Add m-esr52 at 52.6.0

1 files changed, 646 insertions, 0 deletions

diff --git a/netwerk/cache2/CacheIOThread.cpp b/netwerk/cache2/CacheIOThread.cpp
new file mode 100644
index 000000000..b96f03216
--- /dev/null
+++ b/netwerk/cache2/CacheIOThread.cpp
@@ -0,0 +1,646 @@
+/* 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/. */
+
+#include "CacheIOThread.h"
+#include "CacheFileIOManager.h"
+
+#include "nsIRunnable.h"
+#include "nsISupportsImpl.h"
+#include "nsPrintfCString.h"
+#include "nsThreadUtils.h"
+#include "mozilla/IOInterposer.h"
+
+#ifdef XP_WIN
+#include <windows.h>
+#endif
+
+namespace mozilla {
+namespace net {
+
+namespace { // anon
+
+class CacheIOTelemetry
+{
+public:
+  typedef CacheIOThread::EventQueue::size_type size_type;
+  static size_type mMinLengthToReport[CacheIOThread::LAST_LEVEL];
+  static void Report(uint32_t aLevel, size_type aLength);
+};
+
+static CacheIOTelemetry::size_type const kGranularity = 30;
+
+CacheIOTelemetry::size_type 
+CacheIOTelemetry::mMinLengthToReport[CacheIOThread::LAST_LEVEL] = {
+  kGranularity, kGranularity, kGranularity, kGranularity,
+  kGranularity, kGranularity, kGranularity, kGranularity
+};
+
+// static
+void CacheIOTelemetry::Report(uint32_t aLevel, CacheIOTelemetry::size_type aLength)
+{
+  if (mMinLengthToReport[aLevel] > aLength) {
+    return;
+  }
+
+  static Telemetry::ID telemetryID[] = {
+    Telemetry::HTTP_CACHE_IO_QUEUE_2_OPEN_PRIORITY,
+    Telemetry::HTTP_CACHE_IO_QUEUE_2_READ_PRIORITY,
+    Telemetry::HTTP_CACHE_IO_QUEUE_2_MANAGEMENT,
+    Telemetry::HTTP_CACHE_IO_QUEUE_2_OPEN,
+    Telemetry::HTTP_CACHE_IO_QUEUE_2_READ,
+    Telemetry::HTTP_CACHE_IO_QUEUE_2_WRITE_PRIORITY,
+    Telemetry::HTTP_CACHE_IO_QUEUE_2_WRITE,
+    Telemetry::HTTP_CACHE_IO_QUEUE_2_INDEX,
+    Telemetry::HTTP_CACHE_IO_QUEUE_2_EVICT
+  };
+
+  // Each bucket is a multiply of kGranularity (30, 60, 90..., 300+)
+  aLength = (aLength / kGranularity);
+  // Next time report only when over the current length + kGranularity
+  mMinLengthToReport[aLevel] = (aLength + 1) * kGranularity;
+
+  // 10 is number of buckets we have in each probe
+  aLength = std::min<size_type>(aLength, 10);
+
+  Telemetry::Accumulate(telemetryID[aLevel], aLength - 1); // counted from 0
+}
+
+} // anon
+
+namespace detail {
+
+/**
+ * Helper class encapsulating platform-specific code to cancel
+ * any pending IO operation taking too long.  Solely used during
+ * shutdown to prevent any IO shutdown hangs.
+ * Mainly designed for using Win32 CancelSynchronousIo function.
+ */
+class BlockingIOWatcher
+{
+#ifdef XP_WIN
+  typedef BOOL(WINAPI* TCancelSynchronousIo)(HANDLE hThread);
+  TCancelSynchronousIo mCancelSynchronousIo;
+  // The native handle to the thread
+  HANDLE mThread;
+  // Event signaling back to the main thread, see NotifyOperationDone.
+  HANDLE mEvent;
+#endif
+
+public:
+  // Created and destroyed on the main thread only
+  BlockingIOWatcher();
+  ~BlockingIOWatcher();
+
+  // Called on the IO thread to grab the platform specific
+  // reference to it.
+  void InitThread();
+  // If there is a blocking operation being handled on the IO
+  // thread, this is called on the main thread during shutdown.
+  // Waits for notification from the IO thread for up to two seconds.
+  // If that times out, it attempts to cancel the IO operation.
