diff options
Diffstat (limited to 'kernel/rcupdate.c')
| -rw-r--r-- | kernel/rcupdate.c | 99 |
1 files changed, 69 insertions, 30 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 0cf8146bd58..13458bbaa1b 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -47,15 +47,16 @@ #include <linux/notifier.h> #include <linux/rcupdate.h> #include <linux/cpu.h> +#include <linux/mutex.h> /* Definition for rcupdate control block. */ -struct rcu_ctrlblk rcu_ctrlblk = { +static struct rcu_ctrlblk rcu_ctrlblk = { .cur = -300, .completed = -300, .lock = SPIN_LOCK_UNLOCKED, .cpumask = CPU_MASK_NONE, }; -struct rcu_ctrlblk rcu_bh_ctrlblk = { +static struct rcu_ctrlblk rcu_bh_ctrlblk = { .cur = -300, .completed = -300, .lock = SPIN_LOCK_UNLOCKED, @@ -67,7 +68,43 @@ DEFINE_PER_CPU(struct rcu_data, rcu_bh_data) = { 0L }; /* Fake initialization required by compiler */ static DEFINE_PER_CPU(struct tasklet_struct, rcu_tasklet) = {NULL}; -static int maxbatch = 10000; +static int blimit = 10; +static int qhimark = 10000; +static int qlowmark = 100; +#ifdef CONFIG_SMP +static int rsinterval = 1000; +#endif + +static atomic_t rcu_barrier_cpu_count; +static DEFINE_MUTEX(rcu_barrier_mutex); +static struct completion rcu_barrier_completion; + +#ifdef CONFIG_SMP +static void force_quiescent_state(struct rcu_data *rdp, + struct rcu_ctrlblk *rcp) +{ + int cpu; + cpumask_t cpumask; + set_need_resched(); + if (unlikely(rdp->qlen - rdp->last_rs_qlen > rsinterval)) { + rdp->last_rs_qlen = rdp->qlen; + /* + * Don't send IPI to itself. With irqs disabled, + * rdp->cpu is the current cpu. + */ + cpumask = rcp->cpumask; + cpu_clear(rdp->cpu, cpumask); + for_each_cpu_mask(cpu, cpumask) + smp_send_reschedule(cpu); + } +} +#else +static inline void force_quiescent_state(struct rcu_data *rdp, + struct rcu_ctrlblk *rcp) +{ + set_need_resched(); +} +#endif /** * call_rcu - Queue an RCU callback for invocation after a grace period. @@ -92,17 +129,13 @@ void fastcall call_rcu(struct rcu_head *head, rdp = &__get_cpu_var(rcu_data); *rdp->nxttail = head; rdp->nxttail = &head->next; - - if (unlikely(++rdp->count > 10000)) - set_need_resched(); - + if (unlikely(++rdp->qlen > qhimark)) { + rdp->blimit = INT_MAX; + force_quiescent_state(rdp, &rcu_ctrlblk); + } local_irq_restore(flags); } -static atomic_t rcu_barrier_cpu_count; -static struct semaphore rcu_barrier_sema; -static struct completion rcu_barrier_completion; - /** * call_rcu_bh - Queue an RCU for invocation after a quicker grace period. * @head: structure to be used for queueing the RCU updates. @@ -131,12 +164,12 @@ void fastcall call_rcu_bh(struct rcu_head *head, rdp = &__get_cpu_var(rcu_bh_data); *rdp->nxttail = head; rdp->nxttail = &head->next; - rdp->count++; -/* - * Should we directly call rcu_do_batch() here ? - * if (unlikely(rdp->count > 10000)) - * rcu_do_batch(rdp); - */ + + if (unlikely(++rdp->qlen > qhimark)) { + rdp->blimit = INT_MAX; + force_quiescent_state(rdp, &rcu_bh_ctrlblk); + } + local_irq_restore(flags); } @@ -175,13 +208,13 @@ static void rcu_barrier_func(void *notused) void rcu_barrier(void) { BUG_ON(in_interrupt()); - /* Take cpucontrol semaphore to protect against CPU hotplug */ - down(&rcu_barrier_sema); + /* Take cpucontrol mutex to protect against CPU hotplug */ + mutex_lock(&rcu_barrier_mutex); init_completion(&rcu_barrier_completion); atomic_set(&rcu_barrier_cpu_count, 0); on_each_cpu(rcu_barrier_func, NULL, 0, 1); wait_for_completion(&rcu_barrier_completion); - up(&rcu_barrier_sema); + mutex_unlock(&rcu_barrier_mutex); } EXPORT_SYMBOL_GPL(rcu_barrier); @@ -199,10 +232,12 @@ static void rcu_do_batch(struct rcu_data *rdp) next = rdp->donelist = list->next; list->func(list); list = next; - rdp->count--; - if (++count >= maxbatch) + rdp->qlen--; + if (++count >= rdp->blimit) break; } + if (rdp->blimit == INT_MAX && rdp->qlen <= qlowmark) + rdp->blimit = blimit; if (!rdp->donelist) rdp->donetail = &rdp->donelist; else @@ -381,8 +416,8 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp, rdp->curtail = &rdp->curlist; } - local_irq_disable(); if (rdp->nxtlist && !rdp->curlist) { + local_irq_disable(); rdp->curlist = rdp->nxtlist; rdp->curtail = rdp->nxttail; rdp->nxtlist = NULL; @@ -407,9 +442,8 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp, rcu_start_batch(rcp); spin_unlock(&rcp->lock); } - } else { - local_irq_enable(); } + rcu_check_quiescent_state(rcp, rdp); if (rdp->donelist) rcu_do_batch(rdp); @@ -473,6 +507,7 @@ static void rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp, rdp->quiescbatch = rcp->completed; rdp->qs_pending = 0; rdp->cpu = cpu; + rdp->blimit = blimit; } static void __devinit rcu_online_cpu(int cpu) @@ -514,7 +549,6 @@ static struct notifier_block __devinitdata rcu_nb = { */ void __init rcu_init(void) { - sema_init(&rcu_barrier_sema, 1); rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE, (void *)(long)smp_processor_id()); /* Register notifier for non-boot CPUs */ @@ -567,9 +601,14 @@ void synchronize_kernel(void) synchronize_rcu(); } -module_param(maxbatch, int, 0); +module_param(blimit, int, 0); +module_param(qhimark, int, 0); +module_param(qlowmark, int, 0); +#ifdef CONFIG_SMP +module_param(rsinterval, int, 0); +#endif EXPORT_SYMBOL_GPL(rcu_batches_completed); -EXPORT_SYMBOL(call_rcu); /* WARNING: GPL-only in April 2006. */ -EXPORT_SYMBOL(call_rcu_bh); /* WARNING: GPL-only in April 2006. */ +EXPORT_SYMBOL_GPL_FUTURE(call_rcu); /* WARNING: GPL-only in April 2006. */ +EXPORT_SYMBOL_GPL_FUTURE(call_rcu_bh); /* WARNING: GPL-only in April 2006. */ EXPORT_SYMBOL_GPL(synchronize_rcu); -EXPORT_SYMBOL(synchronize_kernel); /* WARNING: GPL-only in April 2006. */ +EXPORT_SYMBOL_GPL_FUTURE(synchronize_kernel); /* WARNING: GPL-only in April 2006. */ |