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Subject[PATCH RFC v2 1/4] perf/core: IRQ-bound performance events
Date
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
---
include/linux/irq.h | 10 +
include/linux/irqdesc.h | 4 +
include/linux/perf_event.h | 24 +++
include/uapi/linux/perf_event.h | 15 ++-
kernel/events/Makefile | 2 +-
kernel/events/core.c | 176 +++++++++++++++++--
kernel/events/hardirq.c | 370 +++++++++++++++++++++++++++++++++++++++
kernel/irq/handle.c | 7 +-
kernel/irq/irqdesc.c | 15 ++
9 files changed, 609 insertions(+), 14 deletions(-)
create mode 100644 kernel/events/hardirq.c

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 7dc1003..c79bbbd 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -632,6 +632,16 @@ static inline int irq_reserve_irq(unsigned int irq)
# define irq_reg_readl(addr) readl(addr)
#endif

+#ifdef CONFIG_PERF_EVENTS
+extern void perf_start_hardirq_events(struct irq_desc *desc, int action_nr);
+extern void perf_stop_hardirq_events(struct irq_desc *desc, int action_nr);
+#else
+static inline void
+perf_start_hardirq_events(struct irq_desc *desc, int action_nr) { }
+static inline void
+perf_stop_hardirq_events(struct irq_desc *desc, int action_nr) { }
+#endif
+
/**
* struct irq_chip_regs - register offsets for struct irq_gci
* @enable: Enable register offset to reg_base
diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index 56fb646..00a2759 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -12,6 +12,7 @@ struct irq_affinity_notify;
struct proc_dir_entry;
struct module;
struct irq_desc;
+struct hardirq_events;

/**
* struct irq_desc - interrupt descriptor
@@ -68,6 +69,9 @@ struct irq_desc {
struct proc_dir_entry *dir;
#endif
int parent_irq;
+#ifdef CONFIG_PERF_EVENTS
+ struct hardirq_events __percpu **events;
+#endif
struct module *owner;
const char *name;
} ____cacheline_internodealigned_in_smp;
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8f4a70f..8bd7860 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -215,6 +215,12 @@ struct pmu {
void (*stop) (struct perf_event *event, int flags);

/*
+ * Start/Stop hardware interrupt context counters present on the PMU.
+ */
+ void (*start_hardirq) (struct perf_event *events[], int count); /* optional */
+ void (*stop_hardirq) (struct perf_event *events[], int count); /* optional */
+
+ /*
* Updates the counter value of the event.
*/
void (*read) (struct perf_event *event);
@@ -313,6 +319,11 @@ struct perf_event {
struct list_head sibling_list;

/*
+ * List of hardware interrupt context numbers and actions
+ */
+ struct list_head hardirq_list;
+
+ /*
* We need storage to track the entries in perf_pmu_migrate_context; we
* cannot use the event_entry because of RCU and we want to keep the
* group in tact which avoids us using the other two entries.
@@ -528,6 +539,12 @@ struct perf_output_handle {
int page;
};

+struct perf_hardirq_param {
+ struct list_head list;
+ int irq;
+ unsigned long mask;
+};
+
#ifdef CONFIG_PERF_EVENTS

extern int perf_pmu_register(struct pmu *pmu, const char *name, int type);
@@ -635,6 +652,11 @@ static inline int is_software_event(struct perf_event *event)
return event->pmu->task_ctx_nr == perf_sw_context;
}

+static inline bool is_hardirq_event(struct perf_event *event)
+{
+ return event->attr.hardirq != 0;
+}
+
extern struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];

extern void __perf_sw_event(u32, u64, struct pt_regs *, u64);
@@ -772,6 +794,8 @@ extern void perf_event_enable(struct perf_event *event);
extern void perf_event_disable(struct perf_event *event);
extern int __perf_event_disable(void *info);
extern void perf_event_task_tick(void);
+extern int perf_event_init_hardirq(void *info);
+extern int perf_event_term_hardirq(void *info);
#else
static inline void
perf_event_task_sched_in(struct task_struct *prev,
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index e1802d6..a033014 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -301,8 +301,9 @@ struct perf_event_attr {
exclude_callchain_kernel : 1, /* exclude kernel callchains */
exclude_callchain_user : 1, /* exclude user callchains */
mmap2 : 1, /* include mmap with inode data */
+ hardirq : 1,

