[Vm-dev] VM Maker: VMMaker.oscog-eem.469.mcz

[Frank Shearar]

On 21 Oct 2013, at 8:18, commits at source.squeak.org wrote:

> 
> Eliot Miranda uploaded a new version of VMMaker to project VM Maker:
> http://source.squeak.org/VMMaker/VMMaker.oscog-eem.469.mcz
> 
> ==================== Summary ====================
> 
> Name: VMMaker.oscog-eem.469
> Author: eem
> Time: 20 October 2013, 5:15:49.893 pm
> UUID: 9a1b817f-2cee-487a-8c07-6444e28a16aa
> Ancestors: VMMaker.oscog-eem.468
> 
> Rethink the sorting of free space for exact-fit compact post global
> GC.  Since the sweep to free unmarked objects is linear through old
> space it can also sort free space.  So
> freeUnmarkedObjectsAndNilUnmarkedWeaklingSlots =>
> freeUnmarkedObjectsNilUnmarkedWeaklingSlotsAndSortAndCoallesceFreeSpace (glup ;-) ).
> 

At the risk of being a pain, you need to coalesce the two l's in 'coallesce'.

frank

> Make sure that bridges are marked so they won't be freed in
> fUONUWASACFS.
> 
> Add freeChunkPrevIndex to link next nodes to their precedessors
> so that free chunks can be quickly removed during coallescing.
> 
> Implement an iterative freeTreeNodesDo: so that Slang can inline the
> block arguments to it.
> 
> Refactor the code that removes a tree node in
> allocateOldSpaceChunkOfBytes: et al, out into
> unlinkSolitaryFreeTreeNode:
> 
> Still have to reverse small list heads post-sweep and account for free space properly.
> 
> =============== Diff against VMMaker.oscog-eem.468 ===============
> 
> Item was added:
> + ----- Method: Spur32BitMemoryManager>>coallesce:and: (in category 'gc - global') -----
> + coallesce: obj1 and: obj2
> +    | header1NumSlots header2NumSlots obj2slots newNumSlots |
> +    header1NumSlots := self rawNumSlotsOf: obj1.
> +    header2NumSlots := self rawNumSlotsOf: obj2.
> + 
> +    "compute total number of slots in obj2, including header"
> +    obj2slots := header2NumSlots = self numSlotsMask
> +                    ifTrue: [(self longAt: obj2 - self baseHeaderSize) + (2 * self baseHeaderSize / self wordSize)]
> +                    ifFalse: [(header2NumSlots = 0 ifTrue: [1] ifFalse: [header2NumSlots]) + (self baseHeaderSize / self wordSize)].
> +    obj2slots := obj2slots + (obj2slots bitAnd: 1).
> +    self assert: obj2slots * self wordSize = (self bytesInObject: obj2).
> + 
> +    "if obj1 already has a double header things are simple..."
> +    header1NumSlots = self numSlotsMask ifTrue:
> +        [self longAt: obj1  - self baseHeaderSize put: obj2slots + (self longAt: obj1 - self baseHeaderSize).
> +         ^obj1].
> + 
> +    "compute total number of slots in obj1, excluding header"
> +    header1NumSlots := header1NumSlots = 0
> +                            ifTrue: [2]
> +                            ifFalse: [header1NumSlots + (header1NumSlots bitAnd: 1)].
> +    self assert: header1NumSlots * self wordSize + self baseHeaderSize = (self bytesInObject: obj1).
> +    newNumSlots := obj2slots + header1NumSlots.
> + 
> +    "if obj1 still only requires a single header things are simple..."
> +    newNumSlots < self numSlotsMask ifTrue:
> +        [self byteAt: obj1 + (self numSlotsFullShift / BitsPerByte)
> +            put: newNumSlots.
> +         ^obj1].
> + 
> +    "convert from single to double header..."
> +    newNumSlots := newNumSlots - (self baseHeaderSize / self wordSize).
> +    self longAt: obj1 + self baseHeaderSize
> +            put: (self longAt: obj1);
> +        longAt: obj1 + 4 + self baseHeaderSize
> +            put: ((self longAt: obj1 + 4) bitOr: self numSlotsMask << self numSlotsHalfShift).
