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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef gc_GCRuntime_h
#define gc_GCRuntime_h
#include "mozilla/Atomics.h"
#include "mozilla/DoublyLinkedList.h"
#include "mozilla/EnumSet.h"
#include "mozilla/Maybe.h"
#include "mozilla/TimeStamp.h"
#include "gc/ArenaList.h"
#include "gc/AtomMarking.h"
#include "gc/GCContext.h"
#include "gc/GCMarker.h"
#include "gc/GCParallelTask.h"
#include "gc/IteratorUtils.h"
#include "gc/Nursery.h"
#include "gc/Scheduling.h"
#include "gc/Statistics.h"
#include "gc/StoreBuffer.h"
#include "js/friend/PerformanceHint.h"
#include "js/GCAnnotations.h"
#include "js/UniquePtr.h"
#include "vm/AtomsTable.h"
namespace js {
class AutoLockGC;
class AutoLockGCBgAlloc;
class AutoLockHelperThreadState;
class FinalizationRegistryObject;
class FinalizationRecordObject;
class FinalizationQueueObject;
class GlobalObject;
class VerifyPreTracer;
class WeakRefObject;
namespace gc {
using BlackGrayEdgeVector = Vector<TenuredCell*, 0, SystemAllocPolicy>;
using ZoneVector = Vector<JS::Zone*, 4, SystemAllocPolicy>;
class AutoCallGCCallbacks;
class AutoGCSession;
class AutoHeapSession;
class AutoTraceSession;
struct FinalizePhase;
class MarkingValidator;
struct MovingTracer;
class ParallelMarkTask;
enum class ShouldCheckThresholds;
class SweepGroupsIter;
// Interface to a sweep action.
struct SweepAction {
// The arguments passed to each action.
struct Args {
GCRuntime* gc;
JS::GCContext* gcx;
JS::SliceBudget& budget;
};
virtual ~SweepAction() = default;
virtual IncrementalProgress run(Args& state) = 0;
virtual void assertFinished() const = 0;
virtual bool shouldSkip() { return false; }
};
class ChunkPool {
TenuredChunk* head_;
size_t count_;
public:
ChunkPool() : head_(nullptr), count_(0) {}
ChunkPool(const ChunkPool& other) = delete;
ChunkPool(ChunkPool&& other) { *this = std::move(other); }
~ChunkPool() {
MOZ_ASSERT(!head_);
MOZ_ASSERT(count_ == 0);
}
ChunkPool& operator=(const ChunkPool& other) = delete;
ChunkPool& operator=(ChunkPool&& other) {
head_ = other.head_;
other.head_ = nullptr;
count_ = other.count_;
other.count_ = 0;
return *this;
}
bool empty() const { return !head_; }
size_t count() const { return count_; }
TenuredChunk* head() {
MOZ_ASSERT(head_);
return head_;
}
TenuredChunk* pop();
void push(TenuredChunk* chunk);
TenuredChunk* remove(TenuredChunk* chunk);
void sort();
private:
TenuredChunk* mergeSort(TenuredChunk* list, size_t count);
bool isSorted() const;
#ifdef DEBUG
public:
bool contains(TenuredChunk* chunk) const;
bool verify() const;
void verifyChunks() const;
#endif
public:
// Pool mutation does not invalidate an Iter unless the mutation
// is of the TenuredChunk currently being visited by the Iter.
class Iter {
public:
explicit Iter(ChunkPool& pool) : current_(pool.head_) {}
bool done() const { return !current_; }
void next();
TenuredChunk* get() const { return current_; }
operator TenuredChunk*() const { return get(); }
TenuredChunk* operator->() const { return get(); }
private:
TenuredChunk* current_;
};
};
class BackgroundMarkTask : public GCParallelTask {
public:
explicit BackgroundMarkTask(GCRuntime* gc);
void setBudget(const JS::SliceBudget& budget) { this->budget = budget; }
void run(AutoLockHelperThreadState& lock) override;
private:
JS::SliceBudget budget;
};
class BackgroundUnmarkTask : public GCParallelTask {
public:
explicit BackgroundUnmarkTask(GCRuntime* gc);
void initZones();
void run(AutoLockHelperThreadState& lock) override;
ZoneVector zones;
};
class BackgroundSweepTask : public GCParallelTask {
public:
explicit BackgroundSweepTask(GCRuntime* gc);
void run(AutoLockHelperThreadState& lock) override;
};
class BackgroundFreeTask : public GCParallelTask {
public:
explicit BackgroundFreeTask(GCRuntime* gc);
void run(AutoLockHelperThreadState& lock) override;
};
// Performs extra allocation off thread so that when memory is required on the
// main thread it will already be available and waiting.
class BackgroundAllocTask : public GCParallelTask {
// Guarded by the GC lock.
GCLockData<ChunkPool&> chunkPool_;
const bool enabled_;
public:
BackgroundAllocTask(GCRuntime* gc, ChunkPool& pool);
bool enabled() const { return enabled_; }
void run(AutoLockHelperThreadState& lock) override;
};
// Search the provided chunks for free arenas and decommit them.
class BackgroundDecommitTask : public GCParallelTask {
public:
explicit BackgroundDecommitTask(GCRuntime* gc);
void run(AutoLockHelperThreadState& lock) override;
};
template <typename F>
struct Callback {
F op;
void* data;
Callback() : op(nullptr), data(nullptr) {}
Callback(F op, void* data) : op(op), data(data) {}
};
template <typename F>
using CallbackVector = Vector<Callback<F>, 4, SystemAllocPolicy>;
using RootedValueMap =
HashMap<Value*, const char*, DefaultHasher<Value*>, SystemAllocPolicy>;
using AllocKinds = mozilla::EnumSet<AllocKind, uint64_t>;
// A singly linked list of zones.
