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Bug 839117 - 'Don't allow a leaking memory reporter to hang workers'. r=jlebar.

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This commit is contained in:
Ben Turner 2013-02-08 03:50:00 -08:00
parent 126d0a8fe7
commit 475f40c407
2 changed files with 227 additions and 179 deletions
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335
dom/workers/WorkerPrivate.cpp
View File

@ -1442,84 +1442,8 @@ public:
}
};
class MemoryReporter MOZ_FINAL : public nsIMemoryMultiReporter
{
friend class WorkerPrivate;
WorkerPrivate* mWorkerPrivate;
nsCString mRtPath;
public:
NS_DECL_ISUPPORTS
MemoryReporter(WorkerPrivate* aWorkerPrivate)
: mWorkerPrivate(aWorkerPrivate)
{
aWorkerPrivate->AssertIsOnWorkerThread();
nsCString escapedDomain(aWorkerPrivate->Domain());
escapedDomain.ReplaceChar('/', '\\');
NS_ConvertUTF16toUTF8 escapedURL(aWorkerPrivate->ScriptURL());
escapedURL.ReplaceChar('/', '\\');
nsAutoCString addressString;
addressString.AppendPrintf("0x%p", static_cast<void*>(aWorkerPrivate));
mRtPath = NS_LITERAL_CSTRING("explicit/workers/workers(") +
escapedDomain + NS_LITERAL_CSTRING(")/worker(") +
escapedURL + NS_LITERAL_CSTRING(", ") + addressString +
NS_LITERAL_CSTRING(")/");
}
~MemoryReporter()
{
mWorkerPrivate->NoteDeadMemoryReporter();
}
NS_IMETHOD
GetName(nsACString& aName)
{
aName.AssignLiteral("workers");
return NS_OK;
}
NS_IMETHOD
CollectReports(nsIMemoryMultiReporterCallback* aCallback,
nsISupports* aClosure)
{
AssertIsOnMainThread();
WorkerJSRuntimeStats rtStats(mRtPath);
if (!mWorkerPrivate->BlockAndCollectRuntimeStats(/* aIsQuick = */ false,
&rtStats)) {
return NS_ERROR_FAILURE;
}
// Always report, even if we're disabled, so that we at least get an entry
// in about::memory.
return xpc::ReportJSRuntimeExplicitTreeStats(rtStats, mRtPath,
aCallback, aClosure);
}
NS_IMETHOD
GetExplicitNonHeap(int64_t* aAmount)
{
AssertIsOnMainThread();
if (!mWorkerPrivate->BlockAndCollectRuntimeStats(/* aIsQuick = */ true,
aAmount)) {
return NS_ERROR_FAILURE;
}
return NS_OK;
}
};
} /* anonymous namespace */
NS_IMPL_THREADSAFE_ISUPPORTS1(MemoryReporter, nsIMemoryMultiReporter)
#ifdef DEBUG
void
mozilla::dom::workers::AssertIsOnMainThread()
@ -1780,6 +1704,103 @@ struct WorkerPrivate::TimeoutInfo
bool mCanceled;
};
class WorkerPrivate::MemoryReporter MOZ_FINAL : public nsIMemoryMultiReporter
{
friend class WorkerPrivate;
SharedMutex mMutex;
WorkerPrivate* mWorkerPrivate;
nsCString mRtPath;
public:
NS_DECL_ISUPPORTS
MemoryReporter(WorkerPrivate* aWorkerPrivate)
: mMutex(aWorkerPrivate->mMutex), mWorkerPrivate(aWorkerPrivate)
{
aWorkerPrivate->AssertIsOnWorkerThread();
nsCString escapedDomain(aWorkerPrivate->Domain());
escapedDomain.ReplaceChar('/', '\\');
NS_ConvertUTF16toUTF8 escapedURL(aWorkerPrivate->ScriptURL());
escapedURL.ReplaceChar('/', '\\');
nsAutoCString addressString;
addressString.AppendPrintf("0x%p", static_cast<void*>(aWorkerPrivate));
mRtPath = NS_LITERAL_CSTRING("explicit/workers/workers(") +
escapedDomain + NS_LITERAL_CSTRING(")/worker(") +
escapedURL + NS_LITERAL_CSTRING(", ") + addressString +
NS_LITERAL_CSTRING(")/");
}
NS_IMETHOD
GetName(nsACString& aName)
{
aName.AssignLiteral("workers");
return NS_OK;
}
NS_IMETHOD
CollectReports(nsIMemoryMultiReporterCallback* aCallback,
nsISupports* aClosure)
{
AssertIsOnMainThread();
WorkerJSRuntimeStats rtStats(mRtPath);
{
MutexAutoLock lock(mMutex);
if (!mWorkerPrivate ||
!mWorkerPrivate->BlockAndCollectRuntimeStats(/* aIsQuick = */ false,
&rtStats)) {
// Returning NS_OK here will effectively report 0 memory.
