[Intel-gfx] [PATCH 1/3] drm: Update GEM refcounting docs
Daniel Vetter
daniel at ffwll.ch
Thu Oct 22 12:46:10 PDT 2015
On Thu, Oct 22, 2015 at 01:54:17PM -0400, Alex Deucher wrote:
> On Thu, Oct 22, 2015 at 1:11 PM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > I just realized that I've forgotten to update all the gem refcounting
> > docs. For pennance also add pretty docs for the overall drm_gem_object
> > structure, with a few links thrown in fore good.
> >
> > As usually we need to make sure the kerneldoc reference is at most a
> > sect2 for otherwise it won't be listed.
> >
> > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
>
> Patches 1 and 3 are:
> Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
Thanks, applied to drm-misc.
-Daniel
>
> > ---
> > Documentation/DocBook/gpu.tmpl | 15 +++---
> > include/drm/drm_gem.h | 106 +++++++++++++++++++++++++++++++++++------
> > 2 files changed, 100 insertions(+), 21 deletions(-)
> >
> > diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl
> > index 90c2aab31269..6c5865bb5ee8 100644
> > --- a/Documentation/DocBook/gpu.tmpl
> > +++ b/Documentation/DocBook/gpu.tmpl
> > @@ -635,10 +635,10 @@ char *date;</synopsis>
> > acquired and release by <function>calling drm_gem_object_reference</function>
> > and <function>drm_gem_object_unreference</function> respectively. The
> > caller must hold the <structname>drm_device</structname>
> > - <structfield>struct_mutex</structfield> lock. As a convenience, GEM
> > - provides the <function>drm_gem_object_reference_unlocked</function> and
> > - <function>drm_gem_object_unreference_unlocked</function> functions that
> > - can be called without holding the lock.
> > + <structfield>struct_mutex</structfield> lock when calling
> > + <function>drm_gem_object_reference</function>. As a convenience, GEM
> > + provides <function>drm_gem_object_unreference_unlocked</function>
> > + functions that can be called without holding the lock.
> > </para>
> > <para>
> > When the last reference to a GEM object is released the GEM core calls
> > @@ -836,10 +836,11 @@ char *date;</synopsis>
> > abstracted from the client in libdrm.
> > </para>
> > </sect3>
> > - <sect3>
> > - <title>GEM Function Reference</title>
> > + </sect2>
> > + <sect2>
> > + <title>GEM Function Reference</title>
> > !Edrivers/gpu/drm/drm_gem.c
> > - </sect3>
> > +!Iinclude/drm/drm_gem.h
> > </sect2>
> > <sect2>
> > <title>VMA Offset Manager</title>
> > diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
> > index 15e7f007380f..0b3e11ab8757 100644
> > --- a/include/drm/drm_gem.h
> > +++ b/include/drm/drm_gem.h
> > @@ -35,76 +35,129 @@
> > */
> >
> > /**
> > - * This structure defines the drm_mm memory object, which will be used by the
> > - * DRM for its buffer objects.
> > + * struct drm_gem_object - GEM buffer object
> > + *
> > + * This structure defines the generic parts for GEM buffer objects, which are
> > + * mostly around handling mmap and userspace handles.
> > + *
> > + * Buffer objects are often abbreviated to BO.
> > */
> > struct drm_gem_object {
> > - /** Reference count of this object */
> > + /**
> > + * @refcount:
> > + *
> > + * Reference count of this object
> > + *
> > + * Please use drm_gem_object_reference() to acquire and
> > + * drm_gem_object_unreference() or drm_gem_object_unreference_unlocked()
> > + * to release a reference to a GEM buffer object.
> > + */
> > struct kref refcount;
> >
> > /**
> > - * handle_count - gem file_priv handle count of this object
> > + * @handle_count:
> > + *
> > + * This is the GEM file_priv handle count of this object.
> > *
> > * Each handle also holds a reference. Note that when the handle_count
> > * drops to 0 any global names (e.g. the id in the flink namespace) will
> > * be cleared.
> > *
> > * Protected by dev->object_name_lock.
> > - * */
> > + */
> > unsigned handle_count;
> >
> > - /** Related drm device */
> > + /**
> > + * @dev: DRM dev this object belongs to.
> > + */
> > struct drm_device *dev;
> >
> > - /** File representing the shmem storage */
> > + /**
> > + * @filp:
> > + *
> > + * SHMEM file node used as backing storage for swappable buffer objects.
> > + * GEM also supports driver private objects with driver-specific backing
> > + * storage (contiguous CMA memory, special reserved blocks). In this
> > + * case @filp is NULL.
> > + */
> > struct file *filp;
> >
> > - /* Mapping info for this object */
> > + /**
> > + * @vma_node:
> > + *
> > + * Mapping info for this object to support mmap. Drivers are supposed to
> > + * allocate the mmap offset using drm_gem_create_mmap_offset(). The
> > + * offset itself can be retrieved using drm_vma_node_offset_addr().
> > + *
> > + * Memory mapping itself is handled by drm_gem_mmap(), which also checks
> > + * that userspace is allowed to access the object.
> > + */
> > struct drm_vma_offset_node vma_node;
> >
> > /**
> > + * @size:
> > + *
> > * Size of the object, in bytes. Immutable over the object's
> > * lifetime.
> > */
> > size_t size;
> >
> > /**
> > + * @name:
> > + *
> > * Global name for this object, starts at 1. 0 means unnamed.
> > - * Access is covered by the object_name_lock in the related drm_device
> > + * Access is covered by dev->object_name_lock. This is used by the GEM_FLINK
> > + * and GEM_OPEN ioctls.
> > */
> > int name;
> >
> > /**
> > - * Memory domains. These monitor which caches contain read/write data
> > + * @read_domains:
> > + *
> > + * Read memory domains. These monitor which caches contain read/write data
> > * related to the object. When transitioning from one set of domains
> > * to another, the driver is called to ensure that caches are suitably
> > - * flushed and invalidated
> > + * flushed and invalidated.
> > */
> > uint32_t read_domains;
> > +
> > + /**
> > + * @write_domain: Corresponding unique write memory domain.
> > + */
> > uint32_t write_domain;
> >
> > /**
> > + * @pending_read_domains:
> > + *
> > * While validating an exec operation, the
> > * new read/write domain values are computed here.
> > * They will be transferred to the above values
> > * at the point that any cache flushing occurs
> > */
> > uint32_t pending_read_domains;
> > +
> > + /**
> > + * @pending_write_domain: Write domain similar to @pending_read_domains.
> > + */
> > uint32_t pending_write_domain;
> >
> > /**
> > - * dma_buf - dma buf associated with this GEM object
> > + * @dma_buf:
> > + *
> > + * dma-buf associated with this GEM object.
> > *
> > * Pointer to the dma-buf associated with this gem object (either
> > * through importing or exporting). We break the resulting reference
> > * loop when the last gem handle for this object is released.
> > *
> > - * Protected by obj->object_name_lock
> > + * Protected by obj->object_name_lock.
> > */
> > struct dma_buf *dma_buf;
> >
> > /**
> > - * import_attach - dma buf attachment backing this object
> > + * @import_attach:
> > + *
> > + * dma-buf attachment backing this object.
> > *
> > * Any foreign dma_buf imported as a gem object has this set to the
> > * attachment point for the device. This is invariant over the lifetime
> > @@ -133,12 +186,30 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
> > struct vm_area_struct *vma);
> > int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma);
> >
> > +/**
> > + * drm_gem_object_reference - acquire a GEM BO reference
> > + * @obj: GEM buffer object
> > + *
> > + * This acquires additional reference to @obj. It is illegal to call this
> > + * without already holding a reference. No locks required.
> > + */
> > static inline void
> > drm_gem_object_reference(struct drm_gem_object *obj)
> > {
> > kref_get(&obj->refcount);
> > }
> >
> > +/**
> > + * drm_gem_object_unreference - release a GEM BO reference
> > + * @obj: GEM buffer object
> > + *
> > + * This releases a reference to @obj. Callers must hold the dev->struct_mutex
> > + * lock when calling this function, even when the driver doesn't use
> > + * dev->struct_mutex for anything.
> > + *
> > + * For drivers not encumbered with legacy locking use
> > + * drm_gem_object_unreference_unlocked() instead.
> > + */
> > static inline void
> > drm_gem_object_unreference(struct drm_gem_object *obj)
> > {
> > @@ -149,6 +220,13 @@ drm_gem_object_unreference(struct drm_gem_object *obj)
> > }
> > }
> >
> > +/**
> > + * drm_gem_object_unreference_unlocked - release a GEM BO reference
> > + * @obj: GEM buffer object
> > + *
> > + * This releases a reference to @obj. Callers must not hold the
> > + * dev->struct_mutex lock when calling this function.
> > + */
> > static inline void
> > drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
> > {
> > --
> > 2.5.1
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
More information about the Intel-gfx
mailing list