Reland "[heap] Don't unmap new space pages while sweeping is active"

src/heap/spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/spaces.h"
 
+#include <utility>
+
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/base/platform/semaphore.h"
 #include "src/full-codegen/full-codegen.h"
 #include "src/heap/array-buffer-tracker.h"
 #include "src/heap/slot-set.h"
 #include "src/macro-assembler.h"
 #include "src/msan.h"
 #include "src/snapshot/snapshot.h"
 #include "src/v8.h"
@@ skipping 324 matching lines @@
   void Run() override {
     unmapper_->PerformFreeMemoryOnQueuedChunks();
     unmapper_->pending_unmapping_tasks_semaphore_.Signal();
   }
 
   Unmapper* unmapper_;
   DISALLOW_COPY_AND_ASSIGN(UnmapFreeMemoryTask);
 };
 
 void MemoryAllocator::Unmapper::FreeQueuedChunks() {
+  ReconsiderDelayedChunks();
   if (FLAG_concurrent_sweeping) {
     V8::GetCurrentPlatform()->CallOnBackgroundThread(
         new UnmapFreeMemoryTask(this), v8::Platform::kShortRunningTask);
     concurrent_unmapping_tasks_active_++;
   } else {
     PerformFreeMemoryOnQueuedChunks();
   }
 }
 
 bool MemoryAllocator::Unmapper::WaitUntilCompleted() {
@@ skipping 13 matching lines @@
     bool pooled = chunk->IsFlagSet(MemoryChunk::POOLED);
     allocator_->PerformFreeMemory(chunk);
     if (pooled) AddMemoryChunkSafe<kPooled>(chunk);
   }
   // Non-regular chunks.
   while ((chunk = GetMemoryChunkSafe<kNonRegular>()) != nullptr) {
     allocator_->PerformFreeMemory(chunk);
   }
 }
 
+void MemoryAllocator::Unmapper::ReconsiderDelayedChunks() {
+  std::list<MemoryChunk*> delayed_chunks(std::move(delayed_regular_chunks_));
+  // Move constructed, so the permanent list should be empty.
+  DCHECK(delayed_regular_chunks_.empty());
+  for (auto it = delayed_chunks.begin(); it != delayed_chunks.end(); ++it) {
+    AddMemoryChunkSafe<kRegular>(*it);
+  }
+}
+
+bool MemoryAllocator::CanFreeMemoryChunk(MemoryChunk* chunk) {
+  MarkCompactCollector* mc = isolate_->heap()->mark_compact_collector();
+  // We cannot free memory chunks in new space while the sweeper is running
+  // since a sweeper thread might be stuck right before trying to lock the
+  // corresponding page.
+  return !chunk->InNewSpace() || (mc == nullptr) ||
+         mc->sweeper().IsSweepingCompleted();
+}
+
 bool MemoryAllocator::CommitMemory(Address base, size_t size,
                                    Executability executable) {
   if (!base::VirtualMemory::CommitRegion(base, size,
                                          executable == EXECUTABLE)) {
     return false;
   }
   UpdateAllocatedSpaceLimits(base, base + size);
   return true;
 }
 
@@ skipping 2751 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8