Global Regions

The 64-bit kernel provides kernel extensions with the capability to create global regions within the kernel address space. Once created, a region is globally accessible to all kernel code until it is destroyed. Regions may be created with unique characteristics, for example, page protection, that suit kernel extension requirements and are different from the global virtual memory allocated from the kernel_heap.

Global regions are also useful for kernel extensions that in the past have organized their data around virtual memory segments and require sizes and alignments that are inappropriate for the kernel heap. Under the 64-bit kernel, this memory can be provided through global regions rather than separate virtual memory segments, thus avoiding the complexity and performance cost of temporarily attaching virtual memory segments.

Global regions are created and destroyed with the vm_galloc and vm_gfree kernel services.