Reorg code so that fast paths stay inlined, shift the slow part of full cache handling into a separate function.

refs #1596

5 files changed, 125 insertions, 114 deletions

diff --git a/src/evict/evict_lru.c b/src/evict/evict_lru.c
index a7e666e31a2..ccabddcf539 100644
--- a/src/evict/evict_lru.c
+++ b/src/evict/evict_lru.c
@@ -1319,6 +1319,94 @@ __wt_evict_lru_page(WT_SESSION_IMPL *session, int is_server)
 	return (ret);
 }
 
+/*
+ * __wt_cache_wait --
+ *	Wait for space in the cache.
+ */
+int
+__wt_cache_wait(WT_SESSION_IMPL *session, int full)
+{
+	WT_CACHE *cache;
+	WT_DECL_RET;
+	WT_TXN_GLOBAL *txn_global;
+	WT_TXN_STATE *txn_state;
+	int busy, count;
+
+	cache = S2C(session)->cache;
+
+	/*
+	 * If the current transaction is keeping the oldest ID pinned, it is in
+	 * the middle of an operation.	This may prevent the oldest ID from
+	 * moving forward, leading to deadlock, so only evict what we can.
+	 * Otherwise, we are at a transaction boundary and we can work harder
+	 * to make sure there is free space in the cache.
+	 */
+	txn_global = &S2C(session)->txn_global;
+	txn_state = &txn_global->states[session->id];
+	busy = txn_state->id != WT_TXN_NONE ||
+	    session->nhazard > 0 ||
+	    (txn_state->snap_min != WT_TXN_NONE &&
+	    txn_global->current != txn_global->oldest_id);
+	if (busy && full < 100)
+		return (0);
+	count = busy ? 1 : 10;
+
+	for (;;) {
+		/*
+		 * A pathological case: if we're the oldest transaction in the
+		 * system and the eviction server is stuck trying to find space,
+		 * abort the transaction to give up all hazard pointers before
+		 * trying again.
+		 */
+		if (F_ISSET(cache, WT_EVICT_STUCK) &&
+		    __wt_txn_am_oldest(session)) {
+			F_CLR(cache, WT_EVICT_STUCK);
+			WT_STAT_FAST_CONN_INCR(session, txn_fail_cache);
+			return (WT_ROLLBACK);
+		}
+
+		switch (ret = __wt_evict_lru_page(session, 0)) {
+		case 0:
+			if (--count == 0)
+				return (0);
+			break;
+		case EBUSY:
+			continue;
+		case WT_NOTFOUND:
+			break;
+		default:
+			return (ret);
+		}
+
+		WT_RET(__wt_eviction_check(session, &full, 0));
+		if (full < 100)
+			return (0);
+		else if (ret == 0)
+			continue;
+
+		/*
+		 * The cache is still full and no pages were found in the queue
+		 * to evict.  If this transaction is the one holding back the
+		 * oldest ID, we can't wait forever.  We'll block next time we
+		 * are not busy.
+		 */
+		if (busy) {
+			__wt_txn_update_oldest(session);
+			if (txn_state->id == txn_global->oldest_id ||
+			    txn_state->snap_min == txn_global->oldest_id)
+				return (0);
+		}
+
+		/* Wait for the queue to re-populate before trying again. */
+		WT_RET(__wt_cond_wait(session,
+		    S2C(session)->cache->evict_waiter_cond, 100000));
+
+		/* Check if things have changed so that we are busy. */
+		if (!busy && txn_state->snap_min != WT_TXN_NONE &&
+		    txn_global->current != txn_global->oldest_id)
+			busy = count = 1;
+	}
+}
 #ifdef HAVE_DIAGNOSTIC
 /*
  * __wt_cache_dump --
diff --git a/src/include/cache.i b/src/include/cache.i
index af6f1bf375d..c5bf8c4221f 100644
--- a/src/include/cache.i
+++ b/src/include/cache.i
@@ -136,13 +136,7 @@ static inline int
 __wt_cache_full_check(WT_SESSION_IMPL *session)
 {
 	WT_BTREE *btree;
-	WT_CACHE *cache;
-	WT_DECL_RET;
-	WT_TXN_GLOBAL *txn_global;
-	WT_TXN_STATE *txn_state;
-	int busy, count, full;
-
-	cache = S2C(session)->cache;
+	int full;
 
