[Sbcl-help] GENCGC-PAGE-SIZE maxed out?

[Benjamin L. <ben...@cm...>]

Dear SBCL people,

I use SBCL frequently at Carnegie Mellon.  We use it mostly for our  
knowledge representation system, Scone, developed by Scott Fahlman, an  
old CMUCL Lisper.

I recently came across a new problem, and I'm not seeing anything in  
the mailing list history.

We're running on an x86-64 Linux machine with 8GB of RAM.  One person  
in our group was getting error #1 below when he used more than around  
1GB of memory.  So, I tried recompiling SBCL (1.0.22) a few times with  
greater values for GENCGC-PAGE-SIZE.  Each time I increased it, he'd  
get error #1 eventually, each time after more memory had been used.   
After bumping this up to 32768, he was getting error #1 at around 6GB  
of RAM used.

I tried increasing it once more, first to 64k, then back down to  
49152.  When I compile with GENCGC-PAGE-SIZE set to either,  
compilation terminates with error #2.  (The main part of this error  
message seems to be this: GC invariant lost, file "gencgc.c", line  
4503).

Is it possible to increase GENCGC-PAGE-SIZE even more?  If so, is that  
desirable?  What exactly is  GENCGC-PAGE-SIZE?

Ben Lambert


Error #1:

fatal error encountered in SBCL pid 18893:
An mprotect call failed with ENOMEM. This probably means that the  
maximum amount
of separate memory mappings was exceeded. To fix the problem, either  
increase
the maximum with e.g. 'echo 262144 > /proc/sys/vm/max_map_count' or  
recompile
SBCL with a larger value for GENCGC-PAGE-SIZE in 'src/target/ 
parms.lisp'.
Welcome to LDB, a low-level debugger for the Lisp runtime environment.

Error #2:

beginning GENESIS, creating core "output/cold-sbcl.core"
obj/from-xc/src/code/show.lisp-obj
....
obj/from-xc/src/code/late-defbangmethod.lisp-obj
obj/from-xc/src/pcl/walk.lisp-obj
[building initial core file in "output/cold-sbcl.core":
writing 8192 bytes [2 pages] from #<SB!FASL::GSPACE :READ-ONLY>
writing 4096 bytes [1 page] from #<SB!FASL::GSPACE :STATIC>
writing 51998720 bytes [12695 pages] from #<SB!FASL::GSPACE :DYNAMIC>
/(DESCRIPTOR-BITS INITIAL-FUN)=#X1002993D19
done]
* //testing for consistency of first and second GENESIS passes
//header files match between first and second GENESIS -- good

real	13m0.960s
user	4m32.852s
sys	0m9.967s
//entering make-target-2.sh
//doing warm init - compilation phase
fatal error encountered in SBCL pid 16153:
GC invariant lost, file "gencgc.c", line 4503


--
Benjamin Lambert
Graduate Student of Computer Science
Carnegie Mellon University
www.cs.cmu.edu/~belamber