[Vm-dev] Why spaceOkay test needed?

Adrian Lienhard adi at netstyle.ch
Mon Aug 20 16:21:47 UTC 2007

Out of curiosity, does anybody know why in...

	"Allocate a new fixed-size instance. Fail if the allocation would  
leave less than lowSpaceThreshold bytes free. May cause a GC"
	| class spaceOkay |
	class := self stackTop.
	"The following may cause GC!"
	spaceOkay := self sufficientSpaceToInstantiate: class indexableSize: 0.
	self success: spaceOkay.
	successFlag ifTrue: [ self push: (self instantiateClass: self  
popStack indexableSize: 0) ]

... there is the call to #sufficientSpaceToInstantiate:indexableSize:  
although #instantiateClass:indexableSize: also indirectly calls  
Both, the primitive fallback code and the vm code signal the low  
space sem in case of failure.


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