diff options
Diffstat (limited to 'drivers/gpu/drm/ttm/ttm_bo_vm.c')
| -rw-r--r-- | drivers/gpu/drm/ttm/ttm_bo_vm.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index 801231c9ae4..0ce48e5a9cb 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -339,11 +339,13 @@ int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma, vma->vm_private_data = bo; /* - * PFNMAP is faster than MIXEDMAP due to reduced page - * administration. So use MIXEDMAP only if private VMA, where - * we need to support COW. + * We'd like to use VM_PFNMAP on shared mappings, where + * (vma->vm_flags & VM_SHARED) != 0, for performance reasons, + * but for some reason VM_PFNMAP + x86 PAT + write-combine is very + * bad for performance. Until that has been sorted out, use + * VM_MIXEDMAP on all mappings. See freedesktop.org bug #75719 */ - vma->vm_flags |= (vma->vm_flags & VM_SHARED) ? VM_PFNMAP : VM_MIXEDMAP; + vma->vm_flags |= VM_MIXEDMAP; vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; return 0; out_unref: @@ -359,7 +361,7 @@ 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 |= (vma->vm_flags & VM_SHARED) ? VM_PFNMAP : VM_MIXEDMAP; + vma->vm_flags |= VM_MIXEDMAP; vma->vm_flags |= VM_IO | VM_DONTEXPAND; return 0; } |