hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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This reverts commit 270507d879d1c4c343603cb299423576e1fb96a1.
Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- arch/x86/kernel/tsc.c | 1 - include/linux/clocksource.h | 3 --- kernel/time/clocksource.c | 48 ++++++++----------------------------- kernel/time/jiffies.c | 15 ++++++------ 4 files changed, 17 insertions(+), 50 deletions(-)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 13d1a0ac8916..f9f1b45e5ddc 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1127,7 +1127,6 @@ static int tsc_cs_enable(struct clocksource *cs) static struct clocksource clocksource_tsc_early = { .name = "tsc-early", .rating = 299, - .uncertainty_margin = 32 * NSEC_PER_MSEC, .read = read_tsc, .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS | diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 5eed1e196900..4c3ecccc44ed 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -42,8 +42,6 @@ struct module; * @shift: Cycle to nanosecond divisor (power of two) * @max_idle_ns: Maximum idle time permitted by the clocksource (nsecs) * @maxadj: Maximum adjustment value to mult (~11%) - * @uncertainty_margin: Maximum uncertainty in nanoseconds per half second. - * Zero says to use default WATCHDOG_THRESHOLD. * @archdata: Optional arch-specific data * @max_cycles: Maximum safe cycle value which won't overflow on * multiplication @@ -95,7 +93,6 @@ struct clocksource { u32 shift; u64 max_idle_ns; u32 maxadj; - u32 uncertainty_margin; #ifdef CONFIG_ARCH_CLOCKSOURCE_DATA struct arch_clocksource_data archdata; #endif diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index d0803a69a200..74492f08660c 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -93,20 +93,6 @@ static char override_name[CS_NAME_LEN]; static int finished_booting; static u64 suspend_start;
-/* - * Threshold: 0.0312s, when doubled: 0.0625s. - * Also a default for cs->uncertainty_margin when registering clocks. - */ -#define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 5) - -/* - * Maximum permissible delay between two readouts of the watchdog - * clocksource surrounding a read of the clocksource being validated. - * This delay could be due to SMIs, NMIs, or to VCPU preemptions. Used as - * a lower bound for cs->uncertainty_margin values when registering clocks. - */ -#define WATCHDOG_MAX_SKEW (50 * NSEC_PER_USEC) - #ifdef CONFIG_CLOCKSOURCE_WATCHDOG static void clocksource_watchdog_work(struct work_struct *work); static void clocksource_select(void); @@ -133,9 +119,17 @@ static int clocksource_watchdog_kthread(void *data); static void __clocksource_change_rating(struct clocksource *cs, int rating);
/* - * Interval: 0.5sec. + * Interval: 0.5sec Threshold: 0.0625s */ #define WATCHDOG_INTERVAL (HZ >> 1) +#define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 4) + +/* + * Maximum permissible delay between two readouts of the watchdog + * clocksource surrounding a read of the clocksource being validated. + * This delay could be due to SMIs, NMIs, or to VCPU preemptions. + */ +#define WATCHDOG_MAX_SKEW (100 * NSEC_PER_USEC)
static void clocksource_watchdog_work(struct work_struct *work) { @@ -290,7 +284,6 @@ static void clocksource_watchdog(struct timer_list *unused) int next_cpu, reset_pending; int64_t wd_nsec, cs_nsec; struct clocksource *cs; - u32 md;
spin_lock(&watchdog_lock); if (!watchdog_running) @@ -337,8 +330,7 @@ static void clocksource_watchdog(struct timer_list *unused) continue;
/* Check the deviation from the watchdog clocksource. */ - md = cs->uncertainty_margin + watchdog->uncertainty_margin; - if (abs(cs_nsec - wd_nsec) > md) { + if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) { pr_warn("timekeeping watchdog on CPU%d: Marking clocksource '%s' as unstable because the skew is too large:\n", smp_processor_id(), cs->name); pr_warn(" '%s' wd_now: %llx wd_last: %llx mask: %llx\n", @@ -993,26 +985,6 @@ void __clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq clocks_calc_mult_shift(&cs->mult, &cs->shift, freq, NSEC_PER_SEC / scale, sec * scale); } - - /* - * If the uncertainty margin is not specified, calculate it. - * If both scale and freq are non-zero, calculate the clock - * period, but bound below at 2*WATCHDOG_MAX_SKEW. However, - * if either of scale or freq is zero, be very conservative and - * take the tens-of-milliseconds WATCHDOG_THRESHOLD value for the - * uncertainty margin. Allow stupidly small uncertainty margins - * to be specified by the caller for testing purposes, but warn - * to discourage production use of this capability. - */ - if (scale && freq && !cs->uncertainty_margin) { - cs->uncertainty_margin = NSEC_PER_SEC / (scale * freq); - if (cs->uncertainty_margin < 2 * WATCHDOG_MAX_SKEW) - cs->uncertainty_margin = 2 * WATCHDOG_MAX_SKEW; - } else if (!cs->uncertainty_margin) { - cs->uncertainty_margin = WATCHDOG_THRESHOLD; - } - WARN_ON_ONCE(cs->uncertainty_margin < 2 * WATCHDOG_MAX_SKEW); - /* * Ensure clocksources that have large 'mult' values don't overflow * when adjusted. diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c index 65409abcca8e..eddcf4970444 100644 --- a/kernel/time/jiffies.c +++ b/kernel/time/jiffies.c @@ -49,14 +49,13 @@ static u64 jiffies_read(struct clocksource *cs) * for "tick-less" systems. */ static struct clocksource clocksource_jiffies = { - .name = "jiffies", - .rating = 1, /* lowest valid rating*/ - .uncertainty_margin = 32 * NSEC_PER_MSEC, - .read = jiffies_read, - .mask = CLOCKSOURCE_MASK(32), - .mult = TICK_NSEC << JIFFIES_SHIFT, /* details above */ - .shift = JIFFIES_SHIFT, - .max_cycles = 10, + .name = "jiffies", + .rating = 1, /* lowest valid rating*/ + .read = jiffies_read, + .mask = CLOCKSOURCE_MASK(32), + .mult = TICK_NSEC << JIFFIES_SHIFT, /* details above */ + .shift = JIFFIES_SHIFT, + .max_cycles = 10, };
__cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(jiffies_lock);