I found they are unused, so save some space.

Index: sys/kern/subr_pool.c
===================================================================
RCS file: /cvs/src/sys/kern/subr_pool.c,v
retrieving revision 1.238
diff -u -p -r1.238 subr_pool.c
--- sys/kern/subr_pool.c	20 May 2025 18:41:06 -0000	1.238
+++ sys/kern/subr_pool.c	20 May 2025 20:22:24 -0000
@@ -424,11 +424,6 @@ pool_init(struct pool *pp, size_t size, 
 	pp->pr_nitems = 0;
 	pp->pr_nout = 0;
 	pp->pr_hardlimit = UINT_MAX;
-	pp->pr_hardlimit_warning = NULL;
-	pp->pr_hardlimit_ratecap.tv_sec = 0;
-	pp->pr_hardlimit_ratecap.tv_usec = 0;
-	pp->pr_hardlimit_warning_last.tv_sec = 0;
-	pp->pr_hardlimit_warning_last.tv_usec = 0;
 	RBT_INIT(phtree, &pp->pr_phtree);
 
 	/*
@@ -1092,7 +1087,7 @@ pool_sethiwat(struct pool *pp, int n)
 }
 
 int
-pool_sethardlimit(struct pool *pp, u_int n, const char *warnmsg, int ratecap)
+pool_sethardlimit(struct pool *pp, u_int n)
 {
 	int error = 0;
 
@@ -1104,10 +1099,6 @@ pool_sethardlimit(struct pool *pp, u_int
 	}
 
 	pp->pr_hardlimit = n;
-	pp->pr_hardlimit_warning = warnmsg;
-	pp->pr_hardlimit_ratecap.tv_sec = ratecap;
-	pp->pr_hardlimit_warning_last.tv_sec = 0;
-	pp->pr_hardlimit_warning_last.tv_usec = 0;
 done:
 	pl_leave(pp, &pp->pr_lock);
 
Index: sys/net/pf_ioctl.c
===================================================================
RCS file: /cvs/src/sys/net/pf_ioctl.c,v
retrieving revision 1.419
diff -u -p -r1.419 pf_ioctl.c
--- sys/net/pf_ioctl.c	29 Apr 2025 13:12:51 -0000	1.419
+++ sys/net/pf_ioctl.c	20 May 2025 20:22:24 -0000
@@ -219,9 +219,9 @@ pfattach(int num)
 	pf_syncookies_init();
 
 	pool_sethardlimit(pf_pool_limits[PF_LIMIT_STATES].pp,
-	    pf_pool_limits[PF_LIMIT_STATES].limit, NULL, 0);
+	    pf_pool_limits[PF_LIMIT_STATES].limit);
 	pool_sethardlimit(pf_pool_limits[PF_LIMIT_ANCHORS].pp,
-	    pf_pool_limits[PF_LIMIT_ANCHORS].limit, NULL, 0);
+	    pf_pool_limits[PF_LIMIT_ANCHORS].limit);
 
 	if (physmem <= atop(100*1024*1024))
 		pf_pool_limits[PF_LIMIT_TABLE_ENTRIES].limit =
@@ -2773,7 +2773,7 @@ pfioctl(dev_t dev, u_long cmd, caddr_t a
 			if (pf_pool_limits[i].limit_new !=
 			    pf_pool_limits[i].limit &&
 			    pool_sethardlimit(pf_pool_limits[i].pp,
-			    pf_pool_limits[i].limit_new, NULL, 0) != 0) {
+			    pf_pool_limits[i].limit_new) != 0) {
 				PF_UNLOCK();
 				NET_UNLOCK();
 				free(table, M_PF, sizeof(*table));
Index: sys/net/pf_norm.c
===================================================================
RCS file: /cvs/src/sys/net/pf_norm.c,v
retrieving revision 1.234
diff -u -p -r1.234 pf_norm.c
--- sys/net/pf_norm.c	1 Feb 2025 21:10:02 -0000	1.234
+++ sys/net/pf_norm.c	20 May 2025 20:22:24 -0000
@@ -168,7 +168,7 @@ pf_normalize_init(void)
 	    IPL_SOFTNET, 0, "pfstscr", NULL);
 
 	pool_sethiwat(&pf_frag_pl, PFFRAG_FRAG_HIWAT);
-	pool_sethardlimit(&pf_frent_pl, PFFRAG_FRENT_HIWAT, NULL, 0);
+	pool_sethardlimit(&pf_frent_pl, PFFRAG_FRENT_HIWAT);
 
