cvs commit: fptools/ghc/includes Regs.h StgMacros.h StgMiscClosures.h StgStorage.h Updates.h mkNativeHdr.c fptools/ghc/rts GC.c HeapStackCheck.hc Interpreter.c Linker.c PrimOps.hc RtsStartup.c Schedule.c Schedule.h StgMiscClosures.hc ...

Thu, 8 Nov 2001 04:46:32 -0800

simonmar    2001/11/08 04:46:32 PST

  Modified files:
    ghc/includes         Regs.h StgMacros.h StgMiscClosures.h 
                         StgStorage.h Updates.h mkNativeHdr.c 
    ghc/rts              GC.c HeapStackCheck.hc Interpreter.c 
                         Linker.c PrimOps.hc RtsStartup.c 
                         Schedule.c Schedule.h StgMiscClosures.hc 
                         StgStdThunks.hc Storage.c StoragePriv.h 
                         Updates.hc 
  Removed files:
    ghc/rts              HeapStackCheck.h 
  Log:
  Fix the large block allocation bug (Yay!)
  -----------------------------------------

  In order to do this, I had to

   1. in each heap-check failure branch, return the amount of heap
      actually requested, in a known location (I added another slot
      in StgRegTable called HpAlloc for this purpose).  This is
      useful for other reasons - in particular it makes it possible
      to get accurate allocation statistics.

   2. In the scheduler, if a heap check fails and we wanted more than
      BLOCK_SIZE_W words, then allocate a special large block and place
      it in the nursery.  The nursery now has to be double-linked so
      we can insert the new block in the middle.

   3. The garbage collector has to be able to deal with multiple objects
      in a large block.  It turns out that this isn't a problem as long as
      the large blocks only occur in the nursery, because we always copy
      objects from the nursery during GC.  One small change had to be
      made: in evacuate(), we may need to follow the link field from the
      block descriptor to get to the block descriptor for the head of a
      large block.

   4. Various other parts of the storage manager had to be modified
      to cope with a nursery containing a mixture of block sizes.

  Point (3) causes a slight pessimization in the garbage collector.  I
  don't see a way to avoid this.  Point (1) causes some code bloat (a
  rough measurement is around 5%), so to offset this I made the
  following change which I'd been meaning to do for some time:

    - Store the values of some commonly-used absolute addresses
      (eg. stg_update_PAP) in the register table.  This lets us use
      shorter instruction forms for some absolute jumps and saves some
      code space.

    - The type of Capability is no longer the same as an StgRegTable.
      MainRegTable renamed to MainCapability.  See Regs.h for details.

  Other minor changes:

    - remove individual declarations for the heap-check-failure jump
      points, and declare them all in StgMiscClosures.h instead.  Remove
      HeapStackCheck.h.

  Updates to the native code generator to follow.

  Revision  Changes    Path
  1.10      +74 -7     fptools/ghc/includes/Regs.h
  1.39      +17 -17    fptools/ghc/includes/StgMacros.h
  1.40      +58 -1     fptools/ghc/includes/StgMiscClosures.h
  1.11      +2 -2      fptools/ghc/includes/StgStorage.h
  1.25      +3 -3      fptools/ghc/includes/Updates.h
  1.6       +18 -1     fptools/ghc/includes/mkNativeHdr.c
  1.126     +9 -1      fptools/ghc/rts/GC.c
  1.18      +8 -7      fptools/ghc/rts/HeapStackCheck.hc
  1.31      +19 -19    fptools/ghc/rts/Interpreter.c
  1.73      +16 -16    fptools/ghc/rts/Linker.c
  1.84      +1 -2      fptools/ghc/rts/PrimOps.hc
  1.55      +4 -4      fptools/ghc/rts/RtsStartup.c
  1.105     +91 -32    fptools/ghc/rts/Schedule.c
  1.23      +2 -7      fptools/ghc/rts/Schedule.h
  1.69      +1 -2      fptools/ghc/rts/StgMiscClosures.hc
  1.17      +3 -4      fptools/ghc/rts/StgStdThunks.hc
  1.53      +42 -28    fptools/ghc/rts/Storage.c
  1.19      +2 -2      fptools/ghc/rts/StoragePriv.h
  1.35      +2 -3      fptools/ghc/rts/Updates.hc