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Backed out changeset 2a613f5a5866 (bug 1119537) for hazard failures

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MozReview-Commit-ID: HjSuYxycsVu
This commit is contained in:
Wes Kocher 2016-02-29 13:02:01 -08:00
parent bdd8f0ca83
commit 2f82f5bc02
7 changed files with 49 additions and 124 deletions
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2
js/src/builtin/TestingFunctions.cpp
View File

@ -798,8 +798,6 @@ GCState(JSContext* cx, unsigned argc, Value* vp)
state = "finalize";
else if (globalState == gc::COMPACT)
state = "compact";
else if (globalState == gc::DECOMMIT)
state = "decommit";
else
MOZ_CRASH("Unobserveable global GC state");

22
js/src/gc/GCRuntime.h
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@ -81,24 +81,7 @@ class BackgroundAllocTask : public GCParallelTask
bool enabled() const { return enabled_; }
protected:
void run() override;
};
// Search the provided Chunks for free arenas and decommit them.
class BackgroundDecommitTask : public GCParallelTask
{
public:
using ChunkVector = mozilla::Vector<Chunk*>;
explicit BackgroundDecommitTask(JSRuntime *rt) : runtime(rt) {}
void setChunksToScan(ChunkVector &chunks);
protected:
void run() override;
private:
JSRuntime* runtime;
ChunkVector toDecommit;
virtual void run() override;
};
/*
@ -967,7 +950,7 @@ class GCRuntime
void endSweepPhase(bool lastGC);
void sweepZones(FreeOp* fop, bool lastGC);
void decommitAllWithoutUnlocking(const AutoLockGC& lock);
void startDecommit();
void decommitArenas(AutoLockGC& lock);
void expireChunksAndArenas(bool shouldShrink, AutoLockGC& lock);
void queueZonesForBackgroundSweep(ZoneList& zones);
void sweepBackgroundThings(ZoneList& zones, LifoAlloc& freeBlocks, ThreadType threadType);
@ -1344,7 +1327,6 @@ class GCRuntime
mozilla::DebugOnly<mozilla::Atomic<PRThread*>> lockOwner;
BackgroundAllocTask allocTask;
BackgroundDecommitTask decommitTask;
GCHelperState helperState;
/*

2
js/src/gc/Nursery.cpp
View File

@ -593,7 +593,7 @@ js::Nursery::FreeMallocedBuffersTask::transferBuffersToFree(MallocedBuffersSet&
{
// Transfer the contents of the source set to the task's buffers_ member by
// swapping the sets, which also clears the source.
MOZ_ASSERT(!isRunningWithLockHeld());
MOZ_ASSERT(!isRunning());
MOZ_ASSERT(buffers_.empty());
mozilla::Swap(buffers_, buffersToFree);
}

5
js/src/jit-test/tests/gc/incremental-state.js
View File

@ -12,7 +12,6 @@ assertEq(gcstate(), "none");
// sized slices while background finalization is on-going, so we need to loop.
gcslice(1000000);
while (gcstate() == "finalize") { gcslice(1); }
while (gcstate() == "decommit") { gcslice(1); }
assertEq(gcstate(), "none");
// Incremental GC in multiple slices: if marking takes more than one slice,
@ -24,7 +23,6 @@ gcslice(1000000);
assertEq(gcstate(), "mark");
gcslice(1000000);
while (gcstate() == "finalize") { gcslice(1); }
while (gcstate() == "decommit") { gcslice(1); }
assertEq(gcstate(), "none");
// Zeal mode 8: Incremental GC in two main slices:
@ -36,7 +34,6 @@ gcslice(1);
assertEq(gcstate(), "mark");
gcslice(1);
while (gcstate() == "finalize") { gcslice(1); }
while (gcstate() == "decommit") { gcslice(1); }
assertEq(gcstate(), "none");
// Zeal mode 9: Incremental GC in two main slices:
@ -48,7 +45,6 @@ gcslice(1);
assertEq(gcstate(), "mark");
gcslice(1);
while (gcstate() == "finalize") { gcslice(1); }
while (gcstate() == "decommit") { gcslice(1); }
assertEq(gcstate(), "none");
// Zeal mode 10: Incremental GC in multiple slices (always yeilds before
@ -59,5 +55,4 @@ gcslice(1000000);
assertEq(gcstate(), "sweep");
gcslice(1000000);
while (gcstate() == "finalize") { gcslice(1); }
while (gcstate() == "decommit") { gcslice(1); }
assertEq(gcstate(), "none");