return NS_OK;
}
}
return xpc::ReportJSRuntimeExplicitTreeStats(rtStats, mRtPath,
aCallback, aClosure);
}
NS_IMETHOD
GetExplicitNonHeap(int64_t* aAmount)
{
AssertIsOnMainThread();
{
MutexAutoLock lock(mMutex);
if (!mWorkerPrivate ||
!mWorkerPrivate->BlockAndCollectRuntimeStats(/* aIsQuick = */ true,
aAmount)) {
*aAmount = 0;
}
}
return NS_OK;
}
private:
~MemoryReporter()
{ }
void
Disable()
{
// Called from WorkerPrivate::DisableMemoryReporter.
mMutex.AssertCurrentThreadOwns();
NS_ASSERTION(mWorkerPrivate, "Disabled more than once!");
mWorkerPrivate = nullptr;
}
};
NS_IMPL_THREADSAFE_ISUPPORTS1(WorkerPrivate::MemoryReporter,
nsIMemoryMultiReporter)
template <class Derived>
WorkerPrivateParent<Derived>::WorkerPrivateParent(
JSContext* aCx, JSObject* aObject,
@ -2385,9 +2406,8 @@ WorkerPrivate::WorkerPrivate(JSContext* aCx, JSObject* aObject,
mJSContext(nullptr), mErrorHandlerRecursionCount(0), mNextTimeoutId(1),
mStatus(Pending), mSuspended(false), mTimerRunning(false),
mRunningExpiredTimeouts(false), mCloseHandlerStarted(false),
mCloseHandlerFinished(false), mMemoryReporterAlive(false),
mMemoryReporterRunning(false), mBlockedForMemoryReporter(false),
mXHRParamsAllowed(aXHRParamsAllowed)
mCloseHandlerFinished(false), mMemoryReporterRunning(false),
mBlockedForMemoryReporter(false), mXHRParamsAllowed(aXHRParamsAllowed)
{
MOZ_COUNT_CTOR(mozilla::dom::workers::WorkerPrivate);
}
@ -2839,55 +2859,48 @@ bool
WorkerPrivate::BlockAndCollectRuntimeStats(bool aIsQuick, void* aData)
{
AssertIsOnMainThread();
mMutex.AssertCurrentThreadOwns();
NS_ASSERTION(aData, "Null data!");
JSRuntime* rt;
NS_ASSERTION(!mMemoryReporterRunning, "How can we get reentered here?!");
{
MutexAutoLock lock(mMutex);
// This signals the worker that it should block itself as soon as possible.
mMemoryReporterRunning = true;
// If the worker is being torn down then we just bail out now.
if (!mMemoryReporter) {
if (aIsQuick) {
*static_cast<int64_t*>(aData) = 0;
}
return true;
}
NS_ASSERTION(mJSContext, "This must never be null!");
JSRuntime* rt = JS_GetRuntime(mJSContext);
// This signals the worker that it should block itself as soon as possible.
mMemoryReporterRunning = true;
// If the worker is not already blocked (e.g. waiting for a worker event or
// currently in a ctypes call) then we need to trigger the operation
// callback to trap the worker.
if (!mBlockedForMemoryReporter) {
JS_TriggerOperationCallback(rt);
NS_ASSERTION(mJSContext, "This must never be null!");
rt = JS_GetRuntime(mJSContext);
// If the worker is not already blocked (e.g. waiting for a worker event or
// currently in a ctypes call) then we need to trigger the operation
// callback to trap the worker.
if (!mBlockedForMemoryReporter) {
JS_TriggerOperationCallback(rt);
// Wait until the worker actually blocks.
while (!mBlockedForMemoryReporter) {
mMemoryReportCondVar.Wait();
}
// Wait until the worker actually blocks.
while (!mBlockedForMemoryReporter) {
mMemoryReportCondVar.Wait();
}
}
bool succeeded;
bool succeeded = false;
// Now do the actual report.
if (aIsQuick) {
*static_cast<int64_t*>(aData) =
JS::GetExplicitNonHeapForRuntime(rt, JsWorkerMallocSizeOf);
succeeded = true;
} else {
succeeded =
JS::CollectRuntimeStats(rt, static_cast<JS::RuntimeStats*>(aData),
nullptr);
// If mMemoryReporter is still set then we can do the actual report. Otherwise
// we're trying to shut down and we don't want to do anything but clean up.
if (mMemoryReporter) {
// Don't hold the lock while doing the actual report.
