Use atomic searchcorespi::index::IndexMaintainer::_flush_serial_num.

2 files changed, 17 insertions, 11 deletions

diff --git a/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.cpp b/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.cpp
index e5bcf5291e5..af273bc5e45 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.cpp
+++ b/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.cpp
@@ -655,7 +655,7 @@ IndexMaintainer::doneFlush(FlushArgs *args, IDiskIndex::SP *disk_index) {
     if (args->_prunedSchema != memoryIndex.getPrunedSchema()) {
         return false;    // Must retry operation
     }
-    _flush_serial_num = std::max(_flush_serial_num, args->flush_serial_num);
+    set_flush_serial_num(std::max(flush_serial_num(), args->flush_serial_num));
     vespalib::system_time timeStamp = search::FileKit::getModificationTime((*disk_index)->getIndexDir());
     _lastFlushTime = timeStamp > _lastFlushTime ? timeStamp : _lastFlushTime;
     const uint32_t old_id = args->old_absolute_id - _last_fusion_id;
@@ -919,13 +919,13 @@ IndexMaintainer::IndexMaintainer(const IndexMaintainerConfig &config,
                                   ? getFusionDir(_next_id - 1)
                                   : getFlushDir(_next_id - 1);
 
-        _flush_serial_num = IndexReadUtilities::readSerialNum(latest_index_dir);
+        set_flush_serial_num(IndexReadUtilities::readSerialNum(latest_index_dir));
         _lastFlushTime = search::FileKit::getModificationTime(latest_index_dir);
-        set_current_serial_num(_flush_serial_num);
+        set_current_serial_num(flush_serial_num());
         const string selector = IndexDiskLayout::getSelectorFileName(latest_index_dir);
         _selector = FixedSourceSelector::load(selector, _next_id - 1);
     } else {
-        _flush_serial_num = 0;
+        set_flush_serial_num(0);
         _selector = std::make_shared<FixedSourceSelector>(0, "sourceselector", 1);
     }
     uint32_t baseId(_selector->getBaseId());
@@ -942,7 +942,7 @@ IndexMaintainer::IndexMaintainer(const IndexMaintainerConfig &config,
     _selector->setDefaultSource(_current_index_id);
     auto sourceList = loadDiskIndexes(spec, std::make_unique<IndexCollection>(_selector));
     _current_index = operations.createMemoryIndex(_schema, *sourceList, current_serial_num());
-    LOG(debug, "Index manager created with flushed serial num %" PRIu64, _flush_serial_num);
+    LOG(debug, "Index manager created with flushed serial num %" PRIu64, flush_serial_num());
     sourceList->append(_current_index_id, _current_index);
     sourceList->setCurrentIndex(_current_index_id);
     _source_list = std::move(sourceList);
@@ -984,11 +984,11 @@ IndexMaintainer::initFlush(SerialNum serialNum, searchcorespi::FlushStats * stat
     if (args._skippedEmptyLast && args._extraIndexes.empty()) {
         // No memory index to flush, it was empty
         LockGuard lock(_state_lock);
-        _flush_serial_num = current_serial_num();
+        set_flush_serial_num(current_serial_num());
         _lastFlushTime = vespalib::system_clock::now();
         LOG(debug, "No memory index to flush. Update serial number and flush time to current: "
             "flushSerialNum(%" PRIu64 "), lastFlushTime(%f)",
-            _flush_serial_num, vespalib::to_s(_lastFlushTime.time_since_epoch()));
+            flush_serial_num(), vespalib::to_s(_lastFlushTime.time_since_epoch()));
         return FlushTask::UP();
     }
     SerialNum realSerialNum = args.flush_serial_num;
diff --git a/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.h b/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.h
index dfae5b4d643..b3fb14e1c2e 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.h
+++ b/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.h
@@ -93,8 +93,8 @@ class IndexMaintainer : public IIndexManager,
     uint32_t               _current_index_id; // Protected by SL + IUL
     IMemoryIndex::SP       _current_index;    // Protected by SL + IUL
     bool                   _flush_empty_current_index;
-    std::atomic<SerialNum> _current_serial_num;// Protected by IUL
-    SerialNum              _flush_serial_num;  // Protected by SL
+    std::atomic<SerialNum> _current_serial_num;// Writes protected by IUL
+    std::atomic<SerialNum> _flush_serial_num;  // Writes protected by SL
     vespalib::system_time  _lastFlushTime; // Protected by SL
     // Extra frozen memory indexes.  This list is empty unless new
     // memory index has been added by force (due to config change or
@@ -270,6 +270,12 @@ class IndexMaintainer : public IIndexManager,
     void set_current_serial_num(SerialNum new_serial_num) noexcept {
         _current_serial_num.store(new_serial_num, std::memory_order_relaxed);
     }
+    [[nodiscard]] SerialNum flush_serial_num() const noexcept {
+        return _flush_serial_num.load(std::memory_order_relaxed);
+    }
+    void set_flush_serial_num(SerialNum new_serial_num) noexcept {
+        _flush_serial_num.store(new_serial_num, std::memory_order_relaxed);
+    }
 
 public:
     IndexMaintainer(const IndexMaintainer &) = delete;
@@ -340,11 +346,11 @@ public:
     void compactLidSpace(uint32_t lidLimit, SerialNum serialNum) override;
 
     SerialNum getCurrentSerialNum() const override {
-        return _current_serial_num.load(std::memory_order_relaxed);
+        return current_serial_num();
     }
 
     SerialNum getFlushedSerialNum() const override {
-        return _flush_serial_num;
+        return flush_serial_num();
     }
 
     IIndexCollection::SP getSourceCollection() const {