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irq_work: Add generic hardirq context callbacks

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Provide a mechanism that allows running code in IRQ context. It is
most useful for NMI code that needs to interact with the rest of the
system -- like wakeup a task to drain buffers.

Perf currently has such a mechanism, so extract that and provide it as
a generic feature, independent of perf so that others may also
benefit.

The IRQ context callback is generated through self-IPIs where
possible, or on architectures like powerpc the decrementer (the
built-in timer facility) is set to generate an interrupt immediately.

Architectures that don't have anything like this get to do with a
callback from the timer tick. These architectures can call
irq_work_run() at the tail of any IRQ handlers that might enqueue such
work (like the perf IRQ handler) to avoid undue latencies in
processing the work.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[ various fixes ]
Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-10-14 14:01:34 +08:00 • committed by Ingo Molnar
parent 8e5fc1a732
commit e360adbe29
39 changed files with 311 additions and 242 deletions
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30
arch/x86/kernel/irq_work.c Normal file
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/*
* x86 specific code for irq_work
*
* Copyright (C) 2010 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
*/
#include <linux/kernel.h>
#include <linux/irq_work.h>
#include <linux/hardirq.h>
#include <asm/apic.h>
void smp_irq_work_interrupt(struct pt_regs *regs)
{
irq_enter();
ack_APIC_irq();
inc_irq_stat(apic_irq_work_irqs);
irq_work_run();
irq_exit();
}
void arch_irq_work_raise(void)
{
#ifdef CONFIG_X86_LOCAL_APIC
if (!cpu_has_apic)
return;
apic->send_IPI_self(IRQ_WORK_VECTOR);
apic_wait_icr_idle();
#endif
}