[GUI] Do not update the GUI so often when reindex/import is being exe…

…cuted.

src/main.cpp

@@ -77,8 +77,8 @@ std::condition_variable g_best_block_cv;
 uint256 g_best_block;
 
 int nScriptCheckThreads = 0;
-bool fImporting = false;
-bool fReindex = false;
+std::atomic<bool> fImporting{false};
+std::atomic<bool> fReindex{false};
 bool fTxIndex = true;
 bool fIsBareMultisigStd = true;
 bool fCheckBlockIndex = false;
@@ -5287,7 +5287,7 @@ bool static LoadBlockIndexDB(string& strError)
     // Check whether we need to continue reindexing
     bool fReindexing = false;
     pblocktree->ReadReindexing(fReindexing);
-    fReindex |= fReindexing;
+    if(fReindexing) fReindex = true;
 
     // Check whether we have a transaction index
     pblocktree->ReadFlag("txindex", fTxIndex);

src/main.h

@@ -32,6 +32,7 @@
 #include "undo.h"
 
 #include <algorithm>
+#include <atomic>
 #include <exception>
 #include <map>
 #include <set>
@@ -153,8 +154,8 @@ extern CWaitableCriticalSection g_best_block_mutex;
 extern std::condition_variable g_best_block_cv;
 extern uint256 g_best_block;
 
-extern bool fImporting;
-extern bool fReindex;
+extern std::atomic<bool> fImporting;
+extern std::atomic<bool> fReindex;
 extern int nScriptCheckThreads;
 extern bool fTxIndex;
 extern bool fIsBareMultisigStd;

src/qt/walletmodel.cpp

@@ -174,8 +174,20 @@ bool WalletModel::isWalletUnlocked() const {
     return status == Unencrypted || status == Unlocked;
 }
 
+bool IsImportingOrReindexing() {
+    return fImporting || fReindex;
+}
+
 void WalletModel::pollBalanceChanged()
 {
+    // Wait a little bit more when the wallet is reindexing and/or importing, no need to lock cs_main so often.
+    if (IsImportingOrReindexing()) {
+        static uint8_t waitLonger = 0;
+        waitLonger++;
+        if (waitLonger < 10) // 10 seconds
+            return;
+        waitLonger = 0;
+    }
     // Get required locks upfront. This avoids the GUI from getting stuck on
     // periodical polls if the core is holding the locks for a longer time -
     // for example, during a wallet rescan.
@@ -186,11 +198,12 @@ void WalletModel::pollBalanceChanged()
     if (!lockWallet)
         return;
 
-    if (fForceCheckBalanceChanged || chainActive.Height() != cachedNumBlocks || nZeromintPercentage != cachedZeromintPercentage || cachedTxLocks != nCompleteTXLocks) {
+    int chainHeight = chainActive.Height();
+    if (fForceCheckBalanceChanged || chainHeight != cachedNumBlocks) {
         fForceCheckBalanceChanged = false;
 
         // Balance and number of transactions might have changed
-        cachedNumBlocks = chainActive.Height();
+        cachedNumBlocks = chainHeight;
         cachedZeromintPercentage = nZeromintPercentage;
 
         checkBalanceChanged();