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Date:      Thu, 1 May 2025 19:52:41 GMT
From:      Michael Tuexen <tuexen@FreeBSD.org>
To:        src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org
Subject:   git: a9114926e2a6 - stable/14 - tcp rack: cleanup storing values for beta and beta_ecn
Message-ID:  <202505011952.541JqfU2072928@gitrepo.freebsd.org>

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The branch stable/14 has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=a9114926e2a609524cbc7c85ff6a76f01ad268e2

commit a9114926e2a609524cbc7c85ff6a76f01ad268e2
Author:     Michael Tuexen <tuexen@FreeBSD.org>
AuthorDate: 2025-03-31 01:40:17 +0000
Commit:     Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2025-05-01 19:52:31 +0000

    tcp rack: cleanup storing values for beta and beta_ecn
    
    beta and beta_ecn were stored using a variable of type struct newreno
    in struct rack_control. Later, struct newreno was extended and now
    contains several more fields.
    This results in a memory inefficiency and also in copying around
    uninitialized memory.
    This patch fixes this by storing beta and beta_ecn individually in
    struct rack_control.
    Please note that the newreno_flags field was only stored and never
    used. Therefore, this is not stored anymore in struct rack_control.
    No functional change intended.
    
    CID:                    1523796
    Reviewed by:            rrs
    Sponsored by:           Netflix, Inc.
    Differential Revision:  https://reviews.freebsd.org/D49578
    
    (cherry picked from commit f6deb9ea0a0ee760e5ff9ad5c15d0bd7a1714355)
---
 sys/netinet/tcp_stacks/rack.c     | 39 +++++++++++++++++++--------------------
 sys/netinet/tcp_stacks/tcp_rack.h |  7 ++++---
 2 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c
index dca7e347d615..aa66b02bcd11 100644
--- a/sys/netinet/tcp_stacks/rack.c
+++ b/sys/netinet/tcp_stacks/rack.c
@@ -610,8 +610,9 @@ rack_swap_beta_values(struct tcp_rack *rack, uint8_t flex8)
 {
 	struct sockopt sopt;
 	struct cc_newreno_opts opt;
-	struct newreno old;
 	struct tcpcb *tp;
+	uint32_t old_beta;
+	uint32_t old_beta_ecn;
 	int error, failed = 0;
 
 	tp = rack->rc_tp;
@@ -631,7 +632,6 @@ rack_swap_beta_values(struct tcp_rack *rack, uint8_t flex8)
 		failed = 2;
 		goto out;
 	}
-	old.newreno_flags = CC_NEWRENO_BETA_ECN_ENABLED;
 	/* Get the current values out */
 	sopt.sopt_valsize = sizeof(struct cc_newreno_opts);
 	sopt.sopt_dir = SOPT_GET;
@@ -641,33 +641,34 @@ rack_swap_beta_values(struct tcp_rack *rack, uint8_t flex8)
 		failed = 3;
 		goto out;
 	}
-	old.beta = opt.val;
+	old_beta = opt.val;
 	opt.name = CC_NEWRENO_BETA_ECN;
 	error = CC_ALGO(tp)->ctl_output(&tp->t_ccv, &sopt, &opt);
 	if (error)  {
 		failed = 4;
 		goto out;
 	}
-	old.beta_ecn = opt.val;
+	old_beta_ecn = opt.val;
 
