xpcom/threads/SchedulerGroup.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/SchedulerGroup.h"
   8
   9 #include <utility>
  10
  11 #include "jsfriendapi.h"
  12 #include "mozilla/Atomics.h"
  13 #include "mozilla/Telemetry.h"
  14 #include "mozilla/Unused.h"
  15 #include "mozilla/dom/DocGroup.h"
  16 #include "mozilla/dom/ScriptSettings.h"
  17 #include "nsINamed.h"
  18 #include "nsQueryObject.h"
  19 #include "nsThreadUtils.h"
  20
  21 using namespace mozilla;
  22
  23 namespace {
  24
  25 static Atomic<uint64_t> gEarliestUnprocessedVsync(0);
  26
  27 }  // namespace
  28
  29 /* static */
  30 nsresult SchedulerGroup::UnlabeledDispatch(
  31     TaskCategory aCategory, already_AddRefed<nsIRunnable>&& aRunnable) {
  32   if (NS_IsMainThread()) {
  33     return NS_DispatchToCurrentThread(std::move(aRunnable));
  34   } else {
  35     return NS_DispatchToMainThread(std::move(aRunnable));
  36   }
  37 }
  38
  39 /* static */
  40 void SchedulerGroup::MarkVsyncReceived() {
  41   // May be called on any thread when a vsync is received and scheduled to be
  42   // processed. This may occur on the main thread due to queued messages when
  43   // the channel is connected.
  44   TimeStamp creation = TimeStamp::ProcessCreation();
  45
  46   // Attempt to set gEarliestUnprocessedVsync to our new value. If we've seen a
  47   // vsync already, but haven't handled it, the `compareExchange` will fail and
  48   // the static won't be updated.
  49   uint64_t unprocessedVsync =
  50       uint64_t((TimeStamp::Now() - creation).ToMicroseconds());
  51   gEarliestUnprocessedVsync.compareExchange(0, unprocessedVsync);
  52 }
  53
  54 /* static */
  55 void SchedulerGroup::MarkVsyncRan() { gEarliestUnprocessedVsync = 0; }
  56
  57 SchedulerGroup::SchedulerGroup() : mIsRunning(false) {}
  58
  59 /* static */
  60 nsresult SchedulerGroup::Dispatch(TaskCategory aCategory,
  61                                   already_AddRefed<nsIRunnable>&& aRunnable) {
  62   return LabeledDispatch(aCategory, std::move(aRunnable), nullptr);
  63 }
  64
  65 /* static */
  66 nsresult SchedulerGroup::LabeledDispatch(
  67     TaskCategory aCategory, already_AddRefed<nsIRunnable>&& aRunnable,
  68     mozilla::PerformanceCounter* aPerformanceCounter) {
  69   nsCOMPtr<nsIRunnable> runnable(aRunnable);
  70   if (XRE_IsContentProcess()) {
  71     RefPtr<Runnable> internalRunnable =
  72         new Runnable(runnable.forget(), aPerformanceCounter);
  73     return InternalUnlabeledDispatch(aCategory, internalRunnable.forget());
  74   }
  75   return UnlabeledDispatch(aCategory, runnable.forget());
  76 }
  77
  78 /*static*/
  79 nsresult SchedulerGroup::InternalUnlabeledDispatch(
  80     TaskCategory aCategory, already_AddRefed<Runnable>&& aRunnable) {
  81   if (NS_IsMainThread()) {
  82     // NS_DispatchToCurrentThread will not leak the passed in runnable
  83     // when it fails, so we don't need to do anything special.
  84     return NS_DispatchToCurrentThread(std::move(aRunnable));
  85   }
  86
  87   RefPtr<Runnable> runnable(aRunnable);
  88   nsresult rv = NS_DispatchToMainThread(do_AddRef(runnable));
  89   if (NS_FAILED(rv)) {
  90     // Dispatch failed.  This is a situation where we would have used
  91     // NS_DispatchToMainThread rather than calling into the SchedulerGroup
  92     // machinery, and the caller would be expecting to leak the nsIRunnable
  93     // originally passed in.  But because we've had to wrap things up
  94     // internally, we were going to leak the nsIRunnable *and* our Runnable
  95     // wrapper.  But there's no reason that we have to leak our Runnable
  96     // wrapper; we can just leak the wrapped nsIRunnable, and let the caller
  97     // take care of unleaking it if they need to.
  98     Unused << runnable->mRunnable.forget().take();
  99     nsrefcnt refcnt = runnable.get()->Release();
 100     MOZ_RELEASE_ASSERT(refcnt == 1, "still holding an unexpected reference!");
 101   }
 102
 103   return rv;
 104 }
 105
 106 SchedulerGroup::Runnable::Runnable(
 107     already_AddRefed<nsIRunnable>&& aRunnable,
 108     mozilla::PerformanceCounter* aPerformanceCounter)
 109     : mozilla::Runnable("SchedulerGroup::Runnable"),
 110       mRunnable(std::move(aRunnable)),
 111       mPerformanceCounter(aPerformanceCounter) {}
 112
 113 mozilla::PerformanceCounter* SchedulerGroup::Runnable::GetPerformanceCounter()
 114     const {
 115   return mPerformanceCounter;
 116 }
 117
 118 #ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
 119 NS_IMETHODIMP
 120 SchedulerGroup::Runnable::GetName(nsACString& aName) {
 121   // Try to get a name from the underlying runnable.
 122   nsCOMPtr<nsINamed> named = do_QueryInterface(mRunnable);
 123   if (named) {
 124     named->GetName(aName);
 125   }
 126   if (aName.IsEmpty()) {
 127     aName.AssignLiteral("anonymous");
 128   }
 129
 130   return NS_OK;
 131 }
 132 #endif
 133
 134 NS_IMETHODIMP
 135 SchedulerGroup::Runnable::Run() {
 136   MOZ_RELEASE_ASSERT(NS_IsMainThread());
 137   // The runnable's destructor can have side effects, so try to execute it in
 138   // the scope of the SchedulerGroup.
 139   nsCOMPtr<nsIRunnable> runnable(std::move(mRunnable));
 140   return runnable->Run();
 141 }
 142
 143 NS_IMETHODIMP
 144 SchedulerGroup::Runnable::GetPriority(uint32_t* aPriority) {
 145   *aPriority = nsIRunnablePriority::PRIORITY_NORMAL;
 146   nsCOMPtr<nsIRunnablePriority> runnablePrio = do_QueryInterface(mRunnable);
 147   return runnablePrio ? runnablePrio->GetPriority(aPriority) : NS_OK;
 148 }
 149
 150 NS_IMPL_ISUPPORTS_INHERITED(SchedulerGroup::Runnable, mozilla::Runnable,
 151                             nsIRunnablePriority, SchedulerGroup::Runnable)