chromium/base/allocator/partition_alloc_features.h

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_ALLOCATOR_PARTITION_ALLOC_FEATURES_H_
#define BASE_ALLOCATOR_PARTITION_ALLOC_FEATURES_H_

#include "base/base_export.h"
#include "base/compiler_specific.h"
#include "base/feature_list.h"
#include "base/metrics/field_trial_params.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "partition_alloc/buildflags.h"
#include "partition_alloc/partition_alloc_base/time/time.h"
#include "partition_alloc/partition_root.h"

namespace base {
namespace features {

extern const BASE_EXPORT Feature kPartitionAllocUnretainedDanglingPtr;
enum class UnretainedDanglingPtrMode { … };
extern const BASE_EXPORT base::FeatureParam<UnretainedDanglingPtrMode>
    kUnretainedDanglingPtrModeParam;

// See /docs/dangling_ptr.md
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocDanglingPtr);
enum class DanglingPtrMode { … };
extern const BASE_EXPORT base::FeatureParam<DanglingPtrMode>
    kDanglingPtrModeParam;
enum class DanglingPtrType { … };
extern const BASE_EXPORT base::FeatureParam<DanglingPtrType>
    kDanglingPtrTypeParam;

#if PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocLargeThreadCacheSize);
BASE_EXPORT int GetPartitionAllocLargeThreadCacheSizeValue();
BASE_EXPORT int GetPartitionAllocLargeThreadCacheSizeValueForLowRAMAndroid();

BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocLargeEmptySlotSpanRing);
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocSchedulerLoopQuarantine);
// Scheduler Loop Quarantine's per-thread capacity in bytes.
extern const BASE_EXPORT base::FeatureParam<int>
    kPartitionAllocSchedulerLoopQuarantineBranchCapacity;

BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocZappingByFreeFlags);
#endif  // PA_BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)

enum class BackupRefPtrEnabledProcesses { … };

enum class BackupRefPtrMode { … };

enum class MemtagMode { … };

enum class RetagMode { … };

enum class MemoryTaggingEnabledProcesses { … };

enum class BucketDistributionMode : uint8_t { … };

// Parameter for 'kPartitionAllocMakeFreeNoOpOnShutdown' feature which
// controls when free() becomes a no-op during Shutdown()
enum class WhenFreeBecomesNoOp { … };

// Inserts a no-op on 'free()' allocator shim at the front of the
// dispatch chain if called from the appropriate callsite.
BASE_EXPORT void MakeFreeNoOp(WhenFreeBecomesNoOp callsite);

BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocMakeFreeNoOpOnShutdown);
extern const BASE_EXPORT base::FeatureParam<WhenFreeBecomesNoOp>
    kPartitionAllocMakeFreeNoOpOnShutdownParam;

BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocBackupRefPtr);
extern const BASE_EXPORT base::FeatureParam<BackupRefPtrEnabledProcesses>
    kBackupRefPtrEnabledProcessesParam;
extern const BASE_EXPORT base::FeatureParam<BackupRefPtrMode>
    kBackupRefPtrModeParam;
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocMemoryTagging);
extern const BASE_EXPORT base::FeatureParam<MemtagMode> kMemtagModeParam;
extern const BASE_EXPORT base::FeatureParam<RetagMode> kRetagModeParam;
extern const BASE_EXPORT base::FeatureParam<MemoryTaggingEnabledProcesses>
    kMemoryTaggingEnabledProcessesParam;
// Kill switch for memory tagging. Skips any code related to memory tagging when
// enabled.
BASE_EXPORT BASE_DECLARE_FEATURE(kKillPartitionAllocMemoryTagging);
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocPermissiveMte);
extern const BASE_EXPORT base::FeatureParam<bool>
    kBackupRefPtrAsanEnableDereferenceCheckParam;
extern const BASE_EXPORT base::FeatureParam<bool>
    kBackupRefPtrAsanEnableExtractionCheckParam;
extern const BASE_EXPORT base::FeatureParam<bool>
    kBackupRefPtrAsanEnableInstantiationCheckParam;
extern const BASE_EXPORT base::FeatureParam<BucketDistributionMode>
    kPartitionAllocBucketDistributionParam;

BASE_EXPORT BASE_DECLARE_FEATURE(kLowerPAMemoryLimitForNonMainRenderers);
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocUseDenserDistribution);

BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocMemoryReclaimer);
extern const BASE_EXPORT base::FeatureParam<TimeDelta>
    kPartitionAllocMemoryReclaimerInterval;
BASE_EXPORT BASE_DECLARE_FEATURE(
    kPartitionAllocStraightenLargerSlotSpanFreeLists);
extern const BASE_EXPORT
    base::FeatureParam<partition_alloc::StraightenLargerSlotSpanFreeListsMode>
        kPartitionAllocStraightenLargerSlotSpanFreeListsMode;
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocSortSmallerSlotSpanFreeLists);
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocSortActiveSlotSpans);

#if BUILDFLAG(IS_WIN)
BASE_EXPORT BASE_DECLARE_FEATURE(kPageAllocatorRetryOnCommitFailure);
#endif

#if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_CHROMEOS)
extern const base::FeatureParam<bool>
    kPartialLowEndModeExcludePartitionAllocSupport;
#endif

BASE_EXPORT BASE_DECLARE_FEATURE(kEnableConfigurableThreadCacheMultiplier);
BASE_EXPORT double GetThreadCacheMultiplier();
BASE_EXPORT double GetThreadCacheMultiplierForAndroid();

BASE_EXPORT BASE_DECLARE_FEATURE(kEnableConfigurableThreadCachePurgeInterval);
extern const partition_alloc::internal::base::TimeDelta
GetThreadCacheMinPurgeInterval();
extern const partition_alloc::internal::base::TimeDelta
GetThreadCacheMaxPurgeInterval();
extern const partition_alloc::internal::base::TimeDelta
GetThreadCacheDefaultPurgeInterval();

BASE_EXPORT BASE_DECLARE_FEATURE(
    kEnableConfigurableThreadCacheMinCachedMemoryForPurging);
BASE_EXPORT int GetThreadCacheMinCachedMemoryForPurgingBytes();

BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocDisableBRPInBufferPartition);

// This feature is additionally gated behind a buildflag because
// pool offset freelists cannot be represented when PartitionAlloc uses
// 32-bit pointers.
#if PA_BUILDFLAG(USE_FREELIST_DISPATCHER)
BASE_EXPORT BASE_DECLARE_FEATURE(kUsePoolOffsetFreelists);
#endif

// When set, partitions use a larger ring buffer and free memory less
// aggressively when in the foreground.
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocAdjustSizeWhenInForeground);

// When enabled, uses a more nuanced heuristic to determine if slot
// spans can be treated as "single-slot."
//
// See also: https://crbug.com/333443437
BASE_EXPORT BASE_DECLARE_FEATURE(kPartitionAllocUseSmallSingleSlotSpans);

}  // namespace features
}  // namespace base

#endif  // BASE_ALLOCATOR_PARTITION_ALLOC_FEATURES_H_