X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=kernel%2Fsoftirq.c;fp=kernel%2Fsoftirq.c;h=18f4be0d5fe0bbf853935972d9b441e95bc61c5a;hb=59f40aff7930052a74ddf5c297aa1974b0838529;hp=07b4f1b1a73a9b6a309a3e7fe249c813007b5d17;hpb=291b7c3a02a7eafbb8ea89a2c0e93676d6972926;p=mv-sheeva.git diff --git a/kernel/softirq.c b/kernel/softirq.c index 07b4f1b1a73..18f4be0d5fe 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -67,7 +67,7 @@ char *softirq_to_name[NR_SOFTIRQS] = { * to the pending events, so lets the scheduler to balance * the softirq load for us. */ -void wakeup_softirqd(void) +static void wakeup_softirqd(void) { /* Interrupts are disabled: no need to stop preemption */ struct task_struct *tsk = __get_cpu_var(ksoftirqd); @@ -76,12 +76,22 @@ void wakeup_softirqd(void) wake_up_process(tsk); } +/* + * preempt_count and SOFTIRQ_OFFSET usage: + * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving + * softirq processing. + * - preempt_count is changed by SOFTIRQ_DISABLE_OFFSET (= 2 * SOFTIRQ_OFFSET) + * on local_bh_disable or local_bh_enable. + * This lets us distinguish between whether we are currently processing + * softirq and whether we just have bh disabled. + */ + /* * This one is for softirq.c-internal use, * where hardirqs are disabled legitimately: */ #ifdef CONFIG_TRACE_IRQFLAGS -static void __local_bh_disable(unsigned long ip) +static void __local_bh_disable(unsigned long ip, unsigned int cnt) { unsigned long flags; @@ -95,32 +105,43 @@ static void __local_bh_disable(unsigned long ip) * We must manually increment preempt_count here and manually * call the trace_preempt_off later. */ - preempt_count() += SOFTIRQ_OFFSET; + preempt_count() += cnt; /* * Were softirqs turned off above: */ - if (softirq_count() == SOFTIRQ_OFFSET) + if (softirq_count() == cnt) trace_softirqs_off(ip); raw_local_irq_restore(flags); - if (preempt_count() == SOFTIRQ_OFFSET) + if (preempt_count() == cnt) trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); } #else /* !CONFIG_TRACE_IRQFLAGS */ -static inline void __local_bh_disable(unsigned long ip) +static inline void __local_bh_disable(unsigned long ip, unsigned int cnt) { - add_preempt_count(SOFTIRQ_OFFSET); + add_preempt_count(cnt); barrier(); } #endif /* CONFIG_TRACE_IRQFLAGS */ void local_bh_disable(void) { - __local_bh_disable((unsigned long)__builtin_return_address(0)); + __local_bh_disable((unsigned long)__builtin_return_address(0), + SOFTIRQ_DISABLE_OFFSET); } EXPORT_SYMBOL(local_bh_disable); +static void __local_bh_enable(unsigned int cnt) +{ + WARN_ON_ONCE(in_irq()); + WARN_ON_ONCE(!irqs_disabled()); + + if (softirq_count() == cnt) + trace_softirqs_on((unsigned long)__builtin_return_address(0)); + sub_preempt_count(cnt); +} + /* * Special-case - softirqs can safely be enabled in * cond_resched_softirq(), or by __do_softirq(), @@ -128,12 +149,7 @@ EXPORT_SYMBOL(local_bh_disable); */ void _local_bh_enable(void) { - WARN_ON_ONCE(in_irq()); - WARN_ON_ONCE(!irqs_disabled()); - - if (softirq_count() == SOFTIRQ_OFFSET) - trace_softirqs_on((unsigned long)__builtin_return_address(0)); - sub_preempt_count(SOFTIRQ_OFFSET); + __local_bh_enable(SOFTIRQ_DISABLE_OFFSET); } EXPORT_SYMBOL(_local_bh_enable); @@ -147,13 +163,13 @@ static inline void _local_bh_enable_ip(unsigned long ip) /* * Are softirqs going to be turned on now: */ - if (softirq_count() == SOFTIRQ_OFFSET) + if (softirq_count() == SOFTIRQ_DISABLE_OFFSET) trace_softirqs_on(ip); /* * Keep preemption disabled until we are done with * softirq processing: */ - sub_preempt_count(SOFTIRQ_OFFSET - 1); + sub_preempt_count(SOFTIRQ_DISABLE_OFFSET - 1); if (unlikely(!in_interrupt() && local_softirq_pending())) do_softirq(); @@ -198,7 +214,8 @@ asmlinkage void __do_softirq(void) pending = local_softirq_pending(); account_system_vtime(current); - __local_bh_disable((unsigned long)__builtin_return_address(0)); + __local_bh_disable((unsigned long)__builtin_return_address(0), + SOFTIRQ_OFFSET); lockdep_softirq_enter(); cpu = smp_processor_id(); @@ -212,18 +229,20 @@ restart: do { if (pending & 1) { + unsigned int vec_nr = h - softirq_vec; int prev_count = preempt_count(); - kstat_incr_softirqs_this_cpu(h - softirq_vec); - trace_softirq_entry(h, softirq_vec); + kstat_incr_softirqs_this_cpu(vec_nr); + + trace_softirq_entry(vec_nr); h->action(h); - trace_softirq_exit(h, softirq_vec); + trace_softirq_exit(vec_nr); if (unlikely(prev_count != preempt_count())) { - printk(KERN_ERR "huh, entered softirq %td %s %p" + printk(KERN_ERR "huh, entered softirq %u %s %p" "with preempt_count %08x," - " exited with %08x?\n", h - softirq_vec, - softirq_to_name[h - softirq_vec], - h->action, prev_count, preempt_count()); + " exited with %08x?\n", vec_nr, + softirq_to_name[vec_nr], h->action, + prev_count, preempt_count()); preempt_count() = prev_count; } @@ -245,7 +264,7 @@ restart: lockdep_softirq_exit(); account_system_vtime(current); - _local_bh_enable(); + __local_bh_enable(SOFTIRQ_OFFSET); } #ifndef __ARCH_HAS_DO_SOFTIRQ @@ -279,10 +298,16 @@ void irq_enter(void) rcu_irq_enter(); if (idle_cpu(cpu) && !in_interrupt()) { - __irq_enter(); + /* + * Prevent raise_softirq from needlessly waking up ksoftirqd + * here, as softirq will be serviced on return from interrupt. + */ + local_bh_disable(); tick_check_idle(cpu); - } else - __irq_enter(); + _local_bh_enable(); + } + + __irq_enter(); } #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED @@ -696,6 +721,7 @@ static int run_ksoftirqd(void * __bind_cpu) { set_current_state(TASK_INTERRUPTIBLE); + current->flags |= PF_KSOFTIRQD; while (!kthread_should_stop()) { preempt_disable(); if (!local_softirq_pending()) { @@ -886,17 +912,14 @@ int __init __weak early_irq_init(void) return 0; } +#ifdef CONFIG_GENERIC_HARDIRQS int __init __weak arch_probe_nr_irqs(void) { - return 0; + return NR_IRQS_LEGACY; } int __init __weak arch_early_irq_init(void) { return 0; } - -int __weak arch_init_chip_data(struct irq_desc *desc, int node) -{ - return 0; -} +#endif