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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2010-10-14 14:01:34 +0800
committerIngo Molnar <mingo@elte.hu>2010-10-18 19:58:50 +0200
commite360adbe29241a0194e10e20595360dd7b98a2b3 (patch)
treeef5fa5f50a895096bfb25bc11b25949603158238 /arch/x86/kernel/irq_work.c
parent8e5fc1a7320baf6076391607515dceb61319b36a (diff)
irq_work: Add generic hardirq context callbacks
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>
Diffstat (limited to 'arch/x86/kernel/irq_work.c')
-rw-r--r--arch/x86/kernel/irq_work.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86/kernel/irq_work.c b/arch/x86/kernel/irq_work.c
new file mode 100644
index 00000000000..ca8f703a1e7
--- /dev/null
+++ b/arch/x86/kernel/irq_work.c
@@ -0,0 +1,30 @@
+/*
+ * 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
+}