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![Linus Torvalds](/assets/img/avatar_default.png)
* 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timer: Use debugobjects to catch deletion of uninitialized timers timer: Setup uninitialized timer with a stub callback debugobjects: Extend to assert that an object is initialized debugobjects: Be smarter about static objects
1842 lines
49 KiB
C
1842 lines
49 KiB
C
/*
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* linux/kernel/timer.c
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*
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* Kernel internal timers, basic process system calls
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better.
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*
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* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
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* "A Kernel Model for Precision Timekeeping" by Dave Mills
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* 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
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* serialize accesses to xtime/lost_ticks).
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* Copyright (C) 1998 Andrea Arcangeli
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* 1999-03-10 Improved NTP compatibility by Ulrich Windl
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* 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love
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* 2000-10-05 Implemented scalable SMP per-CPU timer handling.
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* Copyright (C) 2000, 2001, 2002 Ingo Molnar
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* Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar
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*/
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#include <linux/kernel_stat.h>
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#include <linux/export.h>
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#include <linux/interrupt.h>
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#include <linux/percpu.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/pid_namespace.h>
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#include <linux/notifier.h>
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#include <linux/thread_info.h>
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#include <linux/time.h>
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#include <linux/jiffies.h>
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#include <linux/posix-timers.h>
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#include <linux/cpu.h>
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#include <linux/syscalls.h>
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#include <linux/delay.h>
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#include <linux/tick.h>
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#include <linux/kallsyms.h>
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#include <linux/irq_work.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <asm/uaccess.h>
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#include <asm/unistd.h>
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#include <asm/div64.h>
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#include <asm/timex.h>
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#include <asm/io.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/timer.h>
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u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
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EXPORT_SYMBOL(jiffies_64);
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/*
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* per-CPU timer vector definitions:
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*/
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#define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
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#define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
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#define TVN_SIZE (1 << TVN_BITS)
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#define TVR_SIZE (1 << TVR_BITS)
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#define TVN_MASK (TVN_SIZE - 1)
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#define TVR_MASK (TVR_SIZE - 1)
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struct tvec {
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struct list_head vec[TVN_SIZE];
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};
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struct tvec_root {
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struct list_head vec[TVR_SIZE];
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};
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struct tvec_base {
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spinlock_t lock;
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struct timer_list *running_timer;
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unsigned long timer_jiffies;
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unsigned long next_timer;
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struct tvec_root tv1;
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struct tvec tv2;
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struct tvec tv3;
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struct tvec tv4;
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struct tvec tv5;
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} ____cacheline_aligned;
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struct tvec_base boot_tvec_bases;
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EXPORT_SYMBOL(boot_tvec_bases);
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static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
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/* Functions below help us manage 'deferrable' flag */
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static inline unsigned int tbase_get_deferrable(struct tvec_base *base)
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{
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return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG);
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}
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static inline struct tvec_base *tbase_get_base(struct tvec_base *base)
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{
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return ((struct tvec_base *)((unsigned long)base & ~TBASE_DEFERRABLE_FLAG));
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}
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static inline void timer_set_deferrable(struct timer_list *timer)
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{
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timer->base = TBASE_MAKE_DEFERRED(timer->base);
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}
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static inline void
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timer_set_base(struct timer_list *timer, struct tvec_base *new_base)
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{
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timer->base = (struct tvec_base *)((unsigned long)(new_base) |
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tbase_get_deferrable(timer->base));
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}
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static unsigned long round_jiffies_common(unsigned long j, int cpu,
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bool force_up)
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{
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int rem;
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unsigned long original = j;
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/*
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* We don't want all cpus firing their timers at once hitting the
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* same lock or cachelines, so we skew each extra cpu with an extra
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* 3 jiffies. This 3 jiffies came originally from the mm/ code which
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* already did this.
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* The skew is done by adding 3*cpunr, then round, then subtract this
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* extra offset again.
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*/
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j += cpu * 3;
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rem = j % HZ;
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/*
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* If the target jiffie is just after a whole second (which can happen
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* due to delays of the timer irq, long irq off times etc etc) then
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* we should round down to the whole second, not up. Use 1/4th second
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* as cutoff for this rounding as an extreme upper bound for this.
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* But never round down if @force_up is set.
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*/
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if (rem < HZ/4 && !force_up) /* round down */
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j = j - rem;
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else /* round up */
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j = j - rem + HZ;
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/* now that we have rounded, subtract the extra skew again */
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j -= cpu * 3;
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if (j <= jiffies) /* rounding ate our timeout entirely; */
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return original;
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return j;
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}
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/**
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* __round_jiffies - function to round jiffies to a full second
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* @j: the time in (absolute) jiffies that should be rounded
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* @cpu: the processor number on which the timeout will happen
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*
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* __round_jiffies() rounds an absolute time in the future (in jiffies)
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* up or down to (approximately) full seconds. This is useful for timers
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* for which the exact time they fire does not matter too much, as long as
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* they fire approximately every X seconds.
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*
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* By rounding these timers to whole seconds, all such timers will fire
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* at the same time, rather than at various times spread out. The goal
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* of this is to have the CPU wake up less, which saves power.
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*
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* The exact rounding is skewed for each processor to avoid all
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* processors firing at the exact same time, which could lead
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* to lock contention or spurious cache line bouncing.
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*
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* The return value is the rounded version of the @j parameter.
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*/
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unsigned long __round_jiffies(unsigned long j, int cpu)
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{
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return round_jiffies_common(j, cpu, false);
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}
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EXPORT_SYMBOL_GPL(__round_jiffies);
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/**
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* __round_jiffies_relative - function to round jiffies to a full second
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* @j: the time in (relative) jiffies that should be rounded
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* @cpu: the processor number on which the timeout will happen
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*
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* __round_jiffies_relative() rounds a time delta in the future (in jiffies)
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* up or down to (approximately) full seconds. This is useful for timers
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* for which the exact time they fire does not matter too much, as long as
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* they fire approximately every X seconds.
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*
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* By rounding these timers to whole seconds, all such timers will fire
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* at the same time, rather than at various times spread out. The goal
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* of this is to have the CPU wake up less, which saves power.
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*
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* The exact rounding is skewed for each processor to avoid all
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* processors firing at the exact same time, which could lead
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* to lock contention or spurious cache line bouncing.
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*
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* The return value is the rounded version of the @j parameter.
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*/
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unsigned long __round_jiffies_relative(unsigned long j, int cpu)
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{
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unsigned long j0 = jiffies;
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/* Use j0 because jiffies might change while we run */
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return round_jiffies_common(j + j0, cpu, false) - j0;
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}
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EXPORT_SYMBOL_GPL(__round_jiffies_relative);
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/**
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* round_jiffies - function to round jiffies to a full second
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* @j: the time in (absolute) jiffies that should be rounded
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*
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* round_jiffies() rounds an absolute time in the future (in jiffies)
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* up or down to (approximately) full seconds. This is useful for timers
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* for which the exact time they fire does not matter too much, as long as
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* they fire approximately every X seconds.
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*
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* By rounding these timers to whole seconds, all such timers will fire
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* at the same time, rather than at various times spread out. The goal
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* of this is to have the CPU wake up less, which saves power.
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*
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* The return value is the rounded version of the @j parameter.
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*/
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unsigned long round_jiffies(unsigned long j)
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{
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return round_jiffies_common(j, raw_smp_processor_id(), false);
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}
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EXPORT_SYMBOL_GPL(round_jiffies);
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/**
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* round_jiffies_relative - function to round jiffies to a full second
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* @j: the time in (relative) jiffies that should be rounded
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*
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* round_jiffies_relative() rounds a time delta in the future (in jiffies)
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* up or down to (approximately) full seconds. This is useful for timers
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* for which the exact time they fire does not matter too much, as long as
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* they fire approximately every X seconds.