129
js/src/jsgc.cpp
View File

@ -1031,7 +1031,7 @@ void
GCRuntime::startBackgroundAllocTaskIfIdle()
{
AutoLockHelperThreadState helperLock;
if (allocTask.isRunningWithLockHeld())
if (allocTask.isRunning())
return;
// Join the previous invocation of the task. This will return immediately
@ -1178,7 +1178,6 @@ GCRuntime::GCRuntime(JSRuntime* rt) :
#endif
lock(nullptr),
allocTask(rt, emptyChunks_),
decommitTask(rt),
helperState(rt)
{
setGCMode(JSGC_MODE_GLOBAL);
@ -1362,7 +1361,6 @@ GCRuntime::finish()
*/
helperState.finish();
allocTask.cancel(GCParallelTask::CancelAndWait);
decommitTask.cancel(GCParallelTask::CancelAndWait);
#ifdef JS_GC_ZEAL
/* Free memory associated with GC verification. */
@ -3341,67 +3339,43 @@ GCRuntime::decommitAllWithoutUnlocking(const AutoLockGC& lock)
}
void
GCRuntime::startDecommit()
GCRuntime::decommitArenas(AutoLockGC& lock)
{
MOZ_ASSERT(CurrentThreadCanAccessRuntime(rt));
MOZ_ASSERT(!decommitTask.isRunning());
// Verify that all entries in the empty chunks pool are decommitted.
for (ChunkPool::Iter chunk(emptyChunks(lock)); !chunk.done(); chunk.next())
MOZ_ASSERT(!chunk->info.numArenasFreeCommitted);
BackgroundDecommitTask::ChunkVector toDecommit;
{
AutoLockGC lock(rt);
// Verify that all entries in the empty chunks pool are already decommitted.
for (ChunkPool::Iter chunk(emptyChunks(lock)); !chunk.done(); chunk.next())
MOZ_ASSERT(!chunk->info.numArenasFreeCommitted);
// Since we release the GC lock while doing the decommit syscall below,
// it is dangerous to iterate the available list directly, as the main
// thread could modify it concurrently. Instead, we build and pass an
// explicit Vector containing the Chunks we want to visit.
MOZ_ASSERT(availableChunks(lock).verify());
for (ChunkPool::Iter iter(availableChunks(lock)); !iter.done(); iter.next()) {
if (!toDecommit.append(iter.get())) {
// The OOM handler does a full, immediate decommit.
return onOutOfMallocMemory(lock);
}
// Build a Vector of all current available Chunks. Since we release the
// gc lock while doing the decommit syscall, it is dangerous to iterate
// the available list directly, as concurrent operations can modify it.
mozilla::Vector<Chunk*> toDecommit;
MOZ_ASSERT(availableChunks(lock).verify());
for (ChunkPool::Iter iter(availableChunks(lock)); !iter.done(); iter.next()) {
if (!toDecommit.append(iter.get())) {
// The OOM handler does a full, immediate decommit, so there is
// nothing more to do here in any case.
return onOutOfMallocMemory(lock);
}
}
decommitTask.setChunksToScan(toDecommit);
if (sweepOnBackgroundThread && decommitTask.start())
return;
// Start at the tail and stop before the first chunk: we allocate from the
// head and don't want to thrash with the mutator.
for (size_t i = toDecommit.length(); i > 1; --i) {
Chunk* chunk = toDecommit[i - 1];
MOZ_ASSERT(chunk);
decommitTask.runFromMainThread(rt);
}
void
js::gc::BackgroundDecommitTask::setChunksToScan(ChunkVector &chunks)
{
MOZ_ASSERT(CurrentThreadCanAccessRuntime(runtime));
MOZ_ASSERT(!isRunning());
MOZ_ASSERT(toDecommit.empty());
Swap(toDecommit, chunks);
}
/* virtual */ void
js::gc::BackgroundDecommitTask::run()
{
AutoLockGC lock(runtime);
for (Chunk* chunk : toDecommit) {
// The arena list is not doubly-linked, so we have to work in the free
// list order and not in the natural order.
while (chunk->info.numArenasFreeCommitted) {
bool ok = chunk->decommitOneFreeArena(runtime, lock);
bool ok = chunk->decommitOneFreeArena(rt, lock);
// If we are low enough on memory that we can't update the page
// tables, or if we need to return for any other reason, break out
// of the loop.
if (cancel_ || !ok)
break;
// FIXME Bug 1095620: add cancellation support when this becomes
// a ParallelTask.
if (/* cancel_ || */ !ok)
return;
}
}
toDecommit.clearAndFree();
