Reviewers: Hannes Payer,
Description:
Reland: Fix logic for incremental marking steps on tenured allocation
BUG=
Please review this at https://codereview.chromium.org/1077153004/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+62, -26 lines):
M src/heap/incremental-marking.h
M src/heap/incremental-marking.cc
M src/heap/spaces.h
M src/heap/spaces.cc
Index: src/heap/incremental-marking.cc
diff --git a/src/heap/incremental-marking.cc
b/src/heap/incremental-marking.cc
index
2ba969432d0a009690f08226e19af6086e8da719..17c609c3f64668db620eedd017dcdb541a4222bd
100644
--- a/src/heap/incremental-marking.cc
+++ b/src/heap/incremental-marking.cc
@@ -818,7 +818,7 @@ void IncrementalMarking::OldSpaceStep(intptr_t
allocated) {
if (IsStopped() && ShouldActivateEvenWithoutIdleNotification()) {
Start();
} else {
- Step(allocated * kFastMarking / kInitialMarkingSpeed,
GC_VIA_STACK_GUARD);
+ Step(allocated * kOldSpaceAllocationMarkingFactor, GC_VIA_STACK_GUARD);
}
}
@@ -894,8 +894,7 @@ intptr_t IncrementalMarking::Step(intptr_t
allocated_bytes,
ForceMarkingAction marking,
ForceCompletionAction completion) {
if (heap_->gc_state() != Heap::NOT_IN_GC || !FLAG_incremental_marking ||
- !FLAG_incremental_marking_steps ||
- (state_ != SWEEPING && state_ != MARKING)) {
+ !CanDoSteps()) {
return 0;
}
Index: src/heap/incremental-marking.h
diff --git a/src/heap/incremental-marking.h b/src/heap/incremental-marking.h
index
2e648e7e2fb8d417beeedc8f27aa8bc0c52b848d..51633233fe8acd11dd4920cf14deccf4a2fb5407
100644
--- a/src/heap/incremental-marking.h
+++ b/src/heap/incremental-marking.h
@@ -50,7 +50,10 @@ class IncrementalMarking {
INLINE(bool IsMarking()) { return state() >= MARKING; }
- inline bool IsMarkingIncomplete() { return state() == MARKING; }
+ inline bool CanDoSteps() {
+ return FLAG_incremental_marking_steps &&
+ (state() == MARKING || state() == SWEEPING);
+ }
inline bool IsComplete() { return state() == COMPLETE; }
@@ -102,6 +105,8 @@ class IncrementalMarking {
// But if we are promoting a lot of data we need to mark faster to keep
up
// with the data that is entering the old space through promotion.
static const intptr_t kFastMarking = 3;
+ static const intptr_t kOldSpaceAllocationMarkingFactor =
+ kFastMarking / kInitialMarkingSpeed;
// After this many steps we increase the marking/allocating factor.
static const intptr_t kMarkingSpeedAccellerationInterval = 1024;
// This is how much we increase the marking/allocating factor by.
Index: src/heap/spaces.cc
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
index
23323a4a7daa224fd8f862ec9e4d45b7aa87fa66..15f6c1908b9cbbf29608d6248036ee5744596d24
100644
--- a/src/heap/spaces.cc
+++ b/src/heap/spaces.cc
@@ -2200,6 +2200,7 @@ void FreeList::Reset() {
medium_list_.Reset();
large_list_.Reset();
huge_list_.Reset();
+ unreported_allocation_ = 0;
}
@@ -2347,6 +2348,15 @@ FreeSpace* FreeList::FindNodeFor(int size_in_bytes,
int* node_size) {
}
+void PagedSpace::SetTopAndLimit(Address top, Address limit) {
+ DCHECK(top == limit ||
+ Page::FromAddress(top) == Page::FromAddress(limit - 1));
+ MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
+ allocation_info_.set_top(top);
+ allocation_info_.set_limit(limit);
+}
+
+
// Allocation on the old space free list. If it succeeds then a new linear
// allocation space has been set up with the top and limit of the space.
If
// the allocation fails then NULL is returned, and the caller can perform
a GC
@@ -2364,9 +2374,6 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
// if it is big enough.
owner_->Free(owner_->top(), old_linear_size);
- owner_->heap()->incremental_marking()->OldSpaceStep(size_in_bytes -
- old_linear_size);
-
int new_node_size = 0;
FreeSpace* new_node = FindNodeFor(size_in_bytes, &new_node_size);
if (new_node == NULL) {
@@ -2389,21 +2396,27 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
// candidate.
