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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>
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/alpha/Kconfig
View File

@ -9,6 +9,7 @@ config ALPHA
select HAVE_IDE
select HAVE_OPROFILE
select HAVE_SYSCALL_WRAPPERS
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
select HAVE_DMA_ATTRS
help

5
arch/alpha/include/asm/perf_event.h
View File

@ -1,11 +1,6 @@
#ifndef __ASM_ALPHA_PERF_EVENT_H
#define __ASM_ALPHA_PERF_EVENT_H
/* Alpha only supports software events through this interface. */
extern void set_perf_event_pending(void);
#define PERF_EVENT_INDEX_OFFSET 0
#ifdef CONFIG_PERF_EVENTS
extern void init_hw_perf_events(void);
#else

30
arch/alpha/kernel/time.c
View File

@ -41,7 +41,7 @@
#include <linux/init.h>
#include <linux/bcd.h>
#include <linux/profile.h>
#include <linux/perf_event.h>
#include <linux/irq_work.h>
#include <asm/uaccess.h>
#include <asm/io.h>
@ -83,25 +83,25 @@ static struct {
unsigned long est_cycle_freq;
#ifdef CONFIG_PERF_EVENTS
#ifdef CONFIG_IRQ_WORK
DEFINE_PER_CPU(u8, perf_event_pending);
DEFINE_PER_CPU(u8, irq_work_pending);
#define set_perf_event_pending_flag() __get_cpu_var(perf_event_pending) = 1
#define test_perf_event_pending() __get_cpu_var(perf_event_pending)
#define clear_perf_event_pending() __get_cpu_var(perf_event_pending) = 0
#define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1
#define test_irq_work_pending() __get_cpu_var(irq_work_pending)
#define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0
void set_perf_event_pending(void)
void set_irq_work_pending(void)
{
set_perf_event_pending_flag();
set_irq_work_pending_flag();
}
#else /* CONFIG_PERF_EVENTS */
#else /* CONFIG_IRQ_WORK */
#define test_perf_event_pending() 0
#define clear_perf_event_pending()
#define test_irq_work_pending() 0
#define clear_irq_work_pending()
#endif /* CONFIG_PERF_EVENTS */
#endif /* CONFIG_IRQ_WORK */
static inline __u32 rpcc(void)
@ -191,9 +191,9 @@ irqreturn_t timer_interrupt(int irq, void *dev)
write_sequnlock(&xtime_lock);
if (test_perf_event_pending()) {
clear_perf_event_pending();
perf_event_do_pending();
if (test_irq_work_pending()) {
clear_irq_work_pending();
irq_work_run();
}
#ifndef CONFIG_SMP

1
arch/arm/Kconfig
View File

@ -23,6 +23,7 @@ config ARM
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZO
select HAVE_KERNEL_LZMA
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
select PERF_USE_VMALLOC
select HAVE_REGS_AND_STACK_ACCESS_API

12
arch/arm/include/asm/perf_event.h
View File

@ -12,18 +12,6 @@
#ifndef __ARM_PERF_EVENT_H__
#define __ARM_PERF_EVENT_H__
/*
* NOP: on *most* (read: all supported) ARM platforms, the performance
* counter interrupts are regular interrupts and not an NMI. This
* means that when we receive the interrupt we can call
* perf_event_do_pending() that handles all of the work with
* interrupts disabled.
*/
static inline void
set_perf_event_pending(void)
{
}
/* ARM performance counters start from 1 (in the cp15 accesses) so use the
* same indexes here for consistency. */
#define PERF_EVENT_INDEX_OFFSET 1