class ZoneList {
static Zone* const End;
Zone* head;
Zone* tail;
public:
ZoneList();
~ZoneList();
bool isEmpty() const;
Zone* front() const;
void prepend(Zone* zone);
void append(Zone* zone);
void prependList(ZoneList&& other);
void appendList(ZoneList&& other);
Zone* removeFront();
void clear();
private:
explicit ZoneList(Zone* singleZone);
void check() const;
ZoneList(const ZoneList& other) = delete;
ZoneList& operator=(const ZoneList& other) = delete;
};
struct WeakCacheToSweep {
JS::detail::WeakCacheBase* cache;
JS::Zone* zone;
};
class WeakCacheSweepIterator {
using WeakCacheBase = JS::detail::WeakCacheBase;
JS::Zone* sweepZone;
WeakCacheBase* sweepCache;
public:
explicit WeakCacheSweepIterator(JS::Zone* sweepGroup);
bool done() const;
WeakCacheToSweep get() const;
void next();
private:
void settle();
};
struct SweepingTracer final : public GenericTracerImpl<SweepingTracer> {
explicit SweepingTracer(JSRuntime* rt);
private:
template <typename T>
void onEdge(T** thingp, const char* name);
friend class GenericTracerImpl<SweepingTracer>;
};
class GCRuntime {
public:
explicit GCRuntime(JSRuntime* rt);
[[nodiscard]] bool init(uint32_t maxbytes);
bool wasInitialized() const { return initialized; }
void finishRoots();
void finish();
Zone* atomsZone() {
Zone* zone = zones()[0];
MOZ_ASSERT(JS::shadow::Zone::from(zone)->isAtomsZone());
return zone;
}
Zone* maybeSharedAtomsZone() { return sharedAtomsZone_; }
[[nodiscard]] bool freezeSharedAtomsZone();
void restoreSharedAtomsZone();
JS::HeapState heapState() const { return heapState_; }
bool hasZealMode(ZealMode mode) const;
bool hasAnyZealModeOf(mozilla::EnumSet<ZealMode> mode) const;
void clearZealMode(ZealMode mode);
bool needZealousGC();
bool zealModeControlsYieldPoint() const;
[[nodiscard]] bool addRoot(Value* vp, const char* name);
void removeRoot(Value* vp);
[[nodiscard]] bool setParameter(JSContext* cx, JSGCParamKey key,
uint32_t value);
void resetParameter(JSContext* cx, JSGCParamKey key);
uint32_t getParameter(JSGCParamKey key);
void setPerformanceHint(PerformanceHint hint);
bool isInPageLoad() const { return inPageLoadCount != 0; }
[[nodiscard]] bool triggerGC(JS::GCReason reason);
// Check whether to trigger a zone GC after allocating GC cells.
void maybeTriggerGCAfterAlloc(Zone* zone);
// Check whether to trigger a zone GC after malloc memory.
void maybeTriggerGCAfterMalloc(Zone* zone);
bool maybeTriggerGCAfterMalloc(Zone* zone, const HeapSize& heap,
const HeapThreshold& threshold,
JS::GCReason reason);
// The return value indicates if we were able to do the GC.
bool triggerZoneGC(Zone* zone, JS::GCReason reason, size_t usedBytes,
size_t thresholdBytes);
void maybeGC();
// Return whether we want to run a major GC. If eagerOk is true, include eager
// triggers (eg EAGER_ALLOC_TRIGGER) in this determination, and schedule all
// zones that exceed the eager thresholds.
JS::GCReason wantMajorGC(bool eagerOk);
bool checkEagerAllocTrigger(const HeapSize& size,
const HeapThreshold& threshold);
// Do a minor GC if requested, followed by a major GC if requested. The return
// value indicates whether a major GC was performed.
bool gcIfRequested() { return gcIfRequestedImpl(false); }
// Internal function to do a GC if previously requested. But if not and
// eagerOk, do an eager GC for all Zones that have exceeded the eager
// thresholds.
//
// Return whether a major GC was performed or started.
bool gcIfRequestedImpl(bool eagerOk);
void gc(JS::GCOptions options, JS::GCReason reason);
void startGC(JS::GCOptions options, JS::GCReason reason,
const JS::SliceBudget& budget);
void gcSlice(JS::GCReason reason, const JS::SliceBudget& budget);
void finishGC(JS::GCReason reason);
void abortGC();
void startDebugGC(JS::GCOptions options, const JS::SliceBudget& budget);
void debugGCSlice(const JS::SliceBudget& budget);
void runDebugGC();
void notifyRootsRemoved();
enum TraceOrMarkRuntime { TraceRuntime, MarkRuntime };
void traceRuntime(JSTracer* trc, AutoTraceSession& session);
void traceRuntimeForMinorGC(JSTracer* trc, AutoGCSession& session);
void purgeRuntimeForMinorGC();
void shrinkBuffers();
void onOutOfMallocMemory();
void onOutOfMallocMemory(const AutoLockGC& lock);
Nursery& nursery() { return nursery_.ref(); }
gc::StoreBuffer& storeBuffer() { return storeBuffer_.ref(); }
void minorGC(JS::GCReason reason,
gcstats::PhaseKind phase = gcstats::PhaseKind::MINOR_GC)
JS_HAZ_GC_CALL;
void evictNursery(JS::GCReason reason = JS::GCReason::EVICT_NURSERY) {
minorGC(reason, gcstats::PhaseKind::EVICT_NURSERY);
}
void* addressOfNurseryPosition() {
return nursery_.refNoCheck().addressOfPosition();
}
const void* addressOfLastBufferedWholeCell() {
return storeBuffer_.refNoCheck().addressOfLastBufferedWholeCell();
}
#ifdef JS_GC_ZEAL
const uint32_t* addressOfZealModeBits() { return &zealModeBits.refNoCheck(); }
void getZealBits(uint32_t* zealBits, uint32_t* frequency,
uint32_t* nextScheduled);
void setZeal(uint8_t zeal, uint32_t frequency);
void unsetZeal(uint8_t zeal);
bool parseAndSetZeal(const char* str);
void setNextScheduled(uint32_t count);
void verifyPreBarriers();
void maybeVerifyPreBarriers(bool always);
bool selectForMarking(JSObject* object);
void clearSelectedForMarking();
void setDeterministic(bool enable);
void setMarkStackLimit(size_t limit, AutoLockGC& lock);
#endif
uint64_t nextCellUniqueId() {
MOZ_ASSERT(nextCellUniqueId_ > 0);
uint64_t uid = ++nextCellUniqueId_;
return uid;
}
void setLowMemoryState(bool newState) { lowMemoryState = newState; }
bool systemHasLowMemory() const { return lowMemoryState; }
public:
// Internal public interface
ZoneVector& zones() { return zones_.ref(); }
gcstats::Statistics& stats() { return stats_.ref(); }
const gcstats::Statistics& stats() const { return stats_.ref(); }
State state() const { return incrementalState; }
bool isHeapCompacting() const { return state() == State::Compact; }
bool isForegroundSweeping() const { return state() == State::Sweep; }
bool isBackgroundSweeping() const { return sweepTask.wasStarted(); }
bool isBackgroundMarking() const { return markTask.wasStarted(); }
void waitBackgroundSweepEnd();
void waitBackgroundAllocEnd() { allocTask.cancelAndWait(); }
void waitBackgroundFreeEnd();
void waitForBackgroundTasks();
bool isWaitingOnBackgroundTask() const;
void lockGC() { lock.lock(); }