- __reserved_1 : 40;
+ __reserved_1 : 39;

union {
__u32 wakeup_events; /* wakeup every n events */
@@ -348,6 +349,7 @@ struct perf_event_attr {
#define PERF_EVENT_IOC_SET_OUTPUT _IO ('$', 5)
#define PERF_EVENT_IOC_SET_FILTER _IOW('$', 6, char *)
#define PERF_EVENT_IOC_ID _IOR('$', 7, __u64 *)
+#define PERF_EVENT_IOC_SET_HARDIRQ _IOR('$', 8, __u64 *)

enum perf_event_ioc_flags {
PERF_IOC_FLAG_GROUP = 1U << 0,
@@ -724,6 +726,7 @@ enum perf_callchain_context {
#define PERF_FLAG_FD_NO_GROUP (1U << 0)
#define PERF_FLAG_FD_OUTPUT (1U << 1)
#define PERF_FLAG_PID_CGROUP (1U << 2) /* pid=cgroup id, per-cpu mode only */
+#define PERF_FLAG_PID_HARDIRQ (1U << 3) /* pid=irq number */

union perf_mem_data_src {
__u64 val;
@@ -812,4 +815,14 @@ struct perf_branch_entry {
reserved:60;
};

+struct perf_hardirq_disp {
+ __s32 irq_nr;
+ __u64 actions;
+};
+
+struct perf_hardirq_event_disp {
+ __s32 nr_disp; /* everything if <0 */
+ struct perf_hardirq_disp disp[0];
+};
+
#endif /* _UAPI_LINUX_PERF_EVENT_H */
diff --git a/kernel/events/Makefile b/kernel/events/Makefile
index 103f5d1..8b94980 100644
--- a/kernel/events/Makefile
+++ b/kernel/events/Makefile
@@ -2,7 +2,7 @@ ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_core.o = -pg
endif

-obj-y := core.o ring_buffer.o callchain.o
+obj-y := core.o ring_buffer.o callchain.o hardirq.o

obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_UPROBES) += uprobes.o
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 89d34f9..465ce681 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -118,8 +118,9 @@ static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
}

#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
- PERF_FLAG_FD_OUTPUT |\
- PERF_FLAG_PID_CGROUP)
+ PERF_FLAG_FD_OUTPUT |\
+ PERF_FLAG_PID_CGROUP |\
+ PERF_FLAG_PID_HARDIRQ)

/*
* branch priv levels that need permission checks
@@ -3213,10 +3214,46 @@ static void __free_event(struct perf_event *event)

call_rcu(&event->rcu_head, free_event_rcu);
}
+
+static int __perf_hardirq_add_disp(struct perf_event *event,
+ struct perf_hardirq_disp *disp)
+{
+ struct perf_hardirq_param *param = kmalloc_node(sizeof(*param),
+ GFP_KERNEL, cpu_to_node(event->cpu));
+ if (!param)
+ return -ENOMEM;
+
+ param->irq = disp->irq_nr;
+
+ if (disp->actions == (typeof(disp->actions))-1)
+ param->mask = -1;
+ else
+ param->mask = disp->actions;
+
+ list_add(&param->list, &event->hardirq_list);
+
+ return 0;
+}
+
+static void __perf_hardirq_del_disps(struct perf_event *event)
+{
+ struct perf_hardirq_param *param;
+ struct list_head *pos, *next;
+
+ list_for_each_safe(pos, next, &event->hardirq_list) {
+ param = list_entry(pos, typeof(*param), list);
+ list_del(pos);
+ kfree(param);
+ }
+}
+
static void free_event(struct perf_event *event)
{
irq_work_sync(&event->pending);

+ cpu_function_call(event->cpu, perf_event_term_hardirq, event);
+ __perf_hardirq_del_disps(event);
+
unaccount_event(event);

if (event->rb) {
@@ -3590,6 +3627,7 @@ static inline int perf_fget_light(int fd, struct fd *p)
static int perf_event_set_output(struct perf_event *event,
struct perf_event *output_event);
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
+static int perf_event_set_hardirq(struct perf_event *event, void __user *arg);

static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
@@ -3644,6 +3682,9 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case PERF_EVENT_IOC_SET_FILTER:
return perf_event_set_filter(event, (void __user *)arg);

+ case PERF_EVENT_IOC_SET_HARDIRQ:
+ return perf_event_set_hardirq(event, (void __user *)arg);
+
default:
return -ENOTTY;
}
@@ -6248,6 +6289,10 @@ static void perf_pmu_nop_void(struct pmu *pmu)
{
}

