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>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9815221..fd227d6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -25,6 +25,7 @@
select HAVE_IDE
select HAVE_OPROFILE
select HAVE_PERF_EVENTS if (!M386 && !M486)
+ select HAVE_IRQ_WORK
select HAVE_IOREMAP_PROT
select HAVE_KPROBES
select ARCH_WANT_OPTIONAL_GPIOLIB
diff --git a/arch/x86/include/asm/entry_arch.h b/arch/x86/include/asm/entry_arch.h
index 8e8ec66..b8e96a1 100644
--- a/arch/x86/include/asm/entry_arch.h
+++ b/arch/x86/include/asm/entry_arch.h
@@ -49,8 +49,8 @@
BUILD_INTERRUPT(error_interrupt,ERROR_APIC_VECTOR)
BUILD_INTERRUPT(spurious_interrupt,SPURIOUS_APIC_VECTOR)
-#ifdef CONFIG_PERF_EVENTS
-BUILD_INTERRUPT(perf_pending_interrupt, LOCAL_PENDING_VECTOR)
+#ifdef CONFIG_IRQ_WORK
+BUILD_INTERRUPT(irq_work_interrupt, IRQ_WORK_VECTOR)
#endif
#ifdef CONFIG_X86_THERMAL_VECTOR
diff --git a/arch/x86/include/asm/hardirq.h b/arch/x86/include/asm/hardirq.h
index aeab29a..55e4de6 100644
--- a/arch/x86/include/asm/hardirq.h
+++ b/arch/x86/include/asm/hardirq.h
@@ -14,7 +14,7 @@
#endif
unsigned int x86_platform_ipis; /* arch dependent */
unsigned int apic_perf_irqs;
- unsigned int apic_pending_irqs;
+ unsigned int apic_irq_work_irqs;
#ifdef CONFIG_SMP
unsigned int irq_resched_count;
unsigned int irq_call_count;
diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index 46c0fe0..3a54a1c 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -29,7 +29,7 @@
extern void apic_timer_interrupt(void);
extern void x86_platform_ipi(void);
extern void error_interrupt(void);
-extern void perf_pending_interrupt(void);
+extern void irq_work_interrupt(void);
extern void spurious_interrupt(void);
extern void thermal_interrupt(void);
diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index e2ca300..6af0894 100644
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -114,9 +114,9 @@
#define X86_PLATFORM_IPI_VECTOR 0xed
/*
- * Performance monitoring pending work vector:
+ * IRQ work vector:
*/
-#define LOCAL_PENDING_VECTOR 0xec
+#define IRQ_WORK_VECTOR 0xec
#define UV_BAU_MESSAGE 0xea
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 9d3f485..7490bf8 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -35,6 +35,7 @@
obj-y += traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
obj-y += time.o ioport.o ldt.o dumpstack.o
obj-y += setup.o x86_init.o i8259.o irqinit.o jump_label.o
+obj-$(CONFIG_IRQ_WORK) += irq_work.o
obj-$(CONFIG_X86_VISWS) += visws_quirks.o
obj-$(CONFIG_X86_32) += probe_roms_32.o
obj-$(CONFIG_X86_32) += sys_i386_32.o i386_ksyms_32.o
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index e2513f2..fe73c18 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1196,25 +1196,6 @@
return handled;
}
-void smp_perf_pending_interrupt(struct pt_regs *regs)
-{
- irq_enter();
- ack_APIC_irq();
- inc_irq_stat(apic_pending_irqs);
- perf_event_do_pending();
- irq_exit();
-}
-
-void set_perf_event_pending(void)
-{
-#ifdef CONFIG_X86_LOCAL_APIC
- if (!x86_pmu.apic || !x86_pmu_initialized())
- return;
-
- apic->send_IPI_self(LOCAL_PENDING_VECTOR);
-#endif
-}
-
void perf_events_lapic_init(void)
{
if (!x86_pmu.apic || !x86_pmu_initialized())
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 17be5ec..c375c79 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1023,9 +1023,9 @@
apicinterrupt SPURIOUS_APIC_VECTOR \
spurious_interrupt smp_spurious_interrupt
-#ifdef CONFIG_PERF_EVENTS
-apicinterrupt LOCAL_PENDING_VECTOR \
- perf_pending_interrupt smp_perf_pending_interrupt
+#ifdef CONFIG_IRQ_WORK
+apicinterrupt IRQ_WORK_VECTOR \
+ irq_work_interrupt smp_irq_work_interrupt
#endif
/*
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 91fd0c7..44edb03 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -67,10 +67,10 @@
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->apic_perf_irqs);
seq_printf(p, " Performance monitoring interrupts\n");
- seq_printf(p, "%*s: ", prec, "PND");
+ seq_printf(p, "%*s: ", prec, "IWI");
for_each_online_cpu(j)
- seq_printf(p, "%10u ", irq_stats(j)->apic_pending_irqs);
- seq_printf(p, " Performance pending work\n");
+ seq_printf(p, "%10u ", irq_stats(j)->apic_irq_work_irqs);
+ seq_printf(p, " IRQ work interrupts\n");
#endif
if (x86_platform_ipi_callback) {
seq_printf(p, "%*s: ", prec, "PLT");
@@ -185,7 +185,7 @@
sum += irq_stats(cpu)->apic_timer_irqs;
sum += irq_stats(cpu)->irq_spurious_count;
sum += irq_stats(cpu)->apic_perf_irqs;
- sum += irq_stats(cpu)->apic_pending_irqs;
+ sum += irq_stats(cpu)->apic_irq_work_irqs;
#endif
if (x86_platform_ipi_callback)
sum += irq_stats(cpu)->x86_platform_ipis;
diff --git a/arch/x86/kernel/irq_work.c b/arch/x86/kernel/irq_work.c
new file mode 100644
index 0000000..ca8f703
--- /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
+}
diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index 990ae7c..713969b 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -224,9 +224,9 @@
alloc_intr_gate(SPURIOUS_APIC_VECTOR, spurious_interrupt);
alloc_intr_gate(ERROR_APIC_VECTOR, error_interrupt);
- /* Performance monitoring interrupts: */
-# ifdef CONFIG_PERF_EVENTS
- alloc_intr_gate(LOCAL_PENDING_VECTOR, perf_pending_interrupt);
+ /* IRQ work interrupts: */
+# ifdef CONFIG_IRQ_WORK
+ alloc_intr_gate(IRQ_WORK_VECTOR, irq_work_interrupt);
# endif
#endif