DRM TTM Hugepage Support Lands In Linux 5.7

The work led by VMware on allowing the Direct Rendering Manager's TTM memory management code support huge page tables has been added to Linux 5.7.

This is the work by VMware initially for their VMWgfx driver but also of relevance to other DRM drivers employing TTM for supporting huge and giant page-table entries. This TTM hugepages support is intended to reduce CPU usage and lower TLB misses. Under a VMware test program just doing some example memory mapping and unmapping, the time to execute was about halved.

This DRM TTM hugepage support was merged. For Linux 5.7 just the VMware VMWGFX driver is employing this new capability while with time the other TTM-based drivers like AMDGPU will likely hook into it as well.

This pull came in secondary to the main DRM pull request with all of the other graphics/display driver improvements for Linux 5.7.