2014-12-17 12:38:38

by Felix Fietkau

Subject: [PATCH v2 3.19] 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 <[email protected]>
---
net/mac80211/rc80211_minstrel.c | 6 +++---
net/mac80211/rc80211_minstrel.h | 15 ++++++++-------
2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index d51f6b1..7c86a00 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 97eca86..410efe6 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;
};
--
2.1.2

2014-12-19 20:34:46

by Johannes Berg

Subject: Re: [PATCH v2 3.19] mac80211: minstrel: reduce size of struct minstrel_rate_stats

On Wed, 2014-12-17 at 13:38 +0100, Felix Fietkau wrote:
> 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).

Applied to mac80211-next.

johannes