diff --git a/activities/KioActivities.cpp b/activities/KioActivities.cpp
--- a/activities/KioActivities.cpp
+++ b/activities/KioActivities.cpp
@@ -101,6 +101,7 @@
     KIO::UDSEntry activityEntry(const QString &activity)
     {
         KIO::UDSEntry uds;
+        uds.reserve(8);
         KActivities::Info activityInfo(activity);
         uds.fastInsert(KIO::UDSEntry::UDS_NAME, activity);
         uds.fastInsert(KIO::UDSEntry::UDS_DISPLAY_NAME, activityInfo.name());
@@ -224,6 +225,7 @@
             KIO::UDSEntryList udslist;
 
             KIO::UDSEntry uds;
+            uds.reserve(9);
             uds.fastInsert(KIO::UDSEntry::UDS_NAME, QStringLiteral("current"));
             uds.fastInsert(KIO::UDSEntry::UDS_DISPLAY_NAME, i18n("Current activity"));
             uds.fastInsert(KIO::UDSEntry::UDS_DISPLAY_TYPE, i18n("Activity"));
@@ -305,6 +307,7 @@
         {
             QString dirName = i18n("Activities");
             KIO::UDSEntry uds;
+            uds.reserve(6);
             uds.fastInsert(KIO::UDSEntry::UDS_NAME, dirName);
             uds.fastInsert(KIO::UDSEntry::UDS_DISPLAY_NAME, dirName);
             uds.fastInsert(KIO::UDSEntry::UDS_DISPLAY_TYPE, dirName);
diff --git a/archive/kio_archivebase.cpp b/archive/kio_archivebase.cpp
--- a/archive/kio_archivebase.cpp
+++ b/archive/kio_archivebase.cpp
@@ -177,6 +177,7 @@
 void ArchiveProtocolBase::createRootUDSEntry( KIO::UDSEntry & entry )
 {
     entry.clear();
+    entry.reserve(5);
     entry.fastInsert( KIO::UDSEntry::UDS_NAME, "." );
     entry.fastInsert( KIO::UDSEntry::UDS_FILE_TYPE, S_IFDIR );
     entry.fastInsert( KIO::UDSEntry::UDS_MODIFICATION_TIME, m_mtime );
@@ -188,6 +189,7 @@
 void ArchiveProtocolBase::createUDSEntry( const KArchiveEntry * archiveEntry, UDSEntry & entry )
 {
     entry.clear();
+    entry.reserve(8);
     entry.fastInsert( KIO::UDSEntry::UDS_NAME, archiveEntry->name() );
     entry.fastInsert( KIO::UDSEntry::UDS_FILE_TYPE, archiveEntry->permissions() & S_IFMT ); // keep file type only
     entry.fastInsert( KIO::UDSEntry::UDS_SIZE, archiveEntry->isFile() ? ((KArchiveFile *)archiveEntry)->size() : 0L );
@@ -315,6 +317,7 @@
             error( errorNum, url.toDisplayString() );
             return;
         }
+        entry.reserve(2);
         // Real directory. Return just enough information for KRun to work
         entry.fastInsert( KIO::UDSEntry::UDS_NAME, url.fileName());
         qCDebug(KIO_ARCHIVE_LOG).nospace() << "ArchiveProtocolBase::stat returning name=" << url.fileName();
diff --git a/man/kio_man.cpp b/man/kio_man.cpp
--- a/man/kio_man.cpp
+++ b/man/kio_man.cpp
@@ -672,6 +672,7 @@
     qCDebug(KIO_MAN_LOG) << "URL " << url.url() << " parsed to title='" << title << "' section=" << section;
 
     UDSEntry entry;
+    entry.reserve(3);
     entry.fastInsert(KIO::UDSEntry::UDS_NAME, title);
     entry.fastInsert(KIO::UDSEntry::UDS_FILE_TYPE, S_IFREG);
     entry.fastInsert(KIO::UDSEntry::UDS_MIME_TYPE, QString::fromLatin1("text/html"));
@@ -1381,6 +1382,7 @@
     if (section.isEmpty()) {
         for (QStringList::ConstIterator it = section_names.constBegin(); it != section_names.constEnd(); ++it) {
             UDSEntry     uds_entry;
+            uds_entry.reserve(3);
 
             QString name = "man:/(" + *it + ')';
             uds_entry.fastInsert( KIO::UDSEntry::UDS_NAME, sectionName( *it ) );
@@ -1400,6 +1402,7 @@
         stripExtension( &(*it) );
 