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*
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* By rounding these timers to whole seconds, all such timers will fire
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* at the same time, rather than at various times spread out. The goal
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* of this is to have the CPU wake up less, which saves power.
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*
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* The return value is the rounded version of the @j parameter.
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*/
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unsigned long round_jiffies_relative(unsigned long j)
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{
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return __round_jiffies_relative(j, raw_smp_processor_id());
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}
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EXPORT_SYMBOL_GPL(round_jiffies_relative);
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/**
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* __round_jiffies_up - function to round jiffies up to a full second
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* @j: the time in (absolute) jiffies that should be rounded
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* @cpu: the processor number on which the timeout will happen
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*
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* This is the same as __round_jiffies() except that it will never
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* round down. This is useful for timeouts for which the exact time
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* of firing does not matter too much, as long as they don't fire too
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* early.
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*/
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unsigned long __round_jiffies_up(unsigned long j, int cpu)
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{
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return round_jiffies_common(j, cpu, true);
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}
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EXPORT_SYMBOL_GPL(__round_jiffies_up);
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/**
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* __round_jiffies_up_relative - function to round jiffies up to a full second
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* @j: the time in (relative) jiffies that should be rounded
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* @cpu: the processor number on which the timeout will happen
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*
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* This is the same as __round_jiffies_relative() except that it will never
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* round down. This is useful for timeouts for which the exact time
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* of firing does not matter too much, as long as they don't fire too
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* early.
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*/
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unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
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{
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unsigned long j0 = jiffies;
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/* Use j0 because jiffies might change while we run */
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return round_jiffies_common(j + j0, cpu, true) - j0;
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}
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EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
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/**
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* round_jiffies_up - function to round jiffies up to a full second
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* @j: the time in (absolute) jiffies that should be rounded
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*
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* This is the same as round_jiffies() except that it will never
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* round down. This is useful for timeouts for which the exact time
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* of firing does not matter too much, as long as they don't fire too
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* early.
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*/
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unsigned long round_jiffies_up(unsigned long j)
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{
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return round_jiffies_common(j, raw_smp_processor_id(), true);
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}
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EXPORT_SYMBOL_GPL(round_jiffies_up);
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/**
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* round_jiffies_up_relative - function to round jiffies up to a full second
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* @j: the time in (relative) jiffies that should be rounded
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*
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* This is the same as round_jiffies_relative() except that it will never
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* round down. This is useful for timeouts for which the exact time
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* of firing does not matter too much, as long as they don't fire too
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* early.
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*/
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unsigned long round_jiffies_up_relative(unsigned long j)
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{
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return __round_jiffies_up_relative(j, raw_smp_processor_id());
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}
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EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
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/**
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* set_timer_slack - set the allowed slack for a timer
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* @timer: the timer to be modified
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* @slack_hz: the amount of time (in jiffies) allowed for rounding
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*
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* Set the amount of time, in jiffies, that a certain timer has
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* in terms of slack. By setting this value, the timer subsystem
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* will schedule the actual timer somewhere between
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* the time mod_timer() asks for, and that time plus the slack.
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*
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* By setting the slack to -1, a percentage of the delay is used
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* instead.
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*/
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void set_timer_slack(struct timer_list *timer, int slack_hz)
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{
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timer->slack = slack_hz;
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}
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EXPORT_SYMBOL_GPL(set_timer_slack);
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static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
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{
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unsigned long expires = timer->expires;
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unsigned long idx = expires - base->timer_jiffies;
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struct list_head *vec;
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if (idx < TVR_SIZE) {
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int i = expires & TVR_MASK;
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vec = base->tv1.vec + i;
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} else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
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int i = (expires >> TVR_BITS) & TVN_MASK;
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vec = base->tv2.vec + i;
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} else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
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int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
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vec = base->tv3.vec + i;
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} else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
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int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
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vec = base->tv4.vec + i;
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} else if ((signed long) idx < 0) {
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/*
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* Can happen if you add a timer with expires == jiffies,
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* or you set a timer to go off in the past
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*/
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vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
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} else {
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int i;
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/* If the timeout is larger than 0xffffffff on 64-bit
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* architectures then we use the maximum timeout:
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*/
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if (idx > 0xffffffffUL) {
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idx = 0xffffffffUL;
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expires = idx + base->timer_jiffies;
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}
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i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
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vec = base->tv5.vec + i;
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}
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/*
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* Timers are FIFO:
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*/
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list_add_tail(&timer->entry, vec);
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}
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#ifdef CONFIG_TIMER_STATS
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void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
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{
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if (timer->start_site)
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return;
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timer->start_site = addr;
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memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
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timer->start_pid = current->pid;
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}
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static void timer_stats_account_timer(struct timer_list *timer)
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{
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unsigned int flag = 0;
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if (likely(!timer->start_site))
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return;
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if (unlikely(tbase_get_deferrable(timer->base)))
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flag |= TIMER_STATS_FLAG_DEFERRABLE;
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timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
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timer->function, timer->start_comm, flag);
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}
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#else
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static void timer_stats_account_timer(struct timer_list *timer) {}
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#endif
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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static struct debug_obj_descr timer_debug_descr;
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static void *timer_debug_hint(void *addr)
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{
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return ((struct timer_list *) addr)->function;
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}
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/*
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* fixup_init is called when:
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* - an active object is initialized
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*/
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static int timer_fixup_init(void *addr, enum debug_obj_state state)
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{
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struct timer_list *timer = addr;
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switch (state) {
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case ODEBUG_STATE_ACTIVE:
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del_timer_sync(timer);
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debug_object_init(timer, &timer_debug_descr);
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return 1;
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default:
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return 0;
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}
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}
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/* Stub timer callback for improperly used timers. */
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static void stub_timer(unsigned long data)
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{
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WARN_ON(1);
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}
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/*
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* fixup_activate is called when:
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* - an active object is activated
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* - an unknown object is activated (might be a statically initialized object)
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*/
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static int timer_fixup_activate(void *addr, enum debug_obj_state state)
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{
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struct timer_list *timer = addr;
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switch (state) {
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case ODEBUG_STATE_NOTAVAILABLE:
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/*
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* This is not really a fixup. The timer was
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* statically initialized. We just make sure that it
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* is tracked in the object tracker.
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*/
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if (timer->entry.next == NULL &&
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timer->entry.prev == TIMER_ENTRY_STATIC) {
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debug_object_init(timer, &timer_debug_descr);
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debug_object_activate(timer, &timer_debug_descr);
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return 0;
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} else {
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setup_timer(timer, stub_timer, 0);
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return 1;
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}
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return 0;
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case ODEBUG_STATE_ACTIVE:
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WARN_ON(1);
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default:
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return 0;
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}
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}
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|
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/*
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* fixup_free is called when:
|
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* - an active object is freed
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*/
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static int timer_fixup_free(void *addr, enum debug_obj_state state)
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{
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struct timer_list *timer = addr;
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switch (state) {
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case ODEBUG_STATE_ACTIVE:
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del_timer_sync(timer);
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debug_object_free(timer, &timer_debug_descr);
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return 1;
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|
default:
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* fixup_assert_init is called when:
|
|
* - an untracked/uninit-ed object is found
|
|
*/
|
|
static int timer_fixup_assert_init(void *addr, enum debug_obj_state state)
|
|
{
|
|
struct timer_list *timer = addr;
|
|
|
|
switch (state) {
|
|
case ODEBUG_STATE_NOTAVAILABLE:
|
|
if (timer->entry.prev == TIMER_ENTRY_STATIC) {
|
|
/*
|
|
* This is not really a fixup. The timer was
|
|
* statically initialized. We just make sure that it
|
|
* is tracked in the object tracker.