void unlockGC() { lock.unlock(); }
void lockStoreBuffer() { storeBufferLock.lock(); }
void unlockStoreBuffer() { storeBufferLock.unlock(); }
#ifdef DEBUG
void assertCurrentThreadHasLockedGC() const {
lock.assertOwnedByCurrentThread();
}
void assertCurrentThreadHasLockedStoreBuffer() const {
storeBufferLock.assertOwnedByCurrentThread();
}
#endif // DEBUG
void setAlwaysPreserveCode() { alwaysPreserveCode = true; }
void setIncrementalGCEnabled(bool enabled);
bool isIncrementalGCEnabled() const { return incrementalGCEnabled; }
bool isPerZoneGCEnabled() const { return perZoneGCEnabled; }
bool isCompactingGCEnabled() const;
bool isParallelMarkingEnabled() const { return parallelMarkingEnabled; }
bool isIncrementalGCInProgress() const {
return state() != State::NotActive && !isVerifyPreBarriersEnabled();
}
bool hasForegroundWork() const;
bool isShrinkingGC() const { return gcOptions() == JS::GCOptions::Shrink; }
bool isShutdownGC() const { return gcOptions() == JS::GCOptions::Shutdown; }
#ifdef DEBUG
bool isShuttingDown() const { return hadShutdownGC; }
#endif
bool initSweepActions();
void setGrayRootsTracer(JSGrayRootsTracer traceOp, void* data);
[[nodiscard]] bool addBlackRootsTracer(JSTraceDataOp traceOp, void* data);
void removeBlackRootsTracer(JSTraceDataOp traceOp, void* data);
void clearBlackAndGrayRootTracers();
void setGCCallback(JSGCCallback callback, void* data);
void callGCCallback(JSGCStatus status, JS::GCReason reason) const;
void setObjectsTenuredCallback(JSObjectsTenuredCallback callback, void* data);
void callObjectsTenuredCallback();
[[nodiscard]] bool addFinalizeCallback(JSFinalizeCallback callback,
void* data);
void removeFinalizeCallback(JSFinalizeCallback callback);
void setHostCleanupFinalizationRegistryCallback(
JSHostCleanupFinalizationRegistryCallback callback, void* data);
void callHostCleanupFinalizationRegistryCallback(
JSFunction* doCleanup, GlobalObject* incumbentGlobal);
[[nodiscard]] bool addWeakPointerZonesCallback(
JSWeakPointerZonesCallback callback, void* data);
void removeWeakPointerZonesCallback(JSWeakPointerZonesCallback callback);
[[nodiscard]] bool addWeakPointerCompartmentCallback(
JSWeakPointerCompartmentCallback callback, void* data);
void removeWeakPointerCompartmentCallback(
JSWeakPointerCompartmentCallback callback);
JS::GCSliceCallback setSliceCallback(JS::GCSliceCallback callback);
bool addNurseryCollectionCallback(JS::GCNurseryCollectionCallback callback,
void* data);
void removeNurseryCollectionCallback(JS::GCNurseryCollectionCallback callback,
void* data);
JS::DoCycleCollectionCallback setDoCycleCollectionCallback(
JS::DoCycleCollectionCallback callback);
void callNurseryCollectionCallbacks(JS::GCNurseryProgress progress,
JS::GCReason reason);
bool addFinalizationRegistry(JSContext* cx,
Handle<FinalizationRegistryObject*> registry);
bool registerWithFinalizationRegistry(JSContext* cx, HandleObject target,
HandleObject record);
void queueFinalizationRegistryForCleanup(FinalizationQueueObject* queue);
void nukeFinalizationRecordWrapper(JSObject* wrapper,
FinalizationRecordObject* record);
void nukeWeakRefWrapper(JSObject* wrapper, WeakRefObject* weakRef);
void setFullCompartmentChecks(bool enable);
// Get the main marking tracer.
GCMarker& marker() { return *markers[0]; }
JS::Zone* getCurrentSweepGroup() { return currentSweepGroup; }
unsigned getCurrentSweepGroupIndex() {
MOZ_ASSERT_IF(unsigned(state()) < unsigned(State::Sweep),
sweepGroupIndex == 0);
return sweepGroupIndex;
}
uint64_t gcNumber() const { return number; }
void incGcNumber() { ++number; }
uint64_t minorGCCount() const { return minorGCNumber; }
void incMinorGcNumber() { ++minorGCNumber; }
uint64_t majorGCCount() const { return majorGCNumber; }
void incMajorGcNumber() { ++majorGCNumber; }
uint64_t gcSliceCount() const { return sliceNumber; }
void incGcSliceNumber() { ++sliceNumber; }
int64_t defaultSliceBudgetMS() const { return defaultTimeBudgetMS_; }
bool isIncrementalGc() const { return isIncremental; }
bool isFullGc() const { return isFull; }
bool isCompactingGc() const { return isCompacting; }
bool didCompactZones() const { return isCompacting && zonesCompacted; }
bool areGrayBitsValid() const { return grayBitsValid; }
void setGrayBitsInvalid() { grayBitsValid = false; }
mozilla::TimeStamp lastGCStartTime() const { return lastGCStartTime_; }
mozilla::TimeStamp lastGCEndTime() const { return lastGCEndTime_; }
bool majorGCRequested() const {
return majorGCTriggerReason != JS::GCReason::NO_REASON;
}
double computeHeapGrowthFactor(size_t lastBytes);
size_t computeTriggerBytes(double growthFactor, size_t lastBytes);
inline void updateOnFreeArenaAlloc(const TenuredChunkInfo& info);
void updateOnArenaFree() { ++numArenasFreeCommitted; }
ChunkPool& fullChunks(const AutoLockGC& lock) { return fullChunks_.ref(); }
ChunkPool& availableChunks(const AutoLockGC& lock) {
return availableChunks_.ref();
}
ChunkPool& emptyChunks(const AutoLockGC& lock) { return emptyChunks_.ref(); }
const ChunkPool& fullChunks(const AutoLockGC& lock) const {
return fullChunks_.ref();
}
const ChunkPool& availableChunks(const AutoLockGC& lock) const {
return availableChunks_.ref();
}
const ChunkPool& emptyChunks(const AutoLockGC& lock) const {
return emptyChunks_.ref();
}
using NonEmptyChunksIter = ChainedIterator<ChunkPool::Iter, 2>;
NonEmptyChunksIter allNonEmptyChunks(const AutoLockGC& lock) {
return NonEmptyChunksIter(availableChunks(lock), fullChunks(lock));
}
uint32_t minEmptyChunkCount(const AutoLockGC& lock) const {
return minEmptyChunkCount_;
}
uint32_t maxEmptyChunkCount(const AutoLockGC& lock) const {
return maxEmptyChunkCount_;
}
#ifdef DEBUG
void verifyAllChunks();
#endif
TenuredChunk* getOrAllocChunk(AutoLockGCBgAlloc& lock);
void recycleChunk(TenuredChunk* chunk, const AutoLockGC& lock);
#ifdef JS_GC_ZEAL
void startVerifyPreBarriers();
void endVerifyPreBarriers();
void finishVerifier();
bool isVerifyPreBarriersEnabled() const { return verifyPreData.refNoCheck(); }
bool shouldYieldForZeal(ZealMode mode);
#else
bool isVerifyPreBarriersEnabled() const { return false; }
#endif
#ifdef JSGC_HASH_TABLE_CHECKS
void checkHashTablesAfterMovingGC();
#endif
// Crawl the heap to check whether an arbitary pointer is within a cell of
// the given kind. (TraceKind::Null means to ignore the kind.)
