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Commit 2cc28b9f authored by Robert Richter's avatar Robert Richter
Browse files

oprofile: add op_cpu_buffer_write_reserve() 



This function prepares the cpu buffer to write a sample.

Struct op_entry is used during operations on the ring buffer while
struct op_sample contains the data that is stored in the ring
buffer. Struct entry can be uninitialized. The function reserves a
data array that is specified by size. Use op_cpu_buffer_write_commit()
after preparing the sample. In case of errors a null pointer is
returned, otherwise the pointer to the sample.

Signed-off-by: default avatarRobert Richter <robert.richter@amd.com>
parent d358e75f

drivers/oprofile/cpu_buffer.c

+30 −13
Original line number Diff line number Diff line 
/**

 * @file cpu_buffer.c

 *

 * @remark Copyright 2002 OProfile authors

 * @remark Copyright 2002-2009 OProfile authors

 * @remark Read the file COPYING

 *

 * @author John Levon <levon@movementarian.org>

 * @author Barry Kasindorf <barry.kasindorf@amd.com>

 * @author Robert Richter <robert.richter@amd.com>

 *

 * Each CPU has a local buffer that stores PC value/event

 * pairs. We also log context switches when we notice them.
@@ -143,20 +144,36 @@ void end_cpu_work(void) 
	flush_scheduled_work();

}



int op_cpu_buffer_write_entry(struct op_entry *entry)

/*

 * This function prepares the cpu buffer to write a sample.

 *

 * Struct op_entry is used during operations on the ring buffer while

 * struct op_sample contains the data that is stored in the ring

 * buffer. Struct entry can be uninitialized. The function reserves a

 * data array that is specified by size. Use

 * op_cpu_buffer_write_commit() after preparing the sample. In case of

 * errors a null pointer is returned, otherwise the pointer to the

 * sample.

 *

 */

struct op_sample

*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size)

{

	entry->event = ring_buffer_lock_reserve(op_ring_buffer_write,

						sizeof(struct op_sample),

						&entry->irq_flags);

	entry->event = ring_buffer_lock_reserve

		(op_ring_buffer_write, sizeof(struct op_sample) +

		 size * sizeof(entry->sample->data[0]), &entry->irq_flags);

	if (entry->event)

		entry->sample = ring_buffer_event_data(entry->event);

	else

		entry->sample = NULL;



	if (!entry->sample)

		return -ENOMEM;

		return NULL;



	return 0;

	entry->size = size;

	entry->data = entry->sample->data;



	return entry->sample;

}



int op_cpu_buffer_write_commit(struct op_entry *entry)
@@ -192,14 +209,14 @@ op_add_sample(struct oprofile_cpu_buffer *cpu_buf, 
	      unsigned long pc, unsigned long event)

{

	struct op_entry entry;

	int ret;

	struct op_sample *sample;



	ret = op_cpu_buffer_write_entry(&entry);

	if (ret)

		return ret;

	sample = op_cpu_buffer_write_reserve(&entry, 0);

	if (!sample)

		return -ENOMEM;



	entry.sample->eip = pc;

	entry.sample->event = event;

	sample->eip = pc;

	sample->event = event;



	return op_cpu_buffer_write_commit(&entry);

}

drivers/oprofile/cpu_buffer.h

+7 −2
Original line number Diff line number Diff line 
/**

 * @file cpu_buffer.h

 *

 * @remark Copyright 2002 OProfile authors

 * @remark Copyright 2002-2009 OProfile authors

 * @remark Read the file COPYING

 *

 * @author John Levon <levon@movementarian.org>

 * @author Robert Richter <robert.richter@amd.com>

 */



#ifndef OPROFILE_CPU_BUFFER_H
@@ -31,12 +32,15 @@ void end_cpu_work(void); 
struct op_sample {

	unsigned long eip;

	unsigned long event;

	unsigned long data[0];

};



struct op_entry {

	struct ring_buffer_event *event;

	struct op_sample *sample;

	unsigned long irq_flags;

	unsigned long size;

	unsigned long *data;

};



struct oprofile_cpu_buffer {
@@ -68,7 +72,8 @@ static inline void op_cpu_buffer_reset(int cpu) 
	cpu_buf->last_task = NULL;

}



int op_cpu_buffer_write_entry(struct op_entry *entry);

struct op_sample

*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size);

int op_cpu_buffer_write_commit(struct op_entry *entry);

struct op_sample *op_cpu_buffer_read_entry(int cpu);

unsigned long op_cpu_buffer_entries(int cpu);