8
arch/arm/kernel/perf_event.c
View File

@ -1092,7 +1092,7 @@ armv6pmu_handle_irq(int irq_num,
* platforms that can have the PMU interrupts raised as an NMI, this
* will not work.
*/
perf_event_do_pending();
irq_work_run();
return IRQ_HANDLED;
}
@ -2068,7 +2068,7 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)
* platforms that can have the PMU interrupts raised as an NMI, this
* will not work.
*/
perf_event_do_pending();
irq_work_run();
return IRQ_HANDLED;
}
@ -2436,7 +2436,7 @@ xscale1pmu_handle_irq(int irq_num, void *dev)
armpmu->disable(hwc, idx);
}
perf_event_do_pending();
irq_work_run();
/*
* Re-enable the PMU.
@ -2763,7 +2763,7 @@ xscale2pmu_handle_irq(int irq_num, void *dev)
armpmu->disable(hwc, idx);
}
perf_event_do_pending();
irq_work_run();
/*
* Re-enable the PMU.

1
arch/frv/Kconfig
View File

@ -7,6 +7,7 @@ config FRV
default y
select HAVE_IDE
select HAVE_ARCH_TRACEHOOK
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
config ZONE_DMA

2
arch/frv/lib/Makefile
View File

@ -5,4 +5,4 @@
lib-y := \
__ashldi3.o __lshrdi3.o __muldi3.o __ashrdi3.o __negdi2.o __ucmpdi2.o \
checksum.o memcpy.o memset.o atomic-ops.o atomic64-ops.o \
outsl_ns.o outsl_sw.o insl_ns.o insl_sw.o cache.o perf_event.o
outsl_ns.o outsl_sw.o insl_ns.o insl_sw.o cache.o

19
arch/frv/lib/perf_event.c
View File

@ -1,19 +0,0 @@
/* Performance event handling
*
* Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/perf_event.h>
/*
* mark the performance event as pending
*/
void set_perf_event_pending(void)
{
}

1
arch/parisc/Kconfig
View File

@ -16,6 +16,7 @@ config PARISC
select RTC_DRV_GENERIC
select INIT_ALL_POSSIBLE
select BUG
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
select GENERIC_ATOMIC64 if !64BIT
help

3
arch/parisc/include/asm/perf_event.h
View File

@ -1,7 +1,6 @@
#ifndef __ASM_PARISC_PERF_EVENT_H
#define __ASM_PARISC_PERF_EVENT_H
/* parisc only supports software events through this interface. */
static inline void set_perf_event_pending(void) { }
/* Empty, just to avoid compiling error */
#endif /* __ASM_PARISC_PERF_EVENT_H */

1
arch/powerpc/Kconfig
View File

@ -138,6 +138,7 @@ config PPC
select HAVE_OPROFILE
select HAVE_SYSCALL_WRAPPERS if PPC64
select GENERIC_ATOMIC64 if PPC32
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_HW_BREAKPOINT if PERF_EVENTS && PPC_BOOK3S_64

2
arch/powerpc/include/asm/paca.h
View File

@ -129,7 +129,7 @@ struct paca_struct {
u8 soft_enabled; /* irq soft-enable flag */
u8 hard_enabled; /* set if irqs are enabled in MSR */
u8 io_sync; /* writel() needs spin_unlock sync */
u8 perf_event_pending; /* PM interrupt while soft-disabled */
u8 irq_work_pending; /* IRQ_WORK interrupt while soft-disable */
/* Stuff for accurate time accounting */
u64 user_time; /* accumulated usermode TB ticks */

