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: Robert Richter <robert.richter@amd.com>
diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h
index 65b763a..2d4bfde 100644
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -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 @@
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 @@
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);