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Unified Diff: src/heap/store-buffer.h

Issue 1608583002: New page local store buffer. (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: Rebase and fix signed unsigned conversion Created 4 years, 10 months ago
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Index: src/heap/store-buffer.h
diff --git a/src/heap/store-buffer.h b/src/heap/store-buffer.h
index f5af09904d99aebac2d9ad3a9ec4ce0784c2e46e..9670f62a8a9a1d55a96c374cab1ba7660710d5c2 100644
--- a/src/heap/store-buffer.h
+++ b/src/heap/store-buffer.h
@@ -9,6 +9,7 @@
#include "src/base/logging.h"
#include "src/base/platform/platform.h"
#include "src/globals.h"
+#include "src/heap/slot-set.h"
namespace v8 {
namespace internal {
@@ -24,66 +25,22 @@ typedef void (*ObjectSlotCallback)(HeapObject** from, HeapObject* to);
class StoreBuffer {
public:
explicit StoreBuffer(Heap* heap);
-
static void StoreBufferOverflow(Isolate* isolate);
-
void SetUp();
void TearDown();
- // This is used to add addresses to the store buffer non-concurrently.
- inline void Mark(Address addr);
-
- // This is used by the heap traversal to enter the addresses into the store
- // buffer that should still be in the store buffer after GC. It enters
- // addresses directly into the old buffer because the GC starts by wiping the
- // old buffer and thereafter only visits each cell once so there is no need
- // to attempt to remove any dupes. During the first part of a GC we
- // are using the store buffer to access the old spaces and at the same time
- // we are rebuilding the store buffer using this function. There is, however
- // no issue of overwriting the buffer we are iterating over, because this
- // stage of the scavenge can only reduce the number of addresses in the store
- // buffer (some objects are promoted so pointers to them do not need to be in
- // the store buffer). The later parts of the GC scan the pages that are
- // exempt from the store buffer and process the promotion queue. These steps
- // can overflow this buffer. We check for this and on overflow we call the
- // callback set up with the StoreBufferRebuildScope object.
- inline void EnterDirectlyIntoStoreBuffer(Address addr);
-
- // Iterates over all pointers that go from old space to new space. It will
- // delete the store buffer as it starts so the callback should reenter
- // surviving old-to-new pointers into the store buffer to rebuild it.
- void IteratePointersToNewSpace(ObjectSlotCallback callback);
-
static const int kStoreBufferOverflowBit = 1 << (14 + kPointerSizeLog2);
static const int kStoreBufferSize = kStoreBufferOverflowBit;
static const int kStoreBufferLength = kStoreBufferSize / sizeof(Address);
- static const int kOldStoreBufferLength = kStoreBufferLength * 16;
- static const int kHashSetLengthLog2 = 12;
- static const int kHashSetLength = 1 << kHashSetLengthLog2;
-
- void Compact();
-
- void GCPrologue();
- void GCEpilogue();
-
- Object*** Limit() { return reinterpret_cast<Object***>(old_limit_); }
- Object*** Start() { return reinterpret_cast<Object***>(old_start_); }
- Object*** Top() { return reinterpret_cast<Object***>(old_top_); }
- void SetTop(Object*** top) {
- DCHECK(top >= Start());
- DCHECK(top <= Limit());
- old_top_ = reinterpret_cast<Address*>(top);
- }
-
- bool old_buffer_is_sorted() { return old_buffer_is_sorted_; }
- bool old_buffer_is_filtered() { return old_buffer_is_filtered_; }
- void EnsureSpace(intptr_t space_needed);
- void Verify();
+ // This is used to add addresses to the store buffer non-concurrently.
+ inline void Mark(Address addr);
- bool PrepareForIteration();
+ // Slots that do not point to the ToSpace after callback invocation will be
+ // removed from the set.
+ void IteratePointersToNewSpace(ObjectSlotCallback callback);
- void Filter(int flag);
+ void Verify();
// Eliminates all stale store buffer entries from the store buffer, i.e.,
// slots that are not part of live objects anymore. This method must be
@@ -95,124 +52,30 @@ class StoreBuffer {
private:
Heap* heap_;
- // The store buffer is divided up into a new buffer that is constantly being
- // filled by mutator activity and an old buffer that is filled with the data
- // from the new buffer after compression.
+ // The start and the limit of the buffer that contains store slots
+ // added from the generated code.