42
arch/powerpc/kernel/time.c
View File

@ -53,7 +53,7 @@
#include <linux/posix-timers.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/perf_event.h>
#include <linux/irq_work.h>
#include <asm/trace.h>
#include <asm/io.h>
@ -493,60 +493,60 @@ void __init iSeries_time_init_early(void)
}
#endif /* CONFIG_PPC_ISERIES */
#ifdef CONFIG_PERF_EVENTS
#ifdef CONFIG_IRQ_WORK
/*
* 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
*/
#ifdef CONFIG_PPC64
static inline unsigned long test_perf_event_pending(void)
static inline unsigned long test_irq_work_pending(void)
{
unsigned long x;
asm volatile("lbz %0,%1(13)"
: "=r" (x)
: "i" (offsetof(struct paca_struct, perf_event_pending)));
: "i" (offsetof(struct paca_struct, irq_work_pending)));
return x;
}
static inline void set_perf_event_pending_flag(void)
static inline void set_irq_work_pending_flag(void)
{
asm volatile("stb %0,%1(13)" : :
"r" (1),
"i" (offsetof(struct paca_struct, perf_event_pending)));
"i" (offsetof(struct paca_struct, irq_work_pending)));
}
static inline void clear_perf_event_pending(void)
static inline void clear_irq_work_pending(void)
{
asm volatile("stb %0,%1(13)" : :
"r" (0),
"i" (offsetof(struct paca_struct, perf_event_pending)));
"i" (offsetof(struct paca_struct, irq_work_pending)));
}
#else /* 32-bit */
DEFINE_PER_CPU(u8, perf_event_pending);
DEFINE_PER_CPU(u8, irq_work_pending);
#define set_perf_event_pending_flag() __get_cpu_var(perf_event_pending) = 1
#define test_perf_event_pending() __get_cpu_var(perf_event_pending)
#define clear_perf_event_pending() __get_cpu_var(perf_event_pending) = 0
#define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1
#define test_irq_work_pending() __get_cpu_var(irq_work_pending)
#define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0
#endif /* 32 vs 64 bit */
void set_perf_event_pending(void)
void set_irq_work_pending(void)
{
preempt_disable();
set_perf_event_pending_flag();
set_irq_work_pending_flag();
set_dec(1);
preempt_enable();
}
#else /* CONFIG_PERF_EVENTS */
#else /* CONFIG_IRQ_WORK */
#define test_perf_event_pending() 0
#define clear_perf_event_pending()
#define test_irq_work_pending() 0
#define clear_irq_work_pending()
#endif /* CONFIG_PERF_EVENTS */
#endif /* CONFIG_IRQ_WORK */
/*
* For iSeries shared processors, we have to let the hypervisor
@ -587,9 +587,9 @@ void timer_interrupt(struct pt_regs * regs)
calculate_steal_time();
if (test_perf_event_pending()) {
clear_perf_event_pending();
perf_event_do_pending();
if (test_irq_work_pending()) {
clear_irq_work_pending();
irq_work_run();
}
#ifdef CONFIG_PPC_ISERIES

1
arch/s390/Kconfig
View File

@ -95,6 +95,7 @@ config S390
select HAVE_KVM if 64BIT
select HAVE_ARCH_TRACEHOOK
select INIT_ALL_POSSIBLE
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_BZIP2

3
arch/s390/include/asm/perf_event.h
View File

@ -4,7 +4,6 @@
* Copyright 2009 Martin Schwidefsky, IBM Corporation.
*/
static inline void set_perf_event_pending(void) {}
static inline void clear_perf_event_pending(void) {}
/* Empty, just to avoid compiling error */
#define PERF_EVENT_INDEX_OFFSET 0

1
arch/sh/Kconfig
View File

@ -16,6 +16,7 @@ config SUPERH
select HAVE_ARCH_TRACEHOOK
select HAVE_DMA_API_DEBUG
select HAVE_DMA_ATTRS
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
select PERF_USE_VMALLOC
select HAVE_KERNEL_GZIP

7
arch/sh/include/asm/perf_event.h
View File

@ -26,11 +26,4 @@ extern int register_sh_pmu(struct sh_pmu *);
extern int reserve_pmc_hardware(void);
extern void release_pmc_hardware(void);
static inline void set_perf_event_pending(void)
{
/* Nothing to see here, move along. */
}
#define PERF_EVENT_INDEX_OFFSET 0
#endif /* __ASM_SH_PERF_EVENT_H */

