git: 29acb543931e - main - tcp_hostcache: add bool argument for tcp_hc_lookup() to tell are we looking to only read from the result, or to update it as well. For now doesn't affect locking, but allows to push stats and expire update into single place.

[Gleb Smirnoff]

The branch main has been updated by glebius:

URL: https://cgit.FreeBSD.org/src/commit/?id=29acb543931e390bcfb8672e1474811dc3da88a4

commit 29acb543931e390bcfb8672e1474811dc3da88a4
Author:     Gleb Smirnoff <glebius at FreeBSD.org>
AuthorDate: 2021-03-22 20:51:42 +0000
Commit:     Gleb Smirnoff <glebius at FreeBSD.org>
CommitDate: 2021-04-08 17:58:44 +0000

    tcp_hostcache: add bool argument for tcp_hc_lookup() to tell are we
    looking to only read from the result, or to update it as well.
    For now doesn't affect locking, but allows to push stats and expire
    update into single place.
    
    Reviewed by:    rscheff
---
 sys/netinet/tcp_hostcache.c | 45 ++++++++++++++++++++-------------------------
 1 file changed, 20 insertions(+), 25 deletions(-)

diff --git a/sys/netinet/tcp_hostcache.c b/sys/netinet/tcp_hostcache.c
index e048f926b02b..d138745491f2 100644
--- a/sys/netinet/tcp_hostcache.c
+++ b/sys/netinet/tcp_hostcache.c
@@ -161,7 +161,7 @@ VNET_DEFINE_STATIC(struct tcp_hostcache, tcp_hostcache);
 VNET_DEFINE_STATIC(struct callout, tcp_hc_callout);
 #define	V_tcp_hc_callout	VNET(tcp_hc_callout)
 
-static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
+static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *, bool);
 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
 static int sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS);
@@ -332,7 +332,7 @@ tcp_hc_destroy(void)
  * unlocking the bucket row after he is done reading/modifying the entry.
  */
 static struct hc_metrics *
-tcp_hc_lookup(struct in_conninfo *inc)
+tcp_hc_lookup(struct in_conninfo *inc, bool update)
 {
 	int hash;
 	struct hc_head *hc_head;
@@ -368,11 +368,11 @@ tcp_hc_lookup(struct in_conninfo *inc)
 			/* XXX: check ip6_zoneid */
 			if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
 			    sizeof(inc->inc6_faddr)) == 0)
-				return hc_entry;
+				goto found;
 		} else {
 			if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
 			    sizeof(inc->inc_faddr)) == 0)
-				return hc_entry;
+				goto found;
 		}
 	}
 
@@ -380,7 +380,18 @@ tcp_hc_lookup(struct in_conninfo *inc)
 	 * We were unsuccessful and didn't find anything.
 	 */
 	THC_UNLOCK(&hc_head->hch_mtx);
-	return NULL;
+	return (NULL);
+
+found:
+#ifdef	TCP_HC_COUNTERS
+	if (update)
+		hc_entry->rmx_updates++;
+	else
+		hc_entry->rmx_hits++;
+#endif
+	hc_entry->rmx_expire = V_tcp_hostcache.expire;
+
+	return (hc_entry);
 }
 
 /*
@@ -506,7 +517,7 @@ tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
 	/*
 	 * Find the right bucket.
 	 */
-	hc_entry = tcp_hc_lookup(inc);
+	hc_entry = tcp_hc_lookup(inc, false);
 
 	/*
 	 * If we don't have an existing object.
@@ -515,10 +526,6 @@ tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
 		bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
 		return;
 	}
-#ifdef	TCP_HC_COUNTERS
-	hc_entry->rmx_hits++;
-#endif
-	hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 
 	hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
 	hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
@@ -548,14 +555,10 @@ tcp_hc_getmtu(struct in_conninfo *inc)
 	if (!V_tcp_use_hostcache)
 		return 0;
 
-	hc_entry = tcp_hc_lookup(inc);
+	hc_entry = tcp_hc_lookup(inc, false);
 	if (hc_entry == NULL) {
 		return 0;
 	}
-#ifdef	TCP_HC_COUNTERS
-	hc_entry->rmx_hits++;
-#endif
-	hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 
 	mtu = hc_entry->rmx_mtu;
 	THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
@@ -577,7 +580,7 @@ tcp_hc_updatemtu(struct in_conninfo *inc, uint32_t mtu)
 	/*
 	 * Find the right bucket.
 	 */
-	hc_entry = tcp_hc_lookup(inc);
+	hc_entry = tcp_hc_lookup(inc, true);
 
 	/*
 	 * If we don't have an existing object, try to insert a new one.
@@ -587,10 +590,6 @@ tcp_hc_updatemtu(struct in_conninfo *inc, uint32_t mtu)
 		if (hc_entry == NULL)
 			return;
 	}
-#ifdef	TCP_HC_COUNTERS
-	hc_entry->rmx_updates++;
-#endif
-	hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 
 	hc_entry->rmx_mtu = mtu;
 
@@ -618,16 +617,12 @@ tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
 	if (!V_tcp_use_hostcache)
 		return;
 
-	hc_entry = tcp_hc_lookup(inc);
+	hc_entry = tcp_hc_lookup(inc, true);
 	if (hc_entry == NULL) {
 		hc_entry = tcp_hc_insert(inc);
 		if (hc_entry == NULL)
 			return;
 	}
-#ifdef	TCP_HC_COUNTERS
-	hc_entry->rmx_updates++;
-#endif
-	hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
 
 	if (hcml->rmx_rtt != 0) {
 		if (hc_entry->rmx_rtt == 0)