|
|
*/
|
|
debug_object_init(timer, &timer_debug_descr);
|
|
return 0;
|
|
} else {
|
|
setup_timer(timer, stub_timer, 0);
|
|
return 1;
|
|
}
|
|
default:
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
static struct debug_obj_descr timer_debug_descr = {
|
|
.name = "timer_list",
|
|
.debug_hint = timer_debug_hint,
|
|
.fixup_init = timer_fixup_init,
|
|
.fixup_activate = timer_fixup_activate,
|
|
.fixup_free = timer_fixup_free,
|
|
.fixup_assert_init = timer_fixup_assert_init,
|
|
};
|
|
|
|
static inline void debug_timer_init(struct timer_list *timer)
|
|
{
|
|
debug_object_init(timer, &timer_debug_descr);
|
|
}
|
|
|
|
static inline void debug_timer_activate(struct timer_list *timer)
|
|
{
|
|
debug_object_activate(timer, &timer_debug_descr);
|
|
}
|
|
|
|
static inline void debug_timer_deactivate(struct timer_list *timer)
|
|
{
|
|
debug_object_deactivate(timer, &timer_debug_descr);
|
|
}
|
|
|
|
static inline void debug_timer_free(struct timer_list *timer)
|
|
{
|
|
debug_object_free(timer, &timer_debug_descr);
|
|
}
|
|
|
|
static inline void debug_timer_assert_init(struct timer_list *timer)
|
|
{
|
|
debug_object_assert_init(timer, &timer_debug_descr);
|
|
}
|
|
|
|
static void __init_timer(struct timer_list *timer,
|
|
const char *name,
|
|
struct lock_class_key *key);
|
|
|
|
void init_timer_on_stack_key(struct timer_list *timer,
|
|
const char *name,
|
|
struct lock_class_key *key)
|
|
{
|
|
debug_object_init_on_stack(timer, &timer_debug_descr);
|
|
__init_timer(timer, name, key);
|
|
}
|
|
EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
|
|
|
|
void destroy_timer_on_stack(struct timer_list *timer)
|
|
{
|
|
debug_object_free(timer, &timer_debug_descr);
|
|
}
|
|
EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
|
|
|
|
#else
|
|
static inline void debug_timer_init(struct timer_list *timer) { }
|
|
static inline void debug_timer_activate(struct timer_list *timer) { }
|
|
static inline void debug_timer_deactivate(struct timer_list *timer) { }
|
|
static inline void debug_timer_assert_init(struct timer_list *timer) { }
|
|
#endif
|
|
|
|
static inline void debug_init(struct timer_list *timer)
|
|
{
|
|
debug_timer_init(timer);
|
|
trace_timer_init(timer);
|
|
}
|
|
|
|
static inline void
|
|
debug_activate(struct timer_list *timer, unsigned long expires)
|
|
{
|
|
debug_timer_activate(timer);
|
|
trace_timer_start(timer, expires);
|
|
}
|
|
|
|
static inline void debug_deactivate(struct timer_list *timer)
|
|
{
|
|
debug_timer_deactivate(timer);
|
|
trace_timer_cancel(timer);
|
|
}
|
|
|
|
static inline void debug_assert_init(struct timer_list *timer)
|
|
{
|
|
debug_timer_assert_init(timer);
|
|
}
|
|
|
|
static void __init_timer(struct timer_list *timer,
|
|
const char *name,
|
|
struct lock_class_key *key)
|
|
{
|
|
timer->entry.next = NULL;
|
|
timer->base = __raw_get_cpu_var(tvec_bases);
|
|
timer->slack = -1;
|
|
#ifdef CONFIG_TIMER_STATS
|
|
timer->start_site = NULL;
|
|
timer->start_pid = -1;
|
|
memset(timer->start_comm, 0, TASK_COMM_LEN);
|
|
#endif
|
|
lockdep_init_map(&timer->lockdep_map, name, key, 0);
|
|
}
|
|
|
|
void setup_deferrable_timer_on_stack_key(struct timer_list *timer,
|
|
const char *name,
|
|
struct lock_class_key *key,
|
|
void (*function)(unsigned long),
|
|
unsigned long data)
|
|
{
|
|
timer->function = function;
|
|
timer->data = data;
|
|
init_timer_on_stack_key(timer, name, key);
|
|
timer_set_deferrable(timer);
|
|
}
|
|
EXPORT_SYMBOL_GPL(setup_deferrable_timer_on_stack_key);
|
|
|
|
/**
|
|
* init_timer_key - initialize a timer
|
|
* @timer: the timer to be initialized
|
|
* @name: name of the timer
|
|
* @key: lockdep class key of the fake lock used for tracking timer
|
|
* sync lock dependencies
|
|
*
|
|
* init_timer_key() must be done to a timer prior calling *any* of the
|
|
* other timer functions.
|
|
*/
|
|
void init_timer_key(struct timer_list *timer,
|
|
const char *name,
|
|
struct lock_class_key *key)
|
|
{
|
|
debug_init(timer);
|
|
__init_timer(timer, name, key);
|
|
}
|
|
EXPORT_SYMBOL(init_timer_key);
|
|
|
|
void init_timer_deferrable_key(struct timer_list *timer,
|
|
const char *name,
|
|
struct lock_class_key *key)
|
|
{
|
|
init_timer_key(timer, name, key);
|
|
timer_set_deferrable(timer);
|
|
}
|
|
EXPORT_SYMBOL(init_timer_deferrable_key);
|
|
|
|
static inline void detach_timer(struct timer_list *timer,
|
|
int clear_pending)
|
|
{
|
|
struct list_head *entry = &timer->entry;
|
|
|
|
debug_deactivate(timer);
|
|
|
|
__list_del(entry->prev, entry->next);
|
|
if (clear_pending)
|
|
entry->next = NULL;
|
|
entry->prev = LIST_POISON2;
|
|
}
|
|
|
|
/*
|
|
* We are using hashed locking: holding per_cpu(tvec_bases).lock
|
|
* means that all timers which are tied to this base via timer->base are
|
|
* locked, and the base itself is locked too.
|
|
*
|
|
* So __run_timers/migrate_timers can safely modify all timers which could
|
|
* be found on ->tvX lists.
|
|
*
|
|
* When the timer's base is locked, and the timer removed from list, it is
|
|
* possible to set timer->base = NULL and drop the lock: the timer remains
|
|
* locked.
|
|
*/
|
|
static struct tvec_base *lock_timer_base(struct timer_list *timer,
|
|
unsigned long *flags)
|
|
__acquires(timer->base->lock)
|
|
{
|
|
struct tvec_base *base;
|
|
|
|
for (;;) {
|
|
struct tvec_base *prelock_base = timer->base;
|
|
base = tbase_get_base(prelock_base);
|
|
if (likely(base != NULL)) {
|
|
spin_lock_irqsave(&base->lock, *flags);
|
|
if (likely(prelock_base == timer->base))
|
|
return base;
|
|
/* The timer has migrated to another CPU */
|
|
spin_unlock_irqrestore(&base->lock, *flags);
|
|
}
|
|
cpu_relax();
|
|
}
|
|
}
|
|
|
|
static inline int
|
|
__mod_timer(struct timer_list *timer, unsigned long expires,
|
|
bool pending_only, int pinned)
|
|
{
|
|
struct tvec_base *base, *new_base;
|
|
unsigned long flags;
|
|
int ret = 0 , cpu;
|
|
|
|
timer_stats_timer_set_start_info(timer);
|
|
BUG_ON(!timer->function);
|
|
|
|
base = lock_timer_base(timer, &flags);
|
|
|
|
if (timer_pending(timer)) {
|
|
detach_timer(timer, 0);
|
|
if (timer->expires == base->next_timer &&
|
|
!tbase_get_deferrable(timer->base))
|
|
base->next_timer = base->timer_jiffies;
|
|
ret = 1;
|
|
} else {
|
|
if (pending_only)
|
|
goto out_unlock;
|
|
}
|
|
|
|
debug_activate(timer, expires);
|
|
|
|
cpu = smp_processor_id();
|
|
|
|
#if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
|
|
if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu))
|
|
cpu = get_nohz_timer_target();
|
|
#endif
|
|
new_base = per_cpu(tvec_bases, cpu);
|
|
|
|
if (base != new_base) {
|
|
/*
|
|
* We are trying to schedule the timer on the local CPU.
