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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /xpcom/threads/HangMonitor.cpp
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'xpcom/threads/HangMonitor.cpp')
-rw-r--r--xpcom/threads/HangMonitor.cpp434
1 files changed, 434 insertions, 0 deletions
diff --git a/xpcom/threads/HangMonitor.cpp b/xpcom/threads/HangMonitor.cpp
new file mode 100644
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+++ b/xpcom/threads/HangMonitor.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "mozilla/HangMonitor.h"
+
+#include "mozilla/Atomics.h"
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ProcessedStack.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "nsReadableUtils.h"
+#include "mozilla/StackWalk.h"
+#ifdef _WIN64
+#include "mozilla/StackWalk_windows.h"
+#endif
+#include "nsThreadUtils.h"
+#include "nsXULAppAPI.h"
+
+#ifdef MOZ_CRASHREPORTER
+#include "nsExceptionHandler.h"
+#endif
+
+#ifdef XP_WIN
+#include <windows.h>
+#endif
+
+#if defined(MOZ_ENABLE_PROFILER_SPS) && defined(MOZ_PROFILING) && defined(XP_WIN)
+ #define REPORT_CHROME_HANGS
+#endif
+
+namespace mozilla {
+namespace HangMonitor {
+
+/**
+ * A flag which may be set from within a debugger to disable the hang
+ * monitor.
+ */
+volatile bool gDebugDisableHangMonitor = false;
+
+const char kHangMonitorPrefName[] = "hangmonitor.timeout";
+
+#ifdef REPORT_CHROME_HANGS
+const char kTelemetryPrefName[] = "toolkit.telemetry.enabled";
+#endif
+
+// Monitor protects gShutdown and gTimeout, but not gTimestamp which rely on
+// being atomically set by the processor; synchronization doesn't really matter
+// in this use case.
+Monitor* gMonitor;
+
+// The timeout preference, in seconds.
+int32_t gTimeout;
+
+PRThread* gThread;
+
+// Set when shutdown begins to signal the thread to exit immediately.
+bool gShutdown;
+
+// The timestamp of the last event notification, or PR_INTERVAL_NO_WAIT if
+// we're currently not processing events.
+Atomic<PRIntervalTime> gTimestamp(PR_INTERVAL_NO_WAIT);
+
+#ifdef REPORT_CHROME_HANGS
+// Main thread ID used in reporting chrome hangs under Windows
+static HANDLE winMainThreadHandle = nullptr;
+
+// Default timeout for reporting chrome hangs to Telemetry (5 seconds)
+static const int32_t DEFAULT_CHROME_HANG_INTERVAL = 5;
+
+// Maximum number of PCs to gather from the stack
+static const int32_t MAX_CALL_STACK_PCS = 400;
+#endif
+
+// PrefChangedFunc
+void
+PrefChanged(const char*, void*)
+{
+ int32_t newval = Preferences::GetInt(kHangMonitorPrefName);
+#ifdef REPORT_CHROME_HANGS
+ // Monitor chrome hangs on the profiling branch if Telemetry enabled
+ if (newval == 0) {
+ bool telemetryEnabled = Preferences::GetBool(kTelemetryPrefName);
+ if (telemetryEnabled) {
+ newval = DEFAULT_CHROME_HANG_INTERVAL;
+ }
+ }
+#endif
+ MonitorAutoLock lock(*gMonitor);
+ if (newval != gTimeout) {
+ gTimeout = newval;
+ lock.Notify();
+ }
+}
+
+void
+Crash()
+{
+ if (gDebugDisableHangMonitor) {
+ return;
+ }
+
+#ifdef XP_WIN
+ if (::IsDebuggerPresent()) {
+ return;
+ }
+#endif
+
+#ifdef MOZ_CRASHREPORTER
+ // If you change this, you must also deal with the threadsafety of AnnotateCrashReport in
+ // non-chrome processes!
