linux-stable/include/linux/timer.h
Thomas Gleixner 26456f87ac timers: Reinitialize per cpu bases on hotplug
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
2017-12-29 23:13:09 +01:00

217 lines
6.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_TIMER_H
#define _LINUX_TIMER_H
#include <linux/list.h>
#include <linux/ktime.h>
#include <linux/stddef.h>
#include <linux/debugobjects.h>
#include <linux/stringify.h>
struct tvec_base;
struct timer_list {
/*
* All fields that change during normal runtime grouped to the
* same cacheline
*/
struct hlist_node entry;
unsigned long expires;
void (*function)(struct timer_list *);
u32 flags;
#ifdef CONFIG_LOCKDEP
struct lockdep_map lockdep_map;
#endif
};
#ifdef CONFIG_LOCKDEP
/*
* NB: because we have to copy the lockdep_map, setting the lockdep_map key
* (second argument) here is required, otherwise it could be initialised to
* the copy of the lockdep_map later! We use the pointer to and the string
* "<file>:<line>" as the key resp. the name of the lockdep_map.
*/
#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
.lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
#else
#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
#endif
/*
* A deferrable timer will work normally when the system is busy, but
* will not cause a CPU to come out of idle just to service it; instead,
* the timer will be serviced when the CPU eventually wakes up with a
* subsequent non-deferrable timer.
*
* An irqsafe timer is executed with IRQ disabled and it's safe to wait for
* the completion of the running instance from IRQ handlers, for example,
* by calling del_timer_sync().
*
* Note: The irq disabled callback execution is a special case for
* workqueue locking issues. It's not meant for executing random crap
* with interrupts disabled. Abuse is monitored!
*/
#define TIMER_CPUMASK 0x0003FFFF
#define TIMER_MIGRATING 0x00040000
#define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
#define TIMER_DEFERRABLE 0x00080000
#define TIMER_PINNED 0x00100000
#define TIMER_IRQSAFE 0x00200000
#define TIMER_ARRAYSHIFT 22
#define TIMER_ARRAYMASK 0xFFC00000
#define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
#define __TIMER_INITIALIZER(_function, _flags) { \
.entry = { .next = TIMER_ENTRY_STATIC }, \
.function = (_function), \
.flags = (_flags), \
__TIMER_LOCKDEP_MAP_INITIALIZER( \
__FILE__ ":" __stringify(__LINE__)) \
}
#define DEFINE_TIMER(_name, _function) \
struct timer_list _name = \
__TIMER_INITIALIZER(_function, 0)
/*
* LOCKDEP and DEBUG timer interfaces.
*/
void init_timer_key(struct timer_list *timer,
void (*func)(struct timer_list *), unsigned int flags,
const char *name, struct lock_class_key *key);
#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
extern void init_timer_on_stack_key(struct timer_list *timer,
void (*func)(struct timer_list *),
unsigned int flags, const char *name,
struct lock_class_key *key);
#else
static inline void init_timer_on_stack_key(struct timer_list *timer,
void (*func)(struct timer_list *),
unsigned int flags,
const char *name,
struct lock_class_key *key)
{
init_timer_key(timer, func, flags, name, key);
}
#endif
#ifdef CONFIG_LOCKDEP
#define __init_timer(_timer, _fn, _flags) \
do { \
static struct lock_class_key __key; \
init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
} while (0)
#define __init_timer_on_stack(_timer, _fn, _flags) \
do { \
static struct lock_class_key __key; \
init_timer_on_stack_key((_timer), (_fn), (_flags), \
#_timer, &__key); \
} while (0)
#else
#define __init_timer(_timer, _fn, _flags) \
init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
#define __init_timer_on_stack(_timer, _fn, _flags) \
init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
#endif
/**
* timer_setup - prepare a timer for first use
* @timer: the timer in question
* @callback: the function to call when timer expires
* @flags: any TIMER_* flags
*
* Regular timer initialization should use either DEFINE_TIMER() above,
* or timer_setup(). For timers on the stack, timer_setup_on_stack() must
* be used and must be balanced with a call to destroy_timer_on_stack().
*/
#define timer_setup(timer, callback, flags) \
__init_timer((timer), (callback), (flags))
#define timer_setup_on_stack(timer, callback, flags) \
__init_timer_on_stack((timer), (callback), (flags))
#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
extern void destroy_timer_on_stack(struct timer_list *timer);
#else
static inline void destroy_timer_on_stack(struct timer_list *timer) { }
#endif
#define from_timer(var, callback_timer, timer_fieldname) \
container_of(callback_timer, typeof(*var), timer_fieldname)
/**
* timer_pending - is a timer pending?
* @timer: the timer in question
*
* timer_pending will tell whether a given timer is currently pending,
* or not. Callers must ensure serialization wrt. other operations done
* to this timer, eg. interrupt contexts, or other CPUs on SMP.
*
* return value: 1 if the timer is pending, 0 if not.
*/
static inline int timer_pending(const struct timer_list * timer)
{
return timer->entry.pprev != NULL;
}
extern void add_timer_on(struct timer_list *timer, int cpu);
extern int del_timer(struct timer_list * timer);
extern int mod_timer(struct timer_list *timer, unsigned long expires);
extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
extern int timer_reduce(struct timer_list *timer, unsigned long expires);
/*
* The jiffies value which is added to now, when there is no timer
* in the timer wheel:
*/
#define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
extern void add_timer(struct timer_list *timer);
extern int try_to_del_timer_sync(struct timer_list *timer);
#ifdef CONFIG_SMP
extern int del_timer_sync(struct timer_list *timer);
#else
# define del_timer_sync(t) del_timer(t)
#endif
#define del_singleshot_timer_sync(t) del_timer_sync(t)
extern void init_timers(void);
extern void run_local_timers(void);
struct hrtimer;
extern enum hrtimer_restart it_real_fn(struct hrtimer *);
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
struct ctl_table;
extern unsigned int sysctl_timer_migration;
int timer_migration_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos);
#endif
unsigned long __round_jiffies(unsigned long j, int cpu);
unsigned long __round_jiffies_relative(unsigned long j, int cpu);
unsigned long round_jiffies(unsigned long j);
unsigned long round_jiffies_relative(unsigned long j);
unsigned long __round_jiffies_up(unsigned long j, int cpu);
unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
unsigned long round_jiffies_up(unsigned long j);
unsigned long round_jiffies_up_relative(unsigned long j);
#ifdef CONFIG_HOTPLUG_CPU
int timers_prepare_cpu(unsigned int cpu);
int timers_dead_cpu(unsigned int cpu);
#else
#define timers_prepare_cpu NULL
#define timers_dead_cpu NULL
#endif
#endif