2
arch/sparc/Kconfig
View File

@ -26,6 +26,7 @@ config SPARC
select ARCH_WANT_OPTIONAL_GPIOLIB
select RTC_CLASS
select RTC_DRV_M48T59
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
select PERF_USE_VMALLOC
select HAVE_DMA_ATTRS
@ -54,6 +55,7 @@ config SPARC64
select RTC_DRV_BQ4802
select RTC_DRV_SUN4V
select RTC_DRV_STARFIRE
select HAVE_IRQ_WORK
select HAVE_PERF_EVENTS
select PERF_USE_VMALLOC

4
arch/sparc/include/asm/perf_event.h
View File

@ -1,10 +1,6 @@
#ifndef __ASM_SPARC_PERF_EVENT_H
#define __ASM_SPARC_PERF_EVENT_H
extern void set_perf_event_pending(void);
#define PERF_EVENT_INDEX_OFFSET 0
#ifdef CONFIG_PERF_EVENTS
#include <asm/ptrace.h>

8
arch/sparc/kernel/pcr.c
View File

@ -7,7 +7,7 @@
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/perf_event.h>
#include <linux/irq_work.h>
#include <linux/ftrace.h>
#include <asm/pil.h>
@ -43,14 +43,14 @@ void __irq_entry deferred_pcr_work_irq(int irq, struct pt_regs *regs)
old_regs = set_irq_regs(regs);
irq_enter();
#ifdef CONFIG_PERF_EVENTS
perf_event_do_pending();
#ifdef CONFIG_IRQ_WORK
irq_work_run();
#endif
irq_exit();
set_irq_regs(old_regs);
}
void set_perf_event_pending(void)
void arch_irq_work_raise(void)
{
set_softint(1 << PIL_DEFERRED_PCR_WORK);
}

1
arch/x86/Kconfig
View File

@ -25,6 +25,7 @@ config X86
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

4
arch/x86/include/asm/entry_arch.h
View File

@ -49,8 +49,8 @@ BUILD_INTERRUPT(apic_timer_interrupt,LOCAL_TIMER_VECTOR)
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

2
arch/x86/include/asm/hardirq.h
View File

@ -14,7 +14,7 @@ typedef struct {
#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;

2
arch/x86/include/asm/hw_irq.h
View File

@ -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);

4
arch/x86/include/asm/irq_vectors.h
View File

@ -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

1
arch/x86/kernel/Makefile
View File

@ -35,6 +35,7 @@ obj-y := process_$(BITS).o signal.o entry_$(BITS).o
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

19
arch/x86/kernel/cpu/perf_event.c
View File

@ -1196,25 +1196,6 @@ static int x86_pmu_handle_irq(struct pt_regs *regs)
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())

6
arch/x86/kernel/entry_64.S
View File

@ -1023,9 +1023,9 @@ apicinterrupt ERROR_APIC_VECTOR \
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
/*

8
arch/x86/kernel/irq.c
View File

@ -67,10 +67,10 @@ static int show_other_interrupts(struct seq_file *p, int prec)
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 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
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;

30
arch/x86/kernel/irq_work.c Normal file
View File

@ -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
}

6
arch/x86/kernel/irqinit.c
View File

@ -224,9 +224,9 @@ static void __init apic_intr_init(void)
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

20
include/linux/irq_work.h Normal file
View File

@ -0,0 +1,20 @@
#ifndef _LINUX_IRQ_WORK_H
#define _LINUX_IRQ_WORK_H
struct irq_work {
struct irq_work *next;
void (*func)(struct irq_work *);
};
static inline
void init_irq_work(struct irq_work *entry, void (*func)(struct irq_work *))
{
entry->next = NULL;
entry->func = func;
}
bool irq_work_queue(struct irq_work *entry);
void irq_work_run(void);
void irq_work_sync(struct irq_work *entry);
#endif /* _LINUX_IRQ_WORK_H */