DCHECK(!MarkCompactCollector::IsOnEvacuationCandidate(new_node));
- const int kThreshold = IncrementalMarking::kAllocatedThreshold;
+ // An old-space step will mark more data per byte allocated, because old
space
+ // allocation is more serious. We don't want the pause to be bigger, so
we
+ // do marking after a smaller amount of allocation.
+ const int kThreshold = IncrementalMarking::kAllocatedThreshold *
+
IncrementalMarking::kOldSpaceAllocationMarkingFactor;
// Memory in the linear allocation area is counted as allocated. We may
free
// a little of this again immediately - see below.
owner_->Allocate(new_node_size);
+ unreported_allocation_ += new_node_size;
+
if (owner_->heap()->inline_allocation_disabled()) {
// Keep the linear allocation area empty if requested to do so, just
// return area back to the free list instead.
owner_->Free(new_node->address() + size_in_bytes, bytes_left);
DCHECK(owner_->top() == NULL && owner_->limit() == NULL);
} else if (bytes_left > kThreshold &&
- owner_->heap()->incremental_marking()->IsMarkingIncomplete()
&&
- FLAG_incremental_marking_steps) {
+ owner_->heap()->incremental_marking()->CanDoSteps()) {
int linear_size = owner_->RoundSizeDownToObjectAlignment(kThreshold);
+
// We don't want to give too large linear areas to the allocator while
// incremental marking is going on, because we won't check again
whether
// we want to do another increment until the linear area is used up.
@@ -2411,15 +2424,30 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
new_node_size - size_in_bytes - linear_size);
owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
new_node->address() + size_in_bytes +
linear_size);
- } else if (bytes_left > 0) {
- // Normally we give the rest of the node to the allocator as its new
- // linear allocation area.
- owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
- new_node->address() + new_node_size);
+ // It is important that we are done updating top and limit before we
call
+ // this.
+ owner_->heap()->incremental_marking()->OldSpaceStep(size_in_bytes +
+ linear_size);
+ unreported_allocation_ = 0;
} else {
- // TODO(gc) Try not freeing linear allocation region when bytes_left
- // are zero.
- owner_->SetTopAndLimit(NULL, NULL);
+ if (bytes_left > 0) {
+ // Normally we give the rest of the node to the allocator as its new
+ // linear allocation area.
+ owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
+ new_node->address() + new_node_size);
+ } else {
+ // TODO(gc) Try not freeing linear allocation region when bytes_left
+ // are zero.
+ owner_->SetTopAndLimit(NULL, NULL);
+ }
+ if (unreported_allocation_ > kThreshold) {
+ // This may start the incremental marker, or do a little work if it's
+ // already started. It is important that we are finished updating top
+ // and limit before we call this.
+ owner_->heap()->incremental_marking()->OldSpaceStep(
+ Min(kThreshold, unreported_allocation_));
+ unreported_allocation_ = 0;
+ }
}
return new_node;
@@ -2906,7 +2934,16 @@ AllocationResult LargeObjectSpace::AllocateRaw(int
object_size,
reinterpret_cast<Object**>(object->address())[1] = Smi::FromInt(0);
}
- heap()->incremental_marking()->OldSpaceStep(object_size);
+ // We would like to tell the incremental marker to do a lot of work,
since
+ // we just made a large allocation in old space, but that might cause a
huge
+ // pause. Underreporting here may cause the marker to speed up because it
+ // will perceive that it is not keeping up with allocation. Although this
+ // causes some big incremental marking steps they are not as big as this
one
+ // might have been. In testing, a very large pause was divided up into
about
+ // 12 parts.
+ const int kThreshold = IncrementalMarking::kAllocatedThreshold *
+
IncrementalMarking::kOldSpaceAllocationMarkingFactor;
+ heap()->incremental_marking()->OldSpaceStep(kThreshold);
return object;
}
Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index
e6ec542c9e1f843b66e391f3e85338f187d5c157..74250c7ce8859100f3e0edeef14d86ed441356f1
100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -1583,6 +1583,7 @@ class FreeList {
PagedSpace* owner_;
Heap* heap_;
+ int unreported_allocation_;
static const int kSmallListMax = 0xff * kPointerSize;
static const int kMediumListMax = 0x7ff * kPointerSize;
@@ -1780,13 +1781,7 @@ class PagedSpace : public Space {
void ResetFreeList() { free_list_.Reset(); }
// Set space allocation info.
- void SetTopAndLimit(Address top, Address limit) {
- DCHECK(top == limit ||
- Page::FromAddress(top) == Page::FromAddress(limit - 1));
- MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
- allocation_info_.set_top(top);
- allocation_info_.set_limit(limit);
- }
+ void SetTopAndLimit(Address top, Address limit);
// Empty space allocation info, returning unused area to free list.
void EmptyAllocationInfo() {
--
--
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