+  void WatchAndCancel(Monitor& aMonitor);
+  // Called by the IO thread after each operation has been
+  // finished (after each Run() call).  This wakes the main
+  // thread up and makes WatchAndCancel() early exit and become
+  // a no-op.
+  void NotifyOperationDone();
+};
+
+#ifdef XP_WIN
+
+BlockingIOWatcher::BlockingIOWatcher()
+  : mCancelSynchronousIo(NULL)
+  , mThread(NULL)
+  , mEvent(NULL)
+{
+  HMODULE kernel32_dll = GetModuleHandle("kernel32.dll");
+  if (!kernel32_dll) {
+    return;
+  }
+
+  FARPROC ptr = GetProcAddress(kernel32_dll, "CancelSynchronousIo");
+  if (!ptr) {
+    return;
+  }
+
+  mCancelSynchronousIo = reinterpret_cast<TCancelSynchronousIo>(ptr);
+
+  mEvent = ::CreateEvent(NULL, TRUE, FALSE, NULL);
+}
+
+BlockingIOWatcher::~BlockingIOWatcher()
+{
+  if (mEvent) {
+    CloseHandle(mEvent);
+  }
+  if (mThread) {
+    CloseHandle(mThread);
+  }
+}
+
+void BlockingIOWatcher::InitThread()
+{
+  // GetCurrentThread() only returns a pseudo handle, hence DuplicateHandle
+  BOOL result = ::DuplicateHandle(
+    GetCurrentProcess(),
+    GetCurrentThread(),
+    GetCurrentProcess(),
+    &mThread,
+    0,
+    FALSE,
+    DUPLICATE_SAME_ACCESS);
+}
+
+void BlockingIOWatcher::WatchAndCancel(Monitor& aMonitor)
+{
+  if (!mEvent) {
+    return;
+  }
+
+  // Reset before we enter the monitor to raise the chance we catch
+  // the currently pending IO op completion.
+  ::ResetEvent(mEvent);
+
+  HANDLE thread;
+  {
+    MonitorAutoLock lock(aMonitor);
+    thread = mThread;
+
+    if (!thread) {
+      return;
+    }
+  }
+
+  LOG(("Blocking IO operation pending on IO thread, waiting..."));
+
+  // It seems wise to use the I/O lag time as a maximum time to wait
+  // for an operation to finish.  When that times out and cancelation
+  // succeeds, there will be no other IO operation permitted.  By default
+  // this is two seconds.
+  uint32_t maxLag = std::min<uint32_t>(5, CacheObserver::MaxShutdownIOLag()) * 1000;
+
+  DWORD result = ::WaitForSingleObject(mEvent, maxLag);
+  if (result == WAIT_TIMEOUT) {
+    LOG(("CacheIOThread: Attempting to cancel a long blocking IO operation"));
+    BOOL result = mCancelSynchronousIo(thread);
+    if (result) {
+      LOG(("  cancelation signal succeeded"));
+    } else {
+      DWORD error = GetLastError();
+      LOG(("  cancelation signal failed with GetLastError=%u", error));
+    }
+  }
+}
+
+void BlockingIOWatcher::NotifyOperationDone()
+{
+  if (mEvent) {
+    ::SetEvent(mEvent);
+  }
+}
+
+#else // WIN
+
+// Stub code only (we don't implement IO cancelation for this platform)
+
+BlockingIOWatcher::BlockingIOWatcher() { }
+BlockingIOWatcher::~BlockingIOWatcher() { }
+void BlockingIOWatcher::InitThread() { }
+void BlockingIOWatcher::WatchAndCancel(Monitor&) { }
+void BlockingIOWatcher::NotifyOperationDone() { }
+
+#endif
+
+} // detail
+
+CacheIOThread* CacheIOThread::sSelf = nullptr;
+
+NS_IMPL_ISUPPORTS(CacheIOThread, nsIThreadObserver)
+
+CacheIOThread::CacheIOThread()
+: mMonitor("CacheIOThread")
+, mThread(nullptr)
+, mXPCOMThread(nullptr)
+, mLowestLevelWaiting(LAST_LEVEL)
+, mCurrentlyExecutingLevel(0)
+, mHasXPCOMEvents(false)
+, mRerunCurrentEvent(false)
+, mShutdown(false)
+, mIOCancelableEvents(0)
+#ifdef DEBUG
+, mInsideLoop(true)
+#endif
+{
+  for (uint32_t i = 0; i < LAST_LEVEL; ++i) {
+    mQueueLength[i] = 0;
+  }
+
+  sSelf = this;
+}
+
+CacheIOThread::~CacheIOThread()
+{
+  if (mXPCOMThread) {
+    nsIThread *thread = mXPCOMThread;
+    thread->Release();
+  }
+
+  sSelf = nullptr;
+#ifdef DEBUG
+  for (uint32_t level = 0; level < LAST_LEVEL; ++level) {
+    MOZ_ASSERT(!mEventQueue[level].Length());
+  }
+#endif
+}
+
+nsresult CacheIOThread::Init()
+{
+  {
+    MonitorAutoLock lock(mMonitor);
+    // Yeah, there is not a thread yet, but we want to make sure
+    // the sequencing is correct.