11
include/linux/perf_event.h
View File

@ -486,6 +486,7 @@ struct perf_guest_info_callbacks {
#include <linux/workqueue.h>
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <linux/irq_work.h>
#include <asm/atomic.h>
#include <asm/local.h>
@ -672,11 +673,6 @@ struct perf_buffer {
void *data_pages[0];
};
struct perf_pending_entry {
struct perf_pending_entry *next;
void (*func)(struct perf_pending_entry *);
};
struct perf_sample_data;
typedef void (*perf_overflow_handler_t)(struct perf_event *, int,
@ -784,7 +780,7 @@ struct perf_event {
int pending_wakeup;
int pending_kill;
int pending_disable;
struct perf_pending_entry pending;
struct irq_work pending;
atomic_t event_limit;
@ -898,8 +894,6 @@ extern int perf_event_init_task(struct task_struct *child);
extern void perf_event_exit_task(struct task_struct *child);
extern void perf_event_free_task(struct task_struct *task);
extern void perf_event_delayed_put(struct task_struct *task);
extern void set_perf_event_pending(void);
extern void perf_event_do_pending(void);
extern void perf_event_print_debug(void);
extern void perf_pmu_disable(struct pmu *pmu);
extern void perf_pmu_enable(struct pmu *pmu);
@ -1078,7 +1072,6 @@ static inline int perf_event_init_task(struct task_struct *child) { return 0; }
static inline void perf_event_exit_task(struct task_struct *child) { }
static inline void perf_event_free_task(struct task_struct *task) { }
static inline void perf_event_delayed_put(struct task_struct *task) { }
static inline void perf_event_do_pending(void) { }
static inline void perf_event_print_debug(void) { }
static inline int perf_event_task_disable(void) { return -EINVAL; }
static inline int perf_event_task_enable(void) { return -EINVAL; }

8
init/Kconfig
View File

@ -21,6 +21,13 @@ config CONSTRUCTORS
depends on !UML
default y
config HAVE_IRQ_WORK
bool
config IRQ_WORK
bool
depends on HAVE_IRQ_WORK
menu "General setup"
config EXPERIMENTAL
@ -987,6 +994,7 @@ config PERF_EVENTS
default y if (PROFILING || PERF_COUNTERS)
depends on HAVE_PERF_EVENTS
select ANON_INODES
select IRQ_WORK
help
Enable kernel support for various performance events provided
by software and hardware.

2
kernel/Makefile
View File

@ -23,6 +23,7 @@ CFLAGS_REMOVE_rtmutex-debug.o = -pg
CFLAGS_REMOVE_cgroup-debug.o = -pg
CFLAGS_REMOVE_sched_clock.o = -pg
CFLAGS_REMOVE_perf_event.o = -pg
CFLAGS_REMOVE_irq_work.o = -pg
endif
obj-$(CONFIG_FREEZER) += freezer.o
@ -100,6 +101,7 @@ obj-$(CONFIG_TRACING) += trace/
obj-$(CONFIG_X86_DS) += trace/
obj-$(CONFIG_RING_BUFFER) += trace/
obj-$(CONFIG_SMP) += sched_cpupri.o
obj-$(CONFIG_IRQ_WORK) += irq_work.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o

