X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Frcuclassic.c;h=0f2b0b3113044d02ad8c4e1240845b40302f8bc2;hb=e624859e7eb6ae2930df3923af73406dc6ccdad8;hp=01e761a6b38cd980808a9c79a41147742349bd05;hpb=0c925d79234fe77589d8ff3861f9f8bb9e7fc3f6;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c index 01e761a..0f2b0b3 100644 --- a/kernel/rcuclassic.c +++ b/kernel/rcuclassic.c @@ -63,18 +63,37 @@ static struct rcu_ctrlblk rcu_ctrlblk = { .completed = -300, .pending = -300, .lock = __SPIN_LOCK_UNLOCKED(&rcu_ctrlblk.lock), - .cpumask = CPU_MASK_NONE, + .cpumask = CPU_BITS_NONE, }; + static struct rcu_ctrlblk rcu_bh_ctrlblk = { .cur = -300, .completed = -300, .pending = -300, .lock = __SPIN_LOCK_UNLOCKED(&rcu_bh_ctrlblk.lock), - .cpumask = CPU_MASK_NONE, + .cpumask = CPU_BITS_NONE, }; -DEFINE_PER_CPU(struct rcu_data, rcu_data) = { 0L }; -DEFINE_PER_CPU(struct rcu_data, rcu_bh_data) = { 0L }; +static DEFINE_PER_CPU(struct rcu_data, rcu_data); +static DEFINE_PER_CPU(struct rcu_data, rcu_bh_data); + +/* + * Increment the quiescent state counter. + * The counter is a bit degenerated: We do not need to know + * how many quiescent states passed, just if there was at least + * one since the start of the grace period. Thus just a flag. + */ +void rcu_qsctr_inc(int cpu) +{ + struct rcu_data *rdp = &per_cpu(rcu_data, cpu); + rdp->passed_quiesc = 1; +} + +void rcu_bh_qsctr_inc(int cpu) +{ + struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu); + rdp->passed_quiesc = 1; +} static int blimit = 10; static int qhimark = 10000; @@ -85,7 +104,6 @@ static void force_quiescent_state(struct rcu_data *rdp, struct rcu_ctrlblk *rcp) { int cpu; - cpumask_t cpumask; unsigned long flags; set_need_resched(); @@ -96,10 +114,10 @@ static void force_quiescent_state(struct rcu_data *rdp, * Don't send IPI to itself. With irqs disabled, * rdp->cpu is the current cpu. * - * cpu_online_map is updated by the _cpu_down() + * cpu_online_mask is updated by the _cpu_down() * using __stop_machine(). Since we're in irqs disabled * section, __stop_machine() is not exectuting, hence - * the cpu_online_map is stable. + * the cpu_online_mask is stable. * * However, a cpu might have been offlined _just_ before * we disabled irqs while entering here. @@ -107,13 +125,14 @@ static void force_quiescent_state(struct rcu_data *rdp, * notification, leading to the offlined cpu's bit * being set in the rcp->cpumask. * - * Hence cpumask = (rcp->cpumask & cpu_online_map) to prevent + * Hence cpumask = (rcp->cpumask & cpu_online_mask) to prevent * sending smp_reschedule() to an offlined CPU. */ - cpus_and(cpumask, rcp->cpumask, cpu_online_map); - cpu_clear(rdp->cpu, cpumask); - for_each_cpu_mask_nr(cpu, cpumask) - smp_send_reschedule(cpu); + for_each_cpu_and(cpu, + to_cpumask(rcp->cpumask), cpu_online_mask) { + if (cpu != rdp->cpu) + smp_send_reschedule(cpu); + } } spin_unlock_irqrestore(&rcp->lock, flags); } @@ -164,6 +183,88 @@ static void __call_rcu(struct rcu_head *head, struct rcu_ctrlblk *rcp, } } +#ifdef CONFIG_RCU_CPU_STALL_DETECTOR + +static void record_gp_stall_check_time(struct rcu_ctrlblk *rcp) +{ + rcp->gp_start = jiffies; + rcp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_CHECK; +} + +static void print_other_cpu_stall(struct rcu_ctrlblk *rcp) +{ + int cpu; + long delta; + unsigned long flags; + + /* Only let one CPU complain about others per time interval. */ + + spin_lock_irqsave(&rcp->lock, flags); + delta = jiffies - rcp->jiffies_stall; + if (delta < 2 || rcp->cur != rcp->completed) { + spin_unlock_irqrestore(&rcp->lock, flags); + return; + } + rcp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK; + spin_unlock_irqrestore(&rcp->lock, flags); + + /* OK, time to rat on our buddy... */ + + printk(KERN_ERR "INFO: RCU detected CPU stalls:"); + for_each_possible_cpu(cpu) { + if (cpumask_test_cpu(cpu, to_cpumask(rcp->cpumask))) + printk(" %d", cpu); + } + printk(" (detected by %d, t=%ld jiffies)\n", + smp_processor_id(), (long)(jiffies - rcp->gp_start)); +} + +static void print_cpu_stall(struct rcu_ctrlblk *rcp) +{ + unsigned long flags; + + printk(KERN_ERR "INFO: RCU detected CPU %d stall (t=%lu/%lu jiffies)\n", + smp_processor_id(), jiffies, + jiffies - rcp->gp_start); + dump_stack(); + spin_lock_irqsave(&rcp->lock, flags); + if ((long)(jiffies - rcp->jiffies_stall) >= 0) + rcp->jiffies_stall = + jiffies + RCU_SECONDS_TILL_STALL_RECHECK; + spin_unlock_irqrestore(&rcp->lock, flags); + set_need_resched(); /* kick ourselves to get things going. */ +} + +static void check_cpu_stall(struct rcu_ctrlblk *rcp) +{ + long delta; + + delta = jiffies - rcp->jiffies_stall; + if (cpumask_test_cpu(smp_processor_id(), to_cpumask(rcp->cpumask)) && + delta >= 0) { + + /* We haven't checked in, so go dump stack. */ + print_cpu_stall(rcp); + + } else if (rcp->cur != rcp->completed && delta >= 2) { + + /* They had two seconds to dump stack, so complain. */ + print_other_cpu_stall(rcp); + } +} + +#else /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ + +static void record_gp_stall_check_time(struct rcu_ctrlblk *rcp) +{ +} + +static inline void check_cpu_stall(struct rcu_ctrlblk *rcp) +{ +} + +#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ + /** * call_rcu - Queue an RCU callback for invocation after a grace period. * @head: structure to be used for queueing the RCU updates. @@ -247,6 +348,7 @@ static inline void raise_rcu_softirq(void) */ static void rcu_do_batch(struct rcu_data *rdp) { + unsigned long flags; struct rcu_head *next, *list; int count = 0; @@ -261,9 +363,9 @@ static void rcu_do_batch(struct rcu_data *rdp) } rdp->donelist = list; - local_irq_disable(); + local_irq_save(flags); rdp->qlen -= count; - local_irq_enable(); + local_irq_restore(flags); if (rdp->blimit == INT_MAX && rdp->qlen <= qlowmark) rdp->blimit = blimit; @@ -292,84 +394,6 @@ static void rcu_do_batch(struct rcu_data *rdp) * period (if necessary). */ -#ifdef CONFIG_DEBUG_RCU_STALL - -static inline void record_gp_check_time(struct rcu_ctrlblk *rcp) -{ - rcp->gp_check = get_seconds() + 3; -} - -static void print_other_cpu_stall(struct rcu_ctrlblk *rcp) -{ - int cpu; - long delta; - unsigned long flags; - - /* Only let one CPU complain about others per time interval. */ - - spin_lock_irqsave(&rcp->lock, flags); - delta = get_seconds() - rcp->gp_check; - if (delta < 2L || cpus_empty(rcp->cpumask)) { - spin_unlock(&rcp->lock); - return; - } - rcp->gp_check = get_seconds() + 30; - spin_unlock_irqrestore(&rcp->lock, flags); - - /* OK, time to rat on our buddy... */ - - printk(KERN_ERR "RCU detected CPU stalls:"); - for_each_cpu_mask(cpu, rcp->cpumask) - printk(" %d", cpu); - printk(" (detected by %d, t=%lu/%lu)\n", - smp_processor_id(), get_seconds(), rcp->gp_check); -} - -static void print_cpu_stall(struct rcu_ctrlblk *rcp) -{ - unsigned long flags; - - printk(KERN_ERR "RCU detected CPU %d stall (t=%lu/%lu)\n", - smp_processor_id(), get_seconds(), rcp->gp_check); - dump_stack(); - spin_lock_irqsave(&rcp->lock, flags); - if ((long)(get_seconds() - rcp->gp_check) >= 0L) - rcp->gp_check = get_seconds() + 30; - spin_unlock_irqrestore(&rcp->lock, flags); -} - -static void check_cpu_stall(struct rcu_ctrlblk *rcp, struct rcu_data *rdp) -{ - long delta; - - delta = get_seconds() - rcp->gp_check; - if (cpu_isset(smp_processor_id(), rcp->cpumask) && delta >= 0L) { - - /* We haven't checked in, so go dump stack. */ - - print_cpu_stall(rcp); - - } else { - if (!cpus_empty(rcp->cpumask) && delta >= 2L) { - /* They had two seconds to dump stack, so complain. */ - print_other_cpu_stall(rcp); - } - } -} - -#else /* #ifdef CONFIG_DEBUG_RCU_STALL */ - -static inline void record_gp_check_time(struct rcu_ctrlblk *rcp) -{ -} - -static inline void -check_cpu_stall(struct