The existing comment for mdev_us says "medium deviation", but this term is inaccurate. The field stores the "mean deviation" of RTT, as originally defined in Van Jacobson's paper "Congestion Avoidance and Control", and it is scaled by 4 (<< 2) in the Linux implementation. Update the comment to reflect the correct terminology and storage format.
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| @@ -274,7 +274,7 @@ struct tcp_sock { · 273 unmodified lines | ||
| 274 | 274 | u32 write_seq; /* Tail(+1) of data held in tcp send buffer */ |
| 275 | 275 | u32 pushed_seq; /* Last pushed seq, required to talk to windows */ |
| 276 | 276 | u32 lsndtime; /* timestamp of last sent data packet (for restart window) */ |
| 277 | − u32 mdev_us; /* medium deviation */ | |
| 277 | + u32 mdev_us; /* mean deviation of RTT, scaled by 4 (<< 2) in usecs */ | |
| 278 | 278 | u32 rtt_seq; /* sequence number to update rttvar */ |
| 279 | 279 | u32 max_packets_out; /* max packets_out in last window */ |
| 280 | 280 | u32 cwnd_usage_seq; /* right edge of cwnd usage tracking flight */ |