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Improve dead compartment collection.

master
Fedor 2019-07-08 13:07:44 +03:00
parent 95de016256
commit ca72ef1006
11 changed files with 191 additions and 109 deletions
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11
js/ipc/JavaScriptShared.cpp
View File

@ -61,6 +61,15 @@ IdToObjectMap::find(ObjectId id)
return p->value();
}
JSObject*
IdToObjectMap::findPreserveColor(ObjectId id)
{
Table::Ptr p = table_.lookup(id);
if (!p)
return nullptr;
return p->value().unbarrieredGet();
}
bool
IdToObjectMap::add(ObjectId id, JSObject* obj)
{
@ -757,4 +766,4 @@ CPOWManager*
mozilla::jsipc::CPOWManagerFor(PJavaScriptChild* aChild)
{
return static_cast<JavaScriptChild*>(aChild);
}
}

3
js/ipc/JavaScriptShared.h
View File

@ -96,6 +96,7 @@ class IdToObjectMap
bool add(ObjectId id, JSObject* obj);
JSObject* find(ObjectId id);
JSObject* findPreserveColor(ObjectId id);
void remove(ObjectId id);
void clear();
@ -233,4 +234,4 @@ class JavaScriptShared : public CPOWManager
} // namespace jsipc
} // namespace mozilla
#endif
#endif

4
js/ipc/WrapperAnswer.cpp
View File

@ -789,10 +789,10 @@ WrapperAnswer::RecvDOMInstanceOf(const ObjectId& objId, const int& prototypeID,
bool
WrapperAnswer::RecvDropObject(const ObjectId& objId)
{
JSObject* obj = objects_.find(objId);
JSObject* obj = objects_.findPreserveColor(objId);
if (obj) {
objectIdMap(objId.hasXrayWaiver()).remove(obj);
objects_.remove(objId);
}
return true;
}
}

12
js/src/builtin/TypedObject.cpp
View File

@ -652,7 +652,7 @@ ArrayMetaTypeDescr::create(JSContext* cx,
if (!CreateTraceList(cx, obj))
return nullptr;
if (!cx->zone()->typeDescrObjects.put(obj)) {
if (!cx->zone()->addTypeDescrObject(cx, obj)) {
ReportOutOfMemory(cx);
return nullptr;
}
@ -993,8 +993,8 @@ StructMetaTypeDescr::create(JSContext* cx,
if (!CreateTraceList(cx, descr))
return nullptr;
if (!cx->zone()->typeDescrObjects.put(descr) ||
!cx->zone()->typeDescrObjects.put(fieldTypeVec))
if (!cx->zone()->addTypeDescrObject(cx, descr) ||
!cx->zone()->addTypeDescrObject(cx, fieldTypeVec))
{
ReportOutOfMemory(cx);
return nullptr;
@ -1165,10 +1165,8 @@ DefineSimpleTypeDescr(JSContext* cx,
if (!CreateTraceList(cx, descr))
return false;
if (!cx->zone()->typeDescrObjects.put(descr)) {
ReportOutOfMemory(cx);
if (!cx->zone()->addTypeDescrObject(cx, descr))
return false;
}
return true;
}
@ -3005,4 +3003,4 @@ TypeDescr::finalize(FreeOp* fop, JSObject* obj)
TypeDescr& descr = obj->as<TypeDescr>();
if (descr.hasTraceList())
js_free(const_cast<int32_t*>(descr.traceList()));
}
}

6
js/src/gc/GCRuntime.h
View File

@ -900,7 +900,8 @@ class GCRuntime
void requestMajorGC(JS::gcreason::Reason reason);
SliceBudget defaultBudget(JS::gcreason::Reason reason, int64_t millis);
void budgetIncrementalGC(SliceBudget& budget, AutoLockForExclusiveAccess& lock);
void budgetIncrementalGC(JS::gcreason::Reason reason, SliceBudget& budget,
AutoLockForExclusiveAccess& lock);
void resetIncrementalGC(AbortReason reason, AutoLockForExclusiveAccess& lock);
// Assert if the system state is such that we should never
@ -915,6 +916,7 @@ class GCRuntime
void collect(bool nonincrementalByAPI, SliceBudget budget, JS::gcreason::Reason reason) JS_HAZ_GC_CALL;
MOZ_MUST_USE bool gcCycle(bool nonincrementalByAPI, SliceBudget& budget,
JS::gcreason::Reason reason);
bool shouldRepeatForDeadZone(JS::gcreason::Reason reason);
void incrementalCollectSlice(SliceBudget& budget, JS::gcreason::Reason reason,
AutoLockForExclusiveAccess& lock);
@ -1348,4 +1350,4 @@ class MOZ_RAII AutoMaybeStartBackgroundAllocation
} /* namespace js */
#endif
#endif

