[RFC 5/5] Use NMI return notifier in perf pending

Huang Ying
2010-06-24T03:05:32Z

Use general NMI return notifier mechanism to replace the self
interrupt used in perf pending.

Known issue: don't know how to deal with SPARC architecture.

Signed-off-by: Huang Ying <ying.huang@intel.com>
---
arch/alpha/include/asm/perf_event.h | 1
arch/arm/include/asm/perf_event.h | 12 -----
arch/parisc/include/asm/perf_event.h | 1
arch/powerpc/kernel/time.c | 5 --
arch/s390/include/asm/perf_event.h | 3 -
arch/sh/include/asm/perf_event.h | 5 --
arch/sparc/include/asm/perf_event.h | 2
arch/x86/include/asm/entry_arch.h | 4 -
arch/x86/include/asm/hardirq.h | 1
arch/x86/include/asm/irq_vectors.h | 5 --
arch/x86/kernel/cpu/perf_event.c | 19 --------
arch/x86/kernel/entry_64.S | 5 --
arch/x86/kernel/irq.c | 5 --
arch/x86/kernel/irqinit.c | 6 --
include/linux/perf_event.h | 11 ----
kernel/perf_event.c | 81 +++++------------------------------
kernel/timer.c | 2
17 files changed, 15 insertions(+), 153 deletions(-)

--- a/arch/alpha/include/asm/perf_event.h
+++ b/arch/alpha/include/asm/perf_event.h
@@ -2,7 +2,6 @@
#define __ASM_ALPHA_PERF_EVENT_H

/* Alpha only supports software events through this interface. */
-static inline void set_perf_event_pending(void) { }

#define PERF_EVENT_INDEX_OFFSET 0

--- a/arch/arm/include/asm/perf_event.h
+++ b/arch/arm/include/asm/perf_event.h
@@ -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 enabled.
- */
-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
--- a/arch/parisc/include/asm/perf_event.h
+++ b/arch/parisc/include/asm/perf_event.h
@@ -2,6 +2,5 @@
#define __ASM_PARISC_PERF_EVENT_H

/* parisc only supports software events through this interface. */
-static inline void set_perf_event_pending(void) { }

#endif /* __ASM_PARISC_PERF_EVENT_H */
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -635,11 +635,6 @@ void timer_interrupt(struct pt_regs * re

calculate_steal_time();

- if (test_perf_event_pending()) {
- clear_perf_event_pending();
- perf_event_do_pending();
- }
-
#ifdef CONFIG_PPC_ISERIES
if (firmware_has_feature(FW_FEATURE_ISERIES))
get_lppaca()->int_dword.fields.decr_int = 0;
--- a/arch/s390/include/asm/perf_event.h
+++ b/arch/s390/include/asm/perf_event.h
@@ -4,7 +4,4 @@
* Copyright 2009 Martin Schwidefsky, IBM Corporation.
*/

-static inline void set_perf_event_pending(void) {}
-static inline void clear_perf_event_pending(void) {}
-
#define PERF_EVENT_INDEX_OFFSET 0
--- a/arch/sh/include/asm/perf_event.h
+++ b/arch/sh/include/asm/perf_event.h
@@ -26,11 +26,6 @@ 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 */
--- a/arch/sparc/include/asm/perf_event.h
+++ b/arch/sparc/include/asm/perf_event.h
@@ -1,8 +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
--- a/arch/x86/include/asm/entry_arch.h
+++ b/arch/x86/include/asm/entry_arch.h
@@ -49,10 +49,6 @@ BUILD_INTERRUPT(apic_timer_interrupt,LOC
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)
-#endif
-
#ifdef CONFIG_X86_THERMAL_VECTOR
BUILD_INTERRUPT(thermal_interrupt,THERMAL_APIC_VECTOR)
#endif
--- a/arch/x86/include/asm/hardirq.h
+++ b/arch/x86/include/asm/hardirq.h
@@ -15,7 +15,6 @@ typedef struct {
#endif
unsigned int x86_platform_ipis; /* arch dependent */
unsigned int apic_perf_irqs;
- unsigned int apic_pending_irqs;
#ifdef CONFIG_SMP
unsigned int irq_resched_count;
unsigned int irq_call_count;
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -113,11 +113,6 @@
*/
#define X86_PLATFORM_IPI_VECTOR 0xed

-/*
- * Performance monitoring pending work vector:
- */
-#define LOCAL_PENDING_VECTOR 0xec
-
#define UV_BAU_MESSAGE 0xea

