[PATCH] mac80211: optimize ieee80211_rx_status struct layout

[PATCH] mac80211: optimize ieee80211_rx_status struct layout

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

We waste a lot of space in this struct because it uses
int values where smaller ones would be sufficient. The
upcoming A-MPDU information needs some space, optimize
the struct now.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/net/mac80211.h |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index c5dbb46..7300cb5 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -709,13 +709,13 @@ enum mac80211_rx_flags {
  */
 struct ieee80211_rx_status {
 	u64 mactime;
-	enum ieee80211_band band;
-	int freq;
-	int signal;
-	int antenna;
-	int rate_idx;
-	int flag;
-	unsigned int rx_flags;
+	u16 flag;
+	u16 freq;
+	u8 rate_idx;
+	u8 rx_flags;
+	u8 band;
+	u8 antenna;
+	s8 signal;
 };
 
 /**
-- 
1.7.10.4

Re: [PATCH] mac80211: optimize ieee80211_rx_status struct layout

[Johannes Berg]

On Tue, 2012-07-10 at 11:11 +0200, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@intel.com>
> 
> We waste a lot of space in this struct because it uses
> int values where smaller ones would be sufficient. The
> upcoming A-MPDU information needs some space, optimize
> the struct now.

It'll be a few weeks until the A-MPDU stuff is adopted in radiotap, but
I figured this could still go upstream already. The previous patch (time
sync) was based on it (and accidentally the A-MPDU stuff, so it won't
apply as is, but I've fixed that)

johannes