MutexAutoUnlock unlock(mMutex);
if (aIsQuick) {
*static_cast<int64_t*>(aData) =
JS::GetExplicitNonHeapForRuntime(rt, JsWorkerMallocSizeOf);
succeeded = true;
} else {
succeeded =
JS::CollectRuntimeStats(rt, static_cast<JS::RuntimeStats*>(aData),
nullptr);
}
}
MutexAutoLock lock(mMutex);
NS_ASSERTION(mMemoryReporterRunning, "This isn't possible!");
NS_ASSERTION(mBlockedForMemoryReporter, "Somehow we got unblocked!");
@ -2900,31 +2913,13 @@ WorkerPrivate::BlockAndCollectRuntimeStats(bool aIsQuick, void* aData)
return succeeded;
}
void
WorkerPrivate::NoteDeadMemoryReporter()
{
// This may happen on the worker thread or the main thread.
MutexAutoLock lock(mMutex);
NS_ASSERTION(mMemoryReporterAlive, "Must be alive!");
// Tell the worker that the memory reporter has died.
mMemoryReporterAlive = false;
// The worker may be waiting so we must notify.
mMemoryReportCondVar.Notify();
}
void
WorkerPrivate::EnableMemoryReporter()
{
AssertIsOnWorkerThread();
NS_ASSERTION(!mMemoryReporterAlive, "This isn't possible!");
// No need to lock here since the main thread can't race until we've
// successfully registered the reporter.
mMemoryReporterAlive = true;
mMemoryReporter = new MemoryReporter(this);
if (NS_FAILED(NS_RegisterMemoryMultiReporter(mMemoryReporter))) {
@ -2933,9 +2928,6 @@ WorkerPrivate::EnableMemoryReporter()
// reporter can't start running. Just clean up.
mMemoryReporter = nullptr;
// That should have killed the memory reporter.
NS_ASSERTION(!mMemoryReporterAlive, "Must be dead!");
return;
}
}
@ -2945,45 +2937,48 @@ WorkerPrivate::DisableMemoryReporter()
{
AssertIsOnWorkerThread();
// First swap out our memory reporter so that the main thread stops trying to
// signal us when it's reporting memory.
nsCOMPtr<nsIMemoryMultiReporter> memoryReporter;
nsRefPtr<MemoryReporter> memoryReporter;
{
MutexAutoLock lock(mMutex);
// There is nothing to do here if the memory reporter was never successfully
// registered.
if (!mMemoryReporter) {
return;
}
// We don't need this set any longer. Swap it out so that we can unregister
// below.
mMemoryReporter.swap(memoryReporter);
// Next disable the memory reporter so that the main thread stops trying to
// signal us.
memoryReporter->Disable();
// If the memory reporter is waiting to start then we need to wait for it to
// finish.
if (mMemoryReporterRunning) {
NS_ASSERTION(!mBlockedForMemoryReporter,
"Can't be blocked in more than one place at the same time!");
mBlockedForMemoryReporter = true;
// Tell the main thread that we're blocked.
mMemoryReportCondVar.Notify();
// Wait for it the main thread to finish. Since we swapped out
// mMemoryReporter above the main thread should respond quickly.
while (mMemoryReporterRunning) {
mMemoryReportCondVar.Wait();
}
NS_ASSERTION(mBlockedForMemoryReporter, "Somehow we got unblocked!");
mBlockedForMemoryReporter = false;
}
}
// The main thread could immediately try to report memory again here but it
// will not actually do anything since we've cleared mMemoryReporter.
// If we never registered the memory reporter (e.g. some kind of error in
// NS_RegisterMemoryMultiReporter) then there's nothing else we need to do
// here.
if (!memoryReporter) {
return;
}
NS_ASSERTION(mMemoryReporterAlive, "Huh?!");
// Unregister.
