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Diffstat (limited to 'xpcom/base/nsMemoryReporterManager.h')
| -rw-r--r-- | xpcom/base/nsMemoryReporterManager.h | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/xpcom/base/nsMemoryReporterManager.h b/xpcom/base/nsMemoryReporterManager.h new file mode 100644 index 000000000..8240cbe34 --- /dev/null +++ b/xpcom/base/nsMemoryReporterManager.h @@ -0,0 +1,288 @@ +/* -*- 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/. */ + +#ifndef nsMemoryReporterManager_h__ +#define nsMemoryReporterManager_h__ + +#include "mozilla/Mutex.h" +#include "nsHashKeys.h" +#include "nsIMemoryReporter.h" +#include "nsITimer.h" +#include "nsServiceManagerUtils.h" +#include "nsTHashtable.h" + +namespace mozilla { +namespace dom { +class ContentParent; +class MemoryReport; +} // namespace dom +} // namespace mozilla + +class nsITimer; + +class nsMemoryReporterManager final : public nsIMemoryReporterManager +{ + virtual ~nsMemoryReporterManager(); + +public: + NS_DECL_THREADSAFE_ISUPPORTS + NS_DECL_NSIMEMORYREPORTERMANAGER + + nsMemoryReporterManager(); + + // Gets the memory reporter manager service. + static nsMemoryReporterManager* GetOrCreate() + { + nsCOMPtr<nsIMemoryReporterManager> imgr = + do_GetService("@mozilla.org/memory-reporter-manager;1"); + return static_cast<nsMemoryReporterManager*>(imgr.get()); + } + + typedef nsDataHashtable<nsRefPtrHashKey<nsIMemoryReporter>, bool> StrongReportersTable; + typedef nsDataHashtable<nsPtrHashKey<nsIMemoryReporter>, bool> WeakReportersTable; + + // Inter-process memory reporting proceeds as follows. + // + // - GetReports() (declared within NS_DECL_NSIMEMORYREPORTERMANAGER) + // synchronously gets memory reports for the current process, sets up some + // state (mPendingProcessesState) for when child processes report back -- + // including a timer -- and starts telling child processes to get memory + // reports. Control then returns to the main event loop. + // + // The number of concurrent child process reports is limited by the pref + // "memory.report_concurrency" in order to prevent the memory overhead of + // memory reporting from causing problems, especially on B2G when swapping + // to compressed RAM; see bug 1154053. + // + // - HandleChildReport() is called (asynchronously) once per child process + // reporter callback. + // + // - EndProcessReport() is called (asynchronously) once per process that + // finishes reporting back, including the parent. If all processes do so + // before time-out, the timer is cancelled. If there are child processes + // whose requests have not yet been sent, they will be started until the + // concurrency limit is (again) reached. + // + // - TimeoutCallback() is called (asynchronously) if all the child processes + // don't respond within the time threshold. + // + // - FinishReporting() finishes things off. It is *always* called -- either + // from EndChildReport() (if all child processes have reported back) or + // from TimeoutCallback() (if time-out occurs). + // + // All operations occur on the main thread. + // + // The above sequence of steps is a "request". A partially-completed request + // is described as "in flight". + // + // Each request has a "generation", a unique number that identifies it. This + // is used to ensure that each reports from a child process corresponds to + // the appropriate request from the parent process. (It's easier to + // implement a generation system than to implement a child report request + // cancellation mechanism.) + // + // Failures are mostly ignored, because it's (a) typically the most sensible + // thing to do, and (b) often hard to do anything else. The following are + // the failure cases of note. + // + // - If a request is made while the previous request is in flight, the new + // request is ignored, as per getReports()'s specification. No error is + // reported, because the previous request will complete soon enough. + // + // - If one or more child processes fail to respond within the time limit, + // things will proceed as if they don't exist. No error is reported, + // because partial information is better than nothing. + // + // - If a child process reports after the time-out occurs, it is ignored. + // (Generation checking will ensure it is ignored even if a subsequent + // request is in flight; this is the main use of generations.) No error + // is reported, because there's nothing sensible to be done about it at + // this late stage. + // + // - If the time-out occurs after a child process has sent some reports but + // before it has signaled completion (see bug 1151597), then what it + // successfully sent will be included, with no explicit indication that it + // is incomplete. + // + // Now, what what happens if a child process is created/destroyed in the + // middle of a request? Well, PendingProcessesState is initialized with an array + // of child process actors as of when the report started. So... + // + // - If a process is created after reporting starts, it won't be sent a + // request for reports. So the reported data will reflect how things were + // when the request began. + // + // - If a process is destroyed before it starts reporting back, the reported + // data will reflect how things are when the request ends. + // + // - If a process is destroyed after it starts reporting back but before it + // finishes, the reported data will contain a partial report for it. + // + // - If a process is destroyed after reporting