v8/include/cppgc/internal/caged-heap-local-data.h
Michael Lippautz c7ff90d97d cppgc: Avoid dispatching write barrier during atomic pause
This change avoid dispatching a write barrier during the atomic pause.
The dispatch can generally be triggered through pre-finalizers.

In future, further checks may be added to avoid mis-use of
pre-finalizers.

Bug: chromium:1056170, chromium:1175560
Change-Id: I119e18372633b2375f60e17b4c881f68bb20bf66
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2679685
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72560}
2021-02-08 12:56:09 +00:00

69 lines
1.9 KiB
C++

// Copyright 2020 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.
#ifndef INCLUDE_CPPGC_INTERNAL_CAGED_HEAP_LOCAL_DATA_H_
#define INCLUDE_CPPGC_INTERNAL_CAGED_HEAP_LOCAL_DATA_H_
#include <array>
#include "cppgc/internal/api-constants.h"
#include "cppgc/internal/logging.h"
#include "cppgc/platform.h"
#include "v8config.h" // NOLINT(build/include_directory)
namespace cppgc {
namespace internal {
class HeapBase;
#if defined(CPPGC_YOUNG_GENERATION)
// AgeTable contains entries that correspond to 4KB memory regions. Each entry
// can be in one of three states: kOld, kYoung or kUnknown.
class AgeTable final {
static constexpr size_t kGranularityBits = 12; // 4KiB per byte.
public:
enum class Age : uint8_t { kOld, kYoung, kUnknown };
static constexpr size_t kEntrySizeInBytes = 1 << kGranularityBits;
Age& operator[](uintptr_t offset) { return table_[entry(offset)]; }
Age operator[](uintptr_t offset) const { return table_[entry(offset)]; }
void Reset(PageAllocator* allocator);
private:
static constexpr size_t kAgeTableSize =
api_constants::kCagedHeapReservationSize >> kGranularityBits;
size_t entry(uintptr_t offset) const {
const size_t entry = offset >> kGranularityBits;
CPPGC_DCHECK(table_.size() > entry);
return entry;
}
std::array<Age, kAgeTableSize> table_;
};
static_assert(sizeof(AgeTable) == 1 * api_constants::kMB,
"Size of AgeTable is 1MB");
#endif // CPPGC_YOUNG_GENERATION
struct CagedHeapLocalData final {
explicit CagedHeapLocalData(HeapBase* heap_base) : heap_base(heap_base) {}
bool is_incremental_marking_in_progress = false;
HeapBase* heap_base = nullptr;
#if defined(CPPGC_YOUNG_GENERATION)
AgeTable age_table;
#endif
};
} // namespace internal
} // namespace cppgc
#endif // INCLUDE_CPPGC_INTERNAL_CAGED_HEAP_LOCAL_DATA_H_