+static void perf_pmu_nop_void_arg1_arg2(struct perf_event *events[], int count)
+{
+}
+
static int perf_pmu_nop_int(struct pmu *pmu)
{
return 0;
@@ -6511,6 +6556,11 @@ got_cpu_context:
pmu->pmu_disable = perf_pmu_nop_void;
}

+ if (!pmu->start_hardirq) {
+ pmu->start_hardirq = perf_pmu_nop_void_arg1_arg2;
+ pmu->stop_hardirq = perf_pmu_nop_void_arg1_arg2;
+ }
+
if (!pmu->event_idx)
pmu->event_idx = perf_event_idx_default;

@@ -6668,6 +6718,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
INIT_LIST_HEAD(&event->group_entry);
INIT_LIST_HEAD(&event->event_entry);
INIT_LIST_HEAD(&event->sibling_list);
+ INIT_LIST_HEAD(&event->hardirq_list);
INIT_LIST_HEAD(&event->rb_entry);
INIT_LIST_HEAD(&event->active_entry);

@@ -6977,6 +7028,7 @@ SYSCALL_DEFINE5(perf_event_open,
struct fd group = {NULL, 0};
struct task_struct *task = NULL;
struct pmu *pmu;
+ int hardirq = -1;
int event_fd;
int move_group = 0;
int err;
@@ -6985,6 +7037,27 @@ SYSCALL_DEFINE5(perf_event_open,
if (flags & ~PERF_FLAG_ALL)
return -EINVAL;

+ if ((flags & (PERF_FLAG_PID_CGROUP | PERF_FLAG_PID_HARDIRQ)) ==
+ (PERF_FLAG_PID_CGROUP | PERF_FLAG_PID_HARDIRQ))
+ return -EINVAL;
+
+ /*
+ * In irq mode, the pid argument is used to pass irq number.
+ */
+ if (flags & PERF_FLAG_PID_HARDIRQ) {
+ hardirq = pid;
+ pid = -1;
+ }
+
+ /*
+ * In cgroup mode, the pid argument is used to pass the fd
+ * opened to the cgroup directory in cgroupfs. The cpu argument
+ * designates the cpu on which to monitor threads from that
+ * cgroup.
+ */
+ if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
+ return -EINVAL;
+
err = perf_copy_attr(attr_uptr, &attr);
if (err)
return err;
@@ -6999,15 +7072,6 @@ SYSCALL_DEFINE5(perf_event_open,
return -EINVAL;
}

- /*
- * In cgroup mode, the pid argument is used to pass the fd
- * opened to the cgroup directory in cgroupfs. The cpu argument
- * designates the cpu on which to monitor threads from that
- * cgroup.
- */
- if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
- return -EINVAL;
-
event_fd = get_unused_fd();
if (event_fd < 0)
return event_fd;
@@ -7874,6 +7938,96 @@ static void perf_event_exit_cpu(int cpu)
static inline void perf_event_exit_cpu(int cpu) { }
#endif

