diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | include/linux/interrupt.h | 7 | ||||
| -rw-r--r-- | kernel/irq/Kconfig | 3 | ||||
| -rw-r--r-- | kernel/irq/internals.h | 2 | ||||
| -rw-r--r-- | kernel/irq/manage.c | 67 | ||||
| -rw-r--r-- | kernel/softirq.c | 16 |
6 files changed, 93 insertions, 6 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 89835a4766a..cac6cf9a588 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2436,6 +2436,10 @@ and is between 256 and 4096 characters. It is defined in the file <deci-seconds>: poll all this frequency 0: no polling (default) + threadirqs [KNL] + Force threading of all interrupt handlers except those + marked explicitely IRQF_NO_THREAD. + topology= [S390] Format: {off | on} Specify if the kernel should make use of the cpu diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 0fc3eb9397b..f8a8af108e0 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -383,6 +383,13 @@ static inline int disable_irq_wake(unsigned int irq) } #endif /* CONFIG_GENERIC_HARDIRQS */ + +#ifdef CONFIG_IRQ_FORCED_THREADING +extern bool force_irqthreads; +#else +#define force_irqthreads (0) +#endif + #ifndef __ARCH_SET_SOFTIRQ_PENDING #define set_softirq_pending(x) (local_softirq_pending() = (x)) #define or_softirq_pending(x) (local_softirq_pending() |= (x)) diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index 355b8c7957f..144db9dcfcd 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -38,6 +38,9 @@ config HARDIRQS_SW_RESEND config IRQ_PREFLOW_FASTEOI bool +config IRQ_FORCED_THREADING + bool + config SPARSE_IRQ bool "Support sparse irq numbering" depends on HAVE_SPARSE_IRQ diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index 935bec4bfa8..6c6ec9a4902 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -27,12 +27,14 @@ extern int noirqdebug; * IRQTF_DIED - handler thread died * IRQTF_WARNED - warning "IRQ_WAKE_THREAD w/o thread_fn" has been printed * IRQTF_AFFINITY - irq thread is requested to adjust affinity + * IRQTF_FORCED_THREAD - irq action is force threaded */ enum { IRQTF_RUNTHREAD, IRQTF_DIED, IRQTF_WARNED, IRQTF_AFFINITY, + IRQTF_FORCED_THREAD, }; /* diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 58c86136730..acd599a43bf 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -17,6 +17,17 @@ #include "internals.h" +#ifdef CONFIG_IRQ_FORCED_THREADING +__read_mostly bool force_irqthreads; + +static int __init setup_forced_irqthreads(char *arg) +{ + force_irqthreads = true; + return 0; +} +early_param("threadirqs", setup_forced_irqthreads); +#endif + /** * synchronize_irq - wait for pending IRQ handlers (on other CPUs) * @irq: interrupt number to wait for @@ -702,6 +713,32 @@ irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { } #endif /* + * Interrupts which are not explicitely requested as threaded + * interrupts rely on the implicit bh/preempt disable of the hard irq + * context. So we need to disable bh here to avoid deadlocks and other + * side effects. + */ +static void +irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action) +{ + local_bh_disable(); + action->thread_fn(action->irq, action->dev_id); + irq_finalize_oneshot(desc, action, false); + local_bh_enable(); +} + +/* + * Interrupts explicitely requested as threaded interupts want to be + * preemtible - many of them need to sleep and wait for slow busses to + * complete. + */ +static void irq_thread_fn(struct irq_desc *desc, struct irqaction *action) +{ + action->thread_fn(action->irq, action->dev_id); + irq_finalize_oneshot(desc, action, false); +} + +/* * Interrupt handler thread */ static int irq_thread(void *data) @@ -711,8 +748,15 @@ static int irq_thread(void *data) }; struct irqaction *action = data; struct irq_desc *desc = irq_to_desc(action->irq); + void (*handler_fn)(struct irq_desc *desc, struct irqaction *action); int wake; + if (force_irqthreads & test_bit(IRQTF_FORCED_THREAD, + &action->thread_flags)) + handler_fn = irq_forced_thread_fn; + else + handler_fn = irq_thread_fn; + sched_setscheduler(current, SCHED_FIFO, ¶m); current->irqaction = action; @@ -736,10 +780,7 @@ static int irq_thread(void *data) raw_spin_unlock_irq(&desc->lock); } else { raw_spin_unlock_irq(&desc->lock); - - action->thread_fn(action->irq, action->dev_id); - - irq_finalize_oneshot(desc, action, false); + handler_fn(desc, action); } wake = atomic_dec_and_test(&desc->threads_active); @@ -789,6 +830,22 @@ void exit_irq_thread(void) set_bit(IRQTF_DIED, &tsk->irqaction->flags); } +static void irq_setup_forced_threading(struct irqaction *new) +{ + if (!force_irqthreads) + return; + if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT)) + return; + + new->flags |= IRQF_ONESHOT; + + if (!new->thread_fn) { + set_bit(IRQTF_FORCED_THREAD, &new->thread_flags); + new->thread_fn = new->handler; + new->handler = irq_default_primary_handler; + } +} + /* * Internal function to register an irqaction - typically used to * allocate special interrupts that are part of the architecture. @@ -838,6 +895,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) * dummy function which warns when called. */ new->handler = irq_nested_primary_handler; + } else { + irq_setup_forced_threading(new); } /* diff --git a/kernel/softirq.c b/kernel/softirq.c index c0490464e92..a33fb291124 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -311,9 +311,21 @@ void irq_enter(void) } #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED -# define invoke_softirq() __do_softirq() +static inline void invoke_softirq(void) +{ + if (!force_irqthreads) + __do_softirq(); + else + wakeup_softirqd(); +} #else -# define invoke_softirq() do_softirq() +static inline void invoke_softirq(void) +{ + if (!force_irqthreads) + do_softirq(); + else + wakeup_softirqd(); +} #endif /* |