+    mBlockingIOWatcher = MakeUnique<detail::BlockingIOWatcher>();
+  }
+
+  mThread = PR_CreateThread(PR_USER_THREAD, ThreadFunc, this,
+                            PR_PRIORITY_NORMAL, PR_GLOBAL_THREAD,
+                            PR_JOINABLE_THREAD, 128 * 1024);
+  if (!mThread) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+nsresult CacheIOThread::Dispatch(nsIRunnable* aRunnable, uint32_t aLevel)
+{
+  return Dispatch(do_AddRef(aRunnable), aLevel);
+}
+
+nsresult CacheIOThread::Dispatch(already_AddRefed<nsIRunnable> aRunnable,
+				 uint32_t aLevel)
+{
+  NS_ENSURE_ARG(aLevel < LAST_LEVEL);
+
+  nsCOMPtr<nsIRunnable> runnable(aRunnable);
+
+  // Runnable is always expected to be non-null, hard null-check bellow.
+  MOZ_ASSERT(runnable);
+
+  MonitorAutoLock lock(mMonitor);
+
+  if (mShutdown && (PR_GetCurrentThread() != mThread))
+    return NS_ERROR_UNEXPECTED;
+
+  return DispatchInternal(runnable.forget(), aLevel);
+}
+
+nsresult CacheIOThread::DispatchAfterPendingOpens(nsIRunnable* aRunnable)
+{
+  // Runnable is always expected to be non-null, hard null-check bellow.
+  MOZ_ASSERT(aRunnable);
+
+  MonitorAutoLock lock(mMonitor);
+
+  if (mShutdown && (PR_GetCurrentThread() != mThread))
+    return NS_ERROR_UNEXPECTED;
+
+  // Move everything from later executed OPEN level to the OPEN_PRIORITY level
+  // where we post the (eviction) runnable.
+  mQueueLength[OPEN_PRIORITY] += mEventQueue[OPEN].Length();
+  mQueueLength[OPEN] -= mEventQueue[OPEN].Length();
+  mEventQueue[OPEN_PRIORITY].AppendElements(mEventQueue[OPEN]);
+  mEventQueue[OPEN].Clear();
+
+  return DispatchInternal(do_AddRef(aRunnable), OPEN_PRIORITY);
+}
+
+nsresult CacheIOThread::DispatchInternal(already_AddRefed<nsIRunnable> aRunnable,
+					 uint32_t aLevel)
+{
+  nsCOMPtr<nsIRunnable> runnable(aRunnable);
+
+  if (NS_WARN_IF(!runnable))
+    return NS_ERROR_NULL_POINTER;
+
+  mMonitor.AssertCurrentThreadOwns();
+
+  ++mQueueLength[aLevel];
+  mEventQueue[aLevel].AppendElement(runnable.forget());
+  if (mLowestLevelWaiting > aLevel)
+    mLowestLevelWaiting = aLevel;
+
+  mMonitor.NotifyAll();
+
+  return NS_OK;
+}
+
+bool CacheIOThread::IsCurrentThread()
+{
+  return mThread == PR_GetCurrentThread();
+}
+
+uint32_t CacheIOThread::QueueSize(bool highPriority)
+{
+  MonitorAutoLock lock(mMonitor);
+  if (highPriority) {
+    return mQueueLength[OPEN_PRIORITY] + mQueueLength[READ_PRIORITY];
+  }
+
+  return mQueueLength[OPEN_PRIORITY] + mQueueLength[READ_PRIORITY] +
+         mQueueLength[MANAGEMENT] + mQueueLength[OPEN] + mQueueLength[READ];
+}
+
+bool CacheIOThread::YieldInternal()
+{
+  if (!IsCurrentThread()) {
+    NS_WARNING("Trying to yield to priority events on non-cache2 I/O thread? "
+               "You probably do something wrong.");
+    return false;
+  }
+
+  if (mCurrentlyExecutingLevel == XPCOM_LEVEL) {
+    // Doesn't make any sense, since this handler is the one
+    // that would be executed as the next one.