back, but before all other + // child processes have reported back, it will be included in the reported + // data. So the reported data will reflect how things were when the + // request began. + // + // The inconsistencies between these cases are unfortunate but difficult to + // avoid. It's enough of an edge case to not be worth doing more. + // + void HandleChildReport(uint32_t aGeneration, + const mozilla::dom::MemoryReport& aChildReport); + void EndProcessReport(uint32_t aGeneration, bool aSuccess); + + // Functions that (a) implement distinguished amounts, and (b) are outside of + // this module. + struct AmountFns + { + mozilla::InfallibleAmountFn mJSMainRuntimeGCHeap; + mozilla::InfallibleAmountFn mJSMainRuntimeTemporaryPeak; + mozilla::InfallibleAmountFn mJSMainRuntimeCompartmentsSystem; + mozilla::InfallibleAmountFn mJSMainRuntimeCompartmentsUser; + + mozilla::InfallibleAmountFn mImagesContentUsedUncompressed; + + mozilla::InfallibleAmountFn mStorageSQLite; + + mozilla::InfallibleAmountFn mLowMemoryEventsVirtual; + mozilla::InfallibleAmountFn mLowMemoryEventsPhysical; + + mozilla::InfallibleAmountFn mGhostWindows; + + AmountFns() + { + mozilla::PodZero(this); + } + }; + AmountFns mAmountFns; + + // Convenience function to get RSS easily from other code. This is useful + // when debugging transient memory spikes with printf instrumentation. + static int64_t ResidentFast(); + + // Convenience function to get peak RSS easily from other code. + static int64_t ResidentPeak(); + + // Convenience function to get USS easily from other code. This is useful + // when debugging unshared memory pages for forked processes. + static int64_t ResidentUnique(); + + // Functions that measure per-tab memory consumption. + struct SizeOfTabFns + { + mozilla::JSSizeOfTabFn mJS; + mozilla::NonJSSizeOfTabFn mNonJS; + + SizeOfTabFns() + { + mozilla::PodZero(this); + } + }; + SizeOfTabFns mSizeOfTabFns; + +private: + MOZ_MUST_USE nsresult + RegisterReporterHelper(nsIMemoryReporter* aReporter, + bool aForce, bool aStrongRef, bool aIsAsync); + + MOZ_MUST_USE nsresult StartGettingReports(); + // No MOZ_MUST_USE here because ignoring the result is common and reasonable. + nsresult FinishReporting(); + + void DispatchReporter(nsIMemoryReporter* aReporter, bool aIsAsync, + nsIHandleReportCallback* aHandleReport, + nsISupports* aHandleReportData, + bool aAnonymize); + + static void TimeoutCallback(nsITimer* aTimer, void* aData); + // Note: this timeout needs to be long enough to allow for the + // possibility of DMD reports and/or running on a low-end phone. + static const uint32_t kTimeoutLengthMS = 50000; + + mozilla::Mutex mMutex; + bool mIsRegistrationBlocked; + + StrongReportersTable* mStrongReporters; + WeakReportersTable* mWeakReporters; + + // These two are only used for testing purposes. + StrongReportersTable* mSavedStrongReporters; + WeakReportersTable* mSavedWeakReporters; + + uint32_t mNextGeneration; + + // Used to keep track of state of which processes are currently running and + // waiting to run memory reports. Holds references to parameters needed when + // requesting a memory report and finishing reporting. + struct PendingProcessesState + { + uint32_t mGeneration; + bool mAnonymize; + bool mMinimize; + nsCOMPtr<nsITimer> mTimer; + nsTArray<RefPtr<mozilla::dom::ContentParent>> mChildrenPending; + uint32_t mNumProcessesRunning; + uint32_t mNumProcessesCompleted; + uint32_t mConcurrencyLimit; + nsCOMPtr<nsIHandleReportCallback> mHandleReport; + nsCOMPtr<nsISupports> mHandleReportData; + nsCOMPtr<nsIFinishReportingCallback> mFinishReporting; + nsCOMPtr<nsISupports> mFinishReportingData; + nsString mDMDDumpIdent; + + PendingProcessesState(uint32_t aGeneration, bool aAnonymize, bool aMinimize, + uint32_t aConcurrencyLimit, + nsIHandleReportCallback* aHandleReport, + nsISupports* aHandleReportData, + nsIFinishReportingCallback* aFinishReporting, + nsISupports* aFinishReportingData, + const nsAString& aDMDDumpIdent); + }; + + // Used to keep track of the state of the asynchronously run memory + // reporters. The callback and file handle used when all memory reporters + // have finished are also stored here. + struct PendingReportersState + { + // Number of memory reporters currently running. + uint32_t mReportsPending; + + // Callback for when all memory reporters have completed. + nsCOMPtr<nsIFinishReportingCallback> mFinishReporting; + nsCOMPtr<nsISupports> mFinishReportingData; + + // File handle to write a DMD report to if requested. + FILE* mDMDFile; + + PendingReportersState(nsIFinishReportingCallback* aFinishReporting, + nsISupports* aFinishReportingData, + FILE* aDMDFile) + : mReportsPending(0) + , mFinishReporting(aFinishReporting) + , mFinishReportingData(aFinishReportingData) + , mDMDFile(aDMDFile) + { + } + }; + + // When this is non-null, a request is in flight. Note: We use manual + // new/delete for this because its lifetime doesn't match block scope or + // anything like that. + PendingProcessesState* mPendingProcessesState; + + // This is reinitialized each time a call to GetReports is initiated. + PendingReportersState* mPendingReportersState; + + PendingProcessesState* GetStateForGeneration(uint32_t aGeneration); + static MOZ_MUST_USE bool + StartChildReport(mozilla::dom::ContentParent* aChild, + const PendingProcessesState* aState); +}; + +#define NS_MEMORY_REPORTER_MANAGER_CID \ +{ 0xfb97e4f5, 0x32dd, 0x497a, \ +{ 0xba, 0xa2, 0x7d, 0x1e, 0x55, 0x7, 0x99, 0x10 } } + +#endif // nsMemoryReporterManager_h__ |