diff --git a/clangd/index/Background.h b/clangd/index/Background.h
index ea8ab58..808c03a 100644
--- a/clangd/index/Background.h
+++ b/clangd/index/Background.h
@@ -67,11 +67,12 @@
   /// If BuildIndexPeriodMs is greater than 0, the symbol index will only be
   /// rebuilt periodically (one per \p BuildIndexPeriodMs); otherwise, index is
   /// rebuilt for each indexed file.
-  BackgroundIndex(Context BackgroundContext, const FileSystemProvider &,
-                  const GlobalCompilationDatabase &CDB,
-                  BackgroundIndexStorage::Factory IndexStorageFactory,
-                  size_t BuildIndexPeriodMs = 0,
-                  size_t ThreadPoolSize = llvm::hardware_concurrency());
+  BackgroundIndex(
+      Context BackgroundContext, const FileSystemProvider &,
+      const GlobalCompilationDatabase &CDB,
+      BackgroundIndexStorage::Factory IndexStorageFactory,
+      size_t BuildIndexPeriodMs = 0,
+      size_t ThreadPoolSize = llvm::heavyweight_hardware_concurrency());
   ~BackgroundIndex(); // Blocks while the current task finishes.
 
   // Enqueue translation units for indexing.