|
|
* However we can't change timer's base while it is running,
|
|
* otherwise del_timer_sync() can't detect that the timer's
|
|
* handler yet has not finished. This also guarantees that
|
|
* the timer is serialized wrt itself.
|
|
*/
|
|
if (likely(base->running_timer != timer)) {
|
|
/* See the comment in lock_timer_base() */
|
|
timer_set_base(timer, NULL);
|
|
spin_unlock(&base->lock);
|
|
base = new_base;
|
|
spin_lock(&base->lock);
|
|
timer_set_base(timer, base);
|
|
}
|
|
}
|
|
|
|
timer->expires = expires;
|
|
if (time_before(timer->expires, base->next_timer) &&
|
|
!tbase_get_deferrable(timer->base))
|
|
base->next_timer = timer->expires;
|
|
internal_add_timer(base, timer);
|
|
|
|
out_unlock:
|
|
spin_unlock_irqrestore(&base->lock, flags);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* mod_timer_pending - modify a pending timer's timeout
|
|
* @timer: the pending timer to be modified
|
|
* @expires: new timeout in jiffies
|
|
*
|
|
* mod_timer_pending() is the same for pending timers as mod_timer(),
|
|
* but will not re-activate and modify already deleted timers.
|
|
*
|
|
* It is useful for unserialized use of timers.
|
|
*/
|
|
int mod_timer_pending(struct timer_list *timer, unsigned long expires)
|
|
{
|
|
return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
|
|
}
|
|
EXPORT_SYMBOL(mod_timer_pending);
|
|
|
|
/*
|
|
* Decide where to put the timer while taking the slack into account
|
|
*
|
|
* Algorithm:
|
|
* 1) calculate the maximum (absolute) time
|
|
* 2) calculate the highest bit where the expires and new max are different
|
|
* 3) use this bit to make a mask
|
|
* 4) use the bitmask to round down the maximum time, so that all last
|
|
* bits are zeros
|
|
*/
|
|
static inline
|
|
unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
|
|
{
|
|
unsigned long expires_limit, mask;
|
|
int bit;
|
|
|
|
if (timer->slack >= 0) {
|
|
expires_limit = expires + timer->slack;
|
|
} else {
|
|
long delta = expires - jiffies;
|
|
|
|
if (delta < 256)
|
|
return expires;
|
|
|
|
expires_limit = expires + delta / 256;
|
|
}
|
|
mask = expires ^ expires_limit;
|
|
if (mask == 0)
|
|
return expires;
|
|
|
|
bit = find_last_bit(&mask, BITS_PER_LONG);
|
|
|
|
mask = (1 << bit) - 1;
|
|
|
|
expires_limit = expires_limit & ~(mask);
|
|
|
|
return expires_limit;
|
|
}
|
|
|
|
/**
|
|
* mod_timer - modify a timer's timeout
|
|
* @timer: the timer to be modified
|
|
* @expires: new timeout in jiffies
|
|
*
|
|
* mod_timer() is a more efficient way to update the expire field of an
|
|
* active timer (if the timer is inactive it will be activated)
|
|
*
|
|
* mod_timer(timer, expires) is equivalent to:
|
|
*
|
|
* del_timer(timer); timer->expires = expires; add_timer(timer);
|
|
*
|
|
* Note that if there are multiple unserialized concurrent users of the
|
|
* same timer, then mod_timer() is the only safe way to modify the timeout,
|
|
* since add_timer() cannot modify an already running timer.
|
|
*
|
|
* The function returns whether it has modified a pending timer or not.
|
|
* (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an
|
|
* active timer returns 1.)
|
|
*/
|
|
int mod_timer(struct timer_list *timer, unsigned long expires)
|
|
{
|
|
expires = apply_slack(timer, expires);
|
|
|
|
/*
|
|
* This is a common optimization triggered by the
|
|
* networking code - if the timer is re-modified
|
|
* to be the same thing then just return:
|
|
*/
|
|
if (timer_pending(timer) && timer->expires == expires)
|
|
return 1;
|
|
|
|
return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
|
|
}
|
|
EXPORT_SYMBOL(mod_timer);
|
|
|
|
/**
|
|
* mod_timer_pinned - modify a timer's timeout
|
|
* @timer: the timer to be modified
|
|
* @expires: new timeout in jiffies
|
|
*
|
|
* mod_timer_pinned() is a way to update the expire field of an
|
|
* active timer (if the timer is inactive it will be activated)
|
|
* and not allow the timer to be migrated to a different CPU.
|
|
*
|
|
* mod_timer_pinned(timer, expires) is equivalent to:
|
|
*
|
|
* del_timer(timer); timer->expires = expires; add_timer(timer);
|
|
*/
|
|
int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
|
|
{
|
|
if (timer->expires == expires && timer_pending(timer))
|
|
return 1;
|
|
|
|
return __mod_timer(timer, expires, false, TIMER_PINNED);
|
|
}
|
|
EXPORT_SYMBOL(mod_timer_pinned);
|
|
|
|
/**
|
|
* add_timer - start a timer
|
|
* @timer: the timer to be added
|
|
*
|
|
* The kernel will do a ->function(->data) callback from the
|
|
* timer interrupt at the ->expires point in the future. The
|
|
* current time is 'jiffies'.
|
|
*
|
|
* The timer's ->expires, ->function (and if the handler uses it, ->data)
|
|
* fields must be set prior calling this function.
|
|
*
|
|
* Timers with an ->expires field in the past will be executed in the next
|
|
* timer tick.
|
|
*/
|
|
void add_timer(struct timer_list *timer)
|
|
{
|
|
BUG_ON(timer_pending(timer));
|
|
mod_timer(timer, timer->expires);
|
|
}
|
|
EXPORT_SYMBOL(add_timer);
|
|
|
|
/**
|
|
* add_timer_on - start a timer on a particular CPU
|
|
* @timer: the timer to be added
|
|
* @cpu: the CPU to start it on
|
|
*
|
|
* This is not very scalable on SMP. Double adds are not possible.
|
|
*/
|
|
void add_timer_on(struct timer_list *timer, int cpu)
|
|
{
|
|
struct tvec_base *base = per_cpu(tvec_bases, cpu);
|
|
unsigned long flags;
|
|
|
|
timer_stats_timer_set_start_info(timer);
|
|
BUG_ON(timer_pending(timer) || !timer->function);
|
|
spin_lock_irqsave(&base->lock, flags);
|
|
timer_set_base(timer, base);
|
|
debug_activate(timer, timer->expires);
|
|
if (time_before(timer->expires, base->next_timer) &&
|
|
!tbase_get_deferrable(timer->base))
|
|
base->next_timer = timer->expires;
|
|
internal_add_timer(base, timer);
|
|
/*
|
|
* Check whether the other CPU is idle and needs to be
|
|
* triggered to reevaluate the timer wheel when nohz is
|
|
* active. We are protected against the other CPU fiddling
|
|
* with the timer by holding the timer base lock. This also
|
|
* makes sure that a CPU on the way to idle can not evaluate
|
|
* the timer wheel.
|
|
*/
|
|
wake_up_idle_cpu(cpu);
|
|
spin_unlock_irqrestore(&base->lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(add_timer_on);
|
|
|
|
/**
|
|
* del_timer - deactive a timer.
|
|
* @timer: the timer to be deactivated
|
|
*
|
|
* del_timer() deactivates a timer - this works on both active and inactive
|
|
* timers.
|
|
*
|
|
* The function returns whether it has deactivated a pending timer or not.
|
|
* (ie. del_timer() of an inactive timer returns 0, del_timer() of an
|
|
* active timer returns 1.)
