4788501606
irq work currently only supports local callbacks. However its code is mostly ready to run remote callbacks and we have some potential user. The full nohz subsystem currently open codes its own remote irq work on top of the scheduler ipi when it wants a CPU to reevaluate its next tick. However this ad hoc solution bloats the scheduler IPI. Lets just extend the irq work subsystem to support remote queuing on top of the generic SMP IPI to handle this kind of user. This shouldn't add noticeable overhead. Suggested-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
51 lines
1.2 KiB
C
51 lines
1.2 KiB
C
#ifndef _LINUX_IRQ_WORK_H
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#define _LINUX_IRQ_WORK_H
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#include <linux/llist.h>
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/*
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* An entry can be in one of four states:
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*
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* free NULL, 0 -> {claimed} : free to be used
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* claimed NULL, 3 -> {pending} : claimed to be enqueued
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* pending next, 3 -> {busy} : queued, pending callback
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* busy NULL, 2 -> {free, claimed} : callback in progress, can be claimed
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*/
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#define IRQ_WORK_PENDING 1UL
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#define IRQ_WORK_BUSY 2UL
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#define IRQ_WORK_FLAGS 3UL
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#define IRQ_WORK_LAZY 4UL /* Doesn't want IPI, wait for tick */
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struct irq_work {
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unsigned long flags;
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struct llist_node llnode;
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void (*func)(struct irq_work *);
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};
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static inline
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void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
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{
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work->flags = 0;
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work->func = func;
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}
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#define DEFINE_IRQ_WORK(name, _f) struct irq_work name = { .func = (_f), }
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bool irq_work_queue(struct irq_work *work);
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#ifdef CONFIG_SMP
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bool irq_work_queue_on(struct irq_work *work, int cpu);
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#endif
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void irq_work_run(void);
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void irq_work_sync(struct irq_work *work);
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#ifdef CONFIG_IRQ_WORK
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bool irq_work_needs_cpu(void);
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#else
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static inline bool irq_work_needs_cpu(void) { return false; }
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#endif
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#endif /* _LINUX_IRQ_WORK_H */
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