Bad maximum heap size on large initial heap

[UltimatePea]

In an attempt to work around issue #604, running libgc complied program with env GC_INITIAL_HEAP_SIZE=100G results in the following error on the latest master.

GC Warning: Bad maximum heap size 68719476736 - ignoring it.
Can't start up: not enough memory

[ivmai]

I can't reproduce it on master (Linux, 64-bit).

GC_INITIAL_HEAP_SIZE=100G GC_PRINT_STATS=1 ./gctest
Supported VDBs: manual soft mprotect
Using soft-dirty bit feature
In-use heap: 0% (0 KiB pointers + 0 KiB other)
Grow heap to 104857600 KiB after 0 bytes allocated

[UltimatePea]

GC_INITIAL_HEAP_SIZE=100G ./gctest
Supported VDBs: manual soft mprotect
GC Warning: Bad maximum heap size 68719476736 - ignoring
Switched to incremental mode
Emulating dirty bits with mprotect/signals
Completed 6 tests
Allocated 11792895 collectable objects
Allocated 1224 uncollectable objects
Allocated 720438 atomic objects
Reallocated 36 objects
Garbage collection after fork is tested too
Finalized 13393/13393 objects - finalization is probably OK
Total number of bytes allocated is 1154623152
Total memory use by allocated blocks is 3457024 bytes
Final heap size is 659456 bytes
Unexpected heap growth - collector may be broken (heapsize: 107382521856, expected: 159383552)
Test failed
fish: Job 1, 'GC_INITIAL_HEAP_SIZE=100G ./gct…' terminated by signal SIGABRT (Abort)

Strange. I am suspecting that this may be related to WSL2. I am trying a genuine linux installation.

[ivmai]

I think the root cause of this is that GC_MAXIMUM_HEAP_SIZE environment variable is defined somewhere else to a value which is smaller than GC_INITIAL_HEAP_SIZE, thus you are getting a warning that the initial size value is greater than the maximum one.

[ivmai]

"Can't start up: not enough memory" means libgc can't allocate the amount of memory given in GC_INITIAL_HEAP_SIZE.