// Finally unregister the memory reporter.
if (NS_FAILED(NS_UnregisterMemoryMultiReporter(memoryReporter))) {
// If this fails then the memory reporter will probably never die and we'll
// hang below waiting for it. If this ever happens we need to fix
// NS_UnregisterMemoryMultiReporter.
MOZ_NOT_REACHED("Failed to unregister memory reporter! Worker is going to "
"hang!");
}
// Now drop our reference to the memory reporter. The main thread could be
// holding another reference so it may not die immediately.
memoryReporter = nullptr;
MutexAutoLock lock(mMutex);
// Wait once again to make sure that the main thread is done with the memory
// reporter.
while (mMemoryReporterAlive) {
mMemoryReportCondVar.Wait();
NS_WARNING("Failed to unregister memory reporter!");
}
}

71
dom/workers/WorkerPrivate.h
View File

@ -15,6 +15,7 @@
#include "nsPIDOMWindow.h"
#include "jsapi.h"
#include "mozilla/Assertions.h"
#include "mozilla/CondVar.h"
#include "mozilla/Mutex.h"
#include "mozilla/TimeStamp.h"
@ -148,6 +149,58 @@ protected:
DispatchInternal();
};
// SharedMutex is a small wrapper around an (internal) reference-counted Mutex
// object. It exists to avoid changing a lot of code to use Mutex* instead of
// Mutex&.
class SharedMutex
{
typedef mozilla::Mutex Mutex;
class RefCountedMutex : public Mutex
{
public:
RefCountedMutex(const char* aName)
: Mutex(aName)
{ }
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RefCountedMutex)
private:
~RefCountedMutex()
{ }
};
nsRefPtr<RefCountedMutex> mMutex;
public:
SharedMutex(const char* aName)
: mMutex(new RefCountedMutex(aName))
{ }
SharedMutex(SharedMutex& aOther)
: mMutex(aOther.mMutex)
{ }
operator Mutex&()
{
MOZ_ASSERT(mMutex);
return *mMutex;
}
operator const Mutex&() const
{
MOZ_ASSERT(mMutex);
return *mMutex;
}
void
AssertCurrentThreadOwns() const
{
MOZ_ASSERT(mMutex);
mMutex->AssertCurrentThreadOwns();
}
};
template <class Derived>
class WorkerPrivateParent : public EventTarget
{
@ -165,7 +218,7 @@ public:
};
protected:
mozilla::Mutex mMutex;
SharedMutex mMutex;
mozilla::CondVar mCondVar;
mozilla::CondVar mMemoryReportCondVar;
@ -340,9 +393,10 @@ public:
{
AssertIsOnParentThread();
bool acceptingEvents;
mMutex.Lock();
acceptingEvents = mParentStatus < Terminating;
mMutex.Unlock();
{
mozilla::MutexAutoLock lock(mMutex);
acceptingEvents = mParentStatus < Terminating;
}
return acceptingEvents;
}
@ -553,6 +607,9 @@ class WorkerPrivate : public WorkerPrivateParent<WorkerPrivate>
}
};
class MemoryReporter;
friend class MemoryReporter;
nsTArray<nsAutoPtr<SyncQueue> > mSyncQueues;
// Touched on multiple threads, protected with mMutex.
@ -565,7 +622,7 @@ class WorkerPrivate : public WorkerPrivateParent<WorkerPrivate>
nsTArray<nsAutoPtr<TimeoutInfo> > mTimeouts;
nsCOMPtr<nsITimer> mTimer;
nsCOMPtr<nsIMemoryMultiReporter> mMemoryReporter;
nsRefPtr<MemoryReporter> mMemoryReporter;
mozilla::TimeStamp mKillTime;
uint32_t mErrorHandlerRecursionCount;
@ -576,7 +633,6 @@ class WorkerPrivate : public WorkerPrivateParent<WorkerPrivate>
bool mRunningExpiredTimeouts;
bool mCloseHandlerStarted;
bool mCloseHandlerFinished;
bool mMemoryReporterAlive;
bool mMemoryReporterRunning;
bool mBlockedForMemoryReporter;
bool mXHRParamsAllowed;
@ -721,9 +777,6 @@ public:
bool
BlockAndCollectRuntimeStats(bool aIsQuick, void* aData);
void
NoteDeadMemoryReporter();
bool
XHRParamsAllowed() const
{