         UDSEntry     uds_entry;
+        uds_entry.reserve(3);
         uds_entry.fastInsert(KIO::UDSEntry::UDS_NAME, *it);
         uds_entry.fastInsert(KIO::UDSEntry::UDS_FILE_TYPE, S_IFREG);
         uds_entry.fastInsert(KIO::UDSEntry::UDS_MIME_TYPE, QString::fromLatin1("text/html"));
diff --git a/mtp/kio_mtp.cpp b/mtp/kio_mtp.cpp
--- a/mtp/kio_mtp.cpp
+++ b/mtp/kio_mtp.cpp
@@ -37,6 +37,7 @@
 static UDSEntry getEntry(const KMTPDeviceInterface *device)
 {
     UDSEntry entry;
+    entry.reserve(5);
     entry.fastInsert(UDSEntry::UDS_NAME, device->friendlyName());
     entry.fastInsert(UDSEntry::UDS_ICON_NAME, QStringLiteral("multimedia-player"));
     entry.fastInsert(UDSEntry::UDS_FILE_TYPE, S_IFDIR);
@@ -48,6 +49,7 @@
 static UDSEntry getEntry(const KMTPStorageInterface *storage)
 {
     UDSEntry entry;
+    entry.reserve(5);
     entry.fastInsert(UDSEntry::UDS_NAME, storage->description());
     entry.fastInsert(UDSEntry::UDS_ICON_NAME, QStringLiteral("drive-removable-media"));
     entry.fastInsert(UDSEntry::UDS_FILE_TYPE, S_IFDIR);
@@ -59,6 +61,7 @@
 static UDSEntry getEntry(const KMTPFile &file)
 {
     UDSEntry entry;
+    entry.reserve(9);
     entry.fastInsert(UDSEntry::UDS_NAME, file.filename());
     if (file.isFolder()) {
         entry.fastInsert(UDSEntry::UDS_FILE_TYPE, S_IFDIR);
@@ -175,6 +178,7 @@
 
     // list '.' entry, otherwise files cannot be pasted to empty folders
     KIO::UDSEntry entry;
+    entry.reserve(4);
     entry.fastInsert(KIO::UDSEntry::UDS_NAME, QStringLiteral("."));
     entry.fastInsert(KIO::UDSEntry::UDS_FILE_TYPE, S_IFDIR);
     entry.fastInsert(KIO::UDSEntry::UDS_SIZE, 0);
@@ -278,6 +282,7 @@
     UDSEntry entry;
     // root
     if (pathItems.size() < 1) {
+        entry.reserve(4);
         entry.fastInsert(UDSEntry::UDS_NAME, QLatin1String("mtp:///"));
         entry.fastInsert(UDSEntry::UDS_FILE_TYPE, S_IFDIR);
         entry.fastInsert(UDSEntry::UDS_ACCESS, S_IRUSR | S_IRGRP | S_IROTH | S_IXUSR | S_IXGRP | S_IXOTH);
diff --git a/network/ioslave/networkslave.cpp b/network/ioslave/networkslave.cpp
--- a/network/ioslave/networkslave.cpp
+++ b/network/ioslave/networkslave.cpp
@@ -279,6 +279,7 @@
 
 void NetworkSlave::feedEntryAsNetwork( KIO::UDSEntry* entry )
 {
+    entry->reserve(3);
     entry->fastInsert( KIO::UDSEntry::UDS_FILE_TYPE,    S_IFDIR );
     entry->fastInsert( KIO::UDSEntry::UDS_DISPLAY_NAME, i18n("Network"));
 //     entry->fastInsert( KIO::UDSEntry::UDS_ICON_NAME,    NetworkIconName );
@@ -288,6 +289,7 @@
 
 void NetworkSlave::feedEntryAsDevice( KIO::UDSEntry* entry, const Mollet::NetDevice& deviceData )
 {
+    entry->reserve(4);
     entry->fastInsert( KIO::UDSEntry::UDS_NAME,         deviceData.hostAddress() );
     entry->fastInsert( KIO::UDSEntry::UDS_DISPLAY_NAME, deviceData.name() );
     entry->fastInsert( KIO::UDSEntry::UDS_FILE_TYPE,    S_IFDIR );
@@ -298,6 +300,7 @@
 
