From c637bd066841de6d0a204898a62f1d9bb8fa1b7f Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 4 Dec 2024 07:46:54 +0000 Subject: [PATCH] rxrpc: Generate rtt_min Generate rtt_min as this is required by RACK-TLP. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://patch.msgid.link/20241204074710.990092-27-dhowells@redhat.com Signed-off-by: Jakub Kicinski --- lib/win_minmax.c | 1 + net/rxrpc/ar-internal.h | 2 ++ net/rxrpc/rtt.c | 20 ++++++++++++++++---- 3 files changed, 19 insertions(+), 4 deletions(-) diff --git a/lib/win_minmax.c b/lib/win_minmax.c index ec10506834b6..1682e614309c 100644 --- a/lib/win_minmax.c +++ b/lib/win_minmax.c @@ -97,3 +97,4 @@ u32 minmax_running_min(struct minmax *m, u32 win, u32 t, u32 meas) return minmax_subwin_update(m, win, &val); } +EXPORT_SYMBOL(minmax_running_min); diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index 297be421639c..d0d0ab453909 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -371,6 +371,8 @@ struct rxrpc_peer { spinlock_t rtt_input_lock; /* RTT lock for input routine */ ktime_t rtt_last_req; /* Time of last RTT request */ unsigned int rtt_count; /* Number of samples we've got */ + unsigned int rtt_taken; /* Number of samples taken (wrapping) */ + struct minmax min_rtt; /* Estimated minimum RTT */ u32 srtt_us; /* smoothed round trip time << 3 in usecs */ u32 mdev_us; /* medium deviation */ diff --git a/net/rxrpc/rtt.c b/net/rxrpc/rtt.c index 6dc51486b5a6..8048467f4bee 100644 --- a/net/rxrpc/rtt.c +++ b/net/rxrpc/rtt.c @@ -127,16 +127,27 @@ static void rxrpc_set_rto(struct rxrpc_peer *peer) peer->rto_us = rxrpc_bound_rto(rto); } -static void rxrpc_ack_update_rtt(struct rxrpc_peer *peer, long rtt_us) +static void rxrpc_update_rtt_min(struct rxrpc_peer *peer, ktime_t resp_time, long rtt_us) +{ + /* Window size 5mins in approx usec (ipv4.sysctl_tcp_min_rtt_wlen) */ + u32 wlen_us = 5ULL * NSEC_PER_SEC / 1024; + + minmax_running_min(&peer->min_rtt, wlen_us, resp_time / 1024, + (u32)rtt_us ? : jiffies_to_usecs(1)); +} + +static void rxrpc_ack_update_rtt(struct rxrpc_peer *peer, ktime_t resp_time, long rtt_us) { if (rtt_us < 0) return; - //rxrpc_update_rtt_min(peer, rtt_us); + /* Update RACK min RTT [RFC8985 6.1 Step 1]. */ + rxrpc_update_rtt_min(peer, resp_time, rtt_us); + rxrpc_rtt_estimator(peer, rtt_us); rxrpc_set_rto(peer); - /* RFC6298: only reset backoff on valid RTT measurement. */ + /* Only reset backoff on valid RTT measurement [RFC6298]. */ peer->backoff = 0; } @@ -157,9 +168,10 @@ void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why, return; spin_lock(&peer->rtt_input_lock); - rxrpc_ack_update_rtt(peer, rtt_us); + rxrpc_ack_update_rtt(peer, resp_time, rtt_us); if (peer->rtt_count < 3) peer->rtt_count++; + peer->rtt_taken++; spin_unlock(&peer->rtt_input_lock); trace_rxrpc_rtt_rx(call, why, rtt_slot, send_serial, resp_serial,