bool isPointerWithinTenuredCell(
void* ptr, JS::TraceKind traceKind = JS::TraceKind::Null);
#ifdef DEBUG
bool hasZone(Zone* target);
#endif
// Queue memory memory to be freed on a background thread if possible.
void queueUnusedLifoBlocksForFree(LifoAlloc* lifo);
void queueAllLifoBlocksForFreeAfterMinorGC(LifoAlloc* lifo);
void queueBuffersForFreeAfterMinorGC(Nursery::BufferSet& buffers);
// Public here for ReleaseArenaLists and FinalizeTypedArenas.
void releaseArena(Arena* arena, const AutoLockGC& lock);
// Allocator internals.
static void* refillFreeListInGC(Zone* zone, AllocKind thingKind);
// Delayed marking.
void delayMarkingChildren(gc::Cell* cell, MarkColor color);
bool hasDelayedMarking() const;
void markAllDelayedChildren(ShouldReportMarkTime reportTime);
// If we have yielded to the mutator while foreground finalizing arenas from
// zone |zone| with kind |kind| then return a list of the arenas finalized so
// far. These will have been removed from the main arena lists at this
// point. Otherwise return nullptr.
SortedArenaList* maybeGetForegroundFinalizedArenas(Zone* zone,
AllocKind kind);
/*
* Concurrent sweep infrastructure.
*/
void startTask(GCParallelTask& task, AutoLockHelperThreadState& lock);
void joinTask(GCParallelTask& task, AutoLockHelperThreadState& lock);
void updateHelperThreadCount();
size_t parallelWorkerCount() const;
// GC parallel task dispatch infrastructure.
size_t getMaxParallelThreads() const;
void dispatchOrQueueParallelTask(GCParallelTask* task,
const AutoLockHelperThreadState& lock);
void maybeDispatchParallelTasks(const AutoLockHelperThreadState& lock);
void onParallelTaskEnd(bool wasDispatched,
const AutoLockHelperThreadState& lock);
// Parallel marking.
bool setParallelMarkingEnabled(bool enabled);
bool initOrDisableParallelMarking();
[[nodiscard]] bool updateMarkersVector();
size_t markingWorkerCount() const;
// WeakRefs
bool registerWeakRef(HandleObject target, HandleObject weakRef);
void traceKeptObjects(JSTracer* trc);
JS::GCReason lastStartReason() const { return initialReason; }
void updateAllocationRates();
// Allocator internals
static void* refillFreeList(JSContext* cx, AllocKind thingKind);
void attemptLastDitchGC(JSContext* cx);
// Test mark queue.
#ifdef DEBUG
const GCVector<HeapPtr<JS::Value>, 0, SystemAllocPolicy>& getTestMarkQueue()
const;
[[nodiscard]] bool appendTestMarkQueue(const JS::Value& value);
void clearTestMarkQueue();
size_t testMarkQueuePos() const;
#endif
private:
enum IncrementalResult { ResetIncremental = 0, Ok };
[[nodiscard]] bool setParameter(JSGCParamKey key, uint32_t value,
AutoLockGC& lock);
void resetParameter(JSGCParamKey key, AutoLockGC& lock);
uint32_t getParameter(JSGCParamKey key, const AutoLockGC& lock);
bool setThreadParameter(JSGCParamKey key, uint32_t value, AutoLockGC& lock);
void resetThreadParameter(JSGCParamKey key, AutoLockGC& lock);
void updateThreadDataStructures(AutoLockGC& lock);
JS::GCOptions gcOptions() const { return maybeGcOptions.ref().ref(); }
TriggerResult checkHeapThreshold(Zone* zone, const HeapSize& heapSize,
const HeapThreshold& heapThreshold);
void updateSchedulingStateOnGCStart();
void updateSchedulingStateAfterCollection(mozilla::TimeStamp currentTime);
void updateAllGCStartThresholds();
// For ArenaLists::allocateFromArena()
friend class ArenaLists;
TenuredChunk* pickChunk(AutoLockGCBgAlloc& lock);
Arena* allocateArena(TenuredChunk* chunk, Zone* zone, AllocKind kind,
ShouldCheckThresholds checkThresholds,
const AutoLockGC& lock);
/*
* Return the list of chunks that can be released outside the GC lock.
* Must be called either during the GC or with the GC lock taken.
*/
friend class BackgroundDecommitTask;
bool tooManyEmptyChunks(const AutoLockGC& lock);
ChunkPool expireEmptyChunkPool(const AutoLockGC& lock);
void freeEmptyChunks(const AutoLockGC& lock);
void prepareToFreeChunk(TenuredChunkInfo& info);
void setMinEmptyChunkCount(uint32_t value, const AutoLockGC& lock);
void setMaxEmptyChunkCount(uint32_t value, const AutoLockGC& lock);
friend class BackgroundAllocTask;
bool wantBackgroundAllocation(const AutoLockGC& lock) const;
void startBackgroundAllocTaskIfIdle();
void requestMajorGC(JS::GCReason reason);
JS::SliceBudget defaultBudget(JS::GCReason reason, int64_t millis);
bool maybeIncreaseSliceBudget(JS::SliceBudget& budget);
bool maybeIncreaseSliceBudgetForLongCollections(JS::SliceBudget& budget);
bool maybeIncreaseSliceBudgetForUrgentCollections(JS::SliceBudget& budget);
IncrementalResult budgetIncrementalGC(bool nonincrementalByAPI,
JS::GCReason reason,
JS::SliceBudget& budget);
void checkZoneIsScheduled(Zone* zone, JS::GCReason reason,
const char* trigger);
IncrementalResult resetIncrementalGC(GCAbortReason reason);
// Assert if the system state is such that we should never
// receive a request to do GC work.
void checkCanCallAPI();
// Check if the system state is such that GC has been supressed
// or otherwise delayed.
[[nodiscard]] bool checkIfGCAllowedInCurrentState(JS::GCReason reason);
gcstats::ZoneGCStats scanZonesBeforeGC();
void setGCOptions(JS::GCOptions options);
void collect(bool nonincrementalByAPI, const JS::SliceBudget& budget,
JS::GCReason reason) JS_HAZ_GC_CALL;
/*
* Run one GC "cycle" (either a slice of incremental GC or an entire
* non-incremental GC).
*
* Returns:
* * ResetIncremental if we "reset" an existing incremental GC, which would
* force us to run another cycle or
* * Ok otherwise.
