Re: [Linaro-mm-sig] [PATCHv4 12/12] staging/android: Update Ion TODO list

[Laurent Pinchart]

Hi Daniel,

On Wednesday 19 Apr 2017 10:36:55 Daniel Vetter wrote:
> On Tue, Apr 18, 2017 at 11:27:14AM -0700, Laura Abbott wrote:
> > Most of the items have been taken care of by a clean up series. Remove
> > the completed items and add a few new ones.
> > 
> > Signed-off-by: Laura Abbott 
> > ---
> > 
> >  drivers/staging/android/TODO | 21 -
> >  1 file changed, 4 insertions(+), 17 deletions(-)
> > 
> > diff --git a/drivers/staging/android/TODO b/drivers/staging/android/TODO
> > index 8f3ac37..5f14247 100644
> > --- a/drivers/staging/android/TODO
> > +++ b/drivers/staging/android/TODO
> > 
> > @@ -7,23 +7,10 @@ TODO:
> >  ion/
> > 
> > - - Remove ION_IOC_SYNC: Flushing for devices should be purely a kernel
> > internal -   interface on top of dma-buf. flush_for_device needs to be
> > added to dma-buf -   first.
> > - - Remove ION_IOC_CUSTOM: Atm used for cache flushing for cpu access in
> > some -   vendor trees. Should be replaced with an ioctl on the dma-buf to
> > expose the -   begin/end_cpu_access hooks to userspace.
> > - - Clarify the tricks ion plays with explicitly managing coherency behind
> > the -   dma api's back (this is absolutely needed for high-perf gpu
> > drivers): Add an -   explicit coherency management mode to
> > flush_for_device to be used by drivers -   which want to manage caches
> > themselves and which indicates whether cpu caches -   need flushing.
> > - - With those removed there's probably no use for ION_IOC_IMPORT anymore
> > either -   since ion would just be the central allocator for shared
> > buffers. - - Add dt-binding to expose cma regions as ion heaps, with the
> > rule that any -   such cma regions must already be used by some device
> > for dma. I.e. ion only -   exposes existing cma regions and doesn't
> > reserve unecessarily memory when -   booting a system which doesn't use
> > ion.
> > + - Add dt-bindings for remaining heaps (chunk and carveout heaps). This
> > would +   involve putting appropriate bindings in a memory node for Ion
> > to find. + - Split /dev/ion up into multiple nodes (e.g. /dev/ion/heap0)
> > + - Better test framework (integration with VGEM was suggested)
> 
> Found another one: Integrate the ion kernel-doc into
> Documenation/gpu/ion.rst and link it up within Documenation/gpu/index.rst.

If ion is a generic-purpose allocator, should its documentation really reside 
in Documentation/gpu/ ?

> There's a lot of api and overview stuff already around, would be great to
> make this more accessible.
> 
> But I wouldn't put this as a de-staging blocker, just an idea.
> 
> On the series: Acked-by: Daniel Vetter 
> 
> No full review since a bunch of stuff I'm not too familiar with, but I
> like where this is going.
> -Daniel
> 
> >  Please send patches to Greg Kroah-Hartman  and Cc:
> >  Arve Hjønnevåg  and Riley Andrews
> >  

-- 
Regards,

Laurent Pinchart

Re: [Linaro-mm-sig] [PATCHv4 12/12] staging/android: Update Ion TODO list

[Daniel Vetter]

On Tue, Apr 18, 2017 at 11:27:14AM -0700, Laura Abbott wrote:
> Most of the items have been taken care of by a clean up series. Remove
> the completed items and add a few new ones.
> 
> Signed-off-by: Laura Abbott 
> ---
>  drivers/staging/android/TODO | 21 -
>  1 file changed, 4 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/staging/android/TODO b/drivers/staging/android/TODO
> index 8f3ac37..5f14247 100644
> --- a/drivers/staging/android/TODO
> +++ b/drivers/staging/android/TODO
> @@ -7,23 +7,10 @@ TODO:
>  
>  
>  ion/
> - - Remove ION_IOC_SYNC: Flushing for devices should be purely a kernel 
> internal
> -   interface on top of dma-buf. flush_for_device needs to be added to dma-buf
> -   first.
> - - Remove ION_IOC_CUSTOM: Atm used for cache flushing for cpu access in some
> -   vendor trees. Should be replaced with an ioctl on the dma-buf to expose 
> the
> -   begin/end_cpu_access hooks to userspace.
> - - Clarify the tricks ion plays with explicitly managing coherency behind the
> -   dma api's back (this is absolutely needed for high-perf gpu drivers): Add 
> an
> -   explicit coherency management mode to flush_for_device to be used by 
> drivers
> -   which want to manage caches themselves and which indicates whether cpu 
> caches
> -   need flushing.
> - - With those removed there's probably no use for ION_IOC_IMPORT anymore 
> either
> -   since ion would just be the central allocator for shared buffers.
> - - Add dt-binding to expose cma regions as ion heaps, with the rule that any
> -   such cma regions must already be used by some device for dma. I.e. ion 
> only
> -   exposes existing cma regions and doesn't reserve unecessarily memory when
> -   booting a system which doesn't use ion.
> + - Add dt-bindings for remaining heaps (chunk and carveout heaps). This would
> +   involve putting appropriate bindings in a memory node for Ion to find.
> + - Split /dev/ion up into multiple nodes (e.g. /dev/ion/heap0)
> + - Better test framework (integration with VGEM was suggested)

Found another one: Integrate the ion kernel-doc into
Documenation/gpu/ion.rst and link it up within Documenation/gpu/index.rst.
There's a lot of api and overview stuff already around, would be great to
make this more accessible.

But I wouldn't put this as a de-staging blocker, just an idea.

On the series: Acked-by: Daniel Vetter 

No full review since a bunch of stuff I'm not too familiar with, but I
like where this is going.
-Daniel

>  
>  Please send patches to Greg Kroah-Hartman  and Cc:
>  Arve Hjønnevåg  and Riley Andrews 
> -- 
> 2.7.4
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch