From: Gerd Hoffmann <kraxel@redhat.com>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: dri-devel@lists.freedesktop.org, David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
open list <linux-kernel@vger.kernel.org>,
Huang Rui <ray.huang@amd.com>,
Christian Koenig <christian.koenig@amd.com>
Subject: Re: [PATCH 4/8] drm/ttm: factor out ttm_bo_mmap_vma_setup
Date: Tue, 17 Sep 2019 10:34:25 +0200 [thread overview]
Message-ID: <20190917083425.kwwqyn463gn3mghf@sirius.home.kraxel.org> (raw)
In-Reply-To: <88d5a253-ef9e-c998-6353-5ba8680129f2@suse.de>
On Fri, Sep 13, 2019 at 03:05:34PM +0200, Thomas Zimmermann wrote:
> > +void ttm_bo_mmap_vma_setup(struct ttm_buffer_object *bo, struct vm_area_struct *vma)
> > +{
> > + vma->vm_ops = &ttm_bo_vm_ops;
> > +
> > + /*
> > + * Note: We're transferring the bo reference to
> > + * vma->vm_private_data here.
> > + */
> > +
> > + vma->vm_private_data = bo;
> > +
> > + /*
> > + * 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 |= VM_MIXEDMAP;
> > + vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
> > +}
> > +EXPORT_SYMBOL(ttm_bo_mmap_vma_setup);
>
> To me, this function looks like an internal helper that should rather
> remain internal.
Well, I'm moving that to a helper exactly to avoid drm gem ttm helpers
messing with ttm internals. To not them initialize vm_flags for
example, and to avoid exporting ttm_bo_vm_ops. Also to make sure ttm bo
vma's are initialized the same way no matter which code path was taken
to mmap the object.
> As mentioned in my reply to patch 5, maybe re-using
> ttm_fbdev_mmap() could help.
No, the check in that function prevents that from working.
cheers,
Gerd
next prev parent reply other threads:[~2019-09-17 8:34 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190913122908.784-1-kraxel@redhat.com>
2019-09-13 12:29 ` [PATCH 1/8] drm: add mmap() to drm_gem_object_funcs Gerd Hoffmann
2019-09-17 13:27 ` Daniel Vetter
2019-09-13 12:29 ` [PATCH 2/8] drm/shmem: switch shmem helper to &drm_gem_object_funcs.mmap Gerd Hoffmann
2019-09-13 14:03 ` Steven Price
2019-09-17 8:14 ` Gerd Hoffmann
2019-09-13 12:29 ` [PATCH 3/8] drm/shmem: drop DEFINE_DRM_GEM_SHMEM_FOPS Gerd Hoffmann
2019-09-16 22:07 ` Rob Herring
2019-09-17 8:18 ` Gerd Hoffmann
2019-09-13 12:29 ` [PATCH 4/8] drm/ttm: factor out ttm_bo_mmap_vma_setup Gerd Hoffmann
2019-09-13 12:56 ` Thomas Zimmermann
2019-09-17 8:26 ` Gerd Hoffmann
2019-09-13 13:05 ` Thomas Zimmermann
2019-09-17 8:34 ` Gerd Hoffmann [this message]
2019-09-17 9:38 ` Thomas Zimmermann
2019-09-17 9:54 ` Gerd Hoffmann
2019-09-13 12:29 ` [PATCH 5/8] drm/ttm: add drm_gem_ttm_mmap() Gerd Hoffmann
2019-09-13 13:02 ` Thomas Zimmermann
2019-09-13 12:29 ` [PATCH 6/8] drm/vram: switch vram helper to &drm_gem_object_funcs.mmap() Gerd Hoffmann
2019-09-13 13:10 ` Thomas Zimmermann
2019-09-13 12:29 ` [PATCH 7/8] drm/vram: drop verify_access Gerd Hoffmann
2019-09-13 13:11 ` Thomas Zimmermann
2019-09-13 12:29 ` [PATCH 8/8] drm/vram: drop DRM_VRAM_MM_FILE_OPERATIONS Gerd Hoffmann
2019-09-13 13:18 ` Thomas Zimmermann
2019-09-17 8:39 ` Gerd Hoffmann
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