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authorRobert Richter <robert.richter@amd.com>2008-12-25 11:26:07 -0500
committerRobert Richter <robert.richter@amd.com>2009-01-07 16:37:44 -0500
commit2cc28b9f261dd28d69767a34682ce55a27d928ed (patch)
treeeb99ee33781cc79ab09f2d70c93f14c90c664f91 /drivers/oprofile/cpu_buffer.c
parentd358e75fc40cc3bbab11654ba0a88b232c543d12 (diff)
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>
Diffstat (limited to 'drivers/oprofile/cpu_buffer.c')
-rw-r--r--drivers/oprofile/cpu_buffer.c43
1 files changed, 30 insertions, 13 deletions
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index ac79f6676033..934ff159e70e 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -1,11 +1,12 @@
1/** 1/**
2 * @file cpu_buffer.c 2 * @file cpu_buffer.c
3 * 3 *
4 * @remark Copyright 2002 OProfile authors 4 * @remark Copyright 2002-2009 OProfile authors
5 * @remark Read the file COPYING 5 * @remark Read the file COPYING
6 * 6 *
7 * @author John Levon <levon@movementarian.org> 7 * @author John Levon <levon@movementarian.org>
8 * @author Barry Kasindorf <barry.kasindorf@amd.com> 8 * @author Barry Kasindorf <barry.kasindorf@amd.com>
9 * @author Robert Richter <robert.richter@amd.com>
9 * 10 *
10 * Each CPU has a local buffer that stores PC value/event 11 * Each CPU has a local buffer that stores PC value/event
11 * pairs. We also log context switches when we notice them. 12 * pairs. We also log context switches when we notice them.
@@ -143,20 +144,36 @@ void end_cpu_work(void)
143 flush_scheduled_work(); 144 flush_scheduled_work();
144} 145}
145 146
146int op_cpu_buffer_write_entry(struct op_entry *entry) 147/*
148 * This function prepares the cpu buffer to write a sample.
149 *
150 * Struct op_entry is used during operations on the ring buffer while
151 * struct op_sample contains the data that is stored in the ring
152 * buffer. Struct entry can be uninitialized. The function reserves a
153 * data array that is specified by size. Use
154 * op_cpu_buffer_write_commit() after preparing the sample. In case of
155 * errors a null pointer is returned, otherwise the pointer to the
156 * sample.
157 *
158 */
159struct op_sample
160*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size)
147{ 161{
148 entry->event = ring_buffer_lock_reserve(op_ring_buffer_write, 162 entry->event = ring_buffer_lock_reserve
149 sizeof(struct op_sample), 163 (op_ring_buffer_write, sizeof(struct op_sample) +
150 &entry->irq_flags); 164 size * sizeof(entry->sample->data[0]), &entry->irq_flags);
151 if (entry->event) 165 if (entry->event)
152 entry->sample = ring_buffer_event_data(entry->event); 166 entry->sample = ring_buffer_event_data(entry->event);
153 else 167 else
154 entry->sample = NULL; 168 entry->sample = NULL;
155 169
156 if (!entry->sample) 170 if (!entry->sample)
157 return -ENOMEM; 171 return NULL;
158 172
159 return 0; 173 entry->size = size;
174 entry->data = entry->sample->data;
175
176 return entry->sample;
160} 177}
161 178
162int op_cpu_buffer_write_commit(struct op_entry *entry) 179int op_cpu_buffer_write_commit(struct op_entry *entry)
@@ -192,14 +209,14 @@ op_add_sample(struct oprofile_cpu_buffer *cpu_buf,
192 unsigned long pc, unsigned long event) 209 unsigned long pc, unsigned long event)
193{ 210{
194 struct op_entry entry; 211 struct op_entry entry;
195 int ret; 212 struct op_sample *sample;
196 213
197 ret = op_cpu_buffer_write_entry(&entry); 214 sample = op_cpu_buffer_write_reserve(&entry, 0);
198 if (ret) 215 if (!sample)
199 return ret; 216 return -ENOMEM;
200 217
201 entry.sample->eip = pc; 218 sample->eip = pc;
202 entry.sample->event = event; 219 sample->event = event;
203 220
204 return op_cpu_buffer_write_commit(&entry); 221 return op_cpu_buffer_write_commit(&entry);
205} 222}