*/
[[nodiscard]] IncrementalResult gcCycle(bool nonincrementalByAPI,
const JS::SliceBudget& budgetArg,
JS::GCReason reason);
bool shouldRepeatForDeadZone(JS::GCReason reason);
void incrementalSlice(JS::SliceBudget& budget, JS::GCReason reason,
bool budgetWasIncreased);
bool mightSweepInThisSlice(bool nonIncremental);
void collectNurseryFromMajorGC(JS::GCReason reason);
void collectNursery(JS::GCOptions options, JS::GCReason reason,
gcstats::PhaseKind phase);
friend class AutoCallGCCallbacks;
void maybeCallGCCallback(JSGCStatus status, JS::GCReason reason);
void startCollection(JS::GCReason reason);
void purgeRuntime();
[[nodiscard]] bool beginPreparePhase(JS::GCReason reason,
AutoGCSession& session);
bool prepareZonesForCollection(JS::GCReason reason, bool* isFullOut);
void unmarkWeakMaps();
void endPreparePhase(JS::GCReason reason);
void beginMarkPhase(AutoGCSession& session);
bool shouldPreserveJITCode(JS::Realm* realm,
const mozilla::TimeStamp& currentTime,
JS::GCReason reason, bool canAllocateMoreCode,
bool isActiveCompartment);
void discardJITCodeForGC();
void startBackgroundFreeAfterMinorGC();
void relazifyFunctionsForShrinkingGC();
void purgePropMapTablesForShrinkingGC();
void purgeSourceURLsForShrinkingGC();
void traceRuntimeForMajorGC(JSTracer* trc, AutoGCSession& session);
void traceRuntimeAtoms(JSTracer* trc);
void traceRuntimeCommon(JSTracer* trc, TraceOrMarkRuntime traceOrMark);
void traceEmbeddingBlackRoots(JSTracer* trc);
void traceEmbeddingGrayRoots(JSTracer* trc);
IncrementalProgress traceEmbeddingGrayRoots(JSTracer* trc,
JS::SliceBudget& budget);
void checkNoRuntimeRoots(AutoGCSession& session);
void maybeDoCycleCollection();
void findDeadCompartments();
friend class BackgroundMarkTask;
enum ParallelMarking : bool {
SingleThreadedMarking = false,
AllowParallelMarking = true
};
IncrementalProgress markUntilBudgetExhausted(
JS::SliceBudget& sliceBudget,
ParallelMarking allowParallelMarking = SingleThreadedMarking,
ShouldReportMarkTime reportTime = ReportMarkTime);
bool canMarkInParallel() const;
bool initParallelMarking();
void finishParallelMarkers();
bool reserveMarkingThreads(size_t count);
void releaseMarkingThreads();
bool hasMarkingWork(MarkColor color) const;
void drainMarkStack();
#ifdef DEBUG
void assertNoMarkingWork() const;
#else
void assertNoMarkingWork() const {}
#endif
void markDelayedChildren(gc::Arena* arena, MarkColor color);
void processDelayedMarkingList(gc::MarkColor color);
void rebuildDelayedMarkingList();
void appendToDelayedMarkingList(gc::Arena** listTail, gc::Arena* arena);
void resetDelayedMarking();
template <typename F>
void forEachDelayedMarkingArena(F&& f);
template <class ZoneIterT>
IncrementalProgress markWeakReferences(JS::SliceBudget& budget);
IncrementalProgress markWeakReferencesInCurrentGroup(JS::SliceBudget& budget);
IncrementalProgress markGrayRoots(JS::SliceBudget& budget,
gcstats::PhaseKind phase);
void markBufferedGrayRoots(JS::Zone* zone);
IncrementalProgress markAllWeakReferences();
void markAllGrayReferences(gcstats::PhaseKind phase);
// The mark queue is a testing-only feature for controlling mark ordering and
// yield timing.
enum MarkQueueProgress {
QueueYielded, // End this incremental GC slice, if possible
QueueComplete, // Done with the queue
QueueSuspended // Continue the GC without ending the slice
};
MarkQueueProgress processTestMarkQueue();
// GC Sweeping. Implemented in Sweeping.cpp.
void beginSweepPhase(JS::GCReason reason, AutoGCSession& session);
void dropStringWrappers();
void groupZonesForSweeping(JS::GCReason reason);
[[nodiscard]] bool findSweepGroupEdges();
[[nodiscard]] bool addEdgesForMarkQueue();
void moveToNextSweepGroup();
void resetGrayList(Compartment* comp);
IncrementalProgress beginMarkingSweepGroup(JS::GCContext* gcx,
JS::SliceBudget& budget);
IncrementalProgress markGrayRootsInCurrentGroup(JS::GCContext* gcx,
JS::SliceBudget& budget);
IncrementalProgress markGray(JS::GCContext* gcx, JS::SliceBudget& budget);
IncrementalProgress endMarkingSweepGroup(JS::GCContext* gcx,
JS::SliceBudget& budget);
void markIncomingGrayCrossCompartmentPointers();
IncrementalProgress beginSweepingSweepGroup(JS::GCContext* gcx,
JS::SliceBudget& budget);
void initBackgroundSweep(Zone* zone, JS::GCContext* gcx,
const FinalizePhase& phase);
IncrementalProgress markDuringSweeping(JS::GCContext* gcx,
JS::SliceBudget& budget);
void updateAtomsBitmap();
void sweepCCWrappers();
void sweepRealmGlobals();
void sweepEmbeddingWeakPointers(JS::GCContext* gcx);
void sweepMisc();
void sweepCompressionTasks();
void sweepWeakMaps();
void sweepUniqueIds();
void sweepObjectsWithWeakPointers();
void sweepDebuggerOnMainThread(JS::GCContext* gcx);
void sweepJitDataOnMainThread(JS::GCContext* gcx);
void sweepFinalizationObserversOnMainThread();
void traceWeakFinalizationObserverEdges(JSTracer* trc, Zone* zone);
void sweepWeakRefs();
IncrementalProgress endSweepingSweepGroup(JS::GCContext* gcx,
JS::SliceBudget& budget);
IncrementalProgress performSweepActions(JS::SliceBudget& sliceBudget);
void startSweepingAtomsTable();
IncrementalProgress sweepAtomsTable(JS::GCContext* gcx,
JS::SliceBudget& budget);
IncrementalProgress sweepWeakCaches(JS::GCContext* gcx,
JS::SliceBudget& budget);
IncrementalProgress finalizeAllocKind(JS::GCContext* gcx,
JS::SliceBudget& budget);
bool foregroundFinalize(JS::GCContext* gcx, Zone* zone, AllocKind thingKind,
JS::SliceBudget& sliceBudget,
SortedArenaList& sweepList);
IncrementalProgress sweepPropMapTree(JS::GCContext* gcx,
JS::SliceBudget& budget);
void endSweepPhase(bool destroyingRuntime);
void queueZonesAndStartBackgroundSweep(ZoneList&& zones);
void sweepFromBackgroundThread(AutoLockHelperThreadState& lock);
void startBackgroundFree();
void freeFromBackgroundThread(AutoLockHelperThreadState& lock);
void sweepBackgroundThings(ZoneList& zones);
void backgroundFinalize(JS::GCContext* gcx, Zone* zone, AllocKind kind,
Arena** empty);
void prepareForSweepSlice(JS::GCReason reason);
void assertBackgroundSweepingFinished();
#ifdef DEBUG
bool zoneInCurrentSweepGroup(Zone* zone) const;
#endif
bool allCCVisibleZonesWereCollected();
void sweepZones(JS::GCContext* gcx, bool destroyingRuntime);
bool shouldDecommit() const;
void startDecommit();
void decommitEmptyChunks(const bool& cancel, AutoLockGC& lock);
void decommitFreeArenas(const bool& cancel, AutoLockGC& lock);
void decommitFreeArenasWithoutUnlocking(const AutoLockGC& lock);
// Compacting GC. Implemented in Compacting.cpp.
