xpcom/base/MemoryTelemetry.h

   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 #ifndef mozilla_MemoryTelemetry_h
   8 #define mozilla_MemoryTelemetry_h
   9
  10 #include "mozilla/TimeStamp.h"
  11 #include "mozilla/Result.h"
  12 #include "nsIObserver.h"
  13 #include "nsITimer.h"
  14 #include "nsTArray.h"
  15 #include "nsWeakReference.h"
  16
  17 #include <functional>
  18
  19 class nsIEventTarget;
  20
  21 namespace mozilla {
  22
  23 namespace ipc {
  24 enum class ResponseRejectReason;
  25 }
  26
  27 /**
  28  * Periodically gathers memory usage metrics after cycle collection, and
  29  * populates telemetry histograms with their values.
  30  */
  31 class MemoryTelemetry final : public nsIObserver,
  32                               public nsSupportsWeakReference {
  33  public:
  34   NS_DECL_ISUPPORTS
  35   NS_DECL_NSIOBSERVER
  36
  37   static MemoryTelemetry& Get();
  38
  39   nsresult GatherReports(
  40       const std::function<void()>& aCompletionCallback = nullptr);
  41
  42   void GetUniqueSetSize(std::function<void(const int64_t&)>&& aCallback);
  43
  44   /**
  45    * Does expensive initialization, which should happen only after startup has
  46    * completed, and the event loop is idle.
  47    */
  48   nsresult DelayedInit();
  49
  50   nsresult Shutdown();
  51
  52  private:
  53   MemoryTelemetry();
  54
  55   ~MemoryTelemetry() = default;
  56
  57   void Init();
  58
  59   static Result<uint32_t, nsresult> GetOpenTabsCount();
  60
  61   class TotalMemoryGatherer final : public nsITimerCallback {
  62    public:
  63     NS_DECL_THREADSAFE_ISUPPORTS
  64     NS_DECL_NSITIMERCALLBACK
  65
  66     TotalMemoryGatherer() = default;
  67
  68     void CollectParentSize(int64_t aResident);
  69     void CollectResult(int64_t aChildUSS);
  70     void OnFailure(ipc::ResponseRejectReason aReason);
  71
  72     void Begin(nsIEventTarget* aThreadPool);
  73
  74    private:
  75     ~TotalMemoryGatherer() = default;
  76
  77     nsresult MaybeFinish();
  78
  79     nsCOMPtr<nsITimer> mTimeout;
  80
  81     nsTArray<int64_t> mChildSizes;
  82
  83     int64_t mTotalMemory = 0;
  84     uint32_t mRemainingChildCount = 0;
  85
  86     bool mHaveParentSize = false;
  87   };
  88
  89   nsCOMPtr<nsIEventTarget> mThreadPool;
  90   RefPtr<TotalMemoryGatherer> mTotalMemoryGatherer;
  91
  92   TimeStamp mLastPoll{};
  93 };
  94
  95 }  // namespace mozilla
  96
  97 #endif  // defined mozilla_MemoryTelemetry_h