Introduce a factor which would apply to the NMI watchdog timeout.
This factor is a percentage added to the watchdog_tresh value. The value is
set under the watchdog_mutex protection and lockup_detector_reconfigure()
is called to recompute wd_panic_timeout_tb.
Once the factor is set, it remains until it is set back to 0, which means
no impact.
Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxx>
---
arch/powerpc/include/asm/nmi.h | 2 ++
arch/powerpc/kernel/watchdog.c | 21 ++++++++++++++++++++-
2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/nmi.h b/arch/powerpc/include/asm/nmi.h
index ea0e487f87b1..7d6a8d9b0543 100644
--- a/arch/powerpc/include/asm/nmi.h
+++ b/arch/powerpc/include/asm/nmi.h
@@ -5,8 +5,10 @@
#ifdef CONFIG_PPC_WATCHDOG
extern void arch_touch_nmi_watchdog(void);
long soft_nmi_interrupt(struct pt_regs *regs);
+void watchdog_nmi_set_lpm_factor(u64 factor);
#else
static inline void arch_touch_nmi_watchdog(void) {}
+static inline void watchdog_nmi_set_lpm_factor(u64 factor) {}
#endif
#ifdef CONFIG_NMI_IPI
diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
index 7d28b9553654..80851b228f71 100644
--- a/arch/powerpc/kernel/watchdog.c
+++ b/arch/powerpc/kernel/watchdog.c
@@ -91,6 +91,10 @@ static cpumask_t wd_smp_cpus_pending;
static cpumask_t wd_smp_cpus_stuck;
static u64 wd_smp_last_reset_tb;
+#ifdef CONFIG_PPC_PSERIES
+static u64 wd_factor;
+#endif
+
/*
* Try to take the exclusive watchdog action / NMI IPI / printing lock.
* wd_smp_lock must be held. If this fails, we should return and wait
@@ -527,7 +531,13 @@ static int stop_watchdog_on_cpu(unsigned int cpu)
static void watchdog_calc_timeouts(void)
{
- wd_panic_timeout_tb = watchdog_thresh * ppc_tb_freq;
+ u64 threshold = watchdog_thresh;
+
+#ifdef CONFIG_PPC_PSERIES
+ threshold += (READ_ONCE(wd_factor) * threshold) / 100;
+#endif
+
+ wd_panic_timeout_tb = threshold * ppc_tb_freq;
/* Have the SMP detector trigger a bit later */
wd_smp_panic_timeout_tb = wd_panic_timeout_tb * 3 / 2;
@@ -570,3 +580,12 @@ int __init watchdog_nmi_probe(void)
}
return 0;
}
+
+#ifdef CONFIG_PPC_PSERIES
+void watchdog_nmi_set_lpm_factor(u64 factor)
+{
+ pr_info("Set the NMI watchdog factor to %llu%%\n", factor);
+ WRITE_ONCE(wd_factor, factor);
+ lockup_detector_reconfigure();
+}
+#endif
--
2.36.1