 void NetworkSlave::feedEntryAsService( KIO::UDSEntry* entry, const Mollet::NetService& serviceData )
 {
+    entry->reserve(7);
     entry->fastInsert( KIO::UDSEntry::UDS_NAME,         serviceData.name()+QLatin1Char('.')+serviceData.type() );
     entry->fastInsert( KIO::UDSEntry::UDS_DISPLAY_NAME, serviceData.name() );
     entry->fastInsert( KIO::UDSEntry::UDS_FILE_TYPE,    S_IFLNK );
diff --git a/recentdocuments/recentdocuments.cpp b/recentdocuments/recentdocuments.cpp
--- a/recentdocuments/recentdocuments.cpp
+++ b/recentdocuments/recentdocuments.cpp
@@ -148,6 +148,7 @@
         //
         QString dirName = i18n("Recent Documents");
         KIO::UDSEntry uds;
+        uds.reserve(6);
         uds.fastInsert(KIO::UDSEntry::UDS_NAME, dirName);
         uds.fastInsert(KIO::UDSEntry::UDS_DISPLAY_NAME, dirName);
         uds.fastInsert(KIO::UDSEntry::UDS_DISPLAY_TYPE, dirName);
diff --git a/settings/kio_settings.cpp b/settings/kio_settings.cpp
--- a/settings/kio_settings.cpp
+++ b/settings/kio_settings.cpp
@@ -63,6 +63,7 @@
 static void createFileEntry(KIO::UDSEntry& entry, const KService::Ptr& service)
 {
     entry.clear();
+    entry.reserve(9);
     entry.fastInsert(KIO::UDSEntry::UDS_NAME, KIO::encodeFileName(service->desktopEntryName()));
     entry.fastInsert(KIO::UDSEntry::UDS_DISPLAY_NAME, service->name()); // translated name
     entry.fastInsert(KIO::UDSEntry::UDS_FILE_TYPE, S_IFREG);
@@ -77,6 +78,7 @@
 static void createDirEntry(KIO::UDSEntry& entry, const QString& name, const QString& iconName)
 {
     entry.clear();
+    entry.reserve(6); // +1 for UDS_DISPLAY_NAME
     entry.fastInsert( KIO::UDSEntry::UDS_NAME, name );
     entry.fastInsert( KIO::UDSEntry::UDS_FILE_TYPE, S_IFDIR );
     entry.fastInsert( KIO::UDSEntry::UDS_ACCESS, 0500 );
diff --git a/sftp/kio_sftp.cpp b/sftp/kio_sftp.cpp
--- a/sftp/kio_sftp.cpp
+++ b/sftp/kio_sftp.cpp
@@ -411,6 +411,7 @@
     uint64_t size = 0U;
 
     Q_ASSERT(entry.count() == 0);
+    entry.reserve(10);
 
     sftp_attributes sb = sftp_lstat(mSftp, path.constData());
     if (sb == nullptr) {
@@ -2178,6 +2179,7 @@
         }
 
         entry.clear();
+        entry.reserve(10);
         entry.fastInsert(KIO::UDSEntry::UDS_NAME, QFile::decodeName(dirent->name));
 
         if (dirent->type == SSH_FILEXFER_TYPE_SYMLINK) {
diff --git a/smb/dnssddiscoverer.cpp b/smb/dnssddiscoverer.cpp
--- a/smb/dnssddiscoverer.cpp
+++ b/smb/dnssddiscoverer.cpp
@@ -34,6 +34,7 @@
 KIO::UDSEntry DNSSDDiscovery::toEntry() const
 {
     KIO::UDSEntry entry;
+    entry.reserve(6);
     entry.fastInsert(KIO::UDSEntry::UDS_NAME, udsName());
 
     entry.fastInsert(KIO::UDSEntry::UDS_FILE_TYPE, S_IFDIR);
diff --git a/smb/wsdiscoverer.cpp b/smb/wsdiscoverer.cpp
--- a/smb/wsdiscoverer.cpp
+++ b/smb/wsdiscoverer.cpp
@@ -303,6 +303,7 @@
 KIO::UDSEntry WSDiscovery::toEntry() const
 {
     KIO::UDSEntry entry;
+    entry.reserve(6);
     entry.fastInsert(KIO::UDSEntry::UDS_NAME, udsName());
 
     entry.fastInsert(KIO::UDSEntry::UDS_FILE_TYPE, S_IFDIR);