164
kernel/irq_work.c Normal file
View File

@ -0,0 +1,164 @@
/*
* Copyright (C) 2010 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
*
* Provides a framework for enqueueing and running callbacks from hardirq
* context. The enqueueing is NMI-safe.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/irq_work.h>
#include <linux/hardirq.h>
/*
* An entry can be in one of four states:
*
* free NULL, 0 -> {claimed} : free to be used
* claimed NULL, 3 -> {pending} : claimed to be enqueued
* pending next, 3 -> {busy} : queued, pending callback
* busy NULL, 2 -> {free, claimed} : callback in progress, can be claimed
*
* We use the lower two bits of the next pointer to keep PENDING and BUSY
* flags.
*/
#define IRQ_WORK_PENDING 1UL
#define IRQ_WORK_BUSY 2UL
#define IRQ_WORK_FLAGS 3UL
static inline bool irq_work_is_set(struct irq_work *entry, int flags)
{
return (unsigned long)entry->next & flags;
}
static inline struct irq_work *irq_work_next(struct irq_work *entry)
{
unsigned long next = (unsigned long)entry->next;
next &= ~IRQ_WORK_FLAGS;
return (struct irq_work *)next;
}
static inline struct irq_work *next_flags(struct irq_work *entry, int flags)
{
unsigned long next = (unsigned long)entry;
next |= flags;
return (struct irq_work *)next;
}
static DEFINE_PER_CPU(struct irq_work *, irq_work_list);
/*
* Claim the entry so that no one else will poke at it.
*/
static bool irq_work_claim(struct irq_work *entry)
{
struct irq_work *next, *nflags;
do {
next = entry->next;
if ((unsigned long)next & IRQ_WORK_PENDING)
return false;
nflags = next_flags(next, IRQ_WORK_FLAGS);
} while (cmpxchg(&entry->next, next, nflags) != next);
return true;
}
void __weak arch_irq_work_raise(void)
{
/*
* Lame architectures will get the timer tick callback
*/
}
/*
* Queue the entry and raise the IPI if needed.
*/
static void __irq_work_queue(struct irq_work *entry)
{
struct irq_work **head, *next;
head = &get_cpu_var(irq_work_list);
do {
next = *head;
/* Can assign non-atomic because we keep the flags set. */
entry->next = next_flags(next, IRQ_WORK_FLAGS);
} while (cmpxchg(head, next, entry) != next);
/* The list was empty, raise self-interrupt to start processing. */
if (!irq_work_next(entry))
arch_irq_work_raise();
put_cpu_var(irq_work_list);
}
/*
* Enqueue the irq_work @entry, returns true on success, failure when the
* @entry was already enqueued by someone else.
*
* Can be re-enqueued while the callback is still in progress.
*/
bool irq_work_queue(struct irq_work *entry)
{
if (!irq_work_claim(entry)) {
/*
* Already enqueued, can't do!
*/
return false;
}
__irq_work_queue(entry);
return true;
}
EXPORT_SYMBOL_GPL(irq_work_queue);
/*
* Run the irq_work entries on this cpu. Requires to be ran from hardirq
* context with local IRQs disabled.
*/
void irq_work_run(void)
{
struct irq_work *list, **head;
head = &__get_cpu_var(irq_work_list);
if (*head == NULL)
return;
BUG_ON(!in_irq());
BUG_ON(!irqs_disabled());
list = xchg(head, NULL);
while (list != NULL) {
struct irq_work *entry = list;
list = irq_work_next(list);
/*
* Clear the PENDING bit, after this point the @entry
* can be re-used.
*/
entry->next = next_flags(NULL, IRQ_WORK_BUSY);
entry->func(entry);
/*
* Clear the BUSY bit and return to the free state if
* no-one else claimed it meanwhile.
*/
cmpxchg(&entry->next, next_flags(NULL, IRQ_WORK_BUSY), NULL);
}
}
EXPORT_SYMBOL_GPL(irq_work_run);
/*
* Synchronize against the irq_work @entry, ensures the entry is not
* currently in use.
*/
void irq_work_sync(struct irq_work *entry)
{
WARN_ON_ONCE(irqs_disabled());
while (irq_work_is_set(entry, IRQ_WORK_BUSY))
cpu_relax();
}
EXPORT_SYMBOL_GPL(irq_work_sync);

