X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Ftimer.c;h=f35b3939e9372c5139f0588a9f728b681d225d17;hb=abb1cf3cb9532d824c8bda00a111adb106dd457d;hp=6b812c04737b5b611c9d40257f8c3b28292955c4;hpb=6e07e16404deafadf45895a7d2aeb5feba53b479;p=linux-2.6 diff --git a/kernel/timer.c b/kernel/timer.c index 6b812c0473..f35b3939e9 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -81,9 +81,10 @@ struct tvec_t_base_s { } ____cacheline_aligned_in_smp; typedef struct tvec_t_base_s tvec_base_t; -static DEFINE_PER_CPU(tvec_base_t *, tvec_bases); + tvec_base_t boot_tvec_bases; EXPORT_SYMBOL(boot_tvec_bases); +static DEFINE_PER_CPU(tvec_base_t *, tvec_bases) = { &boot_tvec_bases }; static inline void set_running_timer(tvec_base_t *base, struct timer_list *timer) @@ -382,23 +383,19 @@ EXPORT_SYMBOL(del_timer_sync); static int cascade(tvec_base_t *base, tvec_t *tv, int index) { /* cascade all the timers from tv up one level */ - struct list_head *head, *curr; + struct timer_list *timer, *tmp; + struct list_head tv_list; + + list_replace_init(tv->vec + index, &tv_list); - head = tv->vec + index; - curr = head->next; /* - * We are removing _all_ timers from the list, so we don't have to - * detach them individually, just clear the list afterwards. + * We are removing _all_ timers from the list, so we + * don't have to detach them individually. */ - while (curr != head) { - struct timer_list *tmp; - - tmp = list_entry(curr, struct timer_list, entry); - BUG_ON(tmp->base != base); - curr = curr->next; - internal_add_timer(base, tmp); + list_for_each_entry_safe(timer, tmp, &tv_list, entry) { + BUG_ON(timer->base != base); + internal_add_timer(base, timer); } - INIT_LIST_HEAD(head); return index; } @@ -418,10 +415,10 @@ static inline void __run_timers(tvec_base_t *base) spin_lock_irq(&base->lock); while (time_after_eq(jiffies, base->timer_jiffies)) { - struct list_head work_list = LIST_HEAD_INIT(work_list); + struct list_head work_list; struct list_head *head = &work_list; int index = base->timer_jiffies & TVR_MASK; - + /* * Cascade timers: */ @@ -430,8 +427,8 @@ static inline void __run_timers(tvec_base_t *base) (!cascade(base, &base->tv3, INDEX(1))) && !cascade(base, &base->tv4, INDEX(2))) cascade(base, &base->tv5, INDEX(3)); - ++base->timer_jiffies; - list_splice_init(base->tv1.vec + index, &work_list); + ++base->timer_jiffies; + list_replace_init(base->tv1.vec + index, &work_list); while (!list_empty(head)) { void (*fn)(unsigned long); unsigned long data; @@ -540,6 +537,22 @@ found: } spin_unlock(&base->lock); + /* + * It can happen that other CPUs service timer IRQs and increment + * jiffies, but we have not yet got a local timer tick to process + * the timer wheels. In that case, the expiry time can be before + * jiffies, but since the high-resolution timer here is relative to + * jiffies, the default expression when high-resolution timers are + * not active, + * + * time_before(MAX_JIFFY_OFFSET + jiffies, expires) + * + * would falsely evaluate to true. If that is the case, just + * return jiffies so that we can immediately fire the local timer + */ + if (time_before(expires, jiffies)) + return jiffies; + if (time_before(hr_expires, expires)) return hr_expires; @@ -1224,28 +1237,36 @@ static int __devinit init_timers_cpu(int cpu) { int j; tvec_base_t *base; + static char __devinitdata tvec_base_done[NR_CPUS]; - base = per_cpu(tvec_bases, cpu); - if (!base) { + if (!tvec_base_done[cpu]) { static char boot_done; - /* - * Cannot do allocation in init_timers as that runs before the - * allocator initializes (and would waste memory if there are - * more possible CPUs than will ever be installed/brought up). - */ if (boot_done) { + /* + * The APs use this path later in boot + */ base = kmalloc_node(sizeof(*base), GFP_KERNEL, cpu_to_node(cpu)); if (!base) return -ENOMEM; memset(base, 0, sizeof(*base)); + per_cpu(tvec_bases, cpu) = base; } else { - base = &boot_tvec_bases; + /* + * 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; } - per_cpu(tvec_bases, cpu) = base; + 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); @@ -1305,7 +1326,7 @@ static void __devinit migrate_timers(int cpu) } #endif /* CONFIG_HOTPLUG_CPU */ -static int __devinit timer_cpu_notify(struct notifier_block *self, +static int timer_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { long cpu = (long)hcpu; @@ -1325,7 +1346,7 @@ static int __devinit timer_cpu_notify(struct notifier_block *self, return NOTIFY_OK; } -static struct notifier_block __devinitdata timers_nb = { +static struct notifier_block timers_nb = { .notifier_call = timer_cpu_notify, }; @@ -1455,7 +1476,7 @@ static void time_interpolator_update(long delta_nsec) */ if (jiffies % INTERPOLATOR_ADJUST == 0) { - if (time_interpolator->skips == 0 && time_interpolator->offset > TICK_NSEC) + if (time_interpolator->skips == 0 && time_interpolator->offset > tick_nsec) time_interpolator->nsec_per_cyc--; if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0) time_interpolator->nsec_per_cyc++; @@ -1479,8 +1500,7 @@ register_time_interpolator(struct time_interpolator *ti) unsigned long flags; /* Sanity check */ - if (ti->frequency == 0 || ti->mask == 0) - BUG(); + BUG_ON(ti->frequency == 0 || ti->mask == 0); ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency; spin_lock(&time_interpolator_lock);