Netdev List
 help / color / mirror / Atom feed
From: John Fastabend <john.fastabend@gmail.com>
To: john.fastabend@gmail.com, jhs@mojatatu.com, davem@davemloft.net
Cc: netdev@vger.kernel.org
Subject: [net-next PATCH] net: pack tc_cls_u32_knode struct slighter better
Date: Wed, 17 Feb 2016 14:59:30 -0800	[thread overview]
Message-ID: <20160217225930.25736.17844.stgit@john-Precision-Tower-5810> (raw)

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>
---
 include/net/pkt_cls.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 59789ca..2121df5 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -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 {

             reply	other threads:[~2016-02-17 22:59 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-17 22:59 John Fastabend [this message]
2016-02-18  2:44 ` [net-next PATCH] net: pack tc_cls_u32_knode struct slighter better David Miller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160217225930.25736.17844.stgit@john-Precision-Tower-5810 \
    --to=john.fastabend@gmail.com \
    --cc=davem@davemloft.net \
    --cc=jhs@mojatatu.com \
    --cc=netdev@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox