[heap] Non-contiguous young generation

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 "src/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/full-codegen/full-codegen.h"
 #include "src/heap/slot-set.h"
@@ skipping 298 matching lines @@
 
   size_ = 0;
   size_executable_ = 0;
 
   return true;
 }
 
 
 void MemoryAllocator::TearDown() {
   // Check that spaces were torn down before MemoryAllocator.
-  DCHECK(size_.Value() == 0);
+  DCHECK_EQ(size_.Value(), 0);
   // TODO(gc) this will be true again when we fix FreeMemory.
   // DCHECK(size_executable_ == 0);
   capacity_ = 0;
   capacity_executable_ = 0;
 }
 
-
 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;
 }
 
 
-void MemoryAllocator::FreeNewSpaceMemory(Address addr,
-                                         base::VirtualMemory* reservation,
-                                         Executability executable) {
-  LOG(isolate_, DeleteEvent("NewSpace", addr));
-
-  DCHECK(reservation->IsReserved());
-  const intptr_t size = static_cast<intptr_t>(reservation->size());
-  DCHECK(size_.Value() >= size);
-  size_.Increment(-size);
-  isolate_->counters()->memory_allocated()->Decrement(static_cast<int>(size));
-  FreeMemory(reservation, NOT_EXECUTABLE);
-}
-
-
 void MemoryAllocator::FreeMemory(base::VirtualMemory* reservation,
                                  Executability executable) {
   // TODO(gc) make code_range part of memory allocator?
   // Code which is part of the code-range does not have its own VirtualMemory.
   DCHECK(isolate_->code_range() == NULL ||
          !isolate_->code_range()->contains(
              static_cast<Address>(reservation->address())));
   DCHECK(executable == NOT_EXECUTABLE || isolate_->code_range() == NULL ||
          !isolate_->code_range()->valid() ||
          reservation->size() <= Page::kPageSize);
@@ skipping 64 matching lines @@
   return base;
 }
 
 
 void Page::InitializeAsAnchor(PagedSpace* owner) {
   set_owner(owner);
   set_prev_page(this);
   set_next_page(this);
 }
 
-
-NewSpacePage* NewSpacePage::Initialize(Heap* heap, Address start,
-                                       SemiSpace* semi_space) {
-  Address area_start = start + NewSpacePage::kObjectStartOffset;
-  Address area_end = start + Page::kPageSize;
-
-  MemoryChunk* chunk =
-      MemoryChunk::Initialize(heap, start, Page::kPageSize, area_start,
-                              area_end, NOT_EXECUTABLE, semi_space, nullptr);
-  bool in_to_space = (semi_space->id() != kFromSpace);
-  chunk->SetFlag(in_to_space ? MemoryChunk::IN_TO_SPACE
-                             : MemoryChunk::IN_FROM_SPACE);
-  DCHECK(!chunk->IsFlagSet(in_to_space ? MemoryChunk::IN_FROM_SPACE
-                                       : MemoryChunk::IN_TO_SPACE));
-  NewSpacePage* page = static_cast<NewSpacePage*>(chunk);
-  heap->incremental_marking()->SetNewSpacePageFlags(page);
-  return page;
-}
-
-
 void NewSpacePage::InitializeAsAnchor(SemiSpace* semi_space) {
   set_owner(semi_space);
   set_next_chunk(this);
   set_prev_chunk(this);
   // Flags marks this invalid page as not being in new-space.
   // All real new-space pages will be in new-space.
   SetFlags(0, ~0);
 }
 
 MemoryChunk* MemoryChunk::Initialize(Heap* heap, Address base, size_t size,
@@ skipping 242 matching lines @@
   return MemoryChunk::Initialize(heap, base, chunk_size, area_start, area_end,
                                  executable, owner, &reservation);
 }
 
 
 void Page::ResetFreeListStatistics() {
   wasted_memory_ = 0;
   available_in_free_list_ = 0;
 }
 