|
|
*/
|
|
int del_timer(struct timer_list *timer)
|
|
{
|
|
struct tvec_base *base;
|
|
unsigned long flags;
|
|
int ret = 0;
|
|
|
|
debug_assert_init(timer);
|
|
|
|
timer_stats_timer_clear_start_info(timer);
|
|
if (timer_pending(timer)) {
|
|
base = lock_timer_base(timer, &flags);
|
|
if (timer_pending(timer)) {
|
|
detach_timer(timer, 1);
|
|
if (timer->expires == base->next_timer &&
|
|
!tbase_get_deferrable(timer->base))
|
|
base->next_timer = base->timer_jiffies;
|
|
ret = 1;
|
|
}
|
|
spin_unlock_irqrestore(&base->lock, flags);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(del_timer);
|
|
|
|
/**
|
|
* try_to_del_timer_sync - Try to deactivate a timer
|
|
* @timer: timer do del
|
|
*
|
|
* This function tries to deactivate a timer. Upon successful (ret >= 0)
|
|
* exit the timer is not queued and the handler is not running on any CPU.
|
|
*/
|
|
int try_to_del_timer_sync(struct timer_list *timer)
|
|
{
|
|
struct tvec_base *base;
|
|
unsigned long flags;
|
|
int ret = -1;
|
|
|
|
debug_assert_init(timer);
|
|
|
|
base = lock_timer_base(timer, &flags);
|
|
|
|
if (base->running_timer == timer)
|
|
goto out;
|
|
|
|
timer_stats_timer_clear_start_info(timer);
|
|
ret = 0;
|
|
if (timer_pending(timer)) {
|
|
detach_timer(timer, 1);
|
|
if (timer->expires == base->next_timer &&
|
|
!tbase_get_deferrable(timer->base))
|
|
base->next_timer = base->timer_jiffies;
|
|
ret = 1;
|
|
}
|
|
out:
|
|
spin_unlock_irqrestore(&base->lock, flags);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(try_to_del_timer_sync);
|
|
|
|
#ifdef CONFIG_SMP
|
|
/**
|
|
* del_timer_sync - deactivate a timer and wait for the handler to finish.
|
|
* @timer: the timer to be deactivated
|
|
*
|
|
* This function only differs from del_timer() on SMP: besides deactivating
|
|
* the timer it also makes sure the handler has finished executing on other
|
|
* CPUs.
|
|
*
|
|
* Synchronization rules: Callers must prevent restarting of the timer,
|
|
* otherwise this function is meaningless. It must not be called from
|
|
* interrupt contexts. The caller must not hold locks which would prevent
|
|
* completion of the timer's handler. The timer's handler must not call
|
|
* add_timer_on(). Upon exit the timer is not queued and the handler is
|
|
* not running on any CPU.
|
|
*
|
|
* Note: You must not hold locks that are held in interrupt context
|
|
* while calling this function. Even if the lock has nothing to do
|
|
* with the timer in question. Here's why:
|
|
*
|
|
* CPU0 CPU1
|
|
* ---- ----
|
|
* <SOFTIRQ>
|
|
* call_timer_fn();
|
|
* base->running_timer = mytimer;
|
|
* spin_lock_irq(somelock);
|
|
* <IRQ>
|
|
* spin_lock(somelock);
|
|
* del_timer_sync(mytimer);
|
|
* while (base->running_timer == mytimer);
|
|
*
|
|
* Now del_timer_sync() will never return and never release somelock.
|
|
* The interrupt on the other CPU is waiting to grab somelock but
|
|
* it has interrupted the softirq that CPU0 is waiting to finish.
|
|
*
|
|
* The function returns whether it has deactivated a pending timer or not.
|
|
*/
|
|
int del_timer_sync(struct timer_list *timer)
|
|
{
|
|
#ifdef CONFIG_LOCKDEP
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* If lockdep gives a backtrace here, please reference
|
|
* the synchronization rules above.
|
|
*/
|
|
local_irq_save(flags);
|
|
lock_map_acquire(&timer->lockdep_map);
|
|
lock_map_release(&timer->lockdep_map);
|
|
local_irq_restore(flags);
|
|
#endif
|
|
/*
|
|
* don't use it in hardirq context, because it
|
|
* could lead to deadlock.
|
|
*/
|
|
WARN_ON(in_irq());
|
|
for (;;) {
|
|
int ret = try_to_del_timer_sync(timer);
|
|
if (ret >= 0)
|
|
return ret;
|
|
cpu_relax();
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(del_timer_sync);
|
|
#endif
|
|
|
|
static int cascade(struct tvec_base *base, struct tvec *tv, int index)
|
|
{
|
|
/* cascade all the timers from tv up one level */
|
|
struct timer_list *timer, *tmp;
|
|
struct list_head tv_list;
|
|
|
|
list_replace_init(tv->vec + index, &tv_list);
|
|
|
|
/*
|
|
* We are removing _all_ timers from the list, so we
|
|
* don't have to detach them individually.
|
|
*/
|
|
list_for_each_entry_safe(timer, tmp, &tv_list, entry) {
|
|
BUG_ON(tbase_get_base(timer->base) != base);
|
|
internal_add_timer(base, timer);
|
|
}
|
|
|
|
return index;
|
|
}
|
|
|
|
static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
|
|
unsigned long data)
|
|
{
|
|
int preempt_count = preempt_count();
|
|
|
|
#ifdef CONFIG_LOCKDEP
|
|
/*
|
|
* It is permissible to free the timer from inside the
|
|
* function that is called from it, this we need to take into
|
|
* account for lockdep too. To avoid bogus "held lock freed"
|
|
* warnings as well as problems when looking into
|
|
* timer->lockdep_map, make a copy and use that here.
|
|
*/
|
|
struct lockdep_map lockdep_map = timer->lockdep_map;
|
|
#endif
|
|
/*
|
|
* Couple the lock chain with the lock chain at
|
|
* del_timer_sync() by acquiring the lock_map around the fn()
|
|
* call here and in del_timer_sync().
|
|
*/
|
|
lock_map_acquire(&lockdep_map);
|
|
|
|
trace_timer_expire_entry(timer);
|
|
fn(data);
|
|
trace_timer_expire_exit(timer);
|
|
|
|
lock_map_release(&lockdep_map);
|
|
|
|
if (preempt_count != preempt_count()) {
|
|
WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
|
|
fn, preempt_count, preempt_count());
|
|
/*
|
|
* Restore the preempt count. That gives us a decent
|
|
* chance to survive and extract information. If the
|
|
* callback kept a lock held, bad luck, but not worse
|
|
* than the BUG() we had.
|
|
*/
|
|
preempt_count() = preempt_count;
|
|
}
|
|
}
|
|
|
|
#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
|
|
|
|
/**
|
|
* __run_timers - run all expired timers (if any) on this CPU.
|
|
* @base: the timer vector to be processed.
|
|
*
|
|
* This function cascades all vectors and executes all expired timer
|
|
* vectors.
|
|
*/
|
|
static inline void __run_timers(struct tvec_base *base)
|
|
{
|
|
struct timer_list *timer;
|
|
|
|
spin_lock_irq(&base->lock);
|
|
while (time_after_eq(jiffies, base->timer_jiffies)) {
|
|
struct list_head work_list;
|
|
struct list_head *head = &work_list;
|
|
int index = base->timer_jiffies & TVR_MASK;
|
|
|
|
/*
|
|
* Cascade timers:
|
|
*/
|
|
if (!index &&
|
|
(!cascade(base, &base->tv2, INDEX(0))) &&
|
|
(!cascade(base, &base->tv3, INDEX(1))) &&
|
|
!cascade(base, &base->tv4, INDEX(2)))
|
|
cascade(base, &base->tv5, INDEX(3));
|
|
++base->timer_jiffies;
|
|
list_replace_init(base->tv1.vec + index, &work_list);
|
|
while (!list_empty(head)) {
|
|
void (*fn)(unsigned long);
|
|
unsigned long data;
|
|
|
|
timer = list_first_entry(head, struct timer_list,entry);
|
|
fn = timer->function;
|
|
data = timer->data;
|
|
|
|
timer_stats_account_timer(timer);
|
|
|
|
base->running_timer = timer;
|
|
detach_timer(timer, 1);
|
|
|
|
spin_unlock_irq(&base->lock);
|
|
call_timer_fn(timer, fn, data);
|
|
spin_lock_irq(&base->lock);
|
|
}
|
|
}
|
|
base->running_timer = NULL;
|
|
spin_unlock_irq(&base->lock);
|
|
}
|
|
|
|
#ifdef CONFIG_NO_HZ
|
|
/*
|
|
* Find out when the next timer event is due to happen. This
|
|
* is used on S/390 to stop all activity when a CPU is idle.
