Drop the eviction lock while waiting for LRU eviction to drain: avoid a deadlock where LRU eviction has to take the eviction lock to clear.

1 files changed, 8 insertions, 9 deletions

diff --git a/src/btree/bt_evict.c b/src/btree/bt_evict.c
index 678e2454b9c..a478cf16edf 100644
--- a/src/btree/bt_evict.c
+++ b/src/btree/bt_evict.c
@@ -520,8 +520,11 @@ __evict_file_request_walk(WT_SESSION_IMPL *session)
 	 * to reason about sync or forced eviction if we know there are
 	 * no other threads evicting in the tree.
 	 */
-	while (request_session->btree->lru_count > 0)
+	while (request_session->btree->lru_count > 0) {
+		__wt_spin_unlock(session, &cache->evict_lock);
 		__wt_yield();
+		__wt_spin_lock(session, &cache->evict_lock);
+	}
 
 	ret = __evict_file_request(request_session, syncop);
 
@@ -644,8 +647,11 @@ __evict_page_request_walk(WT_SESSION_IMPL *session)
 		 * to reason about sync or forced eviction if we know there are
 		 * no other threads evicting in the tree.
 		 */
-		while (session->btree->lru_count > 0)
+		while (session->btree->lru_count > 0) {
+			__wt_spin_unlock(session, &cache->evict_lock);
 			__wt_yield();
+			__wt_spin_lock(session, &cache->evict_lock);
+		}
 
 		ref = page->ref;
 		WT_ASSERT(session, ref->page == page);
@@ -653,13 +659,6 @@ __evict_page_request_walk(WT_SESSION_IMPL *session)
 		ref->state = WT_REF_LOCKED;
 
 		/*
-		 * At this point, the page is locked, which stalls new readers.
-		 * Pause before attempting to evict it to give existing readers
-		 * a chance to drop their references.
-		 */
-		__wt_yield();
-
-		/*
 		 * If eviction fails, it will free up the page: hope it works
 		 * next time.  Application threads may be holding a reference
 		 * while trying to get another (e.g., if they have two cursors