4
js/src/gc/RootMarking.cpp
View File

@ -478,6 +478,7 @@ js::gc::GCRuntime::bufferGrayRoots()
for (GCZonesIter zone(rt); !zone.done(); zone.next())
MOZ_ASSERT(zone->gcGrayRoots.empty());
gcstats::AutoPhase ap(stats, gcstats::PHASE_BUFFER_GRAY_ROOTS);
BufferGrayRootsTracer grayBufferer(rt);
if (JSTraceDataOp op = grayRootTracer.op)
@ -539,5 +540,4 @@ GCRuntime::resetBufferedGrayRoots() const
"Do not clear the gray buffers unless we are Failed or becoming Unused");
for (GCZonesIter zone(rt); !zone.done(); zone.next())
zone->gcGrayRoots.clearAndFree();
}
}

17
js/src/gc/Zone.cpp
View File

@ -370,6 +370,21 @@ Zone::fixupAfterMovingGC()
fixupInitialShapeTable();
}
bool
Zone::addTypeDescrObject(JSContext* cx, HandleObject obj)
{
// Type descriptor objects are always tenured so we don't need post barriers
// on the set.
MOZ_ASSERT(!IsInsideNursery(obj));
if (!typeDescrObjects.put(obj)) {
ReportOutOfMemory(cx);
return false;
}
return true;
}
ZoneList::ZoneList()
: head(nullptr), tail(nullptr)
{}
@ -468,4 +483,4 @@ JS_PUBLIC_API(void)
JS::shadow::RegisterWeakCache(JS::Zone* zone, WeakCache<void*>* cachep)
{
zone->registerWeakCache(cachep);
}
}

13
js/src/gc/Zone.h
View File

@ -349,10 +349,17 @@ struct Zone : public JS::shadow::Zone,
// Keep track of all TypeDescr and related objects in this compartment.
// This is used by the GC to trace them all first when compacting, since the
// TypedObject trace hook may access these objects.
using TypeDescrObjectSet = js::GCHashSet<js::HeapPtr<JSObject*>,
js::MovableCellHasher<js::HeapPtr<JSObject*>>,
//
// There are no barriers here - the set contains only tenured objects so no
// post-barrier is required, and these are weak references so no pre-barrier
// is required.
using TypeDescrObjectSet = js::GCHashSet<JSObject*,
js::MovableCellHasher<JSObject*>,
js::SystemAllocPolicy>;
JS::WeakCache<TypeDescrObjectSet> typeDescrObjects;
bool addTypeDescrObject(JSContext* cx, HandleObject obj);
// Malloc counter to measure memory pressure for GC scheduling. It runs from
@ -734,4 +741,4 @@ class ZoneAllocPolicy
} // namespace js
#endif // gc_Zone_h
#endif // gc_Zone_h