+static int __perf_hardirq_check_disp(struct perf_hardirq_disp *disp)
+{
+ struct irq_desc *desc = irq_to_desc(disp->irq_nr);
+ struct irqaction *action;
+ int nr_actions = 0;
+ unsigned long flags;
+
+ if (!desc)
+ return -ENOENT;
+
+ if (!disp->actions)
+ return -EINVAL;
+
+ /*
+ * -1 means all actions
+ */
+ if (disp->actions == (typeof(disp->actions))-1)
+ return 0;
+
+ /*
+ * Check actions existence
+ */
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ for (action = desc->action; action; action = action->next)
+ nr_actions++;
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ if (!nr_actions)
+ return -ENOENT;
+
+ if (__fls(disp->actions) + 1 > nr_actions)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int perf_event_set_hardirq(struct perf_event *event, void __user *arg)
+{
+ struct perf_hardirq_event_disp edisp;
+ struct perf_hardirq_disp idisp;
+ struct perf_hardirq_disp __user *user;
+ struct perf_hardirq_param *param;
+ int ret = 0;
+ int i;
+
+ if (copy_from_user(&edisp, arg, sizeof(edisp.nr_disp)))
+ return -EFAULT;
+
+ /*
+ * TODO Run counters for all actions on all IRQs
+ */
+ if (edisp.nr_disp == (typeof(edisp.nr_disp))-1)
+ return -EINVAL;
+
+ user = arg + offsetof(typeof(edisp), disp);
+ for (i = 0; i < edisp.nr_disp; i++) {
+ if (copy_from_user(&idisp, &user[i], sizeof(idisp))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ /*
+ * Multiple entries against one IRQ are not allowed
+ */
+ list_for_each_entry(param, &event->hardirq_list, list) {
+ if (param->irq == idisp.irq_nr)
+ return -EINVAL;
+ }
+
+ ret = __perf_hardirq_check_disp(&idisp);
+ if (ret)
+ goto err;
+
+ ret = __perf_hardirq_add_disp(event, &idisp);
+ if (ret)
+ goto err;
+ }
+
+ ret = cpu_function_call(event->cpu, perf_event_init_hardirq, event);
+ if (ret)
+ goto err;
+
+ return 0;
+
+err:
+ __perf_hardirq_del_disps(event);
+
+ return ret;
+}
+
static int
perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
{
diff --git a/kernel/events/hardirq.c b/kernel/events/hardirq.c
new file mode 100644
index 0000000..f857be3
--- /dev/null
+++ b/kernel/events/hardirq.c
@@ -0,0 +1,370 @@
+/*
+ * linux/kernel/events/hardirq.c
+ *
+ * Copyright (C) 2012-2014 Red Hat, Inc., Alexander Gordeev
+ *
+ * This file contains the code for h/w interrupt context performance counters
+ */
+
+#include <linux/perf_event.h>
+#include <linux/irq.h>
+#include <linux/percpu.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+
+struct hardirq_event {
+ unsigned long mask; /* action numbers to count on */
+ struct perf_event *event; /* event to count */
+};
+
+struct hardirq_events {
+ int nr_events; /* number of events in array */
+ struct hardirq_event events[0]; /* array of events to count */
+};
+
+struct active_events {
+ int nr_events; /* number of allocated events */
+ int nr_active; /* number of events to count */
+ struct perf_event *events[0]; /* array of events to count */
+};
+
+DEFINE_PER_CPU(struct active_events *, active_events);
+DEFINE_PER_CPU(int, total_events);
+
+static struct hardirq_events *alloc_desc_events(int cpu, int count)
+{
+ struct hardirq_events *events;
+ size_t size;
+
+ size = offsetof(typeof(*events), events) +
+ count * sizeof(events->events[0]);
+ events = kmalloc_node(size, GFP_KERNEL, cpu_to_node(cpu));
+ if (unlikely(!events))
+ return NULL;
+
+ events->nr_events = count;
+
+ return events;
+}
+
+static void free_desc_events(struct hardirq_events *events)
+{
+ kfree(events);
+}
+
+static struct active_events *alloc_active_events(int cpu, int count)
+{
+ struct active_events *active;
+ size_t size;
+
+ size = offsetof(typeof(*active), events) +
+ count * sizeof(active->events[0]);
+ active = kmalloc_node(size, GFP_KERNEL, cpu_to_node(cpu));
+ if (unlikely(!active))
+ return NULL;
+
+ active->nr_events = count;
+
+ return active;
+}
+
+static void free_active_events(struct active_events *active)
+{
+ kfree(active);
+}
+
+static int compare_pmus(const void *event1, const void *event2)
+{
+ return strcmp(((const struct hardirq_event *)event1)->event->pmu->name,
+ ((const struct hardirq_event *)event2)->event->pmu->name);
+}
+
+static int max_active_events(struct hardirq_events *events)
+{
+ /*
+ * TODO Count number of events per action and return the maximum
+ */
+ return events->nr_events;
+}
+
+static int add_event(struct perf_event *event, int irq, unsigned long mask)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ struct hardirq_events __percpu **events_ptr;
+ struct hardirq_events *events, *events_tmp = NULL;
+ struct active_events __percpu *active;
+ struct active_events *active_tmp = NULL;
+ int cpu, max_active, nr_events;
+ unsigned long flags;
+ int ret = 0;
+
+ if (!desc)
+ return -ENOENT;
+
+ cpu = get_cpu();
+ BUG_ON(cpu != event->cpu);
+
+ events_ptr = this_cpu_ptr(desc->events);
+ events = *events_ptr;
+
+ nr_events = events ? events->nr_events : 0;
+ events_tmp = alloc_desc_events(cpu, nr_events + 1);
+ if (!events_tmp) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ memmove(events_tmp->events, events->events,
+ nr_events * sizeof(events_tmp->events[0]));
+
+ events_tmp->events[nr_events].event = event;
+ events_tmp->events[nr_events].mask = mask;
+
+ /*
+ * Group events that belong to same PMUs in contiguous sub-arrays
+ */
+ sort(events_tmp->events, events_tmp->nr_events,
+ sizeof(events_tmp->events[0]), compare_pmus, NULL);
+
+ max_active = max_active_events(events_tmp);
+ active = this_cpu_read(active_events);
