Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (e18a5ebc) · Commits · 戴 / test

arch/x86/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -100,6 +100,7 @@ config X86
		select GENERIC_STRNCPY_FROM_USER
		select GENERIC_STRNLEN_USER
		select GENERIC_TIME_VSYSCALL
		select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
		select HAVE_ACPI_APEI if ACPI
		select HAVE_ACPI_APEI_NMI if ACPI
		select HAVE_ALIGNED_STRUCT_PAGE if SLUB

include/linux/nmi.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -168,6 +168,14 @@ extern int sysctl_hardlockup_all_cpu_backtrace;
		#define sysctl_softlockup_all_cpu_backtrace 0
		#define sysctl_hardlockup_all_cpu_backtrace 0
		#endif

		#if defined(CONFIG_HARDLOCKUP_CHECK_TIMESTAMP) && \
		defined(CONFIG_HARDLOCKUP_DETECTOR)
		void watchdog_update_hrtimer_threshold(u64 period);
		#else
		static inline void watchdog_update_hrtimer_threshold(u64 period) { }
		#endif

		extern bool is_hardlockup(void);
		struct ctl_table;
		extern int proc_watchdog(struct ctl_table *, int ,

kernel/watchdog.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -240,6 +240,7 @@ static void set_sample_period(void)
		* hardlockup detector generates a warning
		*/
		sample_period = get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5);
		watchdog_update_hrtimer_threshold(sample_period);
		}

		/* Commands for resetting the watchdog */

kernel/watchdog_hld.c

+59 −0

Original line number	Diff line number	Diff line
		@@ -37,6 +37,62 @@ void arch_touch_nmi_watchdog(void)
		}
		EXPORT_SYMBOL(arch_touch_nmi_watchdog);

		#ifdef CONFIG_HARDLOCKUP_CHECK_TIMESTAMP
		static DEFINE_PER_CPU(ktime_t, last_timestamp);
		static DEFINE_PER_CPU(unsigned int, nmi_rearmed);
		static ktime_t watchdog_hrtimer_sample_threshold __read_mostly;

		void watchdog_update_hrtimer_threshold(u64 period)
		{
		/*
		* The hrtimer runs with a period of (watchdog_threshold * 2) / 5
		*
		* So it runs effectively with 2.5 times the rate of the NMI
		* watchdog. That means the hrtimer should fire 2-3 times before
		* the NMI watchdog expires. The NMI watchdog on x86 is based on
		* unhalted CPU cycles, so if Turbo-Mode is enabled the CPU cycles
		* might run way faster than expected and the NMI fires in a
		* smaller period than the one deduced from the nominal CPU
		* frequency. Depending on the Turbo-Mode factor this might be fast
		* enough to get the NMI period smaller than the hrtimer watchdog
		* period and trigger false positives.
		*
		* The sample threshold is used to check in the NMI handler whether
		* the minimum time between two NMI samples has elapsed. That
		* prevents false positives.
		*
		* Set this to 4/5 of the actual watchdog threshold period so the
		* hrtimer is guaranteed to fire at least once within the real
		* watchdog threshold.
		*/
		watchdog_hrtimer_sample_threshold = period * 2;
		}

		static bool watchdog_check_timestamp(void)
		{
		ktime_t delta, now = ktime_get_mono_fast_ns();

		delta = now - __this_cpu_read(last_timestamp);
		if (delta < watchdog_hrtimer_sample_threshold) {
		/*
		* If ktime is jiffies based, a stalled timer would prevent
		* jiffies from being incremented and the filter would look
		* at a stale timestamp and never trigger.
		*/
		if (__this_cpu_inc_return(nmi_rearmed) < 10)
		return false;
		}
		__this_cpu_write(nmi_rearmed, 0);
		__this_cpu_write(last_timestamp, now);
		return true;
		}
		#else
		static inline bool watchdog_check_timestamp(void)
		{
		return true;
		}
		#endif

		static struct perf_event_attr wd_hw_attr = {
		.type = PERF_TYPE_HARDWARE,
		.config = PERF_COUNT_HW_CPU_CYCLES,
		@@ -61,6 +117,9 @@ static void watchdog_overflow_callback(struct perf_event *event,
		return;
		}

		if (!watchdog_check_timestamp())
		return;

		/* check for a hardlockup
		* This is done by making sure our timer interrupt
		* is incrementing. The timer interrupt should have

lib/Kconfig.debug

+7 −0

Original line number	Diff line number	Diff line
		@@ -797,6 +797,13 @@ config HARDLOCKUP_DETECTOR_PERF
		bool
		select SOFTLOCKUP_DETECTOR

		#
		# Enables a timestamp based low pass filter to compensate for perf based
		# hard lockup detection which runs too fast due to turbo modes.
		#
		config HARDLOCKUP_CHECK_TIMESTAMP
		bool

		#
		# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
		# lockup detector rather than the perf based detector.

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