for perf event subsystem */
static void watchdog_overflow_callback(struct perf_event *event,
struct perf_sample_data *data,
@@ -298,3 +304,5 @@ int __init hardlockup_detector_perf_init(void)
}
return ret;
}
+
+#endif /* CONFIG_HARDLOCKUP_DETECTOR_PERF */
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index c8b379e2e9ad..1ff53c5995b1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1025,9 +1025,13 @@ config BOOTPARAM_SOFTLOCKUP_PANIC
Say N if unsure.
+config HARDLOCKUP_DETECTOR_CORE
+ bool
+
config HARDLOCKUP_DETECTOR_PERF
bool
select SOFTLOCKUP_DETECTOR
+ select HARDLOCKUP_DETECTOR_CORE
#
# Enables a timestamp based low pass filter to compensate for perf based
--
2.25.1
