Better cache counting, partially revert 1.85

diff --git a/servers/slapd/back-bdb/cache.c b/servers/slapd/back-bdb/cache.c
index a0e436d87ed6170d8156a2e9cebe1e4dfbf07cc9..eaabdf020dbb604dc7217f2afe072b931da93fbe 100644 (file)
--- a/servers/slapd/back-bdb/cache.c
+++ b/servers/slapd/back-bdb/cache.c
@@ -532,16 +532,12 @@ bdb_cache_lru_add(
                        /* Too many probes, not enough idle, give up */
                        if (i > 10) break;
 
-                       /* Leave DB root alone, BDB_HIER needs this */
-                       if ( elru->bei_parent && !elru->bei_parent->bei_parent )
-                               continue;
-
                        /* If we can successfully writelock it, then
                         * the object is idle.
                         */
                        if ( bdb_cache_entry_db_lock( bdb->bi_dbenv, bdb->bi_cache.c_locker, elru, 1, 1,
                                lockp ) == 0 ) {
-                               int lstat;
+                               int stop = 0;
 
                                /* If there's no entry, or this node is in
                                 * the process of linking into the cache,
@@ -552,32 +548,17 @@ bdb_cache_lru_add(
                                        bdb_cache_entry_db_unlock( bdb->bi_dbenv, lockp );
                                        continue;
                                }
-                               /* If this node is in use or has children, just free the
-                                * entry and unlink from the LRU list.
-                                */
-                               lstat = ldap_pvt_thread_mutex_trylock( &elru->bei_kids_mutex );
-                               if ( lstat || elru->bei_kids ) {
-                                       LRU_DELETE( &bdb->bi_cache, elru );
-                                       elru->bei_e->e_private = NULL;
-                                       bdb_entry_return( elru->bei_e );
-                                       elru->bei_e = NULL;
-
-                                       if ( !lstat )
-                                               bdb_cache_entryinfo_unlock( elru );
-
-                               /* Else free the entry and its entryinfo.
-                                */
-                               } else {
-                                       bdb_cache_delete_internal( &bdb->bi_cache, elru, 0 );
-                                       bdb_cache_delete_cleanup( &bdb->bi_cache, elru );
-
-                                       /* break the loop, unsafe to muck with more than one */
-                                       elprev = NULL;
-                               }
-                               bdb_cache_entry_db_unlock( bdb->bi_dbenv, lockp );
+                               LRU_DELETE( &bdb->bi_cache, elru );
+                               elru->bei_e->e_private = NULL;
+                               bdb_entry_return( elru->bei_e );
+                               elru->bei_e = NULL;
+                               ldap_pvt_thread_rdwr_wlock( &bdb->bi_cache.c_rwlock );
                                --bdb->bi_cache.c_cursize;
-                               if (bdb->bi_cache.c_cursize < bdb->bi_cache.c_maxsize)
-                                       break;
+                               if (bdb->bi_cache.c_cursize <= bdb->bi_cache.c_maxsize)
+                                       stop = 1;
+                               ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
+                               bdb_cache_entry_db_unlock( bdb->bi_dbenv, lockp );
+                               if (stop) break;
                        }
                }
        }
@@ -620,7 +601,7 @@ bdb_cache_find_id(
 {
        struct bdb_info *bdb = (struct bdb_info *) op->o_bd->be_private;
        Entry   *ep = NULL;
-       int     rc = 0;
+       int     rc = 0, load = 0;
        EntryInfo ei = { 0 };
 
        ei.bei_id = id;
@@ -683,7 +664,6 @@ again:      ldap_pvt_thread_rdwr_rlock( &bdb->bi_cache.c_rwlock );
                if ( (*eip)->bei_state & CACHE_ENTRY_DELETED ) {
                        rc = DB_NOTFOUND;
                } else {
-                       int load = 0;
                        /* Make sure only one thread tries to load the entry */
 load1:         if ( !(*eip)->bei_e && !((*eip)->bei_state & CACHE_ENTRY_LOADING)) {
                                load = 1;
@@ -794,17 +774,30 @@ load1:            if ( !(*eip)->bei_e && !((*eip)->bei_state & CACHE_ENTRY_LOADING)) {
                bdb_entry_return( ep );
        }
        if ( rc == 0 ) {
-               /* set lru mutex */
+
+               if ( load ) {
+                       ldap_pvt_thread_rdwr_wlock( &bdb->bi_cache.c_rwlock );
+                       bdb->bi_cache.c_cursize++;
+                       ldap_pvt_thread_rdwr_wunlock( &bdb->bi_cache.c_rwlock );
+               }
+
                ldap_pvt_thread_mutex_lock( &bdb->bi_cache.lru_mutex );
-               /* if entry is on LRU list, remove from old spot */
-               if ( (*eip)->bei_lrunext || (*eip)->bei_lruprev ) {
-                       LRU_DELETE( &bdb->bi_cache, *eip );
+
+               /* If the LRU list has only one entry and this is it, it
+                * doesn't need to be added again.
+                */
+               if ( bdb->bi_cache.c_lruhead == bdb->bi_cache.c_lrutail &&
+                       bdb->bi_cache.c_lruhead == *eip ) {
+                       ldap_pvt_thread_mutex_unlock( &bdb->bi_cache.lru_mutex );
                } else {
-               /* if entry is new, bump cache size */
-                       bdb->bi_cache.c_cursize++;
+
+                       /* if entry is on LRU list, remove from old spot */
+                       if ( (*eip)->bei_lrunext || (*eip)->bei_lruprev ) {
+                               LRU_DELETE( &bdb->bi_cache, *eip );
+                       }
+                       /* lru_mutex is unlocked for us */
+                       bdb_cache_lru_add( bdb, locker, *eip );
                }
-               /* lru_mutex is unlocked for us */
-               bdb_cache_lru_add( bdb, locker, *eip );
        }
 
        return rc;