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

[Eliot Miranda]

On Mon, Oct 21, 2013 at 12:25 AM, Frank Shearar <frank.shearar at gmail.com>wrote:

>
>
> 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'.
>

Phew, thanks!  Now
freeUnmarkedObjectsNilUnmarkedWeaklingSlotsAndSortAndCoalesceFreeSpace is
one character shorter ;-).

This is the complete opposite of a pain.  Thank you both, Frank and Henry!


>
> 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)
> >
>



-- 
best,
Eliot
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