|
|
* This function needs to be called with interrupts disabled.
|
|
*/
|
|
static unsigned long __next_timer_interrupt(struct tvec_base *base)
|
|
{
|
|
unsigned long timer_jiffies = base->timer_jiffies;
|
|
unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA;
|
|
int index, slot, array, found = 0;
|
|
struct timer_list *nte;
|
|
struct tvec *varray[4];
|
|
|
|
/* Look for timer events in tv1. */
|
|
index = slot = timer_jiffies & TVR_MASK;
|
|
do {
|
|
list_for_each_entry(nte, base->tv1.vec + slot, entry) {
|
|
if (tbase_get_deferrable(nte->base))
|
|
continue;
|
|
|
|
found = 1;
|
|
expires = nte->expires;
|
|
/* Look at the cascade bucket(s)? */
|
|
if (!index || slot < index)
|
|
goto cascade;
|
|
return expires;
|
|
}
|
|
slot = (slot + 1) & TVR_MASK;
|
|
} while (slot != index);
|
|
|
|
cascade:
|
|
/* Calculate the next cascade event */
|
|
if (index)
|
|
timer_jiffies += TVR_SIZE - index;
|
|
timer_jiffies >>= TVR_BITS;
|
|
|
|
/* Check tv2-tv5. */
|
|
varray[0] = &base->tv2;
|
|
varray[1] = &base->tv3;
|
|
varray[2] = &base->tv4;
|
|
varray[3] = &base->tv5;
|
|
|
|
for (array = 0; array < 4; array++) {
|
|
struct tvec *varp = varray[array];
|
|
|
|
index = slot = timer_jiffies & TVN_MASK;
|
|
do {
|
|
list_for_each_entry(nte, varp->vec + slot, entry) {
|
|
if (tbase_get_deferrable(nte->base))
|
|
continue;
|
|
|
|
found = 1;
|
|
if (time_before(nte->expires, expires))
|
|
expires = nte->expires;
|
|
}
|
|
/*
|
|
* Do we still search for the first timer or are
|
|
* we looking up the cascade buckets ?
|
|
*/
|
|
if (found) {
|
|
/* Look at the cascade bucket(s)? */
|
|
if (!index || slot < index)
|
|
break;
|
|
return expires;
|
|
}
|
|
slot = (slot + 1) & TVN_MASK;
|
|
} while (slot != index);
|
|
|
|
if (index)
|
|
timer_jiffies += TVN_SIZE - index;
|
|
timer_jiffies >>= TVN_BITS;
|
|
}
|
|
return expires;
|
|
}
|
|
|
|
/*
|
|
* Check, if the next hrtimer event is before the next timer wheel
|
|
* event:
|
|
*/
|
|
static unsigned long cmp_next_hrtimer_event(unsigned long now,
|
|
unsigned long expires)
|
|
{
|
|
ktime_t hr_delta = hrtimer_get_next_event();
|
|
struct timespec tsdelta;
|
|
unsigned long delta;
|
|
|
|
if (hr_delta.tv64 == KTIME_MAX)
|
|
return expires;
|
|
|
|
/*
|
|
* Expired timer available, let it expire in the next tick
|
|
*/
|
|
if (hr_delta.tv64 <= 0)
|
|
return now + 1;
|
|
|
|
tsdelta = ktime_to_timespec(hr_delta);
|
|
delta = timespec_to_jiffies(&tsdelta);
|
|
|
|
/*
|
|
* Limit the delta to the max value, which is checked in
|
|
* tick_nohz_stop_sched_tick():
|
|
*/
|
|
if (delta > NEXT_TIMER_MAX_DELTA)
|
|
delta = NEXT_TIMER_MAX_DELTA;
|
|
|
|
/*
|
|
* Take rounding errors in to account and make sure, that it
|
|
* expires in the next tick. Otherwise we go into an endless
|
|
* ping pong due to tick_nohz_stop_sched_tick() retriggering
|
|
* the timer softirq
|
|
*/
|
|
if (delta < 1)
|
|
delta = 1;
|
|
now += delta;
|
|
if (time_before(now, expires))
|
|
return now;
|
|
return expires;
|
|
}
|
|
|
|
/**
|
|
* get_next_timer_interrupt - return the jiffy of the next pending timer
|
|
* @now: current time (in jiffies)
|
|
*/
|
|
unsigned long get_next_timer_interrupt(unsigned long now)
|
|
{
|
|
struct tvec_base *base = __this_cpu_read(tvec_bases);
|
|
unsigned long expires;
|
|
|
|
/*
|
|
* Pretend that there is no timer pending if the cpu is offline.
|
|
* Possible pending timers will be migrated later to an active cpu.
|
|
*/
|
|
if (cpu_is_offline(smp_processor_id()))
|
|
return now + NEXT_TIMER_MAX_DELTA;
|
|
spin_lock(&base->lock);
|
|
if (time_before_eq(base->next_timer, base->timer_jiffies))
|
|
base->next_timer = __next_timer_interrupt(base);
|
|
expires = base->next_timer;
|
|
spin_unlock(&base->lock);
|
|
|
|
if (time_before_eq(expires, now))
|
|
return now;
|
|
|
|
return cmp_next_hrtimer_event(now, expires);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Called from the timer interrupt handler to charge one tick to the current
|
|
* process. user_tick is 1 if the tick is user time, 0 for system.
|
|
*/
|
|
void update_process_times(int user_tick)
|
|
{
|
|
struct task_struct *p = current;
|
|
int cpu = smp_processor_id();
|
|
|
|
/* Note: this timer irq context must be accounted for as well. */
|
|
account_process_tick(p, user_tick);
|
|
run_local_timers();
|
|
rcu_check_callbacks(cpu, user_tick);
|
|
printk_tick();
|
|
#ifdef CONFIG_IRQ_WORK
|
|
if (in_irq())
|
|
irq_work_run();
|
|
#endif
|
|
scheduler_tick();
|
|
run_posix_cpu_timers(p);
|
|
}
|
|
|
|
/*
|
|
* This function runs timers and the timer-tq in bottom half context.
|
|
*/
|
|
static void run_timer_softirq(struct softirq_action *h)
|
|
{
|
|
struct tvec_base *base = __this_cpu_read(tvec_bases);
|
|
|
|
hrtimer_run_pending();
|
|
|
|
if (time_after_eq(jiffies, base->timer_jiffies))
|
|
__run_timers(base);
|
|
}
|
|
|
|
/*
|
|
* Called by the local, per-CPU timer interrupt on SMP.
|
|
*/
|
|
void run_local_timers(void)
|
|
{
|
|
hrtimer_run_queues();
|
|
raise_softirq(TIMER_SOFTIRQ);
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_SYS_ALARM
|
|
|
|
/*
|
|
* For backwards compatibility? This can be done in libc so Alpha
|
|
* and all newer ports shouldn't need it.
|
|
*/
|
|
SYSCALL_DEFINE1(alarm, unsigned int, seconds)
|
|
{
|
|
return alarm_setitimer(seconds);
|
|
}
|
|
|
|
#endif
|
|
|
|
#ifndef __alpha__
|
|
|
|
/*
|
|
* The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this
|
|
* should be moved into arch/i386 instead?
