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authorwin7-7 <win7-7@users.noreply.github.com>2019-04-29 11:59:46 +0300
committerGitHub <noreply@github.com>2019-04-29 11:59:46 +0300
commit5a65d8739d0ad6ef446b278a25fd955f0c734fb1 (patch)
tree6a947b3ad89ee96f62c9a814e93070356162819f /js/src/jsgc.cpp
parentcd296c598a587b58a0e2a579c9be5aa255669829 (diff)
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Improve dead compartment collection js/src
Diffstat (limited to 'js/src/jsgc.cpp')
-rw-r--r--js/src/jsgc.cpp198
1 files changed, 121 insertions, 77 deletions
diff --git a/js/src/jsgc.cpp b/js/src/jsgc.cpp
index 8cee9ec09..1e8e4fc8d 100644
--- a/js/src/jsgc.cpp
+++ b/js/src/jsgc.cpp
@@ -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);
-}
+} \ No newline at end of file