Reviewers: *Hannes Payer, Michael Lippautz,
Message:
Hannes: PTAL.
Mike: FYI.
https://codereview.chromium.org/1293773002/diff/20001/src/heap/mark-compact.h
File src/heap/mark-compact.h (right):
https://codereview.chromium.org/1293773002/diff/20001/src/heap/mark-compact.h#newcode210
src/heap/mark-compact.h:210: INLINE(bool PushBlack(HeapObject* object))
{
Note that {PushBlack} and {PushGrey} can now be unified into one single
{Push} method. Let me know if you want me to do that in this CL or in a
separate CL.
https://codereview.chromium.org/1293773002/diff/20001/src/heap/mark-compact.h#newcode240
src/heap/mark-compact.h:240: INLINE(void UnshiftGrey(HeapObject*
object)) {
Likewise for unification of {UnshiftGrey} and {UnshiftBlack}.
Description:
[heap] Simplify MarkingDeque implementation.
This removes the dependency of the MarkingDeque on the underlying
collector by moving out the live bytes accounting and object color
mutations into a wrapper. The MarkingDeque can now split into a
separate file.
[email protected]
Please review this at https://codereview.chromium.org/1293773002/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+56, -41 lines):
M src/heap/incremental-marking.cc
M src/heap/mark-compact.h
M src/heap/mark-compact.cc
M src/heap/mark-compact-inl.h
Index: src/heap/incremental-marking.cc
diff --git a/src/heap/incremental-marking.cc
b/src/heap/incremental-marking.cc
index
db19165f0a310eb0dec219df1226b8333c17e96e..cb2ac1e75d95f2b9ab0e02a4b0495291f5bae2eb
100644
--- a/src/heap/incremental-marking.cc
+++ b/src/heap/incremental-marking.cc
@@ -198,11 +198,15 @@ class IncrementalMarkingMarkingVisitor
} while (scan_until_end && start_offset < object_size);
chunk->set_progress_bar(start_offset);
if (start_offset < object_size) {
+ MarkCompactCollector* collector = heap->mark_compact_collector();
if (Marking::IsGrey(Marking::MarkBitFrom(object))) {
-
heap->mark_compact_collector()->marking_deque()->UnshiftGrey(object);
+ collector->marking_deque()->UnshiftGrey(object);
} else {
DCHECK(Marking::IsBlack(Marking::MarkBitFrom(object)));
-
heap->mark_compact_collector()->marking_deque()->UnshiftBlack(object);
+ if (!collector->marking_deque()->UnshiftBlack(object)) {
+ MemoryChunk::IncrementLiveBytesFromGC(object, -object->Size());
+ Marking::BlackToGrey(object);
+ }
}
heap->incremental_marking()->NotifyIncompleteScanOfObject(
object_size - (start_offset - already_scanned_offset));
Index: src/heap/mark-compact-inl.h
diff --git a/src/heap/mark-compact-inl.h b/src/heap/mark-compact-inl.h
index
d38e31e55602c14a874814ca5605facc46b61e43..015440bc40f222e314a11de2973cb23e981db854
100644
--- a/src/heap/mark-compact-inl.h
+++ b/src/heap/mark-compact-inl.h
@@ -23,13 +23,21 @@ void MarkCompactCollector::SetFlags(int flags) {
}
+void MarkCompactCollector::PushBlack(HeapObject* obj) {
+ if (marking_deque_.PushBlack(obj)) {
+ MemoryChunk::IncrementLiveBytesFromGC(obj, obj->Size());
+ } else {
+ Marking::BlackToGrey(obj);
+ }
+}
+
+
void MarkCompactCollector::MarkObject(HeapObject* obj, MarkBit mark_bit) {
DCHECK(Marking::MarkBitFrom(obj) == mark_bit);
if (Marking::IsWhite(mark_bit)) {
Marking::WhiteToBlack(mark_bit);
- MemoryChunk::IncrementLiveBytesFromGC(obj, obj->Size());
DCHECK(obj->GetIsolate()->heap()->Contains(obj));
- marking_deque_.PushBlack(obj);
+ PushBlack(obj);
}
}
Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index
e34dbfd2337cc0bec932e2729d51ae1aeb5d1787..95f762c05cc09b6d23400f02114e0a1f1623cd97
100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -1734,21 +1734,18 @@ class MarkCompactWeakObjectRetainer : public
WeakObjectRetainer {
// iterator. Stop when the marking stack is filled or the end of the space
// is reached, whichever comes first.
