diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2012-01-31 13:01:27 +0100 |
---|---|---|
committer | Clark Williams <williams@redhat.com> | 2012-03-14 10:50:06 -0500 |
commit | aee52fd1c8680ce3178a67d6962119d67fe6421f (patch) | |
tree | f5c74dfc04f30c3f23d2f6b808e87c09aa66044f /kernel | |
parent | 1f61b7061dc2406a90a70154a22f866d7620908d (diff) |
genirq: Allow disabling of softirq processing in irq thread context
The processing of softirqs in irq thread context is a performance gain
for the non-rt workloads of a system, but it's counterproductive for
interrupts which are explicitely related to the realtime
workload. Allow such interrupts to prevent softirq processing in their
thread context.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/irq/manage.c | 13 | ||||
-rw-r--r-- | kernel/irq/settings.h | 12 | ||||
-rw-r--r-- | kernel/softirq.c | 7 |
3 files changed, 31 insertions, 1 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 0c1a75942d86..530d894d04e5 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -742,7 +742,15 @@ irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action) local_bh_disable(); ret = action->thread_fn(action->irq, action->dev_id); irq_finalize_oneshot(desc, action, false); - local_bh_enable(); + /* + * Interrupts which have real time requirements can be set up + * to avoid softirq processing in the thread handler. This is + * safe as these interrupts do not raise soft interrupts. + */ + if (irq_settings_no_softirq_call(desc)) + _local_bh_enable(); + else + local_bh_enable(); return ret; } @@ -1072,6 +1080,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) irqd_set(&desc->irq_data, IRQD_NO_BALANCING); } + if (new->flags & IRQF_NO_SOFTIRQ_CALL) + irq_settings_set_no_softirq_call(desc); + /* Set default affinity mask once everything is setup */ setup_affinity(irq, desc, mask); diff --git a/kernel/irq/settings.h b/kernel/irq/settings.h index 1162f1030f18..0d2c381c2bdb 100644 --- a/kernel/irq/settings.h +++ b/kernel/irq/settings.h @@ -14,6 +14,7 @@ enum { _IRQ_NO_BALANCING = IRQ_NO_BALANCING, _IRQ_NESTED_THREAD = IRQ_NESTED_THREAD, _IRQ_PER_CPU_DEVID = IRQ_PER_CPU_DEVID, + _IRQ_NO_SOFTIRQ_CALL = IRQ_NO_SOFTIRQ_CALL, _IRQF_MODIFY_MASK = IRQF_MODIFY_MASK, }; @@ -26,6 +27,7 @@ enum { #define IRQ_NOAUTOEN GOT_YOU_MORON #define IRQ_NESTED_THREAD GOT_YOU_MORON #define IRQ_PER_CPU_DEVID GOT_YOU_MORON +#define IRQ_NO_SOFTIRQ_CALL GOT_YOU_MORON #undef IRQF_MODIFY_MASK #define IRQF_MODIFY_MASK GOT_YOU_MORON @@ -36,6 +38,16 @@ irq_settings_clr_and_set(struct irq_desc *desc, u32 clr, u32 set) desc->status_use_accessors |= (set & _IRQF_MODIFY_MASK); } +static inline bool irq_settings_no_softirq_call(struct irq_desc *desc) +{ + return desc->status_use_accessors & _IRQ_NO_SOFTIRQ_CALL; +} + +static inline void irq_settings_set_no_softirq_call(struct irq_desc *desc) +{ + desc->status_use_accessors |= _IRQ_NO_SOFTIRQ_CALL; +} + static inline bool irq_settings_is_per_cpu(struct irq_desc *desc) { return desc->status_use_accessors & _IRQ_PER_CPU; diff --git a/kernel/softirq.c b/kernel/softirq.c index 92b4ca30eda2..bef08f3cd6d6 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -425,6 +425,13 @@ void local_bh_enable_ip(unsigned long ip) } EXPORT_SYMBOL(local_bh_enable_ip); +void _local_bh_enable(void) +{ + current->softirq_nestcnt--; + migrate_enable(); +} +EXPORT_SYMBOL(_local_bh_enable); + /* For tracing */ int notrace __in_softirq(void) { |