+
+ if (!active || max_active > active->nr_active) {
+ active_tmp = alloc_active_events(cpu, max_active);
+ if (!active_tmp) {
+ ret = -ENOMEM;
+ goto err;
+ }
+ }
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+
+ swap(events, events_tmp);
+ *events_ptr = events;
+
+ if (active_tmp) {
+ swap(active, active_tmp);
+ this_cpu_write(active_events, active);
+ }
+
+ __this_cpu_inc(total_events);
+
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+err:
+ put_cpu();
+
+ free_active_events(active_tmp);
+ free_desc_events(events_tmp);
+
+ return ret;
+}
+
+static int del_event(struct perf_event *event, int irq)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ struct hardirq_events __percpu **events_ptr;
+ struct hardirq_events *events, *events_tmp = NULL;
+ struct active_events __percpu *active;
+ struct active_events *active_tmp = NULL;
+ int cpu, i, nr_events;
+ unsigned long flags;
+ int ret = 0;
+
+ if (!desc)
+ return -ENOENT;
+
+ cpu = get_cpu();
+ BUG_ON(cpu != event->cpu);
+
+ events_ptr = this_cpu_ptr(desc->events);
+ events = *events_ptr;
+
+ nr_events = events->nr_events;
+ for (i = 0; i < nr_events; i++) {
+ if (events->events[i].event == event)
+ break;
+ }
+
+ if (i >= nr_events) {
+ ret = -ENOENT;
+ goto err;
+ }
+
+ if (nr_events > 1) {
+ events_tmp = alloc_desc_events(cpu, nr_events - 1);
+ if (!events_tmp) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ memmove(&events_tmp->events[0], &events->events[0],
+ i * sizeof(events->events[0]));
+ memmove(&events_tmp->events[i], &events->events[i + 1],
+ (nr_events - i - 1) * sizeof(events->events[0]));
+ }
+
+ active = this_cpu_read(active_events);
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+
+ if (!__this_cpu_dec_return(total_events)) {
+ swap(active, active_tmp);
+ this_cpu_write(active_events, active);
+ }
+
+ swap(events, events_tmp);
+ *events_ptr = events;
+
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+err:
+ put_cpu();
+
+ free_active_events(active_tmp);
+ free_desc_events(events_tmp);
+
+ return ret;
+}
+
+int perf_event_init_hardirq(void *info)
+{
+ struct perf_event *event = info;
+ struct perf_hardirq_param *param, *param_tmp;
+ int ret = 0;
+
+ list_for_each_entry(param, &event->hardirq_list, list) {
+ ret = add_event(event, param->irq, param->mask);
+ if (ret)
+ break;
+ }
+
+ if (ret) {
+ list_for_each_entry(param_tmp, &event->hardirq_list, list) {
+ if (param == param_tmp)
+ break;
+ del_event(event, param_tmp->irq);
+ }
+ }
+
+ WARN_ON(ret);
+ return ret;
+}
+
+int perf_event_term_hardirq(void *info)
+{
+ struct perf_event *event = info;
+ struct perf_hardirq_param *param;
+ int ret_tmp, ret = 0;
+
+ list_for_each_entry(param, &event->hardirq_list, list) {
+ ret_tmp = del_event(event, param->irq);
+ if (!ret)
+ ret = ret_tmp;
+ }
+
+ WARN_ON(ret);
+ return ret;
+}
+
+static void update_active_events(struct active_events *active,
+ struct hardirq_events *events,
+ int action_nr)
+{
+ int i, nr_active = 0;
+
+ for (i = 0; i < events->nr_events; i++) {
+ struct hardirq_event *event = &events->events[i];
+
+ if (test_bit(action_nr, &event->mask)) {
+ active->events[nr_active] = event->event;
+ nr_active++;
+ }
+ }
+
+ active->nr_active = nr_active;
+}
+
+int perf_alloc_hardirq_events(struct irq_desc *desc)
+{
+ desc->events = alloc_percpu(struct hardirq_events*);
+ if (!desc->events)
+ return -ENOMEM;
+ return 0;
+}
+
+void perf_free_hardirq_events(struct irq_desc *desc)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ BUG_ON(*per_cpu_ptr(desc->events, cpu));
+
+ free_percpu(desc->events);
+}
+
+static void start_stop_events(struct perf_event *events[], int count, bool start)
+{
+ /*
+ * All events in the list must belong to the same PMU
+ */
+ struct pmu *pmu = events[0]->pmu;
+
+ if (start)
+ pmu->start_hardirq(events, count);
+ else
+ pmu->stop_hardirq(events, count);
+}
+
+static void start_stop_active(struct active_events *active, bool start)
+{
+ struct perf_event **first, **last;
+ int i;
+
+ first = last = active->events;
+
+ for (i = 0; i < active->nr_active; i++) {
+ if ((*last)->pmu != (*first)->pmu) {
+ start_stop_events(first, last - first, start);
+ first = last;
+ }
+ last++;
+ }
+
+ start_stop_events(first, last - first, start);
+}
+
+static void start_stop_desc(struct irq_desc *desc, int action_nr, bool start)
+{
+ struct hardirq_events __percpu *events;
+ struct active_events __percpu *active;
+
+ events = *__this_cpu_ptr(desc->events);
+ if (likely(!events))
+ return;
+
+ active = __this_cpu_read(active_events);
+
+ /*
+ * Assume events to run do not change between start and stop,
+ * thus no reason to update active events when stopping.
+ */
+ if (start)
+ update_active_events(active, events, action_nr);
+
+ if (!active->nr_active)
+ return;
+
+ start_stop_active(active, start);
+}
+
+void perf_start_hardirq_events(struct irq_desc *desc, int action_nr)
+{
+ start_stop_desc(desc, action_nr, true);
+}
+
+void perf_stop_hardirq_events(struct irq_desc *desc, int action_nr)
+{
+ start_stop_desc(desc, action_nr, false);
+}
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 131ca17..7feab55 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -133,13 +133,17 @@ irqreturn_t
handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action)
{
irqreturn_t retval = IRQ_NONE;
- unsigned int flags = 0, irq = desc->irq_data.irq;
+ unsigned int flags = 0, irq = desc->irq_data.irq, action_nr = 0;

