From af399529ecca4c6e082474cada76c9b96a3d8f86 Mon Sep 17 00:00:00 2001
From: vyzo <vyzo@hackzen.org>
Date: Tue, 13 Jul 2021 09:06:40 +0300
Subject: [PATCH] finetune view waiting

---
 blockstore/splitstore/splitstore.go | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/blockstore/splitstore/splitstore.go b/blockstore/splitstore/splitstore.go
index 563b14bc4fe..75989b53c7e 100644
--- a/blockstore/splitstore/splitstore.go
+++ b/blockstore/splitstore/splitstore.go
@@ -146,15 +146,16 @@ type SplitStore struct {
 	debug *debugLog
 
 	// transactional protection for concurrent read/writes during compaction
-	txnLk        sync.RWMutex
-	txnViewsMx   sync.Mutex
-	txnViewsCond sync.Cond
-	txnViews     int
-	txnActive    bool
-	txnProtect   MarkSet
-	txnRefsMx    sync.Mutex
-	txnRefs      map[cid.Cid]struct{}
-	txnMissing   map[cid.Cid]struct{}
+	txnLk           sync.RWMutex
+	txnViewsMx      sync.Mutex
+	txnViewsCond    sync.Cond
+	txnViews        int
+	txnViewsWaiting bool
+	txnActive       bool
+	txnProtect      MarkSet
+	txnRefsMx       sync.Mutex
+	txnRefs         map[cid.Cid]struct{}
+	txnMissing      map[cid.Cid]struct{}
 }
 
 var _ bstore.Blockstore = (*SplitStore)(nil)
@@ -651,7 +652,7 @@ func (s *SplitStore) viewDone() {
 	defer s.txnViewsMx.Unlock()
 
 	s.txnViews--
-	if s.txnViews == 0 {
+	if s.txnViews == 0 && s.txnViewsWaiting {
 		s.txnViewsCond.Signal()
 	}
 }
@@ -660,9 +661,11 @@ func (s *SplitStore) viewWait() {
 	s.txnViewsMx.Lock()
 	defer s.txnViewsMx.Unlock()
 
+	s.txnViewsWaiting = true
 	for s.txnViews > 0 {
 		s.txnViewsCond.Wait()
 	}
+	s.txnViewsWaiting = false
 }
 
 // transactionally protect a reference to an object