bool shouldCompact();
void beginCompactPhase();
IncrementalProgress compactPhase(JS::GCReason reason,
JS::SliceBudget& sliceBudget,
AutoGCSession& session);
void endCompactPhase();
void sweepZoneAfterCompacting(MovingTracer* trc, Zone* zone);
bool canRelocateZone(Zone* zone) const;
[[nodiscard]] bool relocateArenas(Zone* zone, JS::GCReason reason,
Arena*& relocatedListOut,
JS::SliceBudget& sliceBudget);
void updateCellPointers(Zone* zone, AllocKinds kinds);
void updateAllCellPointers(MovingTracer* trc, Zone* zone);
void updateZonePointersToRelocatedCells(Zone* zone);
void updateRuntimePointersToRelocatedCells(AutoGCSession& session);
void clearRelocatedArenas(Arena* arenaList, JS::GCReason reason);
void clearRelocatedArenasWithoutUnlocking(Arena* arenaList,
JS::GCReason reason,
const AutoLockGC& lock);
void releaseRelocatedArenas(Arena* arenaList);
void releaseRelocatedArenasWithoutUnlocking(Arena* arenaList,
const AutoLockGC& lock);
#ifdef DEBUG
void protectOrReleaseRelocatedArenas(Arena* arenaList, JS::GCReason reason);
void protectAndHoldArenas(Arena* arenaList);
void unprotectHeldRelocatedArenas(const AutoLockGC& lock);
void releaseHeldRelocatedArenas();
void releaseHeldRelocatedArenasWithoutUnlocking(const AutoLockGC& lock);
#endif
/*
* Whether to immediately trigger a slice after a background task
* finishes. This may not happen at a convenient time, so the consideration is
* whether the slice will run quickly or may take a long time.
*/
enum ShouldTriggerSliceWhenFinished : bool {
DontTriggerSliceWhenFinished = false,
TriggerSliceWhenFinished = true
};
IncrementalProgress waitForBackgroundTask(
GCParallelTask& task, const JS::SliceBudget& budget,
bool shouldPauseMutator, ShouldTriggerSliceWhenFinished triggerSlice);
void maybeRequestGCAfterBackgroundTask(const AutoLockHelperThreadState& lock);
void cancelRequestedGCAfterBackgroundTask();
void finishCollection(JS::GCReason reason);
void maybeStopPretenuring();
void checkGCStateNotInUse();
IncrementalProgress joinBackgroundMarkTask();
#ifdef JS_GC_ZEAL
void computeNonIncrementalMarkingForValidation(AutoGCSession& session);
void validateIncrementalMarking();
void finishMarkingValidation();
#endif
#ifdef DEBUG
void checkForCompartmentMismatches();
#endif
void callFinalizeCallbacks(JS::GCContext* gcx, JSFinalizeStatus status) const;
void callWeakPointerZonesCallbacks(JSTracer* trc) const;
void callWeakPointerCompartmentCallbacks(JSTracer* trc,
JS::Compartment* comp) const;
void callDoCycleCollectionCallback(JSContext* cx);
public:
JSRuntime* const rt;
// Embedders can use this zone however they wish.
MainThreadData<JS::Zone*> systemZone;
MainThreadData<JS::GCContext> mainThreadContext;
private:
// For parent runtimes, a zone containing atoms that is shared by child
// runtimes.
MainThreadData<Zone*> sharedAtomsZone_;
// All zones in the runtime. The first element is always the atoms zone.
MainThreadOrGCTaskData<ZoneVector> zones_;
// Any activity affecting the heap.
MainThreadOrGCTaskData<JS::HeapState> heapState_;
friend class AutoHeapSession;
friend class JS::AutoEnterCycleCollection;
UnprotectedData<gcstats::Statistics> stats_;
public:
js::StringStats stringStats;
Vector<UniquePtr<GCMarker>, 1, SystemAllocPolicy> markers;
// Delayed marking support in case we OOM pushing work onto the mark stack.
MainThreadOrGCTaskData<js::gc::Arena*> delayedMarkingList;
MainThreadOrGCTaskData<bool> delayedMarkingWorkAdded;
#ifdef DEBUG
/* Count of arenas that are currently in the stack. */
MainThreadOrGCTaskData<size_t> markLaterArenas;
#endif
SweepingTracer sweepingTracer;
/* Track total GC heap size for this runtime. */
HeapSize heapSize;
/* GC scheduling state and parameters. */
GCSchedulingTunables tunables;
GCSchedulingState schedulingState;
MainThreadData<bool> fullGCRequested;
// Helper thread configuration.
MainThreadData<double> helperThreadRatio;
MainThreadData<size_t> maxHelperThreads;
MainThreadOrGCTaskData<size_t> helperThreadCount;
MainThreadData<size_t> maxMarkingThreads;
MainThreadData<size_t> markingThreadCount;
// Per-runtime helper thread task queue. Can be accessed from helper threads
// in maybeDispatchParallelTasks().
HelperThreadLockData<size_t> maxParallelThreads;
HelperThreadLockData<size_t> dispatchedParallelTasks;
HelperThreadLockData<GCParallelTaskList> queuedParallelTasks;
// State used for managing atom mark bitmaps in each zone.
AtomMarkingRuntime atomMarking;
/*
* Pointer to a callback that, if set, will be used to create a
* budget for internally-triggered GCs.
*/
MainThreadData<JS::CreateSliceBudgetCallback> createBudgetCallback;
private:
// Arenas used for permanent things created at startup and shared by child
// runtimes.
MainThreadData<ArenaList> permanentAtoms;
MainThreadData<ArenaList> permanentWellKnownSymbols;
// When chunks are empty, they reside in the emptyChunks pool and are
// re-used as needed or eventually expired if not re-used. The emptyChunks
// pool gets refilled from the background allocation task heuristically so
// that empty chunks should always be available for immediate allocation
// without syscalls.
GCLockData<ChunkPool> emptyChunks_;
// Chunks which have had some, but not all, of their arenas allocated live
// in the available chunk lists. When all available arenas in a chunk have
// been allocated, the chunk is removed from the available list and moved
// to the fullChunks pool. During a GC, if all arenas are free, the chunk
// is moved back to the emptyChunks pool and scheduled for eventual
// release.
GCLockData<ChunkPool> availableChunks_;
// When all arenas in a chunk are used, it is moved to the fullChunks pool
// so as to reduce the cost of operations on the available lists.
GCLockData<ChunkPool> fullChunks_;
/*
* JSGC_MIN_EMPTY_CHUNK_COUNT
* JSGC_MAX_EMPTY_CHUNK_COUNT
*
* Controls the number of empty chunks reserved for future allocation.
*
* They can be read off main thread by the background allocation task and the
* background decommit task.