-
-Page* MemoryAllocator::AllocatePage(intptr_t size, PagedSpace* owner,
-                                    Executability executable) {
-  MemoryChunk* chunk = AllocateChunk(size, size, executable, owner);
-  if (chunk == NULL) return NULL;
-  return Page::Initialize(isolate_->heap(), chunk, executable, owner);
-}
-
-
 LargePage* MemoryAllocator::AllocateLargePage(intptr_t object_size,
                                               Space* owner,
                                               Executability executable) {
   MemoryChunk* chunk =
       AllocateChunk(object_size, object_size, executable, owner);
   if (chunk == NULL) return NULL;
   if (executable && chunk->size() > LargePage::kMaxCodePageSize) {
     STATIC_ASSERT(LargePage::kMaxCodePageSize <= TypedSlotSet::kMaxOffset);
     FATAL("Code page is too large.");
   }
@@ skipping 44 matching lines @@
     FreeMemory(chunk->address(), chunk->size(), chunk->executable());
   }
 }
 
 
 void MemoryAllocator::Free(MemoryChunk* chunk) {
   PreFreeMemory(chunk);
   PerformFreeMemory(chunk);
 }
 
+template <typename SpaceType>
+MemoryChunk* MemoryAllocator::AllocatePagePooled(SpaceType* owner,
+                                                 Executability executable) {
+  if (chunk_pool_.is_empty()) return nullptr;
+  MemoryChunk* chunk = chunk_pool_.RemoveLast();
+  const intptr_t chunk_size = MemoryChunk::kPageSize;
+  const Address start = reinterpret_cast<Address>(chunk);
+  const Address area_start = start + MemoryChunk::kObjectStartOffset;
+  const Address area_end = start + chunk_size;
+  CommitBlock(reinterpret_cast<Address>(chunk), chunk_size, executable);
+  base::VirtualMemory reservation(start, chunk_size);
+  MemoryChunk::Initialize(isolate_->heap(), start, chunk_size, area_start,
+                          area_end, NOT_EXECUTABLE, owner, &reservation);

[ulan, 2016/04/05 08:46:25]

s/NOT_EXECUTABLE/executable?

[Michael Lippautz, 2016/04/05 09:42:34]

Done.

+  if (chunk->executable() == EXECUTABLE) {
+    size_executable_.Increment(chunk_size);
+  }
+  size_.Increment(chunk_size);
+  return chunk;
+}
+
+void MemoryAllocator::FreePooled(MemoryChunk* chunk) {
+  chunk_pool_.Add(chunk);

[ulan, 2016/04/05 08:46:25]

Where a pooled page gets actually release?

[Michael Lippautz, 2016/04/05 09:42:34]

This is now done in MemoryAllocator::TearDown.

I also added now DCHECKs for size and executability as we can only use pooled
allocation for non-executable pages of constant kPageSize. (Non-executable,
because we would need handling to differentiate pages allocated from a CodeRange
vs regular reservations.)

+  intptr_t chunk_size = static_cast<intptr_t>(chunk->size());
+  if (chunk->executable() == EXECUTABLE) {
+    size_executable_.Increment(-chunk_size);
+  }
+  size_.Increment(-chunk_size);
+  UncommitBlock(reinterpret_cast<Address>(chunk), MemoryChunk::kPageSize);
+}
 
 bool MemoryAllocator::CommitBlock(Address start, size_t size,
                                   Executability executable) {
   if (!CommitMemory(start, size, executable)) return false;
 
   if (Heap::ShouldZapGarbage()) {
     ZapBlock(start, size);
   }
 
   isolate_->counters()->memory_allocated()->Increment(static_cast<int>(size));
@@ skipping 351 matching lines @@
 
 
 bool PagedSpace::Expand() {
   intptr_t size = AreaSize();
   if (snapshotable() && !HasPages()) {
     size = Snapshot::SizeOfFirstPage(heap()->isolate(), identity());
   }
 
   if (!CanExpand(size)) return false;
 
-  Page* p = heap()->isolate()->memory_allocator()->AllocatePage(size, this,
-                                                                executable());
+  Page* p = heap()->isolate()->memory_allocator()->AllocatePage<Page>(
+      size, this, executable());
   if (p == NULL) return false;
 
   AccountCommitted(static_cast<intptr_t>(p->size()));
 
   // Pages created during bootstrapping may contain immortal immovable objects.
   if (!heap()->deserialization_complete()) p->MarkNeverEvacuate();
 
   // When incremental marking was activated, old generation pages are allocated
   // black.
   if (heap()->incremental_marking()->black_allocation()) {
@@ skipping 109 matching lines @@
     }
     CHECK_LE(black_size, page->LiveBytes());
   }
   CHECK(allocation_pointer_found_in_space);
 }
 #endif  // VERIFY_HEAP
 
