Created attachment 47022 [details]
Wine identifies 200MB out of 30GB of available userland memory

Occasionally when attempting to run Skyrim (or other memory intensive programs) through Wine on OS X, a "Memory Error: Not enough memory to run application" popup will appear and the program will exit.

Simple workarounds: logging out and back in, rebooting.

I believe this is caused by GlobalMemoryStatusEx() in kernel32/heap.c returning wildly incorrect values (see the attached log for an example from a system with 32GB of memory - most of it available).

On OS X and BSDs, GlobalMemoryStatusEx() still gets the total system memory (ullTotalPhys) by asking sysctl() for the value of HW_PHYSMEM, which is capped at 2GB. The available system memory (ullAvailPhys) is determined by asking sysctl() for HW_USERMEM, which is also apparently 32-bit and overflows dreadfully. On OS X,  Wine temporarily stores both values in an unsigned int.

I recompiled kernel32.dll.so using HW_MEMSIZE in place of HW_PHYSMEM and a kludged value for ullAvailPhys; Skyrim now runs reliably. The example patch will also be attached for anyone who can reproduce this issue.