*/
GCLockData<uint32_t> minEmptyChunkCount_;
GCLockData<uint32_t> maxEmptyChunkCount_;
MainThreadData<RootedValueMap> rootsHash;
// An incrementing id used to assign unique ids to cells that require one.
MainThreadData<uint64_t> nextCellUniqueId_;
/*
* Number of the committed arenas in all GC chunks including empty chunks.
*/
mozilla::Atomic<uint32_t, mozilla::ReleaseAcquire> numArenasFreeCommitted;
MainThreadData<VerifyPreTracer*> verifyPreData;
MainThreadData<mozilla::TimeStamp> lastGCStartTime_;
MainThreadData<mozilla::TimeStamp> lastGCEndTime_;
WriteOnceData<bool> initialized;
MainThreadData<bool> incrementalGCEnabled;
MainThreadData<bool> perZoneGCEnabled;
mozilla::Atomic<size_t, mozilla::ReleaseAcquire> numActiveZoneIters;
/* During shutdown, the GC needs to clean up every possible object. */
MainThreadData<bool> cleanUpEverything;
/*
* The gray bits can become invalid if UnmarkGray overflows the stack. A
* full GC will reset this bit, since it fills in all the gray bits.
*/
UnprotectedData<bool> grayBitsValid;
mozilla::Atomic<JS::GCReason, mozilla::ReleaseAcquire> majorGCTriggerReason;
/* Incremented at the start of every minor GC. */
MainThreadData<uint64_t> minorGCNumber;
/* Incremented at the start of every major GC. */
MainThreadData<uint64_t> majorGCNumber;
/* Incremented on every GC slice or minor collection. */
MainThreadData<uint64_t> number;
/* Incremented on every GC slice. */
MainThreadData<uint64_t> sliceNumber;
/*
* This runtime's current contribution to the global number of helper threads
* 'reserved' for parallel marking. Does not affect other uses of helper
* threads.
*/
MainThreadData<size_t> reservedMarkingThreads;
/* Whether the currently running GC can finish in multiple slices. */
MainThreadOrGCTaskData<bool> isIncremental;
/* Whether all zones are being collected in first GC slice. */
MainThreadData<bool> isFull;
/* Whether the heap will be compacted at the end of GC. */
MainThreadData<bool> isCompacting;
/* Whether to use parallel marking. */
MainThreadData<ParallelMarking> useParallelMarking;
/* The invocation kind of the current GC, set at the start of collection. */
MainThreadOrGCTaskData<mozilla::Maybe<JS::GCOptions>> maybeGcOptions;
/* The initial GC reason, taken from the first slice. */
MainThreadData<JS::GCReason> initialReason;
/*
* The current incremental GC phase. This is also used internally in
* non-incremental GC.
*/
MainThreadOrGCTaskData<State> incrementalState;
/* The incremental state at the start of this slice. */
MainThreadOrGCTaskData<State> initialState;
/* Whether to pay attention the zeal settings in this incremental slice. */
#ifdef JS_GC_ZEAL
MainThreadData<bool> useZeal;
#else
const bool useZeal;
#endif
/* Indicates that the last incremental slice exhausted the mark stack. */
MainThreadData<bool> lastMarkSlice;
// Whether it's currently safe to yield to the mutator in an incremental GC.
MainThreadData<bool> safeToYield;
// Whether to do any marking caused by barriers on a background thread during
// incremental sweeping, while also sweeping zones which have finished
// marking.
MainThreadData<bool> markOnBackgroundThreadDuringSweeping;
// Whether any sweeping and decommitting will run on a separate GC helper
// thread.
MainThreadData<bool> useBackgroundThreads;
// Whether we have already discarded JIT code for all collected zones in this
// slice.
MainThreadData<bool> haveDiscardedJITCodeThisSlice;
#ifdef DEBUG
/* Shutdown has started. Further collections must be shutdown collections. */
MainThreadData<bool> hadShutdownGC;
#endif
/* Singly linked list of zones to be swept in the background. */
HelperThreadLockData<ZoneList> backgroundSweepZones;
/*
* Whether to trigger a GC slice after a background task is complete, so that
* the collector can continue or finsish collecting. This is only used for the
* tasks that run concurrently with the mutator, which are background
* finalization and background decommit.
*/
HelperThreadLockData<bool> requestSliceAfterBackgroundTask;
/*
* Free LIFO blocks are transferred to these allocators before being freed on
* a background thread.
*/
HelperThreadLockData<LifoAlloc> lifoBlocksToFree;
MainThreadData<LifoAlloc> lifoBlocksToFreeAfterFullMinorGC;
MainThreadData<LifoAlloc> lifoBlocksToFreeAfterNextMinorGC;
HelperThreadLockData<Nursery::BufferSet> buffersToFreeAfterMinorGC;
/* Index of current sweep group (for stats). */
MainThreadData<unsigned> sweepGroupIndex;
/*
* Incremental sweep state.
*/
MainThreadData<JS::Zone*> sweepGroups;
MainThreadOrGCTaskData<JS::Zone*> currentSweepGroup;
MainThreadData<UniquePtr<SweepAction>> sweepActions;
MainThreadOrGCTaskData<JS::Zone*> sweepZone;
MainThreadOrGCTaskData<AllocKind> sweepAllocKind;
MainThreadData<mozilla::Maybe<AtomsTable::SweepIterator>> maybeAtomsToSweep;
MainThreadOrGCTaskData<mozilla::Maybe<WeakCacheSweepIterator>>
weakCachesToSweep;
MainThreadData<bool> abortSweepAfterCurrentGroup;
MainThreadOrGCTaskData<IncrementalProgress> sweepMarkResult;
/*
* During incremental foreground finalization, we may have a list of arenas of
* the current AllocKind and Zone whose contents have been finalized but which
* have not yet been merged back into the main arena lists.
*/
MainThreadOrGCTaskData<JS::Zone*> foregroundFinalizedZone;
MainThreadOrGCTaskData<AllocKind> foregroundFinalizedAllocKind;
MainThreadData<mozilla::Maybe<SortedArenaList>> foregroundFinalizedArenas;
#ifdef DEBUG
/*
* List of objects to mark at the beginning of a GC for testing purposes. May
* also contain string directives to change mark color or wait until different
* phases of the GC.
*
* This is a WeakCache because not everything in this list is guaranteed to
* end up marked (eg if you insert an object from an already-processed sweep
* group in the middle of an incremental GC). Also, the mark queue is not
* used during shutdown GCs. In either case, unmarked objects may need to be
* discarded.
*/
JS::WeakCache<GCVector<HeapPtr<JS::Value>, 0, SystemAllocPolicy>>
testMarkQueue;
/* Position within the test mark queue. */
size_t queuePos = 0;
/* The test marking queue might want to be marking a particular color. */
mozilla::Maybe<js::gc::MarkColor> queueMarkColor;
// During gray marking, delay AssertCellIsNotGray checks by
// recording the cell pointers here and checking after marking has
// finished.