Address* start_;
Address* limit_;
- Address* old_start_;
- Address* old_limit_;
- Address* old_top_;
- Address* old_reserved_limit_;
- base::VirtualMemory* old_virtual_memory_;
-
- bool old_buffer_is_sorted_;
- bool old_buffer_is_filtered_;
- bool during_gc_;
- // The garbage collector iterates over many pointers to new space that are not
- // handled by the store buffer. This flag indicates whether the pointers
- // found by the callbacks should be added to the store buffer or not.
- bool store_buffer_rebuilding_enabled_;
- StoreBufferCallback callback_;
- bool may_move_store_buffer_entries_;
-
base::VirtualMemory* virtual_memory_;
- // Two hash sets used for filtering.
- // If address is in the hash set then it is guaranteed to be in the
- // old part of the store buffer.
- uintptr_t* hash_set_1_;
- uintptr_t* hash_set_2_;
- bool hash_sets_are_empty_;
-
// Used for synchronization of concurrent store buffer access.
base::Mutex mutex_;
- void ClearFilteringHashSets();
-
- bool SpaceAvailable(intptr_t space_needed);
- void ExemptPopularPages(int prime_sample_step, int threshold);
+ void InsertEntriesFromBuffer();
- void ProcessOldToNewSlot(Address slot_address,
- ObjectSlotCallback slot_callback);
+ inline uint32_t AddressToSlotSetAndOffset(Address slot_address,
+ SlotSet** slots);
- void FindPointersToNewSpaceInRegion(Address start, Address end,
- ObjectSlotCallback slot_callback);
-
- void IteratePointersInStoreBuffer(ObjectSlotCallback slot_callback);
+ template <typename Callback>
+ void Iterate(Callback callback);
#ifdef VERIFY_HEAP
void VerifyPointers(LargeObjectSpace* space);
#endif
-
- friend class DontMoveStoreBufferEntriesScope;
- friend class FindPointersToNewSpaceVisitor;
- friend class StoreBufferRebuildScope;
};
-class StoreBufferRebuilder {
- public:
- explicit StoreBufferRebuilder(StoreBuffer* store_buffer)
- : store_buffer_(store_buffer) {}
-
- void Callback(MemoryChunk* page, StoreBufferEvent event);
-
- private:
- StoreBuffer* store_buffer_;
-
- // We record in this variable how full the store buffer was when we started
- // iterating over the current page, finding pointers to new space. If the
- // store buffer overflows again we can exempt the page from the store buffer
- // by rewinding to this point instead of having to search the store buffer.
- Object*** start_of_current_page_;
- // The current page we are scanning in the store buffer iterator.
- MemoryChunk* current_page_;
-};
-
-
-class StoreBufferRebuildScope {
- public:
- explicit StoreBufferRebuildScope(Heap* heap, StoreBuffer* store_buffer,
- StoreBufferCallback callback)
- : store_buffer_(store_buffer),
- stored_state_(store_buffer->store_buffer_rebuilding_enabled_),
- stored_callback_(store_buffer->callback_) {
- store_buffer_->store_buffer_rebuilding_enabled_ = true;
- store_buffer_->callback_ = callback;
- (*callback)(heap, NULL, kStoreBufferStartScanningPagesEvent);
- }
-
- ~StoreBufferRebuildScope() {
- store_buffer_->callback_ = stored_callback_;
- store_buffer_->store_buffer_rebuilding_enabled_ = stored_state_;
- }
-
- private:
- StoreBuffer* store_buffer_;
- bool stored_state_;
- StoreBufferCallback stored_callback_;
-};
-
-
-class DontMoveStoreBufferEntriesScope {
- public:
- explicit DontMoveStoreBufferEntriesScope(StoreBuffer* store_buffer)
- : store_buffer_(store_buffer),
- stored_state_(store_buffer->may_move_store_buffer_entries_) {
- store_buffer_->may_move_store_buffer_entries_ = false;
- }
-
- ~DontMoveStoreBufferEntriesScope() {
- store_buffer_->may_move_store_buffer_entries_ = stored_state_;
- }
-
- private:
- StoreBuffer* store_buffer_;
- bool stored_state_;
-};
-
class LocalStoreBuffer BASE_EMBEDDED {
public:
LocalStoreBuffer() : top_(new Node(nullptr)) {}
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