Merge pull request #21628 from vespa-engine/vekterli/make-lid-allocator-active-lids-count-atomic

Make LidAllocator active lid count (relaxed) atomic

2 files changed, 7 insertions, 6 deletions

diff --git a/searchcore/src/vespa/searchcore/proton/documentmetastore/lid_allocator.cpp b/searchcore/src/vespa/searchcore/proton/documentmetastore/lid_allocator.cpp
index 7633b5a32c0..4163b59b4ca 100644
--- a/searchcore/src/vespa/searchcore/proton/documentmetastore/lid_allocator.cpp
+++ b/searchcore/src/vespa/searchcore/proton/documentmetastore/lid_allocator.cpp
@@ -75,7 +75,7 @@ LidAllocator::unregisterLid(DocId lid)
     _usedLids.clearBit(lid);
     if (_activeLids.testBit(lid)) {
         _activeLids.clearBit(lid);
-        _numActiveLids = _activeLids.count();
+        _numActiveLids.store(_activeLids.count(), std::memory_order_relaxed);
     }
 }
 
@@ -90,7 +90,7 @@ LidAllocator::unregister_lids(const std::vector<DocId>& lids)
     _usedLids.clear_bits(lids);
     assert(high < _activeLids.size());
     _activeLids.consider_clear_bits(lids);
-    _numActiveLids = _activeLids.count();
+    _numActiveLids.store(_activeLids.count(), std::memory_order_relaxed);
 }
 
 void
@@ -237,7 +237,7 @@ LidAllocator::updateActiveLids(DocId lid, bool active)
         } else {
             _activeLids.clearBit(lid);
         }
-        _numActiveLids = _activeLids.count();
+        _numActiveLids.store(_activeLids.count(), std::memory_order_relaxed);
     }
 }
 
diff --git a/searchcore/src/vespa/searchcore/proton/documentmetastore/lid_allocator.h b/searchcore/src/vespa/searchcore/proton/documentmetastore/lid_allocator.h
index 947192605e2..08fa4a6489a 100644
--- a/searchcore/src/vespa/searchcore/proton/documentmetastore/lid_allocator.h
+++ b/searchcore/src/vespa/searchcore/proton/documentmetastore/lid_allocator.h
@@ -6,6 +6,7 @@
 #include "lidstatevector.h"
 #include <vespa/searchlib/attribute/attributeguard.h>
 #include <vespa/searchlib/queryeval/blueprint.h>
+#include <atomic>
 
 namespace proton::documentmetastore {
 
@@ -25,7 +26,7 @@ private:
     LidStateVector              _pendingHoldLids;
     bool                        _lidFreeListConstructed;
     LidStateVector              _activeLids;
-    uint32_t                    _numActiveLids;
+    std::atomic<uint32_t>       _numActiveLids;
 
 public:
     LidAllocator(uint32_t size,
@@ -54,8 +55,8 @@ public:
     void clearDocs(DocId lidLow, DocId lidLimit);
     void shrinkLidSpace(DocId committedDocIdLimit);
     uint32_t getNumUsedLids() const { return _usedLids.count(); }
-    uint32_t getNumActiveLids() const {
-        return _numActiveLids;
+    uint32_t getNumActiveLids() const noexcept {
+        return _numActiveLids.load(std::memory_order_relaxed);
     }
     void setFreeListConstructed() {
         _lidFreeListConstructed = true;