MainThreadData<Vector<const Cell*, 0, SystemAllocPolicy>>
cellsToAssertNotGray;
friend void js::gc::detail::AssertCellIsNotGray(const Cell*);
#endif
friend class SweepGroupsIter;
/*
* Incremental compacting state.
*/
MainThreadData<bool> startedCompacting;
MainThreadData<ZoneList> zonesToMaybeCompact;
MainThreadData<size_t> zonesCompacted;
#ifdef DEBUG
GCLockData<Arena*> relocatedArenasToRelease;
#endif
#ifdef JS_GC_ZEAL
MainThreadData<MarkingValidator*> markingValidator;
#endif
/*
* Default budget for incremental GC slice. See js/SliceBudget.h.
*
* JSGC_SLICE_TIME_BUDGET_MS
* pref: javascript.options.mem.gc_incremental_slice_ms,
*/
MainThreadData<int64_t> defaultTimeBudgetMS_;
/*
* Whether compacting GC can is enabled globally.
*
* JSGC_COMPACTING_ENABLED
* pref: javascript.options.mem.gc_compacting
*/
MainThreadData<bool> compactingEnabled;
/*
* Whether parallel marking is enabled globally.
*
* JSGC_PARALLEL_MARKING_ENABLED
* pref: javascript.options.mem.gc_parallel_marking
*/
MainThreadData<bool> parallelMarkingEnabled;
MainThreadData<bool> rootsRemoved;
/*
* These options control the zealousness of the GC. At every allocation,
* nextScheduled is decremented. When it reaches zero we do a full GC.
*
* At this point, if zeal_ is one of the types that trigger periodic
* collection, then nextScheduled is reset to the value of zealFrequency.
* Otherwise, no additional GCs take place.
*
* You can control these values in several ways:
* - Set the JS_GC_ZEAL environment variable
* - Call gczeal() or schedulegc() from inside shell-executed JS code
* (see the help for details)
*
* If gcZeal_ == 1 then we perform GCs in select places (during MaybeGC and
* whenever we are notified that GC roots have been removed). This option is
* mainly useful to embedders.
*
* We use zeal_ == 4 to enable write barrier verification. See the comment
* in gc/Verifier.cpp for more information about this.
*
* zeal_ values from 8 to 10 periodically run different types of
* incremental GC.
*
* zeal_ value 14 performs periodic shrinking collections.
*/
#ifdef JS_GC_ZEAL
static_assert(size_t(ZealMode::Count) <= 32,
"Too many zeal modes to store in a uint32_t");
MainThreadData<uint32_t> zealModeBits;
MainThreadData<int> zealFrequency;
MainThreadData<int> nextScheduled;
MainThreadData<bool> deterministicOnly;
MainThreadData<int> zealSliceBudget;
MainThreadData<size_t> maybeMarkStackLimit;
MainThreadData<PersistentRooted<GCVector<JSObject*, 0, SystemAllocPolicy>>>
selectedForMarking;
#endif
MainThreadData<bool> fullCompartmentChecks;
MainThreadData<uint32_t> gcCallbackDepth;
MainThreadData<Callback<JSGCCallback>> gcCallback;
MainThreadData<Callback<JS::DoCycleCollectionCallback>>
gcDoCycleCollectionCallback;
MainThreadData<Callback<JSObjectsTenuredCallback>> tenuredCallback;
MainThreadData<CallbackVector<JSFinalizeCallback>> finalizeCallbacks;
MainThreadOrGCTaskData<Callback<JSHostCleanupFinalizationRegistryCallback>>
hostCleanupFinalizationRegistryCallback;
MainThreadData<CallbackVector<JSWeakPointerZonesCallback>>
updateWeakPointerZonesCallbacks;
MainThreadData<CallbackVector<JSWeakPointerCompartmentCallback>>
updateWeakPointerCompartmentCallbacks;
MainThreadData<CallbackVector<JS::GCNurseryCollectionCallback>>
nurseryCollectionCallbacks;
/*
* The trace operations to trace embedding-specific GC roots. One is for
* tracing through black roots and the other is for tracing through gray
* roots. The black/gray distinction is only relevant to the cycle
* collector.
*/
MainThreadData<CallbackVector<JSTraceDataOp>> blackRootTracers;
MainThreadOrGCTaskData<Callback<JSGrayRootsTracer>> grayRootTracer;
/* Always preserve JIT code during GCs, for testing. */
MainThreadData<bool> alwaysPreserveCode;
/* Count of the number of zones that are currently in page load. */
MainThreadData<size_t> inPageLoadCount;
MainThreadData<bool> lowMemoryState;
/*
* General purpose GC lock, used for synchronising operations on
* arenas and during parallel marking.
*/
friend class js::AutoLockGC;
friend class js::AutoLockGCBgAlloc;
Mutex lock MOZ_UNANNOTATED;
/*
* Lock used to synchronise access to the store buffer during parallel
* sweeping.
*/
Mutex storeBufferLock MOZ_UNANNOTATED;
/* Lock used to synchronise access to delayed marking state. */
Mutex delayedMarkingLock MOZ_UNANNOTATED;
friend class BackgroundSweepTask;
friend class BackgroundFreeTask;
BackgroundAllocTask allocTask;
BackgroundUnmarkTask unmarkTask;
BackgroundMarkTask markTask;
BackgroundSweepTask sweepTask;
BackgroundFreeTask freeTask;
BackgroundDecommitTask decommitTask;
MainThreadData<Nursery> nursery_;
// The store buffer used to track tenured to nursery edges for generational
// GC. This is accessed off main thread when sweeping WeakCaches.
MainThreadOrGCTaskData<gc::StoreBuffer> storeBuffer_;
mozilla::TimeStamp lastLastDitchTime;
// The last time per-zone allocation rates were updated.
MainThreadData<mozilla::TimeStamp> lastAllocRateUpdateTime;
// Total collector time since per-zone allocation rates were last updated.
MainThreadData<mozilla::TimeDuration> collectorTimeSinceAllocRateUpdate;
friend class MarkingValidator;
friend class AutoEnterIteration;
};
#ifndef JS_GC_ZEAL
inline bool GCRuntime::hasZealMode(ZealMode mode) const { return false; }
inline void GCRuntime::clearZealMode(ZealMode mode) {}
inline bool GCRuntime::needZealousGC() { return false; }
inline bool GCRuntime::zealModeControlsYieldPoint() const { return false; }
#endif
/* Prevent compartments and zones from being collected during iteration. */
class MOZ_RAII AutoEnterIteration {
GCRuntime* gc;
public:
explicit AutoEnterIteration(GCRuntime* gc_) : gc(gc_) {
++gc->numActiveZoneIters;
}
~AutoEnterIteration() {
MOZ_ASSERT(gc->numActiveZoneIters);
--gc->numActiveZoneIters;
}
};
bool IsCurrentlyAnimating(const mozilla::TimeStamp& lastAnimationTime,
const mozilla::TimeStamp& currentTime);
} /* namespace gc */
} /* namespace js */
#endif