 	/*
 	 * LSM sets the no-cache-check flag when holding the LSM tree lock, in
@@ -165,86 +159,15 @@ __wt_cache_full_check(WT_SESSION_IMPL *session)
 	 * Only wake the eviction server the first time through here (if the
 	 * cache is too full).
 	 *
-	 * If the cache is less than 95% full, no work to be done.
+	 * If the cache is less than 95% full, no work to be done.  If we are
+	 * at the API boundary and the cache is more than 95% full, try to
+	 * evict at least one page before we start an operation.  This helps
+	 * with some eviction-dominated workloads.
 	 */
 	WT_RET(__wt_eviction_check(session, &full, 1));
 	if (full < 95)
 		return (0);
 
-	/*
-	 * If we are at the API boundary and the cache is more than 95% full,
-	 * try to evict at least one page before we start an operation.  This
-	 * helps with some eviction-dominated workloads.
-	 *
-	 * If the current transaction is keeping the oldest ID pinned, it is in
-	 * the middle of an operation.	This may prevent the oldest ID from
-	 * moving forward, leading to deadlock, so only evict what we can.
-	 * Otherwise, we are at a transaction boundary and we can work harder
-	 * to make sure there is free space in the cache.
-	 */
-	txn_global = &S2C(session)->txn_global;
-	txn_state = &txn_global->states[session->id];
-	busy = txn_state->id != WT_TXN_NONE ||
-	    session->nhazard > 0 ||
-	    (txn_state->snap_min != WT_TXN_NONE &&
-	    txn_global->current != txn_global->oldest_id);
-	if (busy && full < 100)
-		return (0);
-	count = busy ? 1 : 10;
-
-	for (;;) {
-		/*
-		 * A pathological case: if we're the oldest transaction in the
-		 * system and the eviction server is stuck trying to find space,
-		 * abort the transaction to give up all hazard pointers before
-		 * trying again.
-		 */
-		if (F_ISSET(cache, WT_EVICT_STUCK) &&
-		    __wt_txn_am_oldest(session)) {
-			F_CLR(cache, WT_EVICT_STUCK);
-			WT_STAT_FAST_CONN_INCR(session, txn_fail_cache);
-			return (WT_ROLLBACK);
-		}
-
-		switch (ret = __wt_evict_lru_page(session, 0)) {
-		case 0:
-			if (--count == 0)
-				return (0);
-			break;
-		case EBUSY:
-			continue;
-		case WT_NOTFOUND:
-			break;
-		default:
-			return (ret);
-		}
-
-		WT_RET(__wt_eviction_check(session, &full, 0));
-		if (full < 100)
-			return (0);
-		else if (ret == 0)
-			continue;
-
-		/*
-		 * The cache is still full and no pages were found in the queue
-		 * to evict.  If this transaction is the one holding back the
-		 * oldest ID, we can't wait forever.  We'll block next time we
-		 * are not busy.
-		 */
-		if (busy) {
-			__wt_txn_update_oldest(session);
-			if (txn_state->id == txn_global->oldest_id ||
-			    txn_state->snap_min == txn_global->oldest_id)
-				return (0);
-		}
-
-		/* Wait for the queue to re-populate before trying again. */
-		WT_RET(__wt_cond_wait(session,
-		    S2C(session)->cache->evict_waiter_cond, 100000));
-
-		/* Check if things have changed so that we are busy. */
-		if (!busy && txn_state->snap_min != WT_TXN_NONE &&
-		    txn_global->current != txn_global->oldest_id)
-			busy = count = 1;
-	}
+	return (__wt_cache_wait(session, full));