MOZ_ASSERT(availableChunks(lock).verify());
}
void
@ -3412,6 +3386,9 @@ GCRuntime::expireChunksAndArenas(bool shouldShrink, AutoLockGC& lock)
AutoUnlockGC unlock(lock);
FreeChunkPool(rt, toFree);
}
if (shouldShrink)
decommitArenas(lock);
}
void
@ -5721,7 +5698,6 @@ GCRuntime::endCompactPhase(JS::gcreason::Reason reason)
void
GCRuntime::finishCollection(JS::gcreason::Reason reason)
{
assertBackgroundSweepingFinished();
MOZ_ASSERT(marker.isDrained());
marker.stop();
clearBufferedGrayRoots();
@ -5750,6 +5726,15 @@ GCRuntime::finishCollection(JS::gcreason::Reason reason)
}
lastGCTime = currentTime;
// If this is an OOM GC reason, wait on the background sweeping thread
// before returning to ensure that we free as much as possible. If this is
// a zeal-triggered GC, we want to ensure that the mutator can continue
// allocating on the same pages to reduce fragmentation.
if (IsOOMReason(reason) || reason == JS::gcreason::DEBUG_GC) {
gcstats::AutoPhase ap(stats, gcstats::PHASE_WAIT_BACKGROUND_THREAD);
rt->gc.waitBackgroundSweepOrAllocEnd();
}
}
static const char*
@ -5898,12 +5883,6 @@ GCRuntime::resetIncrementalGC(const char* reason)
break;
}
case DECOMMIT: {
auto unlimited = SliceBudget::unlimited();
incrementalCollectSlice(unlimited, JS::gcreason::RESET);
break;
}
default:
MOZ_CRASH("Invalid incremental GC state");
}
@ -6165,28 +6144,13 @@ GCRuntime::incrementalCollectSlice(SliceBudget& budget, JS::gcreason::Reason rea
endCompactPhase(reason);
}
startDecommit();
incrementalState = DECOMMIT;
MOZ_FALLTHROUGH;
case DECOMMIT:
{
gcstats::AutoPhase ap(stats, gcstats::PHASE_WAIT_BACKGROUND_THREAD);
// Yield until background decommit is done.
if (isIncremental && decommitTask.isRunning())
break;
decommitTask.join();
}
finishCollection(reason);
incrementalState = NO_INCREMENTAL;
break;
default:
MOZ_CRASH("unexpected GC incrementalState");
MOZ_ASSERT(false);
}
}
@ -6315,12 +6279,10 @@ GCRuntime::gcCycle(bool nonincrementalByAPI, SliceBudget& budget, JS::gcreason::
{
gcstats::AutoPhase ap(stats, gcstats::PHASE_WAIT_BACKGROUND_THREAD);
// Background finalization and decommit are finished by defininition
// before we can start a new GC session.
if (!isIncrementalGCInProgress()) {
assertBackgroundSweepingFinished();
MOZ_ASSERT(!decommitTask.isRunning());
}
// As we are about to clear the mark bits, wait for background
// finalization to finish. We only need to wait on the first slice.
if (!isIncrementalGCInProgress())
waitBackgroundSweepEnd();
// We must also wait for background allocation to finish so we can
// avoid taking the GC lock when manipulating the chunks during the GC.
@ -6657,9 +6619,6 @@ GCRuntime::onOutOfMallocMemory()
// Stop allocating new chunks.
allocTask.cancel(GCParallelTask::CancelAndWait);
// Make sure we release anything queued for release.
decommitTask.join();
// Wait for background free of nursery huge slots to finish.
nursery.waitBackgroundFreeEnd();

4
js/src/jsgc.h
View File

@ -49,8 +49,7 @@ enum State {
MARK,
SWEEP,
FINALIZE,
COMPACT,
DECOMMIT
COMPACT
};
/* Map from C++ type to alloc kind. JSObject does not have a 1:1 mapping, so must use Arena::thingSize. */
@ -962,7 +961,6 @@ class GCParallelTask
}
// Check if a task is actively running.
bool isRunningWithLockHeld() const;
bool isRunning() const;
// This should be friended to HelperThread, but cannot be because it

9
js/src/vm/HelperThreads.cpp
View File

@ -1089,19 +1089,12 @@ js::GCParallelTask::runFromHelperThread()
}
bool
js::GCParallelTask::isRunningWithLockHeld() const
js::GCParallelTask::isRunning() const
{
MOZ_ASSERT(HelperThreadState().isLocked());
return state == Dispatched;
}
bool
js::GCParallelTask::isRunning() const
{
AutoLockHelperThreadState helperLock;
return isRunningWithLockHeld();
}
void
HelperThread::handleGCParallelWorkload()
{