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perf: Sysfs enumeration

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Simple sysfs emumeration of the PMUs.

Use a "event_source" bus, and add PMU devices using their name.

Each PMU device has a type attribute which contrains the value needed
for perf_event_attr::type to identify this PMU.

This is the minimal stub needed to start using this interface,
we'll consider extending the sysfs usage later.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101117222056.316982569@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-11-17 23:17:37 +01:00 committed by Ingo Molnar
parent 2e80a82a49
commit abe4340057
2 changed files with 95 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
include/linux/perf_event.h
View file

@ -588,6 +588,7 @@ struct perf_event;
struct pmu {
struct list_head entry;
struct device *dev;
char *name;
int type;

95
kernel/perf_event.c
View file

@ -24,6 +24,7 @@
#include <linux/ptrace.h>
#include <linux/reboot.h>
#include <linux/vmstat.h>
#include <linux/device.h>
#include <linux/vmalloc.h>
#include <linux/hardirq.h>
#include <linux/rculist.h>
@ -5308,6 +5309,58 @@ static void free_pmu_context(struct pmu *pmu)
}
static struct idr pmu_idr;
static ssize_t
type_show(struct device *dev, struct device_attribute *attr, char *page)
{
struct pmu *pmu = dev_get_drvdata(dev);
return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
}
static struct device_attribute pmu_dev_attrs[] = {
__ATTR_RO(type),
__ATTR_NULL,
};
static int pmu_bus_running;
static struct bus_type pmu_bus = {
.name = "event_source",
.dev_attrs = pmu_dev_attrs,
};
static void pmu_dev_release(struct device *dev)
{
kfree(dev);
}
static int pmu_dev_alloc(struct pmu *pmu)
{
int ret = -ENOMEM;
pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
if (!pmu->dev)
goto out;
device_initialize(pmu->dev);
ret = dev_set_name(pmu->dev, "%s", pmu->name);
if (ret)
goto free_dev;
dev_set_drvdata(pmu->dev, pmu);
pmu->dev->bus = &pmu_bus;
pmu->dev->release = pmu_dev_release;
ret = device_add(pmu->dev);
if (ret)
goto free_dev;
out:
return ret;
free_dev:
put_device(pmu->dev);
goto out;
}
int perf_pmu_register(struct pmu *pmu, char *name, int type)
{
int cpu, ret;
@ -5336,6 +5389,12 @@ int perf_pmu_register(struct pmu *pmu, char *name, int type)
}
pmu->type = type;
if (pmu_bus_running) {
ret = pmu_dev_alloc(pmu);
if (ret)
goto free_idr;
}
skip_type:
pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
if (pmu->pmu_cpu_context)
@ -5343,7 +5402,7 @@ int perf_pmu_register(struct pmu *pmu, char *name, int type)
pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
if (!pmu->pmu_cpu_context)
goto free_ird;
goto free_dev;
for_each_possible_cpu(cpu) {
struct perf_cpu_context *cpuctx;
@ -5387,6 +5446,10 @@ int perf_pmu_register(struct pmu *pmu, char *name, int type)
return ret;
free_dev:
device_del(pmu->dev);
put_device(pmu->dev);
free_idr:
if (pmu->type >= PERF_TYPE_MAX)
idr_remove(&pmu_idr, pmu->type);
@ -5412,6 +5475,8 @@ void perf_pmu_unregister(struct pmu *pmu)
free_percpu(pmu->pmu_disable_count);
if (pmu->type >= PERF_TYPE_MAX)
idr_remove(&pmu_idr, pmu->type);
device_del(pmu->dev);
put_device(pmu->dev);
free_pmu_context(pmu);
}
@ -6603,3 +6668,31 @@ void __init perf_event_init(void)
ret = init_hw_breakpoint();
WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
}
static int __init perf_event_sysfs_init(void)
{
struct pmu *pmu;
int ret;
mutex_lock(&pmus_lock);
ret = bus_register(&pmu_bus);
if (ret)
goto unlock;
list_for_each_entry(pmu, &pmus, entry) {
if (!pmu->name || pmu->type < 0)
continue;
ret = pmu_dev_alloc(pmu);
WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
}
pmu_bus_running = 1;
ret = 0;
unlock:
mutex_unlock(&pmus_lock);
return ret;
}
device_initcall(perf_event_sysfs_init);