[Mesa-dev] [PATCH] anv: change BLOCK_POOL_MEMFD_SIZE to exactly 2GB

[Eero Tamminen]

HI,

On 09.03.2017 13:28, Tapani Pälli wrote:
...
> We had some discussion today with Eero and came to conclusion that maybe
> that 2GB is actually too big for 32bit system anyway and should consider
> to have even smaller block pool size in this case? Or should I just send
> a patch that adds '- 1' to ftruncate call? Opinions?

Vulkan driver taking 2GB out of application address space, doesn't leave 
that much for rest of the memory mappings, if the application itself 
would want to mmap() some large data files.

Address pointer size limits address space for user space processes to 
4GB, and at least earlier, last 1GB was reserved for kernel mode, i.e. 
there's only 3GB of user-space addressable memory:
	https://lwn.net/Articles/75174/


	- Eero