Group some variables based on their sizes to reduce hole and avoid padding.
On x86_64, this shrinks the size from 136 to 128 bytes.
Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
---
Using pahole
Before:
======
struct rdma_restrack_entry {
bool valid; /* 0 1 */
u8 no_track:1; /* 1: 0 1 */
/* XXX 7 bits hole, try to pack */
/* XXX 2 bytes hole, try to pack */
struct kref kref; /* 4 4 */
struct completion comp; /* 8 96 */
/* --- cacheline 1 boundary (64 bytes) was 40 bytes ago --- */
struct task_struct * task; /* 104 8 */
const char * kern_name; /* 112 8 */
enum rdma_restrack_type type; /* 120 4 */
bool user; /* 124 1 */
/* XXX 3 bytes hole, try to pack */
/* --- cacheline 2 boundary (128 bytes) --- */
u32 id; /* 128 4 */
/* size: 136, cachelines: 3, members: 9 */
/* sum members: 126, holes: 2, sum holes: 5 */
/* sum bitfield members: 1 bits, bit holes: 1, sum bit holes: 7 bits */
/* padding: 4 */
/* last cacheline: 8 bytes */
};
After:
=====
struct rdma_restrack_entry {
bool valid; /* 0 1 */
u8 no_track:1; /* 1: 0 1 */
/* XXX 7 bits hole, try to pack */
bool user; /* 2 1 */
/* XXX 1 byte hole, try to pack */
struct kref kref; /* 4 4 */
struct completion comp; /* 8 96 */
/* --- cacheline 1 boundary (64 bytes) was 40 bytes ago --- */
struct task_struct * task; /* 104 8 */
const char * kern_name; /* 112 8 */
enum rdma_restrack_type type; /* 120 4 */
u32 id; /* 124 4 */
/* size: 128, cachelines: 2, members: 9 */
/* sum members: 126, holes: 1, sum holes: 1 */
/* sum bitfield members: 1 bits, bit holes: 1, sum bit holes: 7 bits */
};
---
include/rdma/restrack.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/rdma/restrack.h b/include/rdma/restrack.h
index 8b7c46daeb07..da53fefe6f9e 100644
--- a/include/rdma/restrack.h
+++ b/include/rdma/restrack.h
@@ -80,6 +80,10 @@ struct rdma_restrack_entry {
* query stage.
*/
u8 no_track : 1;
+ /**
+ * @user: user resource
+ */
+ bool user;
/*
* @kref: Protect destroy of the resource
*/
@@ -106,10 +110,6 @@ struct rdma_restrack_entry {
* @type: various objects in restrack database
*/
enum rdma_restrack_type type;
- /**
- * @user: user resource
- */
- bool user;
/**
* @id: ID to expose to users
*/
--
2.34.1
