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

[Nicolas Bertolotti]

It seems that the segmentation fault actually corresponds to a different bug.

Here is the end of the log I get using the "gc-messages" flag:
...
[GC: Reading heap at 0x563cb000 of size 1,746,532,092 bytes from disk.]
[GC: Translating heap at 0x55719000 of size 0 bytes from 0x563cb000.]
[GC: Finished gc #160; time 28,789 ms,]
[GC:    heap at 0x55719000 of size 1,760,493,568 bytes,]
[GC:    with nursery of size 880,246,784 bytes (50.0% of heap),]
[GC:    and old-gen of size 0 bytes (0.0% of heap).]
/bin/sh: line 33: 25040 Segmentation fault
...

Still investigating ...

Nicolas

> -----Original Message-----
> From: mlton-bounces at mlton.org [mailto:mlton-bounces at mlton.org] On Behalf
> Of Nicolas Bertolotti
> Sent: Tuesday, April 22, 2008 1:40 AM
> To: Matthew Fluet
> Cc: mlton at mlton.org
> Subject: RE: [MLton] Crash fread(...) failed (only read 0) (Cannot
> allocate memory) during deepFlatten with MLton 20070826
>
> Thanks for the answer.
>
> I applied the patch and tried to rebuild.
>
> Unfortunately, here is what I get now:
>             deepFlatten starting
> /bin/sh: line 33: 26073 Segmentation fault      ./lock-exec.x86-linux
> /tmp/MLton-build.lock /mathworks/GNB/hub/pst/build-tools-R2008b-
> testing/bin/mlton -cc-opt -D_UNIX -align 4 -verbose 2 -const
> 'TextIO.bufSize 65536' -const 'MLton.detectOverflow false' -runtime no-
> load-world -native-split 100000 -cc-opt -s -native-optimize 3 -cc-opt -O2
> -cc-opt -funroll-loops -cc-opt -ffast-math -cc-opt -fomit-frame-pointer -
> cc-opt -fno-exceptions -cc-opt -fexpensive-optimizations -cc-opt -freg-
> struct-return -cc-opt -unroll-all-loops -target i686-pc-linux -link-opt -
> L. -link-opt -lz -output iabc-dfa.cx86-linux sources.mlb MLton_ffi.c
> $EXTRA_C_FILES
>
> I am still investigating but you may know what's going on.
>
> Nicolas
>
> > -----Original Message-----
> > From: Matthew Fluet [mailto:fluet at tti-c.org]
> > Sent: Monday, April 21, 2008 2:00 AM
> > To: Matthew Fluet
> > Cc: Nicolas Bertolotti; mlton at mlton.org
> > Subject: Re: [MLton] Crash fread(...) failed (only read 0) (Cannot
> > allocate memory) during deepFlatten with MLton 20070826
> >
> > On Sun, 20 Apr 2008, Matthew Fluet wrote:
> > > It occurs when the runtime system decides to page the heap to disk in
> > order
> > > to free up virtual memory to reallocate the heap at a larger size.
> > > It will do this if the desired heap size is approaching the physical
> > memory
> > > limit, even if there is plenty of swap space available on the machine.
> >
> > Actually, this isn't right.  The runtime will attempt to page to disk
> only
> > if creating a heap of the minimum size cannot be satisfied with the
> > existing heap resident.
> >
> > It is curious that your program compiles without paging the heap to disk
> > on the 4G machine, but not on the 2G machine, since the virtual memory
> > address space should be the same on the two machines.  That is, the
> amount
> > of physical memory shouldn't affect whether the virtual memory system is
> > able to satisfy the request.
> >
> > Of course, starting off with different physical memory sizes means that
> > different heap sizes will be realized by the compile on the two
> machines,
> > so the point at which the paging occurs on the 2G machine may not
> > correspond to any GC on the 4G machine.
>
>
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