[MLton] Crash fread(...) failed (only read 0) (Cannot allocate memory) during deepFlatten with MLton 20070826

[Matthew Fluet]

On Wed, 30 Apr 2008, Nicolas Bertolotti wrote:
> I actually made some experiments using the attached "ugly" patch which 
> does not really allocate both areas but basically ensures that the 
> card/cross map allocation succeeds after the heap is allocated.
>
> It consists in allocating enough bytes for the heap and the card/cross 
> map with mmap() each time a heap is allocated. Then, it immediately runs 
> remap() in order to release the bytes that correspond to the card/cross 
> map. The consequence is that, when it is necessary to allocate a new 
> card/cross map after that, it always works.
>
> I was wondering whether it would be possible to do something in the same 
> "spirit" rather than merging the heap and the card/cross map.

Not all platforms have mremap (I believe we only use it on linux).  And I 
doubt that there is a guarantee that if you mremap from N bytes to M 
bytes, that you will necessarily be able to mmap N-M bytes.  Same 
thing goes if you munmap the N-M bytes.  I imagine that it would be less 
complicated to merge the heap and card/cross map.