refs #5696 possible fix for drd issues, and for what seems like a typo condition

git-svn-id: file:///svn/toku/tokudb@50158 c7de825b-a66e-492c-adef-691d508d4ae1

ft/cachetable.cc

@@ -3002,8 +3002,17 @@ int cleaner::run_cleaner(void) {
                 // Advance the cleaner head.
                 long score = 0;
                 // only bother with this pair if it has no current users
-                if (m_pl->m_cleaner_head->value_rwlock.users() > 0) {
+                if (m_pl->m_cleaner_head->value_rwlock.users() == 0) {
+                    // cleaner_thread_rate_pair will read this.  The
+                    // contract is that to look at p->attr, you need
+                    // either the pair's value_rwlock write-locked, or you
+                    // need the pair_lock *and* the pair's value_rwlock
+                    // read-locked.  Here we know nobody else has it
+                    // write-locked so it's safe, but DRD seems not to
+                    // understand that.
+                    TOKU_DRD_IGNORE_VAR(m_pl->m_cleaner_head->attr.cache_pressure_size);
                     score = cleaner_thread_rate_pair(m_pl->m_cleaner_head);
+                    TOKU_DRD_STOP_IGNORING_VAR(m_pl->m_cleaner_head->attr.cache_pressure_size);
                     if (score > best_score) {
                         best_score = score;
                         best_pair = m_pl->m_cleaner_head;
@@ -3019,7 +3028,10 @@ int cleaner::run_cleaner(void) {
             else {
                 n_seen++;
                 long score = 0;
+                // See above
+                TOKU_DRD_IGNORE_VAR(m_pl->m_cleaner_head->attr.cache_pressure_size);
                 score = cleaner_thread_rate_pair(m_pl->m_cleaner_head);
+                TOKU_DRD_STOP_IGNORING_VAR(m_pl->m_cleaner_head->attr.cache_pressure_size);
                 if (score > best_score) {
                     best_score = score;
                     // Since we found a new best pair, we need to
@@ -3074,8 +3086,7 @@ int cleaner::run_cleaner(void) {
             // it's theoretically possible that after writing a PAIR for checkpoint, the
             // PAIR's heuristic tells us nothing needs to be done. It is not possible
             // in Dr. Noga, but unit tests verify this behavior works properly.
-            if (cleaner_thread_rate_pair(best_pair) > 0) 
-            {
+            if (cleaner_thread_rate_pair(best_pair) > 0) {
                 r = best_pair->cleaner_callback(best_pair->value_data,
                                                     best_pair->key,
                                                     best_pair->fullhash,