Reland "[heap] Allow LocalHeap on the main thread"

This is a reland of bebb2bdc

Original change's description:
> [heap] Allow LocalHeap on the main thread
>
> This changes the safepoint scope to skip LocalHeap that is active
> for the current thread to avoid deadlocking.
>
> Bug: v8:10315
> Change-Id: I45e80ae66d0dbbe768107aa9cf0603204c644d9f
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2289983
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#68769}

Bug: v8:10315
Tbr: dinfuehr@chromium.org
Change-Id: I1974d8b6ffffbf3244e7ede2d20d9b2d623df150
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2290851
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68785}

src/heap/safepoint.cc

@@ -23,17 +23,25 @@ void GlobalSafepoint::EnterSafepointScope() {
   if (!FLAG_local_heaps) return;
 
   if (++active_safepoint_scopes_ > 1) return;
+
   local_heaps_mutex_.Lock();
+  local_heap_of_this_thread_ = LocalHeap::Current();
 
   barrier_.Arm();
 
   for (LocalHeap* current = local_heaps_head_; current;
        current = current->next_) {
+    if (current == local_heap_of_this_thread_) {
+      continue;
+    }
     current->RequestSafepoint();
   }
 
   for (LocalHeap* current = local_heaps_head_; current;
        current = current->next_) {
+    if (current == local_heap_of_this_thread_) {
+      continue;
+    }
     current->state_mutex_.Lock();
 
     while (current->state_ == LocalHeap::ThreadState::Running) {
@@ -48,13 +56,19 @@ void GlobalSafepoint::LeaveSafepointScope() {
   DCHECK_GT(active_safepoint_scopes_, 0);
   if (--active_safepoint_scopes_ > 0) return;
 
+  DCHECK_EQ(local_heap_of_this_thread_, LocalHeap::Current());
+
   for (LocalHeap* current = local_heaps_head_; current;
        current = current->next_) {
+    if (current == local_heap_of_this_thread_) {
+      continue;
+    }
     current->state_mutex_.Unlock();
   }
 
   barrier_.Disarm();
 
+  local_heap_of_this_thread_ = nullptr;
   local_heaps_mutex_.Unlock();
 }
 

src/heap/safepoint.h

@@ -77,6 +77,8 @@ class GlobalSafepoint {
 
   int active_safepoint_scopes_;
 
+  LocalHeap* local_heap_of_this_thread_;
+
   friend class SafepointScope;
   friend class LocalHeap;
   friend class PersistentHandles;

test/cctest/heap/test-heap.cc

@@ -6770,7 +6770,7 @@ UNINITIALIZED_TEST(OutOfMemorySmallObjects) {
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) return;
 #endif
-  const size_t kOldGenerationLimit = 300 * MB;
+  const size_t kOldGenerationLimit = 50 * MB;
   FLAG_max_old_space_size = kOldGenerationLimit / MB;
   v8::Isolate::CreateParams create_params;
   create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
@@ -6804,7 +6804,7 @@ UNINITIALIZED_TEST(OutOfMemoryLargeObjects) {
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) return;
 #endif
-  const size_t kOldGenerationLimit = 300 * MB;
+  const size_t kOldGenerationLimit = 50 * MB;
   FLAG_max_old_space_size = kOldGenerationLimit / MB;
   v8::Isolate::CreateParams create_params;
   create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
@@ -6842,7 +6842,7 @@ UNINITIALIZED_TEST(RestoreHeapLimit) {
   if (FLAG_verify_heap) return;
 #endif
   ManualGCScope manual_gc_scope;
-  const size_t kOldGenerationLimit = 300 * MB;
+  const size_t kOldGenerationLimit = 50 * MB;
   FLAG_max_old_space_size = kOldGenerationLimit / MB;
   v8::Isolate::CreateParams create_params;
   create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
@@ -7141,6 +7141,19 @@ HEAP_TEST(GCDuringOffThreadMergeWithTransferHandle) {
   CHECK_EQ(transfer_handle.ToHandle()->length(), 10);
 }
 
+TEST(GarbageCollectionWithLocalHeap) {
+  FLAG_local_heaps = true;
+  ManualGCScope manual_gc_scope;
+  CcTest::InitializeVM();
+
+  Heap* heap = CcTest::i_isolate()->heap();
+
+  LocalHeap local_heap(heap);
+  CcTest::CollectGarbage(OLD_SPACE);
+  { ParkedScope parked_scope(&local_heap); }
+  CcTest::CollectGarbage(OLD_SPACE);
+}
+
 }  // namespace heap
 }  // namespace internal
 }  // namespace v8

test/unittests/heap/safepoint-unittest.cc

@@ -138,5 +138,24 @@ TEST_F(SafepointTest, StopRunningThreads) {
   CHECK_EQ(safepoint_count, kRuns * kSafepoints);
 }
 
+TEST_F(SafepointTest, SkipLocalHeapOfThisThread) {
+  Heap* heap = i_isolate()->heap();
+  FLAG_local_heaps = true;
+  LocalHeap local_heap(heap);
+  {
+    SafepointScope scope(heap);
+    local_heap.Safepoint();
+  }
+  {
+    ParkedScope parked_scope(&local_heap);
+    SafepointScope scope(heap);
+    local_heap.Safepoint();
+  }
+  {
+    SafepointScope scope(heap);
+    local_heap.Safepoint();
+  }
+}
+
 }  // namespace internal
 }  // namespace v8