+ if (GeckoProcessType_Default == XRE_GetProcessType()) {
+ CrashReporter::AnnotateCrashReport(NS_LITERAL_CSTRING("Hang"),
+ NS_LITERAL_CSTRING("1"));
+ }
+#endif
+
+ NS_RUNTIMEABORT("HangMonitor triggered");
+}
+
+#ifdef REPORT_CHROME_HANGS
+
+static void
+ChromeStackWalker(uint32_t aFrameNumber, void* aPC, void* aSP, void* aClosure)
+{
+ MOZ_ASSERT(aClosure);
+ std::vector<uintptr_t>* stack =
+ static_cast<std::vector<uintptr_t>*>(aClosure);
+ if (stack->size() == MAX_CALL_STACK_PCS) {
+ return;
+ }
+ MOZ_ASSERT(stack->size() < MAX_CALL_STACK_PCS);
+ stack->push_back(reinterpret_cast<uintptr_t>(aPC));
+}
+
+static void
+GetChromeHangReport(Telemetry::ProcessedStack& aStack,
+ int32_t& aSystemUptime,
+ int32_t& aFirefoxUptime)
+{
+ MOZ_ASSERT(winMainThreadHandle);
+
+ // The thread we're about to suspend might have the alloc lock
+ // so allocate ahead of time
+ std::vector<uintptr_t> rawStack;
+ rawStack.reserve(MAX_CALL_STACK_PCS);
+
+ // Workaround possible deadlock where the main thread is running a
+ // long-standing JS job, and happens to be in the JIT allocator when we
+ // suspend it. Since, on win 64, this requires holding a process lock that
+ // MozStackWalk requires, take this "workaround lock" to avoid deadlock.
+#ifdef _WIN64
+ AcquireStackWalkWorkaroundLock();
+#endif
+ DWORD ret = ::SuspendThread(winMainThreadHandle);
+ bool suspended = false;
+ if (ret != -1) {
+ // SuspendThread is asynchronous, so the thread may still be running. Use
+ // GetThreadContext to ensure it's really suspended.
+ // See https://blogs.msdn.microsoft.com/oldnewthing/20150205-00/?p=44743.
+ CONTEXT context;
+ context.ContextFlags = CONTEXT_CONTROL;
+ if (::GetThreadContext(winMainThreadHandle, &context)) {
+ suspended = true;
+ }
+ }
+
+#ifdef _WIN64
+ ReleaseStackWalkWorkaroundLock();
+#endif
+
+ if (!suspended) {
+ if (ret != -1) {
+ MOZ_ALWAYS_TRUE(::ResumeThread(winMainThreadHandle) != DWORD(-1));
+ }
+ return;
+ }
+
+ MozStackWalk(ChromeStackWalker, /* skipFrames */ 0, /* maxFrames */ 0,
+ reinterpret_cast<void*>(&rawStack),
+ reinterpret_cast<uintptr_t>(winMainThreadHandle), nullptr);
+ ret = ::ResumeThread(winMainThreadHandle);
+ if (ret == -1) {
+ return;
+ }
+ aStack = Telemetry::GetStackAndModules(rawStack);
+
+ // Record system uptime (in minutes) at the time of the hang
+ aSystemUptime = ((GetTickCount() / 1000) - (gTimeout * 2)) / 60;
+
+ // Record Firefox uptime (in minutes) at the time of the hang
+ bool error;
+ TimeStamp processCreation = TimeStamp::ProcessCreation(error);
+ if (!error) {
+ TimeDuration td = TimeStamp::Now() - processCreation;
+ aFirefoxUptime = (static_cast<int32_t>(td.ToSeconds()) - (gTimeout * 2)) / 60;
+ } else {
+ aFirefoxUptime = -1;
+ }
+}
+
+#endif
+
+void
+ThreadMain(void*)
+{
+ PR_SetCurrentThreadName("Hang Monitor");
+
+ MonitorAutoLock lock(*gMonitor);
+
+ // In order to avoid issues with the hang monitor incorrectly triggering
+ // during a general system stop such as sleeping, the monitor thread must
+ // run twice to trigger hang protection.
