Adding new ioctl PERF_EVENT_IOC_SET_TOGGLE to interface
the toggle settings for event.
This ioctl has 2 goals:
- allowing the toggle event being part of the group
- allowing to define toggle setting after event
is created
The ioctl interface is:
u64 args[2] = { toggled_fd, flag };
err = ioctl(fd, PERF_EVENT_IOC_SET_TOGGLE, args);
Where:
toggled_fd - is file description of the event we want to toggle
flag - is one of PERF_FLAG_TOGGLE_ON|PERF_FLAG_TOGGLE_OFF
err - 0 when successful
-1 otherwise with errno:
EBUSY - event has already toggled event defined
EFAULT - could not copy user data
EINVAL - wrong data
Signed-off-by: Jiri Olsa <jo...@redhat.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Corey Ashford <cjash...@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Ingo Molnar <mi...@elte.hu>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
---
include/uapi/linux/perf_event.h | 1 +
kernel/events/core.c | 40 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 41 insertions(+)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index ecb0474..b941c21 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -325,6 +325,7 @@ 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('$', 7, u64 *)
+#define PERF_EVENT_IOC_SET_TOGGLE _IOW('$', 8, u64 *)
enum perf_event_ioc_flags {
PERF_IOC_FLAG_GROUP = 1U << 0,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 40c792d..b41a0d8 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3575,6 +3575,7 @@ 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_toggle_fd(struct perf_event *event, u64 __user *arg);
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
@@ -3629,6 +3630,9 @@ 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_TOGGLE:
+ return perf_event_set_toggle_fd(event, (u64 __user *)arg);
+
default:
return -ENOTTY;
}
@@ -7017,6 +7021,42 @@ perf_event_set_toggle(struct perf_event *event,
return 0;
}
+static int perf_event_set_toggle_fd(struct perf_event *event, u64 __user *arg)
+{
+ struct perf_event *toggled_event;
+ struct fd toggled_fd = { NULL, 0 };
+ u64 fd, flag;
+ int err;
+
+ if (event->toggled_event)
+ return -EBUSY;
+
+ if (copy_from_user(&fd, arg, sizeof(fd)))
+ return -EFAULT;
+
+ if (copy_from_user(&flag, arg + 1, sizeof(flag)))
+ return -EFAULT;
+
+ err = perf_fget_light((int) fd, &toggled_fd);
+ if (err)
+ return -EINVAL;
+
+ toggled_event = toggled_fd.file->private_data;
+
+ if (!atomic_long_inc_not_zero(&toggled_event->refcount)) {
+ fdput(toggled_fd);
+ return -EINVAL;
+ }
+
+ err = perf_event_set_toggle(event, toggled_event, event->ctx, flag);
+ if (err)
+ put_event(toggled_event);
+
+ fdput(toggled_fd);
+ return err;
+}
+
+
/**
* sys_perf_event_open - open a performance event, associate it to a task/cpu
*
--
1.7.11.7
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