do {
irqreturn_t res;

trace_irq_handler_entry(irq, action);
+ perf_start_hardirq_events(desc, action_nr);
+
res = action->handler(irq, action->dev_id);
+
+ perf_stop_hardirq_events(desc, action_nr);
trace_irq_handler_exit(irq, action, res);

if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n",
@@ -170,6 +174,7 @@ handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action)

retval |= res;
action = action->next;
+ action_nr++;
} while (action);

add_interrupt_randomness(irq, flags);
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 192a302..cd02b29 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -131,6 +131,14 @@ static void free_masks(struct irq_desc *desc)
static inline void free_masks(struct irq_desc *desc) { }
#endif

+#ifdef CONFIG_PERF_EVENTS
+extern int perf_alloc_hardirq_events(struct irq_desc *desc);
+extern void perf_free_hardirq_events(struct irq_desc *desc);
+#else
+static inline int perf_alloc_hardirq_events(struct irq_desc *desc) { return 0; }
+static inline void perf_free_hardirq_events(struct irq_desc *desc) { }
+#endif
+
static struct irq_desc *alloc_desc(int irq, int node, struct module *owner)
{
struct irq_desc *desc;
@@ -147,6 +155,10 @@ static struct irq_desc *alloc_desc(int irq, int node, struct module *owner)
if (alloc_masks(desc, gfp, node))
goto err_kstat;

+ if (perf_alloc_hardirq_events(desc))
+ goto err_masks;
+
+
raw_spin_lock_init(&desc->lock);
lockdep_set_class(&desc->lock, &irq_desc_lock_class);

@@ -154,6 +166,8 @@ static struct irq_desc *alloc_desc(int irq, int node, struct module *owner)

return desc;

+err_masks:
+ free_masks(desc);
err_kstat:
free_percpu(desc->kstat_irqs);
err_desc:
@@ -171,6 +185,7 @@ static void free_desc(unsigned int irq)
delete_irq_desc(irq);
mutex_unlock(&sparse_irq_lock);

+ perf_free_hardirq_events(desc);
free_masks(desc);
free_percpu(desc->kstat_irqs);
kfree(desc);
--
1.7.7.6


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