|
|
*/
|
|
|
|
/**
|
|
* sys_getpid - return the thread group id of the current process
|
|
*
|
|
* Note, despite the name, this returns the tgid not the pid. The tgid and
|
|
* the pid are identical unless CLONE_THREAD was specified on clone() in
|
|
* which case the tgid is the same in all threads of the same group.
|
|
*
|
|
* This is SMP safe as current->tgid does not change.
|
|
*/
|
|
SYSCALL_DEFINE0(getpid)
|
|
{
|
|
return task_tgid_vnr(current);
|
|
}
|
|
|
|
/*
|
|
* Accessing ->real_parent is not SMP-safe, it could
|
|
* change from under us. However, we can use a stale
|
|
* value of ->real_parent under rcu_read_lock(), see
|
|
* release_task()->call_rcu(delayed_put_task_struct).
|
|
*/
|
|
SYSCALL_DEFINE0(getppid)
|
|
{
|
|
int pid;
|
|
|
|
rcu_read_lock();
|
|
pid = task_tgid_vnr(rcu_dereference(current->real_parent));
|
|
rcu_read_unlock();
|
|
|
|
return pid;
|
|
}
|
|
|
|
SYSCALL_DEFINE0(getuid)
|
|
{
|
|
/* Only we change this so SMP safe */
|
|
return current_uid();
|
|
}
|
|
|
|
SYSCALL_DEFINE0(geteuid)
|
|
{
|
|
/* Only we change this so SMP safe */
|
|
return current_euid();
|
|
}
|
|
|
|
SYSCALL_DEFINE0(getgid)
|
|
{
|
|
/* Only we change this so SMP safe */
|
|
return current_gid();
|
|
}
|
|
|
|
SYSCALL_DEFINE0(getegid)
|
|
{
|
|
/* Only we change this so SMP safe */
|
|
return current_egid();
|
|
}
|
|
|
|
#endif
|
|
|
|
static void process_timeout(unsigned long __data)
|
|
{
|
|
wake_up_process((struct task_struct *)__data);
|
|
}
|
|
|
|
/**
|
|
* schedule_timeout - sleep until timeout
|
|
* @timeout: timeout value in jiffies
|
|
*
|
|
* Make the current task sleep until @timeout jiffies have
|
|
* elapsed. The routine will return immediately unless
|
|
* the current task state has been set (see set_current_state()).
|
|
*
|
|
* You can set the task state as follows -
|
|
*
|
|
* %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to
|
|
* pass before the routine returns. The routine will return 0
|
|
*
|
|
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
|
|
* delivered to the current task. In this case the remaining time
|
|
* in jiffies will be returned, or 0 if the timer expired in time
|
|
*
|
|
* The current task state is guaranteed to be TASK_RUNNING when this
|
|
* routine returns.
|
|
*
|
|
* Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule
|
|
* the CPU away without a bound on the timeout. In this case the return
|
|
* value will be %MAX_SCHEDULE_TIMEOUT.
|
|
*
|
|
* In all cases the return value is guaranteed to be non-negative.
|
|
*/
|
|
signed long __sched schedule_timeout(signed long timeout)
|
|
{
|
|
struct timer_list timer;
|
|
unsigned long expire;
|
|
|
|
switch (timeout)
|
|
{
|
|
case MAX_SCHEDULE_TIMEOUT:
|
|
/*
|
|
* These two special cases are useful to be comfortable
|
|
* in the caller. Nothing more. We could take
|
|
* MAX_SCHEDULE_TIMEOUT from one of the negative value
|
|
* but I' d like to return a valid offset (>=0) to allow
|
|
* the caller to do everything it want with the retval.
|
|
*/
|
|
schedule();
|
|
goto out;
|
|
default:
|
|
/*
|
|
* Another bit of PARANOID. Note that the retval will be
|
|
* 0 since no piece of kernel is supposed to do a check
|
|
* for a negative retval of schedule_timeout() (since it
|
|
* should never happens anyway). You just have the printk()
|
|
* that will tell you if something is gone wrong and where.
|
|
*/
|
|
if (timeout < 0) {
|
|
printk(KERN_ERR "schedule_timeout: wrong timeout "
|
|
"value %lx\n", timeout);
|
|
dump_stack();
|
|
current->state = TASK_RUNNING;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
expire = timeout + jiffies;
|
|
|
|
setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
|
|
__mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
|
|
schedule();
|
|
del_singleshot_timer_sync(&timer);
|
|
|
|
/* Remove the timer from the object tracker */
|
|
destroy_timer_on_stack(&timer);
|
|
|
|
timeout = expire - jiffies;
|
|
|
|
out:
|
|
return timeout < 0 ? 0 : timeout;
|
|
}
|
|
EXPORT_SYMBOL(schedule_timeout);
|
|
|
|
/*
|
|
* We can use __set_current_state() here because schedule_timeout() calls
|
|
* schedule() unconditionally.
|
|
*/
|
|
signed long __sched schedule_timeout_interruptible(signed long timeout)
|
|
{
|
|
__set_current_state(TASK_INTERRUPTIBLE);
|
|
return schedule_timeout(timeout);
|
|
}
|
|
EXPORT_SYMBOL(schedule_timeout_interruptible);
|
|
|
|
signed long __sched schedule_timeout_killable(signed long timeout)
|
|
{
|
|
__set_current_state(TASK_KILLABLE);
|
|
return schedule_timeout(timeout);
|
|
}
|
|
EXPORT_SYMBOL(schedule_timeout_killable);
|
|
|
|
signed long __sched schedule_timeout_uninterruptible(signed long timeout)
|
|
{
|
|
__set_current_state(TASK_UNINTERRUPTIBLE);
|
|
return schedule_timeout(timeout);
|
|
}
|
|
EXPORT_SYMBOL(schedule_timeout_uninterruptible);
|
|
|
|
/* Thread ID - the internal kernel "pid" */
|
|
SYSCALL_DEFINE0(gettid)
|
|
{
|
|
return task_pid_vnr(current);
|
|
}
|
|
|
|
/**
|
|
* do_sysinfo - fill in sysinfo struct
|
|
* @info: pointer to buffer to fill
|
|
*/
|
|
int do_sysinfo(struct sysinfo *info)
|
|
{
|
|
unsigned long mem_total, sav_total;
|
|
unsigned int mem_unit, bitcount;
|
|
struct timespec tp;
|
|
|
|
memset(info, 0, sizeof(struct sysinfo));
|
|
|
|
ktime_get_ts(&tp);
|
|
monotonic_to_bootbased(&tp);
|
|
info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
|
|
|
|
get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
|
|
|
|
info->procs = nr_threads;
|
|
|
|
si_meminfo(info);
|
|
si_swapinfo(info);
|
|
|
|
/*
|
|
* If the sum of all the available memory (i.e. ram + swap)
|
|
* is less than can be stored in a 32 bit unsigned long then
|
|
* we can be binary compatible with 2.2.x kernels. If not,
|
|
* well, in that case 2.2.x was broken anyways...
|
|
*
|
|
* -Erik Andersen <andersee@debian.org>
|
|
*/
|
|
|
|
mem_total = info->totalram + info->totalswap;
|
|
if (mem_total < info->totalram || mem_total < info->totalswap)
|
|
goto out;
|
|
bitcount = 0;
|
|
mem_unit = info->mem_unit;
|
|
while (mem_unit > 1) {
|
|
bitcount++;
|
|
mem_unit >>= 1;
|
|
sav_total = mem_total;
|
|
mem_total <<= 1;
|
|
if (mem_total < sav_total)
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* If mem_total did not overflow, multiply all memory values by
|
|
* info->mem_unit and set it to 1. This leaves things compatible
|
|
* with 2.2.x, and also retains compatibility with earlier 2.4.x
|
|
* kernels...
