[Vm-dev] Why spaceOkay test needed?
mathk.sue at gmail.com
Thu Aug 23 22:52:29 UTC 2007
So #sufficientSpaceToInstantiate:indexableSize: call can be removed?
On Aug 20, 2007, at 6:37 PM, Andreas Raab wrote:
> Adrian Lienhard wrote:
>> 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
> Where does it do that?
>> Both, the primitive fallback code and the vm code signal the low
>> space sem in case of failure.
> The fallback code in the image is broken IMO. It needs to signal
> OutOfMemory instead of the low space semaphore. We had our servers
> go belly-up because of malformed requests that requested a 1
> gigabyte or more memory.
> - Andreas
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