+ PRIntervalTime lastTimestamp = 0;
+ int waitCount = 0;
+
+#ifdef REPORT_CHROME_HANGS
+ Telemetry::ProcessedStack stack;
+ int32_t systemUptime = -1;
+ int32_t firefoxUptime = -1;
+ UniquePtr<HangAnnotations> annotations;
+#endif
+
+ while (true) {
+ if (gShutdown) {
+ return; // Exit the thread
+ }
+
+ // avoid rereading the volatile value in this loop
+ PRIntervalTime timestamp = gTimestamp;
+
+ PRIntervalTime now = PR_IntervalNow();
+
+ if (timestamp != PR_INTERVAL_NO_WAIT &&
+ now < timestamp) {
+ // 32-bit overflow, reset for another waiting period
+ timestamp = 1; // lowest legal PRInterval value
+ }
+
+ if (timestamp != PR_INTERVAL_NO_WAIT &&
+ timestamp == lastTimestamp &&
+ gTimeout > 0) {
+ ++waitCount;
+#ifdef REPORT_CHROME_HANGS
+ // Capture the chrome-hang stack + Firefox & system uptimes after
+ // the minimum hang duration has been reached (not when the hang ends)
+ if (waitCount == 2) {
+ GetChromeHangReport(stack, systemUptime, firefoxUptime);
+ annotations = ChromeHangAnnotatorCallout();
+ }
+#else
+ // This is the crash-on-hang feature.
+ // See bug 867313 for the quirk in the waitCount comparison
+ if (waitCount >= 2) {
+ int32_t delay =
+ int32_t(PR_IntervalToSeconds(now - timestamp));
+ if (delay >= gTimeout) {
+ MonitorAutoUnlock unlock(*gMonitor);
+ Crash();
+ }
+ }
+#endif
+ } else {
+#ifdef REPORT_CHROME_HANGS
+ if (waitCount >= 2) {
+ uint32_t hangDuration = PR_IntervalToSeconds(now - lastTimestamp);
+ Telemetry::RecordChromeHang(hangDuration, stack, systemUptime,
+ firefoxUptime, Move(annotations));
+ stack.Clear();
+ }
+#endif
+ lastTimestamp = timestamp;
+ waitCount = 0;
+ }
+
+ PRIntervalTime timeout;
+ if (gTimeout <= 0) {
+ timeout = PR_INTERVAL_NO_TIMEOUT;
+ } else {
+ timeout = PR_MillisecondsToInterval(gTimeout * 500);
+ }
+ lock.Wait(timeout);
+ }
+}
+
+void
+Startup()
+{
+ if (GeckoProcessType_Default != XRE_GetProcessType() &&
+ GeckoProcessType_Content != XRE_GetProcessType()) {
+ return;
+ }
+
+ MOZ_ASSERT(!gMonitor, "Hang monitor already initialized");
+ gMonitor = new Monitor("HangMonitor");
+
+ Preferences::RegisterCallback(PrefChanged, kHangMonitorPrefName, nullptr);
+ PrefChanged(nullptr, nullptr);
+
+#ifdef REPORT_CHROME_HANGS
+ Preferences::RegisterCallback(PrefChanged, kTelemetryPrefName, nullptr);
+ winMainThreadHandle =
+ OpenThread(THREAD_ALL_ACCESS, FALSE, GetCurrentThreadId());
+ if (!winMainThreadHandle) {
+ return;
+ }
+#endif
+
+ // Don't actually start measuring hangs until we hit the main event loop.
+ // This potentially misses a small class of really early startup hangs,
+ // but avoids dealing with some xpcshell tests and other situations which
+ // start XPCOM but don't ever start the event loop.
