[PATCH v2 02/14] soundwire: optimize sdw_stream_runtime memory layout

[Bard Liao]

From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>

pahole suggestion: swap position of 'm_rt_count'

before: pahole -C sdw_stream_runtime drivers/soundwire/soundwire-bus.ko
struct sdw_stream_runtime {
	const char  *              name;                 /*     0     8 */
	struct sdw_stream_params   params;               /*     8    12 */
	enum sdw_stream_state      state;                /*    20     4 */
	enum sdw_stream_type       type;                 /*    24     4 */

	/* XXX 4 bytes hole, try to pack */

	struct list_head           master_list;          /*    32    16 */
	int                        m_rt_count;           /*    48     4 */

	/* size: 56, cachelines: 1, members: 6 */
	/* sum members: 48, holes: 1, sum holes: 4 */
	/* padding: 4 */
	/* last cacheline: 56 bytes */
};

after: pahole --reorganize -C sdw_stream_runtime drivers/soundwire/soundwire-bus.ko
struct sdw_stream_runtime {
	const char  *              name;                 /*     0     8 */
	struct sdw_stream_params   params;               /*     8    12 */
	enum sdw_stream_state      state;                /*    20     4 */
	enum sdw_stream_type       type;                 /*    24     4 */
	int                        m_rt_count;           /*    28     4 */
	struct list_head           master_list;          /*    32    16 */

	/* size: 48, cachelines: 1, members: 6 */
	/* last cacheline: 48 bytes */
};   /* saved 8 bytes! */

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
---
 include/linux/soundwire/sdw.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index 5e0dd47a0412..a4fa45132030 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -820,15 +820,15 @@ struct sdw_master_port_ops {
 struct sdw_msg;
 
 /**
- * struct sdw_defer - SDW deffered message
- * @length: message length
+ * struct sdw_defer - SDW deferred message
  * @complete: message completion
  * @msg: SDW message
+ * @length: message length
  */
 struct sdw_defer {
+	struct sdw_msg *msg;
 	int length;
 	struct completion complete;
-	struct sdw_msg *msg;
 };
 
 /**
@@ -1010,18 +1010,18 @@ struct sdw_stream_params {
  * @params: Stream parameters
  * @state: Current state of the stream
  * @type: Stream type PCM or PDM
+ * @m_rt_count: Count of Master runtime(s) in this stream
  * @master_list: List of Master runtime(s) in this stream.
  * master_list can contain only one m_rt per Master instance
  * for a stream
- * @m_rt_count: Count of Master runtime(s) in this stream
  */
 struct sdw_stream_runtime {
 	const char *name;
 	struct sdw_stream_params params;
 	enum sdw_stream_state state;
 	enum sdw_stream_type type;
-	struct list_head master_list;
 	int m_rt_count;
+	struct list_head master_list;
 };
 
 struct sdw_stream_runtime *sdw_alloc_stream(const char *stream_name);
-- 
2.43.0