https://bugs.winehq.org/show_bug.cgi?id=48172
--- Comment #5 from Artem S. Tashkinov aros@gmx.com --- (In reply to Stefan Dösinger from comment #4)
A 32 bit process has only 4GB of available address space no matter how much physical RAM you have. Even if you have less than that a process can theoretically alloc 4 GB, it might just lead to heavy swapping.
My PC currently has 64GB of RAM with usually over 60GB free.
If you want 1.5 gb continuous memory it is vital that the free space is not fragmented. Windows (and thus wine) have a fixed allocation around 2gb at 0x7ffe0000 (KSHARED_USER_DATA), so you won't be able to get an allocation > 2GB no matter what. The area below 2 GB is sprinkled with Windows DLLs at fixed load addresses. The area above 2 GB will likely have a pile of Linux libs loaded. Address space layout randomization (a security feature) is likely to sprinkle libs everywhere.
/proc/<pid>/maps shows you what is loaded where. I guess disable ASLR will help, at the cost of making your system more vulnerable to buffer overflow attacks. On 32 bit Windows ASLR is somewhat limited because many windows libs have a hardcoded load address and applications depend on it.
Is it the same for 32bit and 64bit host OS'es? I'm running a 64bit Linux distro, so seemingly there should be no troubles with 32bit memory allocations. I'd prefer to leave all default protections in place.