template <class T>
-static void DiscoverGreyObjectsWithIterator(Heap* heap,
- MarkingDeque* marking_deque,
- T* it) {
+void MarkCompactCollector::DiscoverGreyObjectsWithIterator(T* it) {
// The caller should ensure that the marking stack is initially not full,
// so that we don't waste effort pointlessly scanning for objects.
- DCHECK(!marking_deque->IsFull());
+ DCHECK(!marking_deque()->IsFull());
- Map* filler_map = heap->one_pointer_filler_map();
+ Map* filler_map = heap()->one_pointer_filler_map();
for (HeapObject* object = it->Next(); object != NULL; object =
it->Next()) {
MarkBit markbit = Marking::MarkBitFrom(object);
if ((object->map() != filler_map) && Marking::IsGrey(markbit)) {
Marking::GreyToBlack(markbit);
- MemoryChunk::IncrementLiveBytesFromGC(object, object->Size());
- marking_deque->PushBlack(object);
- if (marking_deque->IsFull()) return;
+ PushBlack(object);
+ if (marking_deque()->IsFull()) return;
}
}
}
@@ -1757,9 +1754,8 @@ static void DiscoverGreyObjectsWithIterator(Heap*
heap,
static inline int MarkWordToObjectStarts(uint32_t mark_bits, int* starts);
-static void DiscoverGreyObjectsOnPage(MarkingDeque* marking_deque,
- MemoryChunk* p) {
- DCHECK(!marking_deque->IsFull());
+void MarkCompactCollector::DiscoverGreyObjectsOnPage(MemoryChunk* p) {
+ DCHECK(!marking_deque()->IsFull());
DCHECK(strcmp(Marking::kWhiteBitPattern, "00") == 0);
DCHECK(strcmp(Marking::kBlackBitPattern, "10") == 0);
DCHECK(strcmp(Marking::kGreyBitPattern, "11") == 0);
@@ -1791,9 +1787,8 @@ static void DiscoverGreyObjectsOnPage(MarkingDeque*
marking_deque,
Marking::GreyToBlack(markbit);
Address addr = cell_base + offset * kPointerSize;
HeapObject* object = HeapObject::FromAddress(addr);
- MemoryChunk::IncrementLiveBytesFromGC(object, object->Size());
- marking_deque->PushBlack(object);
- if (marking_deque->IsFull()) return;
+ PushBlack(object);
+ if (marking_deque()->IsFull()) return;
offset += 2;
grey_objects >>= 2;
}
@@ -1866,25 +1861,23 @@ int
MarkCompactCollector::DiscoverAndEvacuateBlackObjectsOnPage(
}
-static void DiscoverGreyObjectsInSpace(Heap* heap, MarkingDeque*
marking_deque,
- PagedSpace* space) {
+void MarkCompactCollector::DiscoverGreyObjectsInSpace(PagedSpace* space) {
PageIterator it(space);
while (it.has_next()) {
Page* p = it.next();
- DiscoverGreyObjectsOnPage(marking_deque, p);
- if (marking_deque->IsFull()) return;
+ DiscoverGreyObjectsOnPage(p);
+ if (marking_deque()->IsFull()) return;
}
}
-static void DiscoverGreyObjectsInNewSpace(Heap* heap,
- MarkingDeque* marking_deque) {
- NewSpace* space = heap->new_space();
+void MarkCompactCollector::DiscoverGreyObjectsInNewSpace() {
+ NewSpace* space = heap()->new_space();
NewSpacePageIterator it(space->bottom(), space->top());
while (it.has_next()) {
NewSpacePage* page = it.next();
- DiscoverGreyObjectsOnPage(marking_deque, page);
- if (marking_deque->IsFull()) return;
+ DiscoverGreyObjectsOnPage(page);
+ if (marking_deque()->IsFull()) return;
}
}
@@ -2009,20 +2002,20 @@ void MarkCompactCollector::RefillMarkingDeque() {
isolate()->CountUsage(v8::Isolate::UseCounterFeature::kMarkDequeOverflow);
DCHECK(marking_deque_.overflowed());
- DiscoverGreyObjectsInNewSpace(heap(), &marking_deque_);
