From: Thomas Gleixner Date: Mon, 13 Dec 2010 16:33:39 +0100 Subject: x86: Convert mce timer to hrtimer Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.14/older/patches-4.14.15-rt13.tar.xz mce_timer is started in atomic contexts of cpu bringup. This results in might_sleep() warnings on RT. Convert mce_timer to a hrtimer to avoid this. Signed-off-by: Thomas Gleixner fold in: |From: Mike Galbraith |Date: Wed, 29 May 2013 13:52:13 +0200 |Subject: [PATCH] x86/mce: fix mce timer interval | |Seems mce timer fire at the wrong frequency in -rt kernels since roughly |forever due to 32 bit overflow. 3.8-rt is also missing a multiplier. | |Add missing us -> ns conversion and 32 bit overflow prevention. | |Signed-off-by: Mike Galbraith |[bigeasy: use ULL instead of u64 cast] |Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/kernel/cpu/mcheck/mce.c | 54 ++++++++++++++++++--------------------- 1 file changed, 26 insertions(+), 28 deletions(-) --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -42,6 +42,7 @@ #include #include #include +#include #include #include @@ -1345,7 +1346,7 @@ int memory_failure(unsigned long pfn, in static unsigned long check_interval = INITIAL_CHECK_INTERVAL; static DEFINE_PER_CPU(unsigned long, mce_next_interval); /* in jiffies */ -static DEFINE_PER_CPU(struct timer_list, mce_timer); +static DEFINE_PER_CPU(struct hrtimer, mce_timer); static unsigned long mce_adjust_timer_default(unsigned long interval) { @@ -1354,27 +1355,19 @@ static unsigned long mce_adjust_timer_de static unsigned long (*mce_adjust_timer)(unsigned long interval) = mce_adjust_timer_default; -static void __start_timer(struct timer_list *t, unsigned long interval) +static void __start_timer(struct hrtimer *t, unsigned long iv) { - unsigned long when = jiffies + interval; - unsigned long flags; - - local_irq_save(flags); - - if (!timer_pending(t) || time_before(when, t->expires)) - mod_timer(t, round_jiffies(when)); + if (!iv) + return; - local_irq_restore(flags); + hrtimer_start_range_ns(t, ns_to_ktime(jiffies_to_usecs(iv) * 1000ULL), + 0, HRTIMER_MODE_REL_PINNED); } -static void mce_timer_fn(unsigned long data) +static enum hrtimer_restart mce_timer_fn(struct hrtimer *timer) { - struct timer_list *t = this_cpu_ptr(&mce_timer); - int cpu = smp_processor_id(); unsigned long iv; - WARN_ON(cpu != data); - iv = __this_cpu_read(mce_next_interval); if (mce_available(this_cpu_ptr(&cpu_info))) { @@ -1397,7 +1390,11 @@ static void mce_timer_fn(unsigned long d done: __this_cpu_write(mce_next_interval, iv); - __start_timer(t, iv); + if (!iv) + return HRTIMER_NORESTART; + + hrtimer_forward_now(timer, ns_to_ktime(jiffies_to_nsecs(iv))); + return HRTIMER_RESTART; } /* @@ -1405,7 +1402,7 @@ static void mce_timer_fn(unsigned long d */ void mce_timer_kick(unsigned long interval) { - struct timer_list *t = this_cpu_ptr(&mce_timer); + struct hrtimer *t = this_cpu_ptr(&mce_timer); unsigned long iv = __this_cpu_read(mce_next_interval); __start_timer(t, interval); @@ -1420,7 +1417,7 @@ static void mce_timer_delete_all(void) int cpu; for_each_online_cpu(cpu) - del_timer_sync(&per_cpu(mce_timer, cpu)); + hrtimer_cancel(&per_cpu(mce_timer, cpu)); } /* @@ -1749,7 +1746,7 @@ static void __mcheck_cpu_clear_vendor(st } } -static void mce_start_timer(struct timer_list *t) +static void mce_start_timer(struct hrtimer *t) { unsigned long iv = check_interval * HZ; @@ -1762,18 +1759,19 @@ static void mce_start_timer(struct timer static void __mcheck_cpu_setup_timer(void) { - struct timer_list *t = this_cpu_ptr(&mce_timer); - unsigned int cpu = smp_processor_id(); + struct hrtimer *t = this_cpu_ptr(&mce_timer); - setup_pinned_timer(t, mce_timer_fn, cpu); + hrtimer_init(t, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + t->function = mce_timer_fn; } static void __mcheck_cpu_init_timer(void) { - struct timer_list *t = this_cpu_ptr(&mce_timer); - unsigned int cpu = smp_processor_id(); + struct hrtimer *t = this_cpu_ptr(&mce_timer); + + hrtimer_init(t, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + t->function = mce_timer_fn; - setup_pinned_timer(t, mce_timer_fn, cpu); mce_start_timer(t); } @@ -2275,7 +2273,7 @@ static int mce_cpu_dead(unsigned int cpu static int mce_cpu_online(unsigned int cpu) { - struct timer_list *t = this_cpu_ptr(&mce_timer); + struct hrtimer *t = this_cpu_ptr(&mce_timer); int ret; mce_device_create(cpu); @@ -2292,10 +2290,10 @@ static int mce_cpu_online(unsigned int c static int mce_cpu_pre_down(unsigned int cpu) { - struct timer_list *t = this_cpu_ptr(&mce_timer); + struct hrtimer *t = this_cpu_ptr(&mce_timer); mce_disable_cpu(); - del_timer_sync(t); + hrtimer_cancel(t); mce_threshold_remove_device(cpu); mce_device_remove(cpu); return 0;