+ Suspend();
+
+ gThread = PR_CreateThread(PR_USER_THREAD,
+ ThreadMain,
+ nullptr, PR_PRIORITY_LOW, PR_GLOBAL_THREAD,
+ PR_JOINABLE_THREAD, 0);
+}
+
+void
+Shutdown()
+{
+ if (GeckoProcessType_Default != XRE_GetProcessType() &&
+ GeckoProcessType_Content != XRE_GetProcessType()) {
+ return;
+ }
+
+ MOZ_ASSERT(gMonitor, "Hang monitor not started");
+
+ {
+ // Scope the lock we're going to delete later
+ MonitorAutoLock lock(*gMonitor);
+ gShutdown = true;
+ lock.Notify();
+ }
+
+ // thread creation could theoretically fail
+ if (gThread) {
+ PR_JoinThread(gThread);
+ gThread = nullptr;
+ }
+
+ delete gMonitor;
+ gMonitor = nullptr;
+}
+
+static bool
+IsUIMessageWaiting()
+{
+#ifndef XP_WIN
+ return false;
+#else
+#define NS_WM_IMEFIRST WM_IME_SETCONTEXT
+#define NS_WM_IMELAST WM_IME_KEYUP
+ BOOL haveUIMessageWaiting = FALSE;
+ MSG msg;
+ haveUIMessageWaiting |= ::PeekMessageW(&msg, nullptr, WM_KEYFIRST,
+ WM_IME_KEYLAST, PM_NOREMOVE);
+ haveUIMessageWaiting |= ::PeekMessageW(&msg, nullptr, NS_WM_IMEFIRST,
+ NS_WM_IMELAST, PM_NOREMOVE);
+ haveUIMessageWaiting |= ::PeekMessageW(&msg, nullptr, WM_MOUSEFIRST,
+ WM_MOUSELAST, PM_NOREMOVE);
+ return haveUIMessageWaiting;
+#endif
+}
+
+void
+NotifyActivity(ActivityType aActivityType)
+{
+ MOZ_ASSERT(NS_IsMainThread(),
+ "HangMonitor::Notify called from off the main thread.");
+
+ // Determine the activity type more specifically
+ if (aActivityType == kGeneralActivity) {
+ aActivityType = IsUIMessageWaiting() ? kActivityUIAVail :
+ kActivityNoUIAVail;
+ }
+
+ // Calculate the cumulative amount of lag time since the last UI message
+ static uint32_t cumulativeUILagMS = 0;
+ switch (aActivityType) {
+ case kActivityNoUIAVail:
+ cumulativeUILagMS = 0;
+ break;
+ case kActivityUIAVail:
+ case kUIActivity:
+ if (gTimestamp != PR_INTERVAL_NO_WAIT) {
+ cumulativeUILagMS += PR_IntervalToMilliseconds(PR_IntervalNow() -
+ gTimestamp);
+ }
+ break;
+ default:
+ break;
+ }
+
+ // This is not a locked activity because PRTimeStamp is a 32-bit quantity
+ // which can be read/written atomically, and we don't want to pay locking
+ // penalties here.
+ gTimestamp = PR_IntervalNow();
+
+ // If we have UI activity we should reset the timer and report it
+ if (aActivityType == kUIActivity) {
+ mozilla::Telemetry::Accumulate(mozilla::Telemetry::EVENTLOOP_UI_ACTIVITY_EXP_MS,
+ cumulativeUILagMS);
+ cumulativeUILagMS = 0;
+ }
+
+ if (gThread && !gShutdown) {
+ mozilla::BackgroundHangMonitor().NotifyActivity();
+ }
+}
+
+void
+Suspend()
+{
+ MOZ_ASSERT(NS_IsMainThread(),
+ "HangMonitor::Suspend called from off the main thread.");
+
+ // Because gTimestamp changes this resets the wait count.
+ gTimestamp = PR_INTERVAL_NO_WAIT;
+
+ if (gThread && !gShutdown) {
+ mozilla::BackgroundHangMonitor().NotifyWait();
+ }
+}
+
+} // namespace HangMonitor
+} // namespace mozilla
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