26456f87ac
The timer wheel bases are not (re)initialized on CPU hotplug. That leaves
them with a potentially stale clk and next_expiry valuem, which can cause
trouble then the CPU is plugged.
Add a prepare callback which forwards the clock, sets next_expiry to far in
the future and reset the control flags to a known state.
Set base->must_forward_clk so the first timer which is queued will try to
forward the clock to current jiffies.
Fixes: 500462a9de ("timers: Switch to a non-cascading wheel")
Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272152200.2431@nanos
217 lines
6.7 KiB
C
217 lines
6.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_TIMER_H
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#define _LINUX_TIMER_H
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#include <linux/list.h>
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#include <linux/ktime.h>
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#include <linux/stddef.h>
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#include <linux/debugobjects.h>
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#include <linux/stringify.h>
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struct tvec_base;
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struct timer_list {
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/*
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* All fields that change during normal runtime grouped to the
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* same cacheline
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*/
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struct hlist_node entry;
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unsigned long expires;
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void (*function)(struct timer_list *);
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u32 flags;
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#ifdef CONFIG_LOCKDEP
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struct lockdep_map lockdep_map;
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#endif
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};
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#ifdef CONFIG_LOCKDEP
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/*
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* NB: because we have to copy the lockdep_map, setting the lockdep_map key
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* (second argument) here is required, otherwise it could be initialised to
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* the copy of the lockdep_map later! We use the pointer to and the string
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* "<file>:<line>" as the key resp. the name of the lockdep_map.
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*/
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#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
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.lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
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#else
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#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
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#endif
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/*
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* A deferrable timer will work normally when the system is busy, but
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* will not cause a CPU to come out of idle just to service it; instead,
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* the timer will be serviced when the CPU eventually wakes up with a
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* subsequent non-deferrable timer.
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*
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* An irqsafe timer is executed with IRQ disabled and it's safe to wait for
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* the completion of the running instance from IRQ handlers, for example,
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* by calling del_timer_sync().
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*
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* Note: The irq disabled callback execution is a special case for
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* workqueue locking issues. It's not meant for executing random crap
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* with interrupts disabled. Abuse is monitored!
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*/
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#define TIMER_CPUMASK 0x0003FFFF
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#define TIMER_MIGRATING 0x00040000
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#define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
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#define TIMER_DEFERRABLE 0x00080000
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#define TIMER_PINNED 0x00100000
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#define TIMER_IRQSAFE 0x00200000
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#define TIMER_ARRAYSHIFT 22
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#define TIMER_ARRAYMASK 0xFFC00000
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#define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
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#define __TIMER_INITIALIZER(_function, _flags) { \
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.entry = { .next = TIMER_ENTRY_STATIC }, \
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.function = (_function), \
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.flags = (_flags), \
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__TIMER_LOCKDEP_MAP_INITIALIZER( \
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__FILE__ ":" __stringify(__LINE__)) \
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}
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#define DEFINE_TIMER(_name, _function) \
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struct timer_list _name = \
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__TIMER_INITIALIZER(_function, 0)
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/*
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* LOCKDEP and DEBUG timer interfaces.
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*/
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void init_timer_key(struct timer_list *timer,
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void (*func)(struct timer_list *), unsigned int flags,
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const char *name, struct lock_class_key *key);
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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extern void init_timer_on_stack_key(struct timer_list *timer,
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void (*func)(struct timer_list *),
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unsigned int flags, const char *name,
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struct lock_class_key *key);
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#else
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static inline void init_timer_on_stack_key(struct timer_list *timer,
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void (*func)(struct timer_list *),
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unsigned int flags,
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const char *name,
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struct lock_class_key *key)
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{
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init_timer_key(timer, func, flags, name, key);
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}
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#endif
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#ifdef CONFIG_LOCKDEP
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#define __init_timer(_timer, _fn, _flags) \
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do { \
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static struct lock_class_key __key; \
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init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
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} while (0)
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#define __init_timer_on_stack(_timer, _fn, _flags) \
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do { \
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static struct lock_class_key __key; \
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init_timer_on_stack_key((_timer), (_fn), (_flags), \
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#_timer, &__key); \
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} while (0)
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#else
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#define __init_timer(_timer, _fn, _flags) \
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init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
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#define __init_timer_on_stack(_timer, _fn, _flags) \
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init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
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#endif
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/**
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* timer_setup - prepare a timer for first use
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* @timer: the timer in question
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* @callback: the function to call when timer expires
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* @flags: any TIMER_* flags
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*
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* Regular timer initialization should use either DEFINE_TIMER() above,
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* or timer_setup(). For timers on the stack, timer_setup_on_stack() must
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* be used and must be balanced with a call to destroy_timer_on_stack().
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*/
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#define timer_setup(timer, callback, flags) \
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__init_timer((timer), (callback), (flags))
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#define timer_setup_on_stack(timer, callback, flags) \
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__init_timer_on_stack((timer), (callback), (flags))
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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extern void destroy_timer_on_stack(struct timer_list *timer);
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#else
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static inline void destroy_timer_on_stack(struct timer_list *timer) { }
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#endif
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#define from_timer(var, callback_timer, timer_fieldname) \
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container_of(callback_timer, typeof(*var), timer_fieldname)
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/**
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* timer_pending - is a timer pending?
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* @timer: the timer in question
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*
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* timer_pending will tell whether a given timer is currently pending,
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* or not. Callers must ensure serialization wrt. other operations done
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* to this timer, eg. interrupt contexts, or other CPUs on SMP.
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*
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* return value: 1 if the timer is pending, 0 if not.
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*/
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static inline int timer_pending(const struct timer_list * timer)
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{
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return timer->entry.pprev != NULL;
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}
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extern void add_timer_on(struct timer_list *timer, int cpu);
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extern int del_timer(struct timer_list * timer);
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extern int mod_timer(struct timer_list *timer, unsigned long expires);
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extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
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extern int timer_reduce(struct timer_list *timer, unsigned long expires);
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/*
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* The jiffies value which is added to now, when there is no timer
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* in the timer wheel:
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*/
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#define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
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extern void add_timer(struct timer_list *timer);
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extern int try_to_del_timer_sync(struct timer_list *timer);
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#ifdef CONFIG_SMP
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extern int del_timer_sync(struct timer_list *timer);
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#else
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# define del_timer_sync(t) del_timer(t)
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#endif
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#define del_singleshot_timer_sync(t) del_timer_sync(t)
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extern void init_timers(void);
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extern void run_local_timers(void);
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struct hrtimer;
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extern enum hrtimer_restart it_real_fn(struct hrtimer *);
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#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
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struct ctl_table;
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extern unsigned int sysctl_timer_migration;
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int timer_migration_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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#endif
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unsigned long __round_jiffies(unsigned long j, int cpu);
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unsigned long __round_jiffies_relative(unsigned long j, int cpu);
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unsigned long round_jiffies(unsigned long j);
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unsigned long round_jiffies_relative(unsigned long j);
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unsigned long __round_jiffies_up(unsigned long j, int cpu);
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unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
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unsigned long round_jiffies_up(unsigned long j);
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unsigned long round_jiffies_up_relative(unsigned long j);
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#ifdef CONFIG_HOTPLUG_CPU
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int timers_prepare_cpu(unsigned int cpu);
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int timers_dead_cpu(unsigned int cpu);
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#else
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#define timers_prepare_cpu NULL
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#define timers_dead_cpu NULL
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#endif
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#endif
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