 	TAILQ_INIT(&pf_fragqueue);
 
Index: sys/netinet/tcp_subr.c
===================================================================
RCS file: /cvs/src/sys/netinet/tcp_subr.c,v
retrieving revision 1.209
diff -u -p -r1.209 tcp_subr.c
--- sys/netinet/tcp_subr.c	2 Mar 2025 21:28:32 -0000	1.209
+++ sys/netinet/tcp_subr.c	20 May 2025 20:22:24 -0000
@@ -154,10 +154,10 @@ tcp_init(void)
 	    "tcpcb", NULL);
 	pool_init(&tcpqe_pool, sizeof(struct tcpqent), 0, IPL_SOFTNET, 0,
 	    "tcpqe", NULL);
-	pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0);
+	pool_sethardlimit(&tcpqe_pool, tcp_reass_limit);
 	pool_init(&sackhl_pool, sizeof(struct sackhole), 0, IPL_SOFTNET, 0,
 	    "sackhl", NULL);
-	pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit, NULL, 0);
+	pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit);
 	in_pcbinit(&tcbtable, TCB_INITIAL_HASH_SIZE);
 #ifdef INET6
 	in_pcbinit(&tcb6table, TCB_INITIAL_HASH_SIZE);
Index: sys/netinet/tcp_usrreq.c
===================================================================
RCS file: /cvs/src/sys/netinet/tcp_usrreq.c,v
retrieving revision 1.247
diff -u -p -r1.247 tcp_usrreq.c
--- sys/netinet/tcp_usrreq.c	20 May 2025 18:41:06 -0000	1.247
+++ sys/netinet/tcp_usrreq.c	20 May 2025 20:22:24 -0000
@@ -1482,8 +1482,7 @@ tcp_sysctl(int *name, u_int namelen, voi
 			if (error)
 				return (error);
 			if (nval != atomic_load_int(var)) {
-				error = pool_sethardlimit(pool, nval,
-				    NULL, 0);
+				error = pool_sethardlimit(pool, nval);
 				if (error == 0)
 					atomic_store_int(var, nval);
 			}
Index: sys/sys/pool.h
===================================================================
RCS file: /cvs/src/sys/sys/pool.h,v
retrieving revision 1.80
diff -u -p -r1.80 pool.h
--- sys/sys/pool.h	4 Jan 2025 09:26:01 -0000	1.80
+++ sys/sys/pool.h	20 May 2025 20:22:24 -0000
@@ -211,14 +211,6 @@ struct pool {
 	int		pr_phoffset;	/* Offset in page of page header */
 
 	/*
-	 * Warning message to be issued, and a per-time-delta rate cap,
-	 * if the hard limit is reached.
-	 */
-	const char	*pr_hardlimit_warning;
-	struct timeval	pr_hardlimit_ratecap;
-	struct timeval	pr_hardlimit_warning_last;
-
-	/*
 	 * pool item requests queue
 	 */
 	union pool_lock	pr_requests_lock;
@@ -262,7 +254,7 @@ void		pool_cache_init(struct pool *);
 void		pool_destroy(struct pool *);
 void		pool_setlowat(struct pool *, int);
 void		pool_sethiwat(struct pool *, int);
-int		pool_sethardlimit(struct pool *, u_int, const char *, int);
+int		pool_sethardlimit(struct pool *, u_int);
 void		pool_set_constraints(struct pool *,
 		    const struct kmem_pa_mode *mode);