198
js/src/jsgc.cpp
View File

@ -1524,20 +1524,11 @@ GCMarker::delayMarkingChildren(const void* thing)
}
inline void
ArenaLists::prepareForIncrementalGC(JSRuntime* rt)
ArenaLists::prepareForIncrementalGC()
{
for (auto i : AllAllocKinds()) {
FreeSpan* span = freeLists[i];
if (span != &placeholder) {
if (!span->isEmpty()) {
Arena* arena = span->getArena();
arena->allocatedDuringIncremental = true;
rt->gc.marker.delayMarkingArena(arena);
} else {
freeLists[i] = &placeholder;
}
}
}
purge();
for (auto i : AllAllocKinds())
arenaLists[i].moveCursorToEnd();
}
/* Compacting GC */
@ -2251,7 +2242,7 @@ GCRuntime::updateTypeDescrObjects(MovingTracer* trc, Zone* zone)
{
zone->typeDescrObjects.sweep();
for (auto r = zone->typeDescrObjects.all(); !r.empty(); r.popFront())
UpdateCellPointers(trc, r.front().get());
UpdateCellPointers(trc, r.front());
}
void
@ -3579,6 +3570,23 @@ RelazifyFunctions(Zone* zone, AllocKind kind)
}
}
static bool
ShouldCollectZone(Zone* zone, JS::gcreason::Reason reason)
{
// Normally we collect all scheduled zones.
if (reason != JS::gcreason::COMPARTMENT_REVIVED)
return zone->isGCScheduled();
// If we are repeating a GC becuase we noticed dead compartments haven't
// been collected, then only collect zones contianing those compartments.
for (CompartmentsInZoneIter comp(zone); !comp.done(); comp.next()) {
if (comp->scheduledForDestruction)
return true;
}
return false;
}
bool
GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAccess& lock)
{
@ -3602,7 +3610,7 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
#endif
/* Set up which zones will be collected. */
if (zone->isGCScheduled()) {
if (ShouldCollectZone(zone, reason)) {
if (!zone->isAtomsZone()) {
any = true;
zone->setGCState(Zone::Mark);
@ -3621,7 +3629,7 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
for (CompartmentsIter c(rt, WithAtoms); !c.done(); c.next()) {
c->marked = false;
c->scheduledForDestruction = false;
c->maybeAlive = false;
c->maybeAlive = c->hasBeenEntered() || !c->zone()->isGCScheduled();
if (shouldPreserveJITCode(c, currentTime, reason, canAllocateMoreCode))
c->zone()->setPreservingCode(true);
}
@ -3640,6 +3648,12 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
* keepAtoms() will only change on the main thread, which we are currently
* on. If the value of keepAtoms() changes between GC slices, then we'll
* cancel the incremental GC. See IsIncrementalGCSafe.
*/
if (isFull && !rt->keepAtoms()) {
Zone* atomsZone = rt->atomsCompartment(lock)->zone();
@ -3655,15 +3669,12 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
return false;
/*
* At the end of each incremental slice, we call prepareForIncrementalGC,
* which marks objects in all arenas that we're currently allocating
* into. This can cause leaks if unreachable objects are in these
* arenas. This purge call ensures that we only mark arenas that have had
* allocations after the incremental GC started.
* Ensure that after the start of a collection we don't allocate into any
* existing arenas, as this can cause unreachable things to be marked.
*/
if (isIncremental) {
for (GCZonesIter zone(rt); !zone.done(); zone.next())
zone->arenas.purge();
zone->arenas.prepareForIncrementalGC();
}
MemProfiler::MarkTenuredStart(rt);
@ -3747,13 +3758,11 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason, AutoLockForExclusiveAcces
gcstats::AutoPhase ap2(stats, gcstats::PHASE_MARK_ROOTS);
if (isIncremental) {
gcstats::AutoPhase ap3(stats, gcstats::PHASE_BUFFER_GRAY_ROOTS);
bufferGrayRoots();
}
markCompartments();
if (isIncremental) {
bufferGrayRoots();
markCompartments();
}
return true;
}
@ -3766,9 +3775,14 @@ GCRuntime::markCompartments()
* This code ensures that if a compartment is "dead", then it will be
* collected in this GC. A compartment is considered dead if its maybeAlive
* flag is false. The maybeAlive flag is set if:
* (1) the compartment has incoming cross-compartment edges, or
* (2) an object in the compartment was marked during root marking, either
* as a black root or a gray root.
* (1) the compartment has been entered (set in beginMarkPhase() above)
* (2) the compartment is not being collected (set in beginMarkPhase()
* above)
* (3) an object in the compartment was marked during root marking, either
* as a black root or a gray root (set in RootMarking.cpp), or
* (4) the compartment has incoming cross-compartment edges from another
* compartment that has maybeAlive set (set by this method).
*
* If the maybeAlive is false, then we set the scheduledForDestruction flag.
* At the end of the GC, we look for compartments where
* scheduledForDestruction is true. These are compartments that were somehow
@ -3786,26 +3800,37 @@ GCRuntime::markCompartments()
* allocation and read barriers during JS_TransplantObject and the like.
*/
/* Set the maybeAlive flag based on cross-compartment edges. */
for (CompartmentsIter c(rt, SkipAtoms); !c.done(); c.next()) {
for (JSCompartment::WrapperEnum e(c); !e.empty(); e.popFront()) {
/* Propagate the maybeAlive flag via cross-compartment edges. */
Vector<JSCompartment*, 0, js::SystemAllocPolicy> workList;
for (CompartmentsIter comp(rt, SkipAtoms); !comp.done(); comp.next()) {