> +    self longAt: obj1
> +            put: newNumSlots.
> +    self longAt: obj1 + 4
> +            put: self numSlotsMask << self numSlotsHalfShift.
> +    ^obj1 + self baseHeaderSize!
> 
> Item was changed:
>  ----- Method: Spur32BitMemoryManager>>initSegmentBridgeWithBytes:at: (in category 'segments') -----
>  initSegmentBridgeWithBytes: numBytes at: address
>      <var: #numBytes type: #usqLong>
>      | numSlots |
>      "must have room for a double header"
>      self assert: (numBytes \\ self allocationUnit = 0
>                   and: [numBytes >= (self baseHeaderSize + self baseHeaderSize)]).
>      self flag: #endianness.
>      numSlots := numBytes - self baseHeaderSize - self baseHeaderSize >> self shiftForWord.
>      self longAt: address put: numSlots;
>          longAt: address + 4 put: self numSlotsMask << self numSlotsHalfShift;
>          longAt: address + 8 put: (1 << self pinnedBitShift)
>                                  + (self wordIndexableFormat << self formatShift)
>                                  + self segmentBridgePun;
> +        longAt: address + 12 put: self numSlotsMask << self numSlotsHalfShift
> +                                + (1 << self markedBitHalfShift)!
> -            longAt: address + 12 put: self numSlotsMask << self numSlotsHalfShift!
> 
> Item was removed:
> - ----- Method: Spur32BitMemoryManager>>reInitSegmentBridge: (in category 'segments') -----
> - reInitSegmentBridge: bridgeOop
> -    "On image write the segment manager replaces the header of the bridge
> -     with the size of the following segment.  This method restores that header."
> -    <var: #numBytes type: #usqLong>
> -    self longAt: bridgeOop put: (1 << self pinnedBitShift)
> -                                + (self wordIndexableFormat << self formatShift)
> -                                + self segmentBridgePun;
> -            longAt: bridgeOop + 4 put: self numSlotsMask << self numSlotsHalfShift!
> 
> Item was added:
> + ----- Method: Spur32BitMemoryManager>>sortedFreeObject: (in category 'free space') -----
> + sortedFreeObject: objOop
> +    "A variant of freeObject: that assumes objOop already has its valid number of slots, etc,
> +     but makes sure the freeChunkPrevIndex is valid."
> +    | bytes treeNode nextNode |
> +    bytes := self bytesInObject: objOop.
> +    totalFreeOldSpace := totalFreeOldSpace + bytes.
> +    self longAt: objOop put: 0.
> +    treeNode := self addToFreeList: objOop bytes: bytes.
> +    treeNode ~= 0 ifTrue:
> +        [self storePointer: self freeChunkPrevIndex ofFreeChunk: objOop withValue: treeNode].
> +    nextNode := self fetchPointer: self freeChunkNextIndex ofObject: objOop.
> +    nextNode ~= 0 ifTrue:
> +        [self storePointer: self freeChunkPrevIndex ofFreeChunk: nextNode withValue: objOop]!
> 
> Item was changed:
>  ----- Method: Spur64BitMemoryManager>>initSegmentBridgeWithBytes:at: (in category 'segments') -----
>  initSegmentBridgeWithBytes: numBytes at: address
>      | numSlots |
>      <var: #numBytes type: #usqLong>
>      self assert: (numBytes >= (self baseHeaderSize + self baseHeaderSize)
>              and: [numBytes \\ self allocationUnit = 0]).
>      numSlots := numBytes - self baseHeaderSize - self baseHeaderSize >> self shiftForWord.
>      self longAt: address
>              put: self numSlotsMask << self numSlotsFullShift + numSlots;
>          longAt: address + self baseHeaderSize
>              put: (self numSlotsMask << self numSlotsFullShift)
>                  + (1 << self pinnedBitShift)
>