diff --git a/clang-tools-extra/clangd/ClangdLSPServer.cpp b/clang-tools-extra/clangd/ClangdLSPServer.cpp
--- a/clang-tools-extra/clangd/ClangdLSPServer.cpp
+++ b/clang-tools-extra/clangd/ClangdLSPServer.cpp
@@ -163,14 +163,23 @@
     log("<-- {0}", Method);
     if (Method == "exit")
       return false;
-    if (!Server.Server)
+    if (!Server.Server) {
       elog("Notification {0} before initialization", Method);
-    else if (Method == "$/cancelRequest")
+      return true;
+    }
+    if (Method == "$/cancelRequest")
       onCancel(std::move(Params));
     else if (auto Handler = Notifications.lookup(Method))
       Handler(std::move(Params));
     else
       log("unhandled notification {0}", Method);
+
+    // Record memory usage after each memory usage. This currently takes <1ms,
+    // so it is safe to do frequently.
+    trace::Span Tracer("RecordMemoryUsage");
+    MemoryTree MT;
+    Server.Server->attachMemoryUsage(MT);
+    MT.traverseTree(trace::recordMemoryUsage, "clangd_server");
     return true;
   }
 
diff --git a/clang-tools-extra/clangd/ClangdServer.h b/clang-tools-extra/clangd/ClangdServer.h
--- a/clang-tools-extra/clangd/ClangdServer.h
+++ b/clang-tools-extra/clangd/ClangdServer.h
@@ -25,6 +25,7 @@
 #include "refactor/Tweak.h"
 #include "support/Cancellation.h"
 #include "support/Function.h"
+#include "support/MemoryTree.h"
 #include "support/ThreadsafeFS.h"
 #include "clang/Tooling/CompilationDatabase.h"
 #include "clang/Tooling/Core/Replacement.h"
@@ -337,6 +338,9 @@
   LLVM_NODISCARD bool
   blockUntilIdleForTest(llvm::Optional<double> TimeoutSeconds = 10);
 
+  /// Builds a nested representation of memory used by components.
+  void attachMemoryUsage(MemoryTree &MT) const;
+
 private:
   void formatCode(PathRef File, llvm::StringRef Code,
                   ArrayRef<tooling::Range> Ranges,
diff --git a/clang-tools-extra/clangd/ClangdServer.cpp b/clang-tools-extra/clangd/ClangdServer.cpp
--- a/clang-tools-extra/clangd/ClangdServer.cpp
+++ b/clang-tools-extra/clangd/ClangdServer.cpp
@@ -28,6 +28,7 @@
 #include "refactor/Tweak.h"
 #include "support/Logger.h"
 #include "support/Markup.h"
+#include "support/MemoryTree.h"
 #include "support/ThreadsafeFS.h"
 #include "support/Trace.h"
 #include "clang/Format/Format.h"
@@ -833,5 +834,12 @@
           BackgroundIdx->blockUntilIdleForTest(TimeoutSeconds));
 }
 
+void ClangdServer::attachMemoryUsage(MemoryTree &MT) const {
+  if (DynamicIdx)
+    DynamicIdx->attachMemoryUsage(*MT.addChild("dynamic_index"));
+  if (BackgroundIdx)
+    BackgroundIdx->attachMemoryUsage(*MT.addChild("background_index"));
+  WorkScheduler.attachMemoryUsage(*MT.addChild("tuscheduler"));
+}
 } // namespace clangd
 } // namespace clang
diff --git a/clang-tools-extra/clangd/unittests/ClangdTests.cpp b/clang-tools-extra/clangd/unittests/ClangdTests.cpp
--- a/clang-tools-extra/clangd/unittests/ClangdTests.cpp
+++ b/clang-tools-extra/clangd/unittests/ClangdTests.cpp
@@ -17,6 +17,7 @@
 #include "TestFS.h"
 #include "TestTU.h"
 #include "URI.h"
+#include "support/MemoryTree.h"
 #include "support/Path.h"
 #include "support/Threading.h"
 #include "clang/Config/config.h"
@@ -27,6 +28,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Allocator.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Regex.h"
@@ -48,6 +50,7 @@
 namespace {
 
 using ::testing::AllOf;
+using ::testing::Contains;
 using ::testing::ElementsAre;
 using ::testing::Field;
 using ::testing::Gt;
@@ -1236,6 +1239,31 @@
   EXPECT_FALSE(DiagConsumer.HadDiagsInLastCallback);
 }
 
+TEST(ClangdServer, MemoryUsageTest) {
+  MockFS FS;
+  MockCompilationDatabase CDB;
+  ClangdServer Server(CDB, FS, ClangdServer::optsForTest());
+
+  std::vector<std::string> SeenComponents;
+  auto CB = [&SeenComponents](size_t Size, llvm::StringRef CompName) {
+    SeenComponents.emplace_back(CompName.str());
+  };
+
+  llvm::BumpPtrAllocator Alloc;
+  MemoryTree MT(&Alloc);
+  Server.attachMemoryUsage(MT);
+  MT.traverseTree(CB, "clangd_server");
+  EXPECT_THAT(SeenComponents, Contains("clangd_server"));
+  SeenComponents.clear();
+
+  auto FooCpp = testPath("foo.cpp");
+  Server.addDocument(FooCpp, "");
+  ASSERT_TRUE(Server.blockUntilIdleForTest());
+  Server.attachMemoryUsage(MT);
+  MT.traverseTree(CB, "clangd_server");
+  EXPECT_THAT(SeenComponents,
+              Contains("clangd_server.tuscheduler.preambles." + FooCpp));
+}
 } // namespace
 } // namespace clangd
 } // namespace clang