 // -----------------------------------------------------------------------------
 // NewSpace implementation
 
-
-bool NewSpace::SetUp(int reserved_semispace_capacity,
+bool NewSpace::SetUp(int initial_semispace_capacity,
                      int maximum_semispace_capacity) {
-  // Set up new space based on the preallocated memory block defined by
-  // start and size. The provided space is divided into two semi-spaces.
-  // To support fast containment testing in the new space, the size of
-  // this chunk must be a power of two and it must be aligned to its size.
-  int initial_semispace_capacity = heap()->InitialSemiSpaceSize();
-
-  size_t size = 2 * reserved_semispace_capacity;
-  Address base = heap()->isolate()->memory_allocator()->ReserveAlignedMemory(
-      size, size, &reservation_);
-  if (base == NULL) return false;
-
-  chunk_base_ = base;
-  chunk_size_ = static_cast<uintptr_t>(size);
-  LOG(heap()->isolate(), NewEvent("InitialChunk", chunk_base_, chunk_size_));
-
   DCHECK(initial_semispace_capacity <= maximum_semispace_capacity);
   DCHECK(base::bits::IsPowerOfTwo32(maximum_semispace_capacity));
 
+  to_space_.SetUp(initial_semispace_capacity, maximum_semispace_capacity);
+  from_space_.SetUp(initial_semispace_capacity, maximum_semispace_capacity);
+  if (!to_space_.Commit()) {
+    return false;
+  }
+  DCHECK(!from_space_.is_committed());  // No need to use memory yet.
+  ResetAllocationInfo();
+
   // Allocate and set up the histogram arrays if necessary.
   allocated_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
   promoted_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
-
 #define SET_NAME(name)                        \
   allocated_histogram_[name].set_name(#name); \
   promoted_histogram_[name].set_name(#name);
   INSTANCE_TYPE_LIST(SET_NAME)
 #undef SET_NAME
 
-  DCHECK(reserved_semispace_capacity == heap()->ReservedSemiSpaceSize());
-  DCHECK(static_cast<intptr_t>(chunk_size_) >=
-         2 * heap()->ReservedSemiSpaceSize());
-  DCHECK(IsAddressAligned(chunk_base_, 2 * reserved_semispace_capacity, 0));
-
-  to_space_.SetUp(chunk_base_, initial_semispace_capacity,
-                  maximum_semispace_capacity);
-  from_space_.SetUp(chunk_base_ + reserved_semispace_capacity,
-                    initial_semispace_capacity, maximum_semispace_capacity);
-  if (!to_space_.Commit()) {
-    return false;
-  }
-  DCHECK(!from_space_.is_committed());  // No need to use memory yet.
-
-  ResetAllocationInfo();
-
   return true;
 }
 
 
 void NewSpace::TearDown() {
   if (allocated_histogram_) {
     DeleteArray(allocated_histogram_);
     allocated_histogram_ = NULL;
   }
   if (promoted_histogram_) {
     DeleteArray(promoted_histogram_);
     promoted_histogram_ = NULL;
   }
 
   allocation_info_.Reset(nullptr, nullptr);
 
   to_space_.TearDown();
   from_space_.TearDown();
-
-  heap()->isolate()->memory_allocator()->FreeNewSpaceMemory(
-      chunk_base_, &reservation_, NOT_EXECUTABLE);
-
-  chunk_base_ = NULL;
-  chunk_size_ = 0;
 }
 
 
 void NewSpace::Flip() { SemiSpace::Swap(&from_space_, &to_space_); }
 
 
 void NewSpace::Grow() {
   // Double the semispace size but only up to maximum capacity.
   DCHECK(TotalCapacity() < MaximumCapacity());
   int new_capacity =
@@ skipping 296 matching lines @@
   CHECK_EQ(from_space_.id(), kFromSpace);
   CHECK_EQ(to_space_.id(), kToSpace);
   from_space_.Verify();
   to_space_.Verify();
 }
 #endif
 
 // -----------------------------------------------------------------------------
 // SemiSpace implementation
 