+ DiscoverGreyObjectsInNewSpace();
if (marking_deque_.IsFull()) return;
- DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->old_space());
+ DiscoverGreyObjectsInSpace(heap()->old_space());
if (marking_deque_.IsFull()) return;
- DiscoverGreyObjectsInSpace(heap(), &marking_deque_,
heap()->code_space());
+ DiscoverGreyObjectsInSpace(heap()->code_space());
if (marking_deque_.IsFull()) return;
- DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->map_space());
+ DiscoverGreyObjectsInSpace(heap()->map_space());
if (marking_deque_.IsFull()) return;
LargeObjectIterator lo_it(heap()->lo_space());
- DiscoverGreyObjectsWithIterator(heap(), &marking_deque_, &lo_it);
+ DiscoverGreyObjectsWithIterator(&lo_it);
if (marking_deque_.IsFull()) return;
marking_deque_.ClearOverflowed();
Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index
6168436ee06d684986d9ad208aece45e8ebf4547..51a117d43d69ac22a9fb8d0a6c37bc77dc92ea76
100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -205,18 +205,17 @@ class MarkingDeque {
void SetOverflowed() { overflowed_ = true; }
- // Push the (marked) object on the marking stack if there is room,
- // otherwise mark the object as overflowed and wait for a rescan of the
- // heap.
- INLINE(void PushBlack(HeapObject* object)) {
+ // Push the (marked) object on the marking stack if there is room,
otherwise
+ // mark the deque as overflowed and wait for a rescan of the heap.
+ INLINE(bool PushBlack(HeapObject* object)) {
DCHECK(object->IsHeapObject());
if (IsFull()) {
- Marking::BlackToGrey(object);
- MemoryChunk::IncrementLiveBytesFromGC(object, -object->Size());
SetOverflowed();
+ return false;
} else {
array_[top_] = object;
top_ = ((top_ + 1) & mask_);
+ return true;
}
}
@@ -248,16 +247,16 @@ class MarkingDeque {
}
}
- INLINE(void UnshiftBlack(HeapObject* object)) {
+ INLINE(bool UnshiftBlack(HeapObject* object)) {
DCHECK(object->IsHeapObject());
DCHECK(Marking::IsBlack(Marking::MarkBitFrom(object)));
if (IsFull()) {
- Marking::BlackToGrey(object);
- MemoryChunk::IncrementLiveBytesFromGC(object, -object->Size());
SetOverflowed();
+ return false;
} else {
bottom_ = ((bottom_ - 1) & mask_);
array_[bottom_] = object;
+ return true;
}
}
@@ -778,6 +777,9 @@ class MarkCompactCollector {
void AfterMarking();
+ // Pushes a black object onto the marking stack and accounts for live
bytes.
+ INLINE(void PushBlack(HeapObject* obj));
+
// Marks the object black and pushes it on the marking stack.
// This is for non-incremental marking only.
INLINE(void MarkObject(HeapObject* obj, MarkBit mark_bit));
@@ -826,6 +828,14 @@ class MarkCompactCollector {
// flag on the marking stack.
void RefillMarkingDeque();
+ // Helper methods for refilling the marking stack by discovering grey
objects
+ // on various pages of the heap. Used by {RefillMarkingDeque} only.
+ template <class T>
+ void DiscoverGreyObjectsWithIterator(T* it);
+ void DiscoverGreyObjectsOnPage(MemoryChunk* p);
+ void DiscoverGreyObjectsInSpace(PagedSpace* space);
+ void DiscoverGreyObjectsInNewSpace();
+
// Callback function for telling whether the object *p is an unmarked
// heap object.
static bool IsUnmarkedHeapObject(Object** p);
--
--
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