 	/* Now lets set in the values we have stored */
 	sopt.sopt_dir = SOPT_SET;
 	opt.name = CC_NEWRENO_BETA;
-	opt.val = rack->r_ctl.rc_saved_beta.beta;
+	opt.val = rack->r_ctl.rc_saved_beta;
 	error = CC_ALGO(tp)->ctl_output(&tp->t_ccv, &sopt, &opt);
 	if (error)  {
 		failed = 5;
 		goto out;
 	}
 	opt.name = CC_NEWRENO_BETA_ECN;
-	opt.val = rack->r_ctl.rc_saved_beta.beta_ecn;
+	opt.val = rack->r_ctl.rc_saved_beta_ecn;
 	error = CC_ALGO(tp)->ctl_output(&tp->t_ccv, &sopt, &opt);
 	if (error) {
 		failed = 6;
 		goto out;
 	}
 	/* Save off the values for restoral */
-	memcpy(&rack->r_ctl.rc_saved_beta, &old, sizeof(struct newreno));
+	rack->r_ctl.rc_saved_beta = old_beta;
+	rack->r_ctl.rc_saved_beta_ecn = old_beta_ecn;
 out:
 	if (rack_verbose_logging && tcp_bblogging_on(rack->rc_tp)) {
 		union tcp_log_stackspecific log;
@@ -680,8 +681,8 @@ out:
 		log.u_bbr.flex1 = ptr->beta;
 		log.u_bbr.flex2 = ptr->beta_ecn;
 		log.u_bbr.flex3 = ptr->newreno_flags;
-		log.u_bbr.flex4 = rack->r_ctl.rc_saved_beta.beta;
-		log.u_bbr.flex5 = rack->r_ctl.rc_saved_beta.beta_ecn;
+		log.u_bbr.flex4 = rack->r_ctl.rc_saved_beta;
+		log.u_bbr.flex5 = rack->r_ctl.rc_saved_beta_ecn;
 		log.u_bbr.flex6 = failed;
 		log.u_bbr.flex7 = rack->gp_ready;
 		log.u_bbr.flex7 <<= 1;
@@ -15059,7 +15060,7 @@ rack_init(struct tcpcb *tp, void **ptr)
 	rack->rc_new_rnd_needed = 1;
 	rack->r_ctl.rc_split_limit = V_tcp_map_split_limit;
 	/* We want abe like behavior as well */
-	rack->r_ctl.rc_saved_beta.newreno_flags |= CC_NEWRENO_BETA_ECN_ENABLED;
+
 	rack->r_ctl.rc_reorder_fade = rack_reorder_fade;
 	rack->rc_allow_data_af_clo = rack_ignore_data_after_close;
 	rack->r_ctl.rc_tlp_threshold = rack_tlp_thresh;
@@ -15095,13 +15096,13 @@ rack_init(struct tcpcb *tp, void **ptr)
 	rack->rc_user_set_max_segs = rack_hptsi_segments;
 	rack->rc_force_max_seg = 0;
 	TAILQ_INIT(&rack->r_ctl.opt_list);
-	rack->r_ctl.rc_saved_beta.beta = V_newreno_beta_ecn;
-	rack->r_ctl.rc_saved_beta.beta_ecn = V_newreno_beta_ecn;
+	rack->r_ctl.rc_saved_beta = V_newreno_beta_ecn;
+	rack->r_ctl.rc_saved_beta_ecn = V_newreno_beta_ecn;
 	if (rack_hibeta_setting) {
 		rack->rack_hibeta = 1;
 		if ((rack_hibeta_setting >= 50) &&
 		    (rack_hibeta_setting <= 100)) {
-			rack->r_ctl.rc_saved_beta.beta = rack_hibeta_setting;
+			rack->r_ctl.rc_saved_beta = rack_hibeta_setting;
 			rack->r_ctl.saved_hibeta = rack_hibeta_setting;
 		}
 	} else {
@@ -23051,7 +23052,7 @@ rack_process_option(struct tcpcb *tp, struct tcp_rack *rack, int sopt_name,
 				rack->r_ctl.saved_hibeta = optval;
 				if (rack->rc_pacing_cc_set)
 					rack_undo_cc_pacing(rack);
-				rack->r_ctl.rc_saved_beta.beta = optval;
+				rack->r_ctl.rc_saved_beta = optval;
 			}
 			if (rack->rc_pacing_cc_set == 0)
 				rack_set_cc_pacing(rack);
@@ -23088,7 +23089,7 @@ rack_process_option(struct tcpcb *tp, struct tcp_rack *rack, int sopt_name,
 			 * Not pacing yet so set it into our local
 			 * rack pcb storage.
 			 */
-			rack->r_ctl.rc_saved_beta.beta = optval;
+			rack->r_ctl.rc_saved_beta = optval;
 		}
 		break;
 	case TCP_RACK_TIMER_SLOP:
@@ -23129,8 +23130,7 @@ rack_process_option(struct tcpcb *tp, struct tcp_rack *rack, int sopt_name,
 			 * Not pacing yet so set it into our local
 			 * rack pcb storage.
 			 */
-			rack->r_ctl.rc_saved_beta.beta_ecn = optval;
-			rack->r_ctl.rc_saved_beta.newreno_flags = CC_NEWRENO_BETA_ECN_ENABLED;
+			rack->r_ctl.rc_saved_beta_ecn = optval;
 		}
 		break;
 	case TCP_DEFER_OPTIONS:
@@ -23680,7 +23680,6 @@ rack_process_option(struct tcpcb *tp, struct tcp_rack *rack, int sopt_name,
 	return (error);
 }
 
-
 static void
 rack_apply_deferred_options(struct tcp_rack *rack)
 {
@@ -24050,7 +24049,7 @@ rack_get_sockopt(struct tcpcb *tp, struct sockopt *sopt)
 		if (strcmp(tp->t_cc->name, CCALGONAME_NEWRENO) != 0)
 			error = EINVAL;
 		else if (rack->rc_pacing_cc_set == 0)
-			optval = rack->r_ctl.rc_saved_beta.beta;
+			optval = rack->r_ctl.rc_saved_beta;
 		else {
 			/*
 			 * Reach out into the CC data and report back what
@@ -24074,7 +24073,7 @@ rack_get_sockopt(struct tcpcb *tp, struct sockopt *sopt)
 		if (strcmp(tp->t_cc->name, CCALGONAME_NEWRENO) != 0)
 			error = EINVAL;
 		else if (rack->rc_pacing_cc_set == 0)
-			optval = rack->r_ctl.rc_saved_beta.beta_ecn;
+			optval = rack->r_ctl.rc_saved_beta_ecn;
 		else {
 			/*
 			 * Reach out into the CC data and report back what
diff --git a/sys/netinet/tcp_stacks/tcp_rack.h b/sys/netinet/tcp_stacks/tcp_rack.h
index 4152a1a5d7ba..1251dabbed37 100644
--- a/sys/netinet/tcp_stacks/tcp_rack.h
+++ b/sys/netinet/tcp_stacks/tcp_rack.h
@@ -504,9 +504,10 @@ struct rack_control {
 	uint32_t input_pkt;
 	uint32_t saved_input_pkt;
 	uint32_t saved_rxt_clamp_val; 	/* The encoded value we used to setup clamping */
-	struct newreno rc_saved_beta;	/*
-					 * For newreno cc:
-					 * rc_saved_cc are the values we have had
+	uint32_t rc_saved_beta;
+	uint32_t rc_saved_beta_ecn;	/*
+					 * For newreno cc: rc_saved_beta and
+					 * rc_saved_beta_ecn are the values we have had
 					 * set by the user, if pacing is not happening
 					 * (i.e. its early and we have not turned on yet
 					 *  or it was turned off). The minute pacing



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