https://bugs.winehq.org/show_bug.cgi?id=44375
--- Comment #20 from William Pierce dpierce1983@hotmail.com --- Empirically trying out __GL_DevShmPageableAllocations=2, I can see that the [anon] mappings increase for an OGL app that tries to do tons of allocations. [anon] mappings are those used for stack and heap allocations, so the driver is paging those [anon] mappings it's using out.
However, in https://github.com/doitsujin/dxvk/issues/1318, the problem case is with mappings against nvidiactl. For those, the driver is directly mmap'ing system memory VA space it gets from vm_insert_page into the address space rather than using the glibc functions, so it shows up as VA space against nvidiactl rather than [anon] mappings.
The apps afflicted in this wine bug probably do benefit from the __GL_DevShmPageableAllocations feature implemented in the Nvidia drivers and probably makes some of the repro cases go away on Nvidia HW/SW.
That makes sense.. But even if memory was swapped out to /dev/shm, shouldn't that have been measurable?
It is measurable -- in the size of /dev/shm, rather than the VA space.
Also, I'm not sure if "__GL_DevShmPageableAllocations" also applies to Vulkan or only to OpenGL.
It doesn't seem to have any effect setting it to some different values when using Vulkan.
If some users report that this wine bug still exists, I'd be curious what my pmap parsing output from https://github.com/doitsujin/dxvk/issues/1318#issuecomment-574464662 shows (with some modifications to the script for whatever game it is).