-void SemiSpace::SetUp(Address start, int initial_capacity,
-                      int maximum_capacity) {
+void SemiSpace::SetUp(int initial_capacity, int maximum_capacity) {
   DCHECK_GE(maximum_capacity, Page::kPageSize);
   minimum_capacity_ = RoundDown(initial_capacity, Page::kPageSize);
   current_capacity_ = minimum_capacity_;
   maximum_capacity_ = RoundDown(maximum_capacity, Page::kPageSize);
   committed_ = false;
-  start_ = start;
-  age_mark_ = start_ + NewSpacePage::kObjectStartOffset;
 }
 
 
 void SemiSpace::TearDown() {
-  start_ = nullptr;
-  current_capacity_ = 0;
+  // Properly uncommit memory to keep the allocator counters in sync.
+  if (is_committed()) Uncommit();
+  current_capacity_ = maximum_capacity_ = 0;
 }
 
 
 bool SemiSpace::Commit() {
   DCHECK(!is_committed());
-  if (!heap()->isolate()->memory_allocator()->CommitBlock(
-          start_, current_capacity_, executable())) {
-    return false;
-  }
-  AccountCommitted(current_capacity_);
-
   NewSpacePage* current = anchor();
   const int num_pages = current_capacity_ / Page::kPageSize;
   for (int i = 0; i < num_pages; i++) {
     NewSpacePage* new_page =
-        NewSpacePage::Initialize(heap(), start_ + i * Page::kPageSize, this);
+        heap()
+            ->isolate()
+            ->memory_allocator()
+            ->AllocatePage<NewSpacePage, MemoryAllocator::kPooled>(
+                NewSpacePage::kAllocatableMemory, this, executable());

[ulan, 2016/04/05 08:46:25]

s/executable()/NOT_EXECUTABLE?

or fix SemiSpace::GrowTo to be consistent.

[Michael Lippautz, 2016/04/05 09:42:34]

Fixed SemiSpace::GrowTo.

     new_page->InsertAfter(current);
     current = new_page;
   }
   Reset();
-
-  set_current_capacity(current_capacity_);
+  AccountCommitted(current_capacity_);
+  if (age_mark_ == nullptr) {
+    age_mark_ = first_page()->area_start();
+  }
   committed_ = true;
   return true;
 }
 
 
 bool SemiSpace::Uncommit() {
   DCHECK(is_committed());
-  Address start = start_ + maximum_capacity_ - current_capacity_;
-  if (!heap()->isolate()->memory_allocator()->UncommitBlock(
-          start, current_capacity_)) {
-    return false;
+  NewSpacePageIterator it(this);
+  while (it.has_next()) {
+    heap()->isolate()->memory_allocator()->FreePooled(it.next());
   }
-  AccountUncommitted(current_capacity_);
-
   anchor()->set_next_page(anchor());
   anchor()->set_prev_page(anchor());
-
+  AccountUncommitted(current_capacity_);
   committed_ = false;
   return true;
 }
 
 
 size_t SemiSpace::CommittedPhysicalMemory() {
   if (!is_committed()) return 0;
   size_t size = 0;
   NewSpacePageIterator it(this);
   while (it.has_next()) {
     size += it.next()->CommittedPhysicalMemory();
   }
   return size;
 }
 
 
 bool SemiSpace::GrowTo(int new_capacity) {
   if (!is_committed()) {
     if (!Commit()) return false;
   }
-  DCHECK_EQ(new_capacity & Page::kPageAlignmentMask, 0);
+  DCHECK_EQ(new_capacity & NewSpacePage::kPageAlignmentMask, 0);
   DCHECK_LE(new_capacity, maximum_capacity_);
   DCHECK_GT(new_capacity, current_capacity_);
-  int pages_before = current_capacity_ / Page::kPageSize;
-  int pages_after = new_capacity / Page::kPageSize;
-
-  size_t delta = new_capacity - current_capacity_;
-
+  const int delta = new_capacity - current_capacity_;
   DCHECK(IsAligned(delta, base::OS::AllocateAlignment()));
-  if (!heap()->isolate()->memory_allocator()->CommitBlock(
-          start_ + current_capacity_, delta, executable())) {
-    return false;
-  }
-  AccountCommitted(static_cast<intptr_t>(delta));
-  set_current_capacity(new_capacity);
+  int delta_pages = delta / NewSpacePage::kPageSize;
   NewSpacePage* last_page = anchor()->prev_page();
   DCHECK_NE(last_page, anchor());
-  for (int i = pages_before; i < pages_after; i++) {
-    Address page_address = start_ + i * Page::kPageSize;
+  while (delta_pages > 0) {
     NewSpacePage* new_page =
-        NewSpacePage::Initialize(heap(), page_address, this);
+        heap()
+            ->isolate()
+            ->memory_allocator()
+            ->AllocatePage<NewSpacePage, MemoryAllocator::kPooled>(
+                NewSpacePage::kAllocatableMemory, this, NOT_EXECUTABLE);
     new_page->InsertAfter(last_page);
     Bitmap::Clear(new_page);
     // Duplicate the flags that was set on the old page.
     new_page->SetFlags(last_page->GetFlags(),
                        NewSpacePage::kCopyOnFlipFlagsMask);
     last_page = new_page;
+    delta_pages--;
   }
+  AccountCommitted(static_cast<intptr_t>(delta));
+  current_capacity_ = new_capacity;
   return true;
 }
 
