Virtual GEM Is Coming For Linux 4.1

There's already been a fair amount of code building up for the DRM graphics subsystem for the Linux 4.1 kernel and a new feature was just committed to Git last night.

Virtual GEM (vGEM) is coming! VGEM can increase Mesa's software rasterizer performance and this fake GEM memory management support was devised by a Google engineer, Zach Reizner.

Reizer's patch has been committed to DRM-Next, meaning it will land in mainline for the Linux 4.1 kernel merge window. The patch explains, "This patch implements the virtual GEM driver with PRIME sharing which allows vgem to import a gem object from other drivers for the purpose of mmap-ing them to userspace. The mmap is done using the mmap operation exported by other drivers."

This virtual GEM provider adds just over 500 lines of new code to the kernel's DRM subsystem. The DRM_VGEM option adds, "Choose this option to get a virtual graphics memory manager, as used by Mesa's software renderer for enhanced performance. If M is selected the module will be called vgem."