|
|
*/
|
|
|
|
info->mem_unit = 1;
|
|
info->totalram <<= bitcount;
|
|
info->freeram <<= bitcount;
|
|
info->sharedram <<= bitcount;
|
|
info->bufferram <<= bitcount;
|
|
info->totalswap <<= bitcount;
|
|
info->freeswap <<= bitcount;
|
|
info->totalhigh <<= bitcount;
|
|
info->freehigh <<= bitcount;
|
|
|
|
out:
|
|
return 0;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
|
|
{
|
|
struct sysinfo val;
|
|
|
|
do_sysinfo(&val);
|
|
|
|
if (copy_to_user(info, &val, sizeof(struct sysinfo)))
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __cpuinit init_timers_cpu(int cpu)
|
|
{
|
|
int j;
|
|
struct tvec_base *base;
|
|
static char __cpuinitdata tvec_base_done[NR_CPUS];
|
|
|
|
if (!tvec_base_done[cpu]) {
|
|
static char boot_done;
|
|
|
|
if (boot_done) {
|
|
/*
|
|
* The APs use this path later in boot
|
|
*/
|
|
base = kmalloc_node(sizeof(*base),
|
|
GFP_KERNEL | __GFP_ZERO,
|
|
cpu_to_node(cpu));
|
|
if (!base)
|
|
return -ENOMEM;
|
|
|
|
/* Make sure that tvec_base is 2 byte aligned */
|
|
if (tbase_get_deferrable(base)) {
|
|
WARN_ON(1);
|
|
kfree(base);
|
|
return -ENOMEM;
|
|
}
|
|
per_cpu(tvec_bases, cpu) = base;
|
|
} else {
|
|
/*
|
|
* This is for the boot CPU - we use compile-time
|
|
* static initialisation because per-cpu memory isn't
|
|
* ready yet and because the memory allocators are not
|
|
* initialised either.
|
|
*/
|
|
boot_done = 1;
|
|
base = &boot_tvec_bases;
|
|
}
|
|
tvec_base_done[cpu] = 1;
|
|
} else {
|
|
base = per_cpu(tvec_bases, cpu);
|
|
}
|
|
|
|
spin_lock_init(&base->lock);
|
|
|
|
for (j = 0; j < TVN_SIZE; j++) {
|
|
INIT_LIST_HEAD(base->tv5.vec + j);
|
|
INIT_LIST_HEAD(base->tv4.vec + j);
|
|
INIT_LIST_HEAD(base->tv3.vec + j);
|
|
INIT_LIST_HEAD(base->tv2.vec + j);
|
|
}
|
|
for (j = 0; j < TVR_SIZE; j++)
|
|
INIT_LIST_HEAD(base->tv1.vec + j);
|
|
|
|
base->timer_jiffies = jiffies;
|
|
base->next_timer = base->timer_jiffies;
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head)
|
|
{
|
|
struct timer_list *timer;
|
|
|
|
while (!list_empty(head)) {
|
|
timer = list_first_entry(head, struct timer_list, entry);
|
|
detach_timer(timer, 0);
|
|
timer_set_base(timer, new_base);
|
|
if (time_before(timer->expires, new_base->next_timer) &&
|
|
!tbase_get_deferrable(timer->base))
|
|
new_base->next_timer = timer->expires;
|
|
internal_add_timer(new_base, timer);
|
|
}
|
|
}
|
|
|
|
static void __cpuinit migrate_timers(int cpu)
|
|
{
|
|
struct tvec_base *old_base;
|
|
struct tvec_base *new_base;
|
|
int i;
|
|
|
|
BUG_ON(cpu_online(cpu));
|
|
old_base = per_cpu(tvec_bases, cpu);
|
|
new_base = get_cpu_var(tvec_bases);
|
|
/*
|
|
* The caller is globally serialized and nobody else
|
|
* takes two locks at once, deadlock is not possible.
|
|
*/
|
|
spin_lock_irq(&new_base->lock);
|
|
spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
|
|
|
|
BUG_ON(old_base->running_timer);
|
|
|
|
for (i = 0; i < TVR_SIZE; i++)
|
|
migrate_timer_list(new_base, old_base->tv1.vec + i);
|
|
for (i = 0; i < TVN_SIZE; i++) {
|
|
migrate_timer_list(new_base, old_base->tv2.vec + i);
|
|
migrate_timer_list(new_base, old_base->tv3.vec + i);
|
|
migrate_timer_list(new_base, old_base->tv4.vec + i);
|
|
migrate_timer_list(new_base, old_base->tv5.vec + i);
|
|
}
|
|
|
|
spin_unlock(&old_base->lock);
|
|
spin_unlock_irq(&new_base->lock);
|
|
put_cpu_var(tvec_bases);
|
|
}
|
|
#endif /* CONFIG_HOTPLUG_CPU */
|
|
|
|
static int __cpuinit timer_cpu_notify(struct notifier_block *self,
|
|
unsigned long action, void *hcpu)
|
|
{
|
|
long cpu = (long)hcpu;
|
|
int err;
|
|
|
|
switch(action) {
|
|
case CPU_UP_PREPARE:
|
|
case CPU_UP_PREPARE_FROZEN:
|
|
err = init_timers_cpu(cpu);
|
|
if (err < 0)
|
|
return notifier_from_errno(err);
|
|
break;
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
case CPU_DEAD:
|
|
case CPU_DEAD_FROZEN:
|
|
migrate_timers(cpu);
|
|
break;
|
|
#endif
|
|
default:
|
|
break;
|
|
}
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block __cpuinitdata timers_nb = {
|
|
.notifier_call = timer_cpu_notify,
|
|
};
|
|
|
|
|
|
void __init init_timers(void)
|
|
{
|
|
int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
|
|
(void *)(long)smp_processor_id());
|
|
|
|
init_timer_stats();
|
|
|
|
BUG_ON(err != NOTIFY_OK);
|
|
register_cpu_notifier(&timers_nb);
|
|
open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
|
|
}
|
|
|
|
/**
|
|
* msleep - sleep safely even with waitqueue interruptions
|
|
* @msecs: Time in milliseconds to sleep for
|
|
*/
|
|
void msleep(unsigned int msecs)
|
|
{
|
|
unsigned long timeout = msecs_to_jiffies(msecs) + 1;
|
|
|
|
while (timeout)
|
|
timeout = schedule_timeout_uninterruptible(timeout);
|
|
}
|
|
|
|
EXPORT_SYMBOL(msleep);
|
|
|
|
/**
|
|
* msleep_interruptible - sleep waiting for signals
|
|
* @msecs: Time in milliseconds to sleep for
|
|
*/
|
|
unsigned long msleep_interruptible(unsigned int msecs)
|
|
{
|
|
unsigned long timeout = msecs_to_jiffies(msecs) + 1;
|
|
|
|
while (timeout && !signal_pending(current))
|
|
timeout = schedule_timeout_interruptible(timeout);
|
|
return jiffies_to_msecs(timeout);
|
|
}
|
|
|
|
EXPORT_SYMBOL(msleep_interruptible);
|
|
|
|
static int __sched do_usleep_range(unsigned long min, unsigned long max)
|
|
{
|
|
ktime_t kmin;
|
|
unsigned long delta;
|
|
|
|
kmin = ktime_set(0, min * NSEC_PER_USEC);
|
|
delta = (max - min) * NSEC_PER_USEC;
|
|
return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL);
|
|
}
|
|
|
|
/**
|
|
* usleep_range - Drop in replacement for udelay where wakeup is flexible
|
|
* @min: Minimum time in usecs to sleep
|
|
* @max: Maximum time in usecs to sleep
|
|
*/
|
|
void usleep_range(unsigned long min, unsigned long max)
|
|
{
|
|
__set_current_state(TASK_UNINTERRUPTIBLE);
|
|
do_usleep_range(min, max);
|
|
}
|
|
EXPORT_SYMBOL(usleep_range);
|