104
kernel/perf_event.c
View File

@ -2206,12 +2206,11 @@ static void free_event_rcu(struct rcu_head *head)
kfree(event);
}
static void perf_pending_sync(struct perf_event *event);
static void perf_buffer_put(struct perf_buffer *buffer);
static void free_event(struct perf_event *event)
{
perf_pending_sync(event);
irq_work_sync(&event->pending);
if (!event->parent) {
atomic_dec(&nr_events);
@ -3162,16 +3161,7 @@ void perf_event_wakeup(struct perf_event *event)
}
}
/*
* Pending wakeups
*
* Handle the case where we need to wakeup up from NMI (or rq->lock) context.
*
* The NMI bit means we cannot possibly take locks. Therefore, maintain a
* single linked list and use cmpxchg() to add entries lockless.
*/
static void perf_pending_event(struct perf_pending_entry *entry)
static void perf_pending_event(struct irq_work *entry)
{
struct perf_event *event = container_of(entry,
struct perf_event, pending);
@ -3187,89 +3177,6 @@ static void perf_pending_event(struct perf_pending_entry *entry)
}
}
#define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
PENDING_TAIL,
};
static void perf_pending_queue(struct perf_pending_entry *entry,
void (*func)(struct perf_pending_entry *))
{
struct perf_pending_entry **head;
if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
return;
entry->func = func;
head = &get_cpu_var(perf_pending_head);
do {
entry->next = *head;
} while (cmpxchg(head, entry->next, entry) != entry->next);
set_perf_event_pending();
put_cpu_var(perf_pending_head);
}
static int __perf_pending_run(void)
{
struct perf_pending_entry *list;
int nr = 0;
list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
while (list != PENDING_TAIL) {
void (*func)(struct perf_pending_entry *);
struct perf_pending_entry *entry = list;
list = list->next;
func = entry->func;
entry->next = NULL;
/*
* Ensure we observe the unqueue before we issue the wakeup,
* so that we won't be waiting forever.
* -- see perf_not_pending().
*/
smp_wmb();
func(entry);
nr++;
}
return nr;
}
static inline int perf_not_pending(struct perf_event *event)
{
/*
* If we flush on whatever cpu we run, there is a chance we don't
* need to wait.
*/
get_cpu();
__perf_pending_run();
put_cpu();
/*
* Ensure we see the proper queue state before going to sleep
* so that we do not miss the wakeup. -- see perf_pending_handle()
*/
smp_rmb();
return event->pending.next == NULL;
}
static void perf_pending_sync(struct perf_event *event)
{
wait_event(event->waitq, perf_not_pending(event));
}
void perf_event_do_pending(void)
{
__perf_pending_run();
}
/*
* We assume there is only KVM supporting the callbacks.
* Later on, we might change it to a list if there is
@ -3319,8 +3226,7 @@ static void perf_output_wakeup(struct perf_output_handle *handle)
if (handle->nmi) {
handle->event->pending_wakeup = 1;
perf_pending_queue(&handle->event->pending,
perf_pending_event);
irq_work_queue(&handle->event->pending);
} else
perf_event_wakeup(handle->event);
}
@ -4356,8 +4262,7 @@ static int __perf_event_overflow(struct perf_event *event, int nmi,
event->pending_kill = POLL_HUP;
if (nmi) {
event->pending_disable = 1;
perf_pending_queue(&event->pending,
perf_pending_event);
irq_work_queue(&event->pending);
} else
perf_event_disable(event);
}
@ -5374,6 +5279,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
INIT_LIST_HEAD(&event->event_entry);
INIT_LIST_HEAD(&event->sibling_list);
init_waitqueue_head(&event->waitq);
init_irq_work(&event->pending, perf_pending_event);
mutex_init(&event->mmap_mutex);

7
kernel/timer.c
View File

@ -37,7 +37,7 @@
#include <linux/delay.h>
#include <linux/tick.h>
#include <linux/kallsyms.h>
#include <linux/perf_event.h>
#include <linux/irq_work.h>
#include <linux/sched.h>
#include <linux/slab.h>
@ -1279,7 +1279,10 @@ void update_process_times(int user_tick)
run_local_timers();
rcu_check_callbacks(cpu, user_tick);
printk_tick();
perf_event_do_pending();
#ifdef CONFIG_IRQ_WORK
if (in_irq())
irq_work_run();
#endif
scheduler_tick();
run_posix_cpu_timers(p);
}