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oprofile: add op_cpu_buffer_write_reserve()

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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: Robert Richter <robert.richter@amd.com>
This commit is contained in:
Robert Richter 2008-12-25 17:26:07 +01:00
parent d358e75fc4
commit 2cc28b9f26
2 changed files with 37 additions and 15 deletions
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43
drivers/oprofile/cpu_buffer.c
View file

@ -1,11 +1,12 @@
/**
* @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);
}

9
drivers/oprofile/cpu_buffer.h
View file

@ -1,10 +1,11 @@
/**
* @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);