if (comp->maybeAlive) {
if (!workList.append(comp))
return;
}
}
while (!workList.empty()) {
JSCompartment* comp = workList.popCopy();
for (JSCompartment::WrapperEnum e(comp); !e.empty(); e.popFront()) {
if (e.front().key().is<JSString*>())
continue;
JSCompartment* dest = e.front().mutableKey().compartment();
if (dest)
if (dest && !dest->maybeAlive) {
dest->maybeAlive = true;
if (!workList.append(dest))
return;
}
}
}
/*
* For black roots, code in gc/Marking.cpp will already have set maybeAlive
* during MarkRuntime.
*/
/* Propogate maybeAlive to scheduleForDestruction. */
for (GCCompartmentsIter c(rt); !c.done(); c.next()) {
if (!c->maybeAlive && !rt->isAtomsCompartment(c))
c->scheduledForDestruction = true;
/* Set scheduleForDestruction based on maybeAlive. */
for (GCCompartmentsIter comp(rt); !comp.done(); comp.next()) {
MOZ_ASSERT(!comp->scheduledForDestruction);
if (!comp->maybeAlive && !rt->isAtomsCompartment(comp))
comp->scheduledForDestruction = true;
}
}
@ -5306,7 +5331,7 @@ AutoGCSlice::~AutoGCSlice()
for (ZonesIter zone(runtime, WithAtoms); !zone.done(); zone.next()) {
if (zone->isGCMarking()) {
zone->setNeedsIncrementalBarrier(true, Zone::UpdateJit);
zone->arenas.prepareForIncrementalGC(runtime);
zone->arenas.purge();
} else {
zone->setNeedsIncrementalBarrier(false, Zone::UpdateJit);
}
@ -5487,9 +5512,9 @@ gc::AbortReason
gc::IsIncrementalGCUnsafe(JSRuntime* rt)
{
MOZ_ASSERT(!rt->mainThread.suppressGC);
if (rt->keepAtoms())
return gc::AbortReason::KeepAtomsSet;
if (rt->keepAtoms())
return gc::AbortReason::KeepAtomsSet;
if (!rt->gc.isIncrementalGCAllowed())
return gc::AbortReason::IncrementalDisabled;
@ -5498,9 +5523,17 @@ gc::IsIncrementalGCUnsafe(JSRuntime* rt)
}
void
GCRuntime::budgetIncrementalGC(SliceBudget& budget, AutoLockForExclusiveAccess& lock)
GCRuntime::budgetIncrementalGC(JS::gcreason::Reason reason, SliceBudget& budget,
AutoLockForExclusiveAccess& lock)
{
AbortReason unsafeReason = IsIncrementalGCUnsafe(rt);
if (unsafeReason == AbortReason::None) {
if (reason == JS::gcreason::COMPARTMENT_REVIVED)
unsafeReason = gc::AbortReason::CompartmentRevived;
else if (mode != JSGC_MODE_INCREMENTAL)
unsafeReason = gc::AbortReason::ModeChange;
}
if (unsafeReason != AbortReason::None) {
resetIncrementalGC(unsafeReason, lock);
budget.makeUnlimited();
@ -5508,12 +5541,7 @@ GCRuntime::budgetIncrementalGC(SliceBudget& budget, AutoLockForExclusiveAccess&
return;
}
if (mode != JSGC_MODE_INCREMENTAL) {
resetIncrementalGC(AbortReason::ModeChange, lock);
budget.makeUnlimited();
stats.nonincremental(AbortReason::ModeChange);
return;
}
if (isTooMuchMalloc()) {
budget.makeUnlimited();
@ -5660,6 +5688,10 @@ GCRuntime::gcCycle(bool nonincrementalByAPI, SliceBudget& budget, JS::gcreason::
}
State prevState = incrementalState;
if (nonincrementalByAPI) {
// Reset any in progress incremental GC if this was triggered via the
@ -5672,7 +5704,7 @@ GCRuntime::gcCycle(bool nonincrementalByAPI, SliceBudget& budget, JS::gcreason::
stats.nonincremental(gc::AbortReason::NonIncrementalRequested);
budget.makeUnlimited();
} else {
budgetIncrementalGC(budget, session.lock);
budgetIncrementalGC(reason, budget, session.lock);
}
/* The GC was reset, so we need a do-over. */
@ -5764,6 +5796,22 @@ GCRuntime::checkIfGCAllowedInCurrentState(JS::gcreason::Reason reason)
return true;
}
bool
GCRuntime::shouldRepeatForDeadZone(JS::gcreason::Reason reason)
{
MOZ_ASSERT_IF(reason == JS::gcreason::COMPARTMENT_REVIVED, !isIncremental);
if (!isIncremental || isIncrementalGCInProgress())
return false;
for (CompartmentsIter c(rt, SkipAtoms); !c.done(); c.next()) {
if (c->scheduledForDestruction)
return true;
}
return false;
}
void
GCRuntime::collect(bool nonincrementalByAPI, SliceBudget budget, JS::gcreason::Reason reason)
{
@ -5782,27 +5830,23 @@ GCRuntime::collect(bool nonincrementalByAPI, SliceBudget budget, JS::gcreason::R
do {
poked = false;
bool wasReset = gcCycle(nonincrementalByAPI, budget, reason);
/* Need to re-schedule all zones for GC. */
if (poked && cleanUpEverything)
bool repeatForDeadZone = false;
if (poked && cleanUpEverything) {
/* Need to re-schedule all zones for GC. */
JS::PrepareForFullGC(rt->contextFromMainThread());
/*
* This code makes an extra effort to collect compartments that we
* thought were dead at the start of the GC. See the large comment in
* beginMarkPhase.
*/
bool repeatForDeadZone = false;
if (!nonincrementalByAPI && !isIncrementalGCInProgress()) {
for (CompartmentsIter c(rt, SkipAtoms); !c.done(); c.next()) {
if (c->scheduledForDestruction) {
nonincrementalByAPI = true;
repeatForDeadZone = true;
reason = JS::gcreason::COMPARTMENT_REVIVED;
c->zone()->scheduleGC();
}
}
}
} else if (shouldRepeatForDeadZone(reason) && !wasReset) {
/*
* This code makes an extra effort to collect compartments that we
* thought were dead at the start of the GC. See the large comment
* in beginMarkPhase.
*/
repeatForDeadZone = true;
reason = JS::gcreason::COMPARTMENT_REVIVED;
}
/*
* If we reset an existing GC, we need to start a new one. Also, we
@ -7070,4 +7114,4 @@ js::gc::detail::CellIsMarkedGrayIfKnown(const Cell* cell)
}
return detail::CellIsMarkedGray(tc);
}
}

