VM_PFNMAP is faster than VM_MIXEDMAP due to reduced page administration so
use it for shared maps where we don't have any Copy-On-Write pages. For
private maps, we continue to use VM_MIXEDMAP.
This might also help a bit for bo mmap dirty tracking, if implemented,
depending on the used interface.
Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
---
drivers/gpu/drm/ttm/ttm_bo_vm.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index ac617f3..05f4bd9 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -206,7 +206,11 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma,
struct vm_fault *vmf)
pfn = page_to_pfn(page);
}
- ret = vm_insert_mixed(&cvma, address, pfn);
+ if (vma->vm_flags & VM_MIXEDMAP)
+ ret = vm_insert_mixed(&cvma, address, pfn);
+ else
+ ret = vm_insert_pfn(&cvma, address, pfn);
+
/*
* Somebody beat us to this PTE or prefaulting to
* an already populated PTE, or prefaulting error.
@@ -303,9 +307,15 @@ int ttm_bo_mmap(struct file *filp, struct vm_area_struct
*vma,
* Note: We're transferring the bo reference to
* vma->vm_private_data here.
*/
-
vma->vm_private_data = bo;
- vma->vm_flags |= VM_IO | VM_MIXEDMAP | VM_DONTEXPAND | VM_DONTDUMP;
+
+ /*
+ * PFNMAP is faster than MIXEDMAP due to reduced page
+ * administration. So use MIXEDMAP only if private VMA, where
+ * we need to support COW.
+ */
+ vma->vm_flags |= (vma->vm_flags & VM_SHARED) ? VM_PFNMAP : VM_MIXEDMAP;
+ vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
return 0;
out_unref:
ttm_bo_unref(&bo);
@@ -320,7 +330,8 @@ int ttm_fbdev_mmap(struct vm_area_struct *vma, struct
ttm_buffer_object *bo)
vma->vm_ops = &ttm_bo_vm_ops;
vma->vm_private_data = ttm_bo_reference(bo);
- vma->vm_flags |= VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
+ vma->vm_flags |= (vma->vm_flags & VM_SHARED) ? VM_PFNMAP : VM_MIXEDMAP;
+ vma->vm_flags |= VM_IO | VM_DONTEXPAND;
return 0;
}
EXPORT_SYMBOL(ttm_fbdev_mmap);
--
1.7.10.4
