From fe0f49768d807a8fe6336b097feb8c4441951710 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 30 Sep 2014 17:37:52 +0200 Subject: [PATCH] s390/nohz: use a per-cpu flag for arch_needs_cpu Move the nohz_delay bit from the s390_idle data structure to the per-cpu flags. Clear the nohz delay flag in __cpu_disable and remove the cpu hotplug notifier that used to do this. Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/cputime.h | 8 -------- arch/s390/include/asm/processor.h | 4 ++++ arch/s390/kernel/irq.c | 2 +- arch/s390/kernel/smp.c | 1 + arch/s390/kernel/vtime.c | 19 +------------------ drivers/s390/cio/airq.c | 2 +- drivers/s390/cio/cio.c | 2 +- include/linux/tick.h | 2 +- kernel/time/tick-sched.c | 2 +- 9 files changed, 11 insertions(+), 31 deletions(-) diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h index f65bd3634519..01887b1fade5 100644 --- a/arch/s390/include/asm/cputime.h +++ b/arch/s390/include/asm/cputime.h @@ -166,7 +166,6 @@ static inline clock_t cputime64_to_clock_t(cputime64_t cputime) } struct s390_idle_data { - int nohz_delay; unsigned int sequence; unsigned long long idle_count; unsigned long long idle_time; @@ -182,11 +181,4 @@ cputime64_t s390_get_idle_time(int cpu); #define arch_idle_time(cpu) s390_get_idle_time(cpu) -static inline int s390_nohz_delay(int cpu) -{ - return __get_cpu_var(s390_idle).nohz_delay != 0; -} - -#define arch_needs_cpu(cpu) s390_nohz_delay(cpu) - #endif /* _S390_CPUTIME_H */ diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h index e568fc8a7250..bc796d73129b 100644 --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -13,9 +13,11 @@ #define CIF_MCCK_PENDING 0 /* machine check handling is pending */ #define CIF_ASCE 1 /* user asce needs fixup / uaccess */ +#define CIF_NOHZ_DELAY 2 /* delay HZ disable for a tick */ #define _CIF_MCCK_PENDING (1<int_code; if (ext_code.code != EXT_IRQ_CLK_COMP) - __get_cpu_var(s390_idle).nohz_delay = 1; + set_cpu_flag(CIF_NOHZ_DELAY); index = ext_hash(ext_code.code); rcu_read_lock(); diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index abec97b4ddbf..46317d6951c4 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -720,6 +720,7 @@ int __cpu_disable(void) cregs[6] &= ~0xff000000UL; /* disable all I/O interrupts */ cregs[14] &= ~0x1f000000UL; /* disable most machine checks */ __ctl_load(cregs, 0, 15); + clear_cpu_flag(CIF_NOHZ_DELAY); return 0; } diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c index 8c34363d6f1e..40709821abde 100644 --- a/arch/s390/kernel/vtime.c +++ b/arch/s390/kernel/vtime.c @@ -163,7 +163,7 @@ void __kprobes vtime_stop_cpu(void) /* Wait for external, I/O or machine check interrupt. */ psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; - idle->nohz_delay = 0; + clear_cpu_flag(CIF_NOHZ_DELAY); /* Call the assembler magic in entry.S */ psw_idle(idle, psw_mask); @@ -378,25 +378,8 @@ void init_cpu_vtimer(void) set_vtimer(VTIMER_MAX_SLICE); } -static int s390_nohz_notify(struct notifier_block *self, unsigned long action, - void *hcpu) -{ - struct s390_idle_data *idle; - long cpu = (long) hcpu; - - idle = &per_cpu(s390_idle, cpu); - switch (action & ~CPU_TASKS_FROZEN) { - case CPU_DYING: - idle->nohz_delay = 0; - default: - break; - } - return NOTIFY_OK; -} - void __init vtime_init(void) { /* Enable cpu timer interrupts on the boot cpu. */ init_cpu_vtimer(); - cpu_notifier(s390_nohz_notify, 0); } diff --git a/drivers/s390/cio/airq.c b/drivers/s390/cio/airq.c index 00bfbee0af9e..56eb4ee4deba 100644 --- a/drivers/s390/cio/airq.c +++ b/drivers/s390/cio/airq.c @@ -87,7 +87,7 @@ static irqreturn_t do_airq_interrupt(int irq, void *dummy) struct airq_struct *airq; struct hlist_head *head; - __this_cpu_write(s390_idle.nohz_delay, 1); + set_cpu_flag(CIF_NOHZ_DELAY); tpi_info = (struct tpi_info *) &get_irq_regs()->int_code; head = &airq_lists[tpi_info->isc]; rcu_read_lock(); diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c index 2905d8b0ec95..d5a6f287d2fe 100644 --- a/drivers/s390/cio/cio.c +++ b/drivers/s390/cio/cio.c @@ -561,7 +561,7 @@ static irqreturn_t do_cio_interrupt(int irq, void *dummy) struct subchannel *sch; struct irb *irb; - __this_cpu_write(s390_idle.nohz_delay, 1); + set_cpu_flag(CIF_NOHZ_DELAY); tpi_info = (struct tpi_info *) &get_irq_regs()->int_code; irb = &__get_cpu_var(cio_irb); sch = (struct subchannel *)(unsigned long) tpi_info->intparm; diff --git a/include/linux/tick.h b/include/linux/tick.h index 9a82c7dc3fdd..e5832d03da19 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -108,7 +108,7 @@ extern struct tick_sched *tick_get_tick_sched(int cpu); extern void tick_irq_enter(void); extern int tick_oneshot_mode_active(void); # ifndef arch_needs_cpu -# define arch_needs_cpu(cpu) (0) +# define arch_needs_cpu() (0) # endif # else static inline void tick_clock_notify(void) { } diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index f654a8a298fa..01d512fd45f1 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -572,7 +572,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, } while (read_seqretry(&jiffies_lock, seq)); if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || - arch_needs_cpu(cpu) || irq_work_needs_cpu()) { + arch_needs_cpu() || irq_work_needs_cpu()) { next_jiffies = last_jiffies + 1; delta_jiffies = 1; } else { -- 2.20.1