ydb/contrib/libs/tcmalloc/patches/handler.patch

--- contrib/libs/tcmalloc/tcmalloc/malloc_extension.cc	(index)
+++ contrib/libs/tcmalloc/tcmalloc/malloc_extension.cc	(working tree)
@@ -468,6 +468,20 @@ void MallocExtension::EnableForkSupport() {
 #endif
 }
 
+static std::atomic<MallocExtension::SoftMemoryLimitCallback*> SoftMemoryLimitHandler_;
+
+void MallocExtension::SetSoftMemoryLimitHandler(SoftMemoryLimitCallback* handler) {
+#if ABSL_INTERNAL_HAVE_WEAK_MALLOCEXTENSION_STUBS
+  SoftMemoryLimitHandler_.store(handler);
+#endif
+}
+
+MallocExtension::SoftMemoryLimitCallback* MallocExtension::GetSoftMemoryLimitHandler() {
+#if ABSL_INTERNAL_HAVE_WEAK_MALLOCEXTENSION_STUBS
+  return SoftMemoryLimitHandler_.load();
+#endif
+}
+
 void MallocExtension::SetSampleUserDataCallbacks(
     CreateSampleUserDataCallback create,
     CopySampleUserDataCallback copy,
--- contrib/libs/tcmalloc/tcmalloc/malloc_extension.h	(index)
+++ contrib/libs/tcmalloc/tcmalloc/malloc_extension.h	(working tree)
@@ -475,6 +475,10 @@ class MallocExtension final {
   // Allocator will continue to function correctly in the child, after calling fork().
   static void EnableForkSupport();
 
+  using SoftMemoryLimitCallback = void();
+  static void SetSoftMemoryLimitHandler(SoftMemoryLimitCallback* handler);
+  static SoftMemoryLimitCallback* GetSoftMemoryLimitHandler();
+
   using CreateSampleUserDataCallback = void*();
   using CopySampleUserDataCallback = void*(void*);
   using DestroySampleUserDataCallback = void(void*);
--- contrib/libs/tcmalloc/tcmalloc/page_allocator.cc	(index)
+++ contrib/libs/tcmalloc/tcmalloc/page_allocator.cc	(working tree)
@@ -151,6 +151,10 @@ void PageAllocator::ShrinkToUsageLimit() {
   warned = true;
   Log(kLogWithStack, __FILE__, __LINE__, "Couldn't respect usage limit of ",
       limit_, "and OOM is likely to follow.");
+
+  if (auto* handler = MallocExtension::GetSoftMemoryLimitHandler()) {
+    (*handler)();
+  }
 }
 
 bool PageAllocator::ShrinkHardBy(Length pages) {