Commit b2041425 authored Dec 04, 2019 by Thomas Hellstrom

drm/vmwgfx: Use VM_PFNMAP instead of VM_MIXEDMAP when possible

For shared, and read-only private mappings of graphics memory, use
VM_PFNMAP instead of VM_MIXEDMAP. This means less accounting overhead
when inserting and removing page-table entries. TTM doesn't do this
by default, since there was a performance problem with book-keeping of
write-combined mappings. Since vmwgfx solely uses cached mappings, that's
not a problem and now that the TTM vm has largely been turned into
helpers, we can use VM_PFNMAP on a per-driver basis

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>

parent 61780dd7

drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,10 @@ int vmw_mmap(struct file filp, struct vm_area_struct vma)

		vma->vm_ops = &vmw_vm_ops;

		/* Use VM_PFNMAP rather than VM_MIXEDMAP if not a COW mapping */
		if ((vma->vm_flags & (VM_SHARED \| VM_MAYWRITE)) != VM_MAYWRITE)
		vma->vm_flags = (vma->vm_flags & ~VM_MIXEDMAP) \| VM_PFNMAP;

		return 0;
		}

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