net: pack tc_cls_u32_knode struct slighter better
authorJohn Fastabend <john.fastabend@gmail.com>
Wed, 17 Feb 2016 22:59:30 +0000 (14:59 -0800)
committerDavid S. Miller <davem@davemloft.net>
Thu, 18 Feb 2016 02:44:12 +0000 (21:44 -0500)
By packing the structure we can remove a few holes as Jamal
suggests.

before:

struct tc_cls_u32_knode {
struct tcf_exts *          exts;                 /*     0     8 */
u8                         fshift;               /*     8     1 */

/* XXX 3 bytes hole, try to pack */

u32                        handle;               /*    12     4 */
u32                        val;                  /*    16     4 */
u32                        mask;                 /*    20     4 */
u32                        link_handle;          /*    24     4 */

/* XXX 4 bytes hole, try to pack */

struct tc_u32_sel *        sel;                  /*    32     8 */

/* size: 40, cachelines: 1, members: 7 */
/* sum members: 33, holes: 2, sum holes: 7 */
/* last cacheline: 40 bytes */
};

after:

struct tc_cls_u32_knode {
struct tcf_exts *          exts;                 /*     0     8 */
struct tc_u32_sel *        sel;                  /*     8     8 */
u32                        handle;               /*    16     4 */
u32                        val;                  /*    20     4 */
u32                        mask;                 /*    24     4 */
u32                        link_handle;          /*    28     4 */
u8                         fshift;               /*    32     1 */

/* size: 40, cachelines: 1, members: 7 */
/* padding: 7 */
/* last cacheline: 40 bytes */
};

Suggested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/net/pkt_cls.h

index 59789ca6e2c81a7588fbaa383999cd643a21d24e..2121df5742621044a78bd4d23775343342a921b0 100644 (file)
@@ -360,12 +360,12 @@ tcf_match_indev(struct sk_buff *skb, int ifindex)
 
 struct tc_cls_u32_knode {
        struct tcf_exts *exts;
-       u8 fshift;
+       struct tc_u32_sel *sel;
        u32 handle;
        u32 val;
        u32 mask;
        u32 link_handle;
-       struct tc_u32_sel *sel;
+       u8 fshift;
 };
 
 struct tc_cls_u32_hnode {