 }
+
diff --git a/src/include/extern.h b/src/include/extern.h
index 1850aec75ce..a40f9fec368 100644
--- a/src/include/extern.h
+++ b/src/include/extern.h
@@ -299,6 +299,7 @@ extern int __wt_evict_page(WT_SESSION_IMPL *session, WT_REF *ref);
 extern int __wt_evict_file_exclusive_on(WT_SESSION_IMPL *session);
 extern void __wt_evict_file_exclusive_off(WT_SESSION_IMPL *session);
 extern int __wt_evict_lru_page(WT_SESSION_IMPL *session, int is_server);
+extern int __wt_cache_wait(WT_SESSION_IMPL *session, int full);
 extern void __wt_cache_dump(WT_SESSION_IMPL *session);
 extern int __wt_evict(WT_SESSION_IMPL *session, WT_REF *ref, int exclusive);
 extern void __wt_rec_page_clean_update(WT_SESSION_IMPL *session, WT_REF *ref);
@@ -633,7 +634,6 @@ extern void __wt_stat_init_connection_stats(WT_CONNECTION_STATS *stats);
 extern void __wt_stat_refresh_connection_stats(void *stats_arg);
 extern int __wt_txnid_cmp(const void *v1, const void *v2);
 extern void __wt_txn_release_snapshot(WT_SESSION_IMPL *session);
-extern int __wt_txn_am_oldest(WT_SESSION_IMPL *session);
 extern void __wt_txn_update_oldest(WT_SESSION_IMPL *session);
 extern void __wt_txn_refresh(WT_SESSION_IMPL *session, int get_snapshot);
 extern int __wt_txn_begin(WT_SESSION_IMPL *session, const char *cfg[]);
diff --git a/src/include/txn.i b/src/include/txn.i
index be8af9ae77b..f5f9b662e6f 100644
--- a/src/include/txn.i
+++ b/src/include/txn.i
@@ -359,3 +359,32 @@ __wt_txn_cursor_op(WT_SESSION_IMPL *session)
 	    !F_ISSET(txn, TXN_HAS_SNAPSHOT))
 		__wt_txn_refresh(session, 1);
 }
+
+/*
+ * __wt_txn_am_oldest --
+ *	Am I the oldest transaction in the system?
+ */
+static inline int
+__wt_txn_am_oldest(WT_SESSION_IMPL *session)
+{
+	WT_CONNECTION_IMPL *conn;
+	WT_TXN *txn;
+	WT_TXN_GLOBAL *txn_global;
+	WT_TXN_STATE *s;
+	uint64_t id;
+	uint32_t i, session_cnt;
+
+	conn = S2C(session);
+	txn = &session->txn;
+	txn_global = &conn->txn_global;
+
+	if (txn->id == WT_TXN_NONE)
+		return (0);
+
+	WT_ORDERED_READ(session_cnt, conn->session_cnt);
+	for (i = 0, s = txn_global->states; i < session_cnt; i++, s++)
+		if ((id = s->id) != WT_TXN_NONE && TXNID_LT(id, txn->id))
+			return (0);
+
+	return (1);
+}
diff --git a/src/txn/txn.c b/src/txn/txn.c
index 7eef7ad20ac..5b8f11a88a5 100644
--- a/src/txn/txn.c
+++ b/src/txn/txn.c
@@ -67,35 +67,6 @@ __wt_txn_release_snapshot(WT_SESSION_IMPL *session)
 }
 
 /*
- * __wt_txn_am_oldest --
- *	Am I the oldest transaction in the system?
- */
-int
-__wt_txn_am_oldest(WT_SESSION_IMPL *session)
-{
-	WT_CONNECTION_IMPL *conn;
-	WT_TXN *txn;
-	WT_TXN_GLOBAL *txn_global;
-	WT_TXN_STATE *s;
-	uint64_t id;
-	uint32_t i, session_cnt;
-
-	conn = S2C(session);
-	txn = &session->txn;
-	txn_global = &conn->txn_global;
-
-	if (txn->id == WT_TXN_NONE)
-		return (0);
-
-	WT_ORDERED_READ(session_cnt, conn->session_cnt);
-	for (i = 0, s = txn_global->states; i < session_cnt; i++, s++)
-		if ((id = s->id) != WT_TXN_NONE && TXNID_LT(id, txn->id))
-			return (0);
-
-	return (1);
-}
-
-/*
  * __wt_txn_update_oldest --
  *	Sweep the running transactions to update the oldest ID required.
  */