From bb195749c89cb8996b14dca9849d52f21572ce63 Mon Sep 17 00:00:00 2001
From: Troels Bjerre Lund <troels@google.com>
Date: Thu, 28 Sep 2023 16:05:26 +0200
Subject: [PATCH] [K/N] Re-enable mutator assist

Also remove disabling of GC scheduling during GC
---
 kotlin-native/runtime/src/alloc/custom/cpp/Heap.cpp         | 6 ++++++
 .../src/gcScheduler/adaptive/cpp/GCSchedulerImpl.hpp        | 1 -
 .../src/gcScheduler/common/cpp/GCSchedulerConfig.hpp        | 2 +-
 .../src/gcScheduler/common/cpp/HeapGrowthController.hpp     | 4 ----
 4 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/kotlin-native/runtime/src/alloc/custom/cpp/Heap.cpp b/kotlin-native/runtime/src/alloc/custom/cpp/Heap.cpp
index 9fc1695fd56..01548cc5d8f 100644
--- a/kotlin-native/runtime/src/alloc/custom/cpp/Heap.cpp
+++ b/kotlin-native/runtime/src/alloc/custom/cpp/Heap.cpp
@@ -116,6 +116,12 @@ std::vector<ObjHeader*> Heap::GetAllocatedObjects() noexcept {
     return unfinalized;
 }
 
+// This overhead is calculated under the assumption that each thread holds on
+// to one almost empty page of each page type currently in use. Thus, the
+// per-thread-overhead is the sum of the page sizes of the page types that the
+// Heap has currently allocated, i.e., whose PageStores are not empty. This
+// estimate has two-sided error, and there are still pathological allocation
+// patterns that would lead to constant GC triggering.
 size_t Heap::EstimateOverheadPerThread() noexcept {
     size_t overHeadPerThread = 0;
     if (!nextFitPages_.isEmpty()) overHeadPerThread += NEXT_FIT_PAGE_SIZE;
diff --git a/kotlin-native/runtime/src/gcScheduler/adaptive/cpp/GCSchedulerImpl.hpp b/kotlin-native/runtime/src/gcScheduler/adaptive/cpp/GCSchedulerImpl.hpp
index a42173841a1..0d8940e45de 100644
--- a/kotlin-native/runtime/src/gcScheduler/adaptive/cpp/GCSchedulerImpl.hpp
+++ b/kotlin-native/runtime/src/gcScheduler/adaptive/cpp/GCSchedulerImpl.hpp
@@ -64,7 +64,6 @@ public:
 
     void onGCStart() noexcept {
         regularIntervalPacer_.OnPerformFullGC();
-        heapGrowthController_.unsetBoundaries();
         timer_.restart(config_.regularGcInterval());
     }
 
diff --git a/kotlin-native/runtime/src/gcScheduler/common/cpp/GCSchedulerConfig.hpp b/kotlin-native/runtime/src/gcScheduler/common/cpp/GCSchedulerConfig.hpp
index 6d236210ba4..798f2c566f6 100644
--- a/kotlin-native/runtime/src/gcScheduler/common/cpp/GCSchedulerConfig.hpp
+++ b/kotlin-native/runtime/src/gcScheduler/common/cpp/GCSchedulerConfig.hpp
@@ -40,7 +40,7 @@ struct GCSchedulerConfig {
     std::atomic<double> heapTriggerCoefficient = 0.9;
     // See `mutatorAssists()`.
     std::atomic<std::underlying_type_t<MutatorAssists>> mutatorAssistsImpl =
-            static_cast<std::underlying_type_t<MutatorAssists>>(MutatorAssists::kDisable);
+            static_cast<std::underlying_type_t<MutatorAssists>>(MutatorAssists::kDefault);
 
     std::chrono::microseconds regularGcInterval() const { return std::chrono::microseconds(regularGcIntervalMicroseconds.load()); }
 
diff --git a/kotlin-native/runtime/src/gcScheduler/common/cpp/HeapGrowthController.hpp b/kotlin-native/runtime/src/gcScheduler/common/cpp/HeapGrowthController.hpp
index ea19ca01d2c..1d7f30e731c 100644
--- a/kotlin-native/runtime/src/gcScheduler/common/cpp/HeapGrowthController.hpp
+++ b/kotlin-native/runtime/src/gcScheduler/common/cpp/HeapGrowthController.hpp
@@ -31,10 +31,6 @@ public:
         triggerHeapBytes_ = targetHeapBytes_ * config_.heapTriggerCoefficient.load(std::memory_order_relaxed);
     }
 
-    void unsetBoundaries() noexcept {
-        targetHeapBytes_ = triggerHeapBytes_ = std::numeric_limits<int64_t>::max();
-    }
-
     // Can be called by any thread.
     MemoryBoundary boundaryForHeapSize(size_t totalAllocatedBytes) noexcept {
         if (totalAllocatedBytes >= targetHeapBytes_) {