 
 bool SemiSpace::ShrinkTo(int new_capacity) {
-  DCHECK_EQ(new_capacity & Page::kPageAlignmentMask, 0);
+  DCHECK_EQ(new_capacity & NewSpacePage::kPageAlignmentMask, 0);
   DCHECK_GE(new_capacity, minimum_capacity_);
   DCHECK_LT(new_capacity, current_capacity_);
   if (is_committed()) {
-    size_t delta = current_capacity_ - new_capacity;
+    const int delta = current_capacity_ - new_capacity;
     DCHECK(IsAligned(delta, base::OS::AllocateAlignment()));
-
-    MemoryAllocator* allocator = heap()->isolate()->memory_allocator();
-    if (!allocator->UncommitBlock(start_ + new_capacity, delta)) {
-      return false;
+    int delta_pages = delta / NewSpacePage::kPageSize;
+    NewSpacePage* new_last_page;
+    NewSpacePage* last_page;
+    while (delta_pages > 0) {
+      last_page = anchor()->prev_page();
+      new_last_page = last_page->prev_page();
+      new_last_page->set_next_page(anchor());
+      anchor()->set_prev_page(new_last_page);
+      heap()->isolate()->memory_allocator()->FreePooled(last_page);
+      delta_pages--;
     }
     AccountUncommitted(static_cast<intptr_t>(delta));
-
-    int pages_after = new_capacity / Page::kPageSize;
-    NewSpacePage* new_last_page =
-        NewSpacePage::FromAddress(start_ + (pages_after - 1) * Page::kPageSize);
-    new_last_page->set_next_page(anchor());
-    anchor()->set_prev_page(new_last_page);
-    DCHECK((current_page_ >= first_page()) && (current_page_ <= new_last_page));
   }
-
-  set_current_capacity(new_capacity);
-
+  current_capacity_ = new_capacity;
   return true;
 }
 
 void SemiSpace::FixPagesFlags(intptr_t flags, intptr_t mask) {
   anchor_.set_owner(this);
   // Fixup back-pointers to anchor. Address of anchor changes when we swap.
   anchor_.prev_page()->set_next_page(&anchor_);
   anchor_.next_page()->set_prev_page(&anchor_);
 
   NewSpacePageIterator it(this);
@@ skipping 26 matching lines @@
   // We won't be swapping semispaces without data in them.
   DCHECK_NE(from->anchor_.next_page(), &from->anchor_);
   DCHECK_NE(to->anchor_.next_page(), &to->anchor_);
 
   intptr_t saved_to_space_flags = to->current_page()->GetFlags();
 
   // We swap all properties but id_.
   std::swap(from->current_capacity_, to->current_capacity_);
   std::swap(from->maximum_capacity_, to->maximum_capacity_);
   std::swap(from->minimum_capacity_, to->minimum_capacity_);
-  std::swap(from->start_, to->start_);
   std::swap(from->age_mark_, to->age_mark_);
   std::swap(from->committed_, to->committed_);
   std::swap(from->anchor_, to->anchor_);
   std::swap(from->current_page_, to->current_page_);
 
   to->FixPagesFlags(saved_to_space_flags, NewSpacePage::kCopyOnFlipFlagsMask);
   from->FixPagesFlags(0, 0);
 }
 
 
@@ skipping 1295 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8