+    return false;
+  }
+
+  if (!EventsPending(mCurrentlyExecutingLevel))
+    return false;
+
+  mRerunCurrentEvent = true;
+  return true;
+}
+
+void CacheIOThread::Shutdown()
+{
+  if (!mThread) {
+    return;
+  }
+
+  {
+    MonitorAutoLock lock(mMonitor);
+    mShutdown = true;
+    mMonitor.NotifyAll();
+  }
+
+  PR_JoinThread(mThread);
+  mThread = nullptr;
+}
+
+void CacheIOThread::CancelBlockingIO()
+{
+  // This is an attempt to cancel any blocking I/O operation taking
+  // too long time.
+  if (!mBlockingIOWatcher) {
+    return;
+  }
+
+  if (!mIOCancelableEvents) {
+    LOG(("CacheIOThread::CancelBlockingIO, no blocking operation to cancel"));
+    return;
+  }
+
+  // OK, when we are here, we are processing an IO on the thread that
+  // can be cancelled.
+  mBlockingIOWatcher->WatchAndCancel(mMonitor);
+}
+
+already_AddRefed<nsIEventTarget> CacheIOThread::Target()
+{
+  nsCOMPtr<nsIEventTarget> target;
+
+  target = mXPCOMThread;
+  if (!target && mThread)
+  {
+    MonitorAutoLock lock(mMonitor);
+    while (!mXPCOMThread) {
+      lock.Wait();
+    }
+
+    target = mXPCOMThread;
+  }
+
+  return target.forget();
+}
+
+// static
+void CacheIOThread::ThreadFunc(void* aClosure)
+{
+  PR_SetCurrentThreadName("Cache2 I/O");
+  mozilla::IOInterposer::RegisterCurrentThread();
+  CacheIOThread* thread = static_cast<CacheIOThread*>(aClosure);
+  thread->ThreadFunc();
+  mozilla::IOInterposer::UnregisterCurrentThread();
+}
+
+void CacheIOThread::ThreadFunc()
+{
+  nsCOMPtr<nsIThreadInternal> threadInternal;
+
+  {
+    MonitorAutoLock lock(mMonitor);
+
+    MOZ_ASSERT(mBlockingIOWatcher);
+    mBlockingIOWatcher->InitThread();
+
+    // This creates nsThread for this PRThread
+    nsCOMPtr<nsIThread> xpcomThread = NS_GetCurrentThread();
+
+    threadInternal = do_QueryInterface(xpcomThread);
+    if (threadInternal)
+      threadInternal->SetObserver(this);
+
+    mXPCOMThread = xpcomThread.forget().take();
+
+    lock.NotifyAll();
+
+    do {
+loopStart:
+      // Reset the lowest level now, so that we can detect a new event on
+      // a lower level (i.e. higher priority) has been scheduled while
+      // executing any previously scheduled event.
+      mLowestLevelWaiting = LAST_LEVEL;
+
+      // Process xpcom events first
+      while (mHasXPCOMEvents) {
+        mHasXPCOMEvents = false;
+        mCurrentlyExecutingLevel = XPCOM_LEVEL;
+
+        MonitorAutoUnlock unlock(mMonitor);
+
+        bool processedEvent;
+        nsresult rv;
+        do {
+          nsIThread *thread = mXPCOMThread;
+          rv = thread->ProcessNextEvent(false, &processedEvent);
+
+          MOZ_ASSERT(mBlockingIOWatcher);
+          mBlockingIOWatcher->NotifyOperationDone();
+        } while (NS_SUCCEEDED(rv) && processedEvent);
+      }
+
+      uint32_t level;
+      for (level = 0; level < LAST_LEVEL; ++level) {
+        if (!mEventQueue[level].Length()) {
+          // no events on this level, go to the next level
+          continue;
+        }
+
+        LoopOneLevel(level);
+
+        // Go to the first (lowest) level again
+        goto loopStart;
+      }
+
+      if (EventsPending()) {
+        continue;
+      }
+
+      if (mShutdown) {
+        break;
+      }
+
+      lock.Wait(PR_INTERVAL_NO_TIMEOUT);
+
+    } while (true);
+
+    MOZ_ASSERT(!EventsPending());
+
+#ifdef DEBUG
+    // This is for correct assertion on XPCOM events dispatch.
