mac80211: minstrel: reduce size of struct minstrel_rate_stats

On minstrel_ht, the size of the per-sta struct is almost 18k, making it
an order-3 allocation.
A few fields inside the per-rate statistics are bigger than they need to
be. This patch reduces the size enough to cut down the per-sta struct to
about 13k (order-2 allocation).

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 11 insertions, 10 deletions

diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index d51f6b1c549b..7c86a002df95 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -263,12 +263,12 @@ static inline unsigned int
 minstrel_get_retry_count(struct minstrel_rate *mr,
                          struct ieee80211_tx_info *info)
 {
-        unsigned int retry = mr->adjusted_retry_count;
+        u8 retry = mr->adjusted_retry_count;
 
         if (info->control.use_rts)
-                retry = max(2U, min(mr->stats.retry_count_rtscts, retry));
+                retry = max_t(u8, 2, min(mr->stats.retry_count_rtscts, retry));
         else if (info->control.use_cts_prot)
-                retry = max(2U, min(mr->retry_count_cts, retry));
+                retry = max_t(u8, 2, min(mr->retry_count_cts, retry));
         return retry;
 }
 
diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h
index 97eca86a4af0..410efe620c57 100644
--- a/net/mac80211/rc80211_minstrel.h
+++ b/net/mac80211/rc80211_minstrel.h
@@ -33,8 +33,8 @@ minstrel_ewma(int old, int new, int weight)
 
 struct minstrel_rate_stats {
         /* current / last sampling period attempts/success counters */
-        unsigned int attempts, last_attempts;
-        unsigned int success, last_success;
+        u16 attempts, last_attempts;
+        u16 success, last_success;
 
         /* total attempts/success counters */
         u64 att_hist, succ_hist;
@@ -46,8 +46,8 @@ struct minstrel_rate_stats {
         unsigned int cur_prob, probability;
 
         /* maximum retry counts */
-        unsigned int retry_count;
-        unsigned int retry_count_rtscts;
+        u8 retry_count;
+        u8 retry_count_rtscts;
 
         u8 sample_skipped;
         bool retry_updated;
@@ -55,14 +55,15 @@ struct minstrel_rate_stats {
 
 struct minstrel_rate {
         int bitrate;
-        int rix;
+
+        s8 rix;
+        u8 retry_count_cts;
+        u8 adjusted_retry_count;
 
         unsigned int perfect_tx_time;
         unsigned int ack_time;
 
         int sample_limit;
-        unsigned int retry_count_cts;
-        unsigned int adjusted_retry_count;
 
         struct minstrel_rate_stats stats;
 };