pleriche / FastMM5

FastMM is a fast replacement memory manager for Embarcadero Delphi applications that scales well across multiple threads and CPU cores, is not prone to memory fragmentation, and supports shared memory without the use of external .DLL files.
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Possible error or defect #50

Open sezuk opened 7 months ago

sezuk commented 7 months ago

In the function FastMM_GetMem_GetLargeBlock

    {Insert the block in the first available arena.}
    while True do
    begin

      LPLargeBlockManager := @LargeBlockManagers[0];
      for LArenaIndex := 0 to CFastMM_LargeBlockArenaCount - 1 do
      begin

        if (LPLargeBlockManager.LargeBlockManagerLocked = 0)
          and (AtomicExchange(LPLargeBlockManager.LargeBlockManagerLocked, 1) = 0) then
        begin
          PLargeBlockHeader(Result).LargeBlockManager := LPLargeBlockManager;

          {Insert the large block into the linked list of large blocks}
          LOldFirstLargeBlock := LPLargeBlockManager.FirstLargeBlockHeader;
          PLargeBlockHeader(Result).PreviousLargeBlockHeader := Pointer(LPLargeBlockManager);
          LPLargeBlockManager.FirstLargeBlockHeader := Result;
          PLargeBlockHeader(Result).NextLargeBlockHeader := LOldFirstLargeBlock;
          LOldFirstLargeBlock.PreviousLargeBlockHeader := Result;

          LPLargeBlockManager.LargeBlockManagerLocked := 0;

          {Add the size of the header}
          Inc(PByte(Result), CLargeBlockHeaderSize);

          Exit;
        end;

        {Try the next arena.}
        Inc(LPLargeBlockManager);
      end;

    end;

    {All large block managers are locked:  Back off and try again.}
    LogLargeBlockThreadContentionAndYieldToOtherThread;

The call to LogLargeBlockThreadContentionAndYieldToOtherThread must be inside a loop, otherwise it will never reach it.

pleriche commented 7 months ago

Fixed. Thank you!