13
js/src/jsgc.h
View File

@ -61,7 +61,8 @@ enum class State {
D(ModeChange) \
D(MallocBytesTrigger) \
D(GCBytesTrigger) \
D(ZoneChange)
D(ZoneChange) \
D(CompartmentRevived)
enum class AbortReason {
#define MAKE_REASON(name) name,
GC_ABORT_REASONS(MAKE_REASON)
@ -353,7 +354,6 @@ struct SortedArenaListSegment
* be treated as an invariant, however, as the free lists may be cleared,
* leaving arenas previously used for allocation partially full. Sorting order
* is restored during sweeping.
* Arenas following the cursor should not be full.
*/
class ArenaList {
@ -453,6 +453,11 @@ class ArenaList {
check();
return !*cursorp_;
}
void moveCursorToEnd() {
while (!isCursorAtEnd())
cursorp_ = &(*cursorp_)->next;
}
// This can return nullptr.
Arena* arenaAfterCursor() const {
@ -739,7 +744,7 @@ class ArenaLists
freeLists[i] = &placeholder;
}
inline void prepareForIncrementalGC(JSRuntime* rt);
inline void prepareForIncrementalGC();
/* Check if this arena is in use. */
bool arenaIsInUse(Arena* arena, AllocKind kind) const {
@ -1504,4 +1509,4 @@ UninlinedIsInsideNursery(const gc::Cell* cell);
} /* namespace js */
#endif /* jsgc_h */
#endif /* jsgc_h */

19
js/src/jswatchpoint.cpp
View File

@ -185,17 +185,18 @@ WatchpointMap::markAll(JSTracer* trc)
{
for (Map::Enum e(map); !e.empty(); e.popFront()) {
Map::Entry& entry = e.front();
WatchKey key = entry.key();
WatchKey prior = key;
MOZ_ASSERT(JSID_IS_STRING(prior.id) || JSID_IS_INT(prior.id) || JSID_IS_SYMBOL(prior.id));
JSObject* object = entry.key().object;
jsid id = entry.key().id;
JSObject* priorObject = object;
jsid priorId = id;
MOZ_ASSERT(JSID_IS_STRING(priorId) || JSID_IS_INT(priorId) || JSID_IS_SYMBOL(priorId));
TraceEdge(trc, const_cast<PreBarrieredObject*>(&key.object),
"held Watchpoint object");
TraceEdge(trc, const_cast<PreBarrieredId*>(&key.id), "WatchKey::id");
TraceManuallyBarrieredEdge(trc, &object, "held Watchpoint object");
TraceManuallyBarrieredEdge(trc, &id, "WatchKey::id");
TraceEdge(trc, &entry.value().closure, "Watchpoint::closure");
if (prior.object != key.object || prior.id != key.id)
e.rekeyFront(key);
if (priorObject != object || priorId != id)
e.rekeyFront(WatchKey(object, id));
}
}
@ -242,4 +243,4 @@ WatchpointMap::trace(WeakMapTracer* trc)
JS::GCCellPtr(entry.key().object.get()),
JS::GCCellPtr(entry.value().closure.get()));
}
}
}