+    mInsideLoop = false;
+#endif
+  } // lock
+
+  if (threadInternal)
+    threadInternal->SetObserver(nullptr);
+}
+
+void CacheIOThread::LoopOneLevel(uint32_t aLevel)
+{
+  EventQueue events;
+  events.SwapElements(mEventQueue[aLevel]);
+  EventQueue::size_type length = events.Length();
+
+  mCurrentlyExecutingLevel = aLevel;
+
+  bool returnEvents = false;
+  bool reportTelementry = true;
+
+  EventQueue::size_type index;
+  {
+    MonitorAutoUnlock unlock(mMonitor);
+
+    for (index = 0; index < length; ++index) {
+      if (EventsPending(aLevel)) {
+        // Somebody scheduled a new event on a lower level, break and harry
+        // to execute it!  Don't forget to return what we haven't exec.
+        returnEvents = true;
+        break;
+      }
+
+      if (reportTelementry) {
+        reportTelementry = false;
+        CacheIOTelemetry::Report(aLevel, length);
+      }
+
+      // Drop any previous flagging, only an event on the current level may set
+      // this flag.
+      mRerunCurrentEvent = false;
+
+      events[index]->Run();
+
+      MOZ_ASSERT(mBlockingIOWatcher);
+      mBlockingIOWatcher->NotifyOperationDone();
+
+      if (mRerunCurrentEvent) {
+        // The event handler yields to higher priority events and wants to rerun.
+        returnEvents = true;
+        break;
+      }
+
+      --mQueueLength[aLevel];
+
+      // Release outside the lock.
+      events[index] = nullptr;
+    }
+  }
+
+  if (returnEvents)
+    mEventQueue[aLevel].InsertElementsAt(0, events.Elements() + index, length - index);
+}
+
+bool CacheIOThread::EventsPending(uint32_t aLastLevel)
+{
+  return mLowestLevelWaiting < aLastLevel || mHasXPCOMEvents;
+}
+
+NS_IMETHODIMP CacheIOThread::OnDispatchedEvent(nsIThreadInternal *thread)
+{
+  MonitorAutoLock lock(mMonitor);
+  mHasXPCOMEvents = true;
+  MOZ_ASSERT(mInsideLoop);
+  lock.Notify();
+  return NS_OK;
+}
+
+NS_IMETHODIMP CacheIOThread::OnProcessNextEvent(nsIThreadInternal *thread, bool mayWait)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP CacheIOThread::AfterProcessNextEvent(nsIThreadInternal *thread,
+                                                   bool eventWasProcessed)
+{
+  return NS_OK;
+}
+
+// Memory reporting
+
+size_t CacheIOThread::SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const
+{
+  MonitorAutoLock lock(const_cast<CacheIOThread*>(this)->mMonitor);
+
+  size_t n = 0;
+  n += mallocSizeOf(mThread);
+  for (uint32_t level = 0; level < LAST_LEVEL; ++level) {
+    n += mEventQueue[level].ShallowSizeOfExcludingThis(mallocSizeOf);
+    // Events referenced by the queues are arbitrary objects we cannot be sure
+    // are reported elsewhere as well as probably not implementing nsISizeOf
+    // interface.  Deliberatly omitting them from reporting here.
+  }
+
+  return n;
+}
+
+size_t CacheIOThread::SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const
+{
+  return mallocSizeOf(this) + SizeOfExcludingThis(mallocSizeOf);
+}
+
+CacheIOThread::Cancelable::Cancelable(bool aCancelable)
+  : mCancelable(aCancelable)
+{
+  // This will only ever be used on the I/O thread,
+  // which is expected to be alive longer than this class.
+  MOZ_ASSERT(CacheIOThread::sSelf);
+  MOZ_ASSERT(CacheIOThread::sSelf->IsCurrentThread());
+
+  if (mCancelable) {
+    ++CacheIOThread::sSelf->mIOCancelableEvents;
+  }
+}
+
+CacheIOThread::Cancelable::~Cancelable()
+{
+  MOZ_ASSERT(CacheIOThread::sSelf);
+
+  if (mCancelable) {
+    --CacheIOThread::sSelf->mIOCancelableEvents;
+  }
+}
+
+} // namespace net
+} // namespace mozilla