genirq: Provide forced interrupt threading (8d32a307) · Commits · 戴 / test

Documentation/kernel-parameters.txt

+4 −0

Original line number	Diff line number	Diff line
		@@ -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

include/linux/interrupt.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -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))

kernel/irq/Kconfig

+3 −0

Original line number	Diff line number	Diff line
		@@ -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

kernel/irq/internals.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -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,
		};

		/*

kernel/irq/manage.c

+63 −4

Original line number	Diff line number	Diff line
		@@ -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
		@@ -701,6 +712,32 @@ static inline void
		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
		*/
		@@ -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, &param);
		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);
		}

		/*

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