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Commit 97eaf530 authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

perf/core: Add a callback to perf events 



A simple callback in a perf event can be used for multiple purposes.
For example it is useful for triggered based events like hardware
breakpoints that need a callback to dispatch a triggered breakpoint
event.

v2: Simplify a bit the callback attribution as suggested by Paul
    Mackerras

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "K.Prasad" <prasad@linux.vnet.ibm.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mundt <lethal@linux-sh.org>
parent 41a48d14

include/linux/perf_event.h

+6 −1
Original line number Diff line number Diff line
@@ -544,6 +544,8 @@ struct perf_pending_entry { 
	void (*func)(struct perf_pending_entry *);

};



typedef void (*perf_callback_t)(struct perf_event *, void *);



/**

 * struct perf_event - performance event kernel representation:

 */
@@ -639,6 +641,8 @@ struct perf_event { 
	struct event_filter		*filter;

#endif



	perf_callback_t			callback;



#endif /* CONFIG_PERF_EVENTS */

};
@@ -748,7 +752,8 @@ extern int perf_event_release_kernel(struct perf_event *event); 
extern struct perf_event *

perf_event_create_kernel_counter(struct perf_event_attr *attr,

				int cpu,

				pid_t pid);

				pid_t pid,

				perf_callback_t callback);

extern u64 perf_event_read_value(struct perf_event *event);



struct perf_sample_data {

kernel/perf_event.c

+10 −4
Original line number Diff line number Diff line
@@ -4293,6 +4293,7 @@ perf_event_alloc(struct perf_event_attr *attr, 
		   struct perf_event_context *ctx,

		   struct perf_event *group_leader,

		   struct perf_event *parent_event,

		   perf_callback_t callback,

		   gfp_t gfpflags)

{

	const struct pmu *pmu;
@@ -4335,6 +4336,11 @@ perf_event_alloc(struct perf_event_attr *attr, 


	event->state		= PERF_EVENT_STATE_INACTIVE;



	if (!callback && parent_event)

		callback = parent_event->callback;

	

	event->callback	= callback;



	if (attr->disabled)

		event->state = PERF_EVENT_STATE_OFF;
@@ -4611,7 +4617,7 @@ SYSCALL_DEFINE5(perf_event_open, 
	}



	event = perf_event_alloc(&attr, cpu, ctx, group_leader,

				     NULL, GFP_KERNEL);

				     NULL, NULL, GFP_KERNEL);

	err = PTR_ERR(event);

	if (IS_ERR(event))

		goto err_put_context;
@@ -4668,7 +4674,7 @@ SYSCALL_DEFINE5(perf_event_open, 
 */

struct perf_event *

perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,

				 pid_t pid)

				 pid_t pid, perf_callback_t callback)

{

	struct perf_event *event;

	struct perf_event_context *ctx;
@@ -4683,7 +4689,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 
		return NULL ;



	event = perf_event_alloc(attr, cpu, ctx, NULL,

				     NULL, GFP_KERNEL);

				     NULL, callback, GFP_KERNEL);

	err = PTR_ERR(event);

	if (IS_ERR(event))

		goto err_put_context;
@@ -4736,7 +4742,7 @@ inherit_event(struct perf_event *parent_event, 
	child_event = perf_event_alloc(&parent_event->attr,

					   parent_event->cpu, child_ctx,

					   group_leader, parent_event,

					   GFP_KERNEL);

					   NULL, GFP_KERNEL);

	if (IS_ERR(child_event))

		return child_event;

	get_ctx(child_ctx);