Index: sys/netinet/tcp_hostcache.c =================================================================== --- sys/netinet/tcp_hostcache.c +++ sys/netinet/tcp_hostcache.c @@ -121,6 +121,7 @@ static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *); 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); static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS); static void tcp_hc_purge_internal(int); static void tcp_hc_purge(void *); @@ -168,6 +169,11 @@ 0, 0, sysctl_tcp_hc_list, "A", "List of all hostcache entries"); +SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, histo, + CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE, + 0, 0, sysctl_tcp_hc_histo, "A", + "Print a histogram of hostcache hashbucket utilization"); + SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, sysctl_tcp_hc_purgenow, "I", @@ -390,6 +396,11 @@ return NULL; } TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q); + KASSERT(V_tcp_hostcache.hashbase[hash].hch_length > 0 && + V_tcp_hostcache.hashbase[hash].hch_length <= + V_tcp_hostcache.bucket_limit, + ("tcp_hostcache: bucket length range violated at %u: %u", + hash, V_tcp_hostcache.hashbase[hash].hch_length)); V_tcp_hostcache.hashbase[hash].hch_length--; atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); TCPSTAT_INC(tcps_hc_bucketoverflow); @@ -424,6 +435,10 @@ */ TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q); V_tcp_hostcache.hashbase[hash].hch_length++; + KASSERT(V_tcp_hostcache.hashbase[hash].hch_length < + V_tcp_hostcache.bucket_limit, + ("tcp_hostcache: bucket length too high at %u: %u", + hash, V_tcp_hostcache.hashbase[hash].hch_length)); atomic_add_int(&V_tcp_hostcache.cache_count, 1); TCPSTAT_INC(tcps_hc_added); @@ -696,6 +711,48 @@ return(error); } +/* + * Sysctl function: prints a histogram of the hostcache hashbucket + * utilization. + */ +static int +sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS) +{ + const int linesize = 50; + struct sbuf sb; + int i, error; + int *histo; + int hch_length; + + if (jailed_without_vnet(curthread->td_ucred) != 0) + return (EPERM); + + histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1), + M_TEMP, M_NOWAIT|M_ZERO); + if (histo == NULL) + return(ENOMEM); + + for (i = 0; i < V_tcp_hostcache.hashsize; i++) { + hch_length = V_tcp_hostcache.hashbase[i].hch_length; + KASSERT(hch_length <= V_tcp_hostcache.bucket_limit, + ("tcp_hostcache: bucket limit exceeded at %u: %u", + i, hch_length)); + histo[hch_length]++; + } + + /* Use a buffer for 16 lines */ + sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req); + + sbuf_printf(&sb, "\nLength\tCount\n"); + for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) { + sbuf_printf(&sb, "%u\t%u\n", i, histo[i]); + } + error = sbuf_finish(&sb); + sbuf_delete(&sb); + free(histo, M_TEMP); + return(error); +} + /* * Caller has to make sure the curvnet is set properly. */ @@ -717,6 +774,11 @@ atomic_subtract_int(&V_tcp_hostcache.cache_count, 1); } else hc_entry->rmx_expire -= V_tcp_hostcache.prune; + KASSERT(V_tcp_hostcache.hashbase[i].hch_length >= 0 && + V_tcp_hostcache.hashbase[i].hch_length <= + V_tcp_hostcache.bucket_limit, + ("tcp_hostcache: bucket langth out of range at %u: %u", + i, V_tcp_hostcache.hashbase[i].hch_length)); } THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx); }