rcu_ctrlblk *rcp, struct rcu_data *rdp) -{ -} - -#endif /* #else #ifdef CONFIG_DEBUG_RCU_STALL */ - /* * Register a new batch of callbacks, and start it up if there is currently no * active batch and the batch to be registered has not already occurred. @@ -380,7 +404,7 @@ static void rcu_start_batch(struct rcu_ctrlblk *rcp) if (rcp->cur != rcp->pending && rcp->completed == rcp->cur) { rcp->cur++; - record_gp_check_time(rcp); + record_gp_stall_check_time(rcp); /* * Accessing nohz_cpu_mask before incrementing rcp->cur needs a @@ -389,7 +413,8 @@ static void rcu_start_batch(struct rcu_ctrlblk *rcp) * unnecessarily. */ smp_mb(); - cpus_andnot(rcp->cpumask, cpu_online_map, nohz_cpu_mask); + cpumask_andnot(to_cpumask(rcp->cpumask), + cpu_online_mask, nohz_cpu_mask); rcp->signaled = 0; } @@ -402,8 +427,8 @@ static void rcu_start_batch(struct rcu_ctrlblk *rcp) */ static void cpu_quiet(int cpu, struct rcu_ctrlblk *rcp) { - cpu_clear(cpu, rcp->cpumask); - if (cpus_empty(rcp->cpumask)) { + cpumask_clear_cpu(cpu, to_cpumask(rcp->cpumask)); + if (cpumask_empty(to_cpumask(rcp->cpumask))) { /* batch completed ! */ rcp->completed = rcp->cur; rcu_start_batch(rcp); @@ -464,12 +489,14 @@ static void rcu_check_quiescent_state(struct rcu_ctrlblk *rcp, static void rcu_move_batch(struct rcu_data *this_rdp, struct rcu_head *list, struct rcu_head **tail, long batch) { + unsigned long flags; + if (list) { - local_irq_disable(); + local_irq_save(flags); this_rdp->batch = batch; *this_rdp->nxttail[2] = list; this_rdp->nxttail[2] = tail; - local_irq_enable(); + local_irq_restore(flags); } } @@ -521,10 +548,11 @@ static void rcu_offline_cpu(int cpu) static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp, struct rcu_data *rdp) { + unsigned long flags; long completed_snap; if (rdp->nxtlist) { - local_irq_disable(); + local_irq_save(flags); completed_snap = ACCESS_ONCE(rcp->completed); /* @@ -554,18 +582,18 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp, rdp->nxttail[0] = &rdp->nxtlist; } - local_irq_enable(); + local_irq_restore(flags); if (rcu_batch_after(rdp->batch, rcp->pending)) { - unsigned long flags; + unsigned long flags2; /* and start it/schedule start if it's a new batch */ - spin_lock_irqsave(&rcp->lock, flags); + spin_lock_irqsave(&rcp->lock, flags2); if (rcu_batch_after(rdp->batch, rcp->pending)) { rcp->pending = rdp->batch; rcu_start_batch(rcp); } - spin_unlock_irqrestore(&rcp->lock, flags); + spin_unlock_irqrestore(&rcp->lock, flags2); } } @@ -599,7 +627,7 @@ static void rcu_process_callbacks(struct softirq_action *unused) static int __rcu_pending(struct rcu_ctrlblk *rcp, struct rcu_data *rdp) { /* Check for CPU stalls, if enabled. */ - check_cpu_stall(rcp, rdp); + check_cpu_stall(rcp); if (rdp->nxtlist) { long completed_snap = ACCESS_ONCE(rcp->completed); @@ -670,8 +698,8 @@ int rcu_needs_cpu(int cpu) void rcu_check_callbacks(int cpu, int user) { if (user || - (idle_cpu(cpu) && !in_softirq() && - hardirq_count() <= (1 << HARDIRQ_SHIFT))) { + (idle_cpu(cpu) && rcu_scheduler_active && + !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) { /* * Get here if this CPU took its interrupt from user @@ -707,10 +735,10 @@ void rcu_check_callbacks(int cpu, int user) raise_rcu_softirq(); } -static void rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp, +static void __cpuinit rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp, struct rcu_data *rdp) { - long flags; + unsigned long flags; spin_lock_irqsave(&rcp->lock, flags); memset(rdp, 0, sizeof(*rdp)); @@ -765,6 +793,9 @@ static struct notifier_block __cpuinitdata rcu_nb = { */ void __init __rcu_init(void) { +#ifdef CONFIG_RCU_CPU_STALL_DETECTOR + printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n"); +#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE, (void *)(long)smp_processor_id()); /* Register notifier for non-boot CPUs */