/*
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1160,25 +1160,6 @@ static int x86_pmu_handle_irq(struct pt_
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())
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1023,11 +1023,6 @@ 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
-#endif
-
/*
* Exception entry points.
*/
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -73,10 +73,6 @@ static int show_other_interrupts(struct
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");
- for_each_online_cpu(j)
- seq_printf(p, "%10u ", irq_stats(j)->apic_pending_irqs);
- seq_printf(p, " Performance pending work\n");
#endif
if (x86_platform_ipi_callback) {
seq_printf(p, "%*s: ", prec, "PLT");
@@ -192,7 +188,6 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
sum += irq_stats(cpu)->irq_spurious_count;
sum += irq_stats(cpu)->apic_nmi_return_notifier_irqs;
sum += irq_stats(cpu)->apic_perf_irqs;
- sum += irq_stats(cpu)->apic_pending_irqs;
#endif
if (x86_platform_ipi_callback)
sum += irq_stats(cpu)->x86_platform_ipis;
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -223,12 +223,6 @@ static void __init apic_intr_init(void)
/* IPI vectors for APIC spurious and error interrupts */
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);
-# endif
-
#endif
}

--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -484,6 +484,7 @@ struct perf_guest_info_callbacks {
#include <linux/workqueue.h>
#include <linux/ftrace.h>
#include <linux/cpu.h>
+#include <linux/nmi.h>
#include <asm/atomic.h>
#include <asm/local.h>

@@ -608,11 +609,6 @@ struct perf_mmap_data {
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,
@@ -719,7 +715,7 @@ struct perf_event {
int pending_wakeup;
int pending_kill;
int pending_disable;
- struct perf_pending_entry pending;
+ struct nmi_return_notifier pending;

atomic_t event_limit;

@@ -831,8 +827,6 @@ extern void perf_event_task_tick(struct
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 set_perf_event_pending(void);
-extern void perf_event_do_pending(void);
extern void perf_event_print_debug(void);
extern void __perf_disable(void);
extern bool __perf_enable(void);
@@ -1031,7 +1025,6 @@ perf_event_task_tick(struct task_struct
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_do_pending(void) { }
static inline void perf_event_print_debug(void) { }
static inline void perf_disable(void) { }
static inline void perf_enable(void) { }
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -2829,15 +2829,17 @@ void perf_event_wakeup(struct perf_event
*
* 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.
+ * The NMI bit means we cannot possibly take locks. Therefore, use
+ * nmi_return_notifier.
*/

-static void perf_pending_event(struct perf_pending_entry *entry)
+static void perf_pending_event(struct nmi_return_notifier *nrn)
{
- struct perf_event *event = container_of(entry,
+ struct perf_event *event = container_of(nrn,
struct perf_event, pending);

+ nrn->data = NULL;
+
if (event->pending_disable) {
event->pending_disable = 0;
__perf_event_disable(event);
@@ -2849,59 +2851,12 @@ static void perf_pending_event(struct pe
}
}

-#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 *))
+static void perf_pending_queue(struct nmi_return_notifier *nrn,
+ void (*func)(struct nmi_return_notifier *))
{
- 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;
+ nrn->on_nmi_return = func;
+ nrn->data = nrn;
+ nmi_return_notifier_schedule(nrn);
}

static inline int perf_not_pending(struct perf_event *event)
@@ -2911,15 +2866,10 @@ static inline int perf_not_pending(struc
* need to wait.
*/
get_cpu();
- __perf_pending_run();
+ fire_nmi_return_notifiers();
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;
+ return event->pending.data == NULL;
}

static void perf_pending_sync(struct perf_event *event)
@@ -2927,11 +2877,6 @@ static void perf_pending_sync(struct per
wait_event(event->waitq, perf_not_pending(event));
}

-void perf_event_do_pending(void)
-{
- __perf_pending_run();
-}
-
/*
* Callchain support -- arch specific
*/
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -37,7 +37,6 @@
#include <linux/delay.h>
#include <linux/tick.h>
#include <linux/kallsyms.h>
-#include <linux/perf_event.h>
#include <linux/sched.h>
#include <linux/slab.h>

@@ -1264,7 +1263,6 @@ void update_process_times(int user_tick)
run_local_timers();
rcu_check_callbacks(cpu, user_tick);
printk_tick();
- perf_event_do_pending();
scheduler_tick();
run_posix_cpu_timers(p);
}