Memory Reporter State

memory_reporter_state.md

Currently two focuses:

• GetReportsState: roughly the interprocess state, keeps track of which subprocesses need to callled / are running. This is only in the parent process.
• CollectReportsState: intraprocess state, used in runnable, keeps track of which CollectReports calls are pending. This is in all processes and created in GetReportsForThisProcessExtended

  struct GetReportsState                                                                                               
  {
    uint32_t                             mGeneration;                                                                  
    bool                                 mAnonymize;                                                                   
    bool                                 mMinimize;
    nsCOMPtr<nsITimer>                   mTimer;
    nsTArray<nsRefPtr<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;                                                                
  }

  struct CollectReportsState
  {
    uint32_t mReportsPending;
    nsCOMPtr<nsIHandleReportCallback> mHandleReport;
    nsCOMPtr<nsISupports> mHandleReportData;
    nsCOMPtr<nsIFinishReportingCallback> mFinishReporting;
    nsCOMPtr<nsISupports> mFinishReportingData;
    bool mAnonymize;
    FILE* mDMDFile;
  }

Unique to CollectReportsState

Param	Details
mReportsPending	Number of memory reporters that have not yet finished
mDMDFile	GetReportsState has mDMDDumpIdent which is used to open the file. Needs to be stored so that report can be written when all Reporters complete.

Unique to GetReportsState

Param	Details
mGeneration	used to discard old reports from child processes that timed out
mMinimize	stored param, indicates child process should minimize before reporting
mTimer	used to decide if child process has timed out
mChildrenPending	child processes that have not been asked to report yet
mNumProcessesRunning	number of child processes currently reporting
mNumProcessesCompleted	number of child processes that have finished reporting
mConcurrencyLimit	max number of child processes that can report at the same time
mDMDDumpIdent	prefix for DMD file opened for each process

Common

Param	Details
mHandleReport	callback invoked for every measurement
mHandleReportData	user data passed to mHandleReport callback
mFinishReporting	callback invoked when all reports have finished
mFinishReportingData	user data passed to mFinishReporting
mAnonymize	whether or not a reporter should anonymized data