Re: [PATCH] drm/ttm: Don't evict BOs outside of the requested placement range

["Michel Dänzer" <michel@daenzer.net>]

On 12.10.2014 05:24, Greg KH wrote:
> On Sat, Oct 11, 2014 at 08:31:49PM +0200, Daniel Vetter wrote:
>> On Fri, Oct 10, 2014 at 05:59:19PM +0900, Michel Dänzer wrote:
>>> On 10.10.2014 17:51, Alan Swanson wrote:
>>>> On Fri, 2014-10-10 at 12:20 +0900, Michel Dänzer wrote:
>>>>> On 09.10.2014 19:22, Alan Swanson wrote:
>>>>>> On 2014-10-09 07:02, Michel Dänzer wrote:
>>>>>>> From: Michel Dänzer <michel.daenzer@amd.com>
>>>>>>>
>>>>>>> The radeon driver uses placement range restrictions for several reasons,
>>>>>>> in particular to make sure BOs in VRAM can be accessed by the CPU, e.g.
>>>>>>> during a page fault.
>>>>>>>
>>>>>>> Without this change, TTM could evict other BOs while trying to satisfy
>>>>>>> the requested placement, even if the evicted BOs were outside of the
>>>>>>> requested placement range. Doing so didn't free up any space in the
>>>>>>> requested placement range, so the (potentially high) eviction cost was
>>>>>>> incurred for no benefit.
>>>>>>>
>>>>>>> Nominating for stable because radeon driver changes in 3.17 made this
>>>>>>> much more noticeable than before.
>>>>>>>
>>>>>>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84662
>>>>>>> Cc: stable@vger.kernel.org
>>>>>>> Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
>>>>>>> ---
>>>>>>>   drivers/gpu/drm/ttm/ttm_bo.c | 20 +++++++++++++++++---
>>>>>>>   1 file changed, 17 insertions(+), 3 deletions(-)
>>>>>>>
>>>>> [...]
>>>>>
>>>>>> I believe you need to "s/place/placement/" over this patch.
>>>>>
>>>>> The fpfn and lpfn members were moved from struct ttm_placement to a new
>>>>> struct ttm_place in f1217ed09f827e42a49ffa6a5aab672aa6f57a65.
>>>>>
>>>>> If you mean something else, please elaborate.
>>>>
>>>> This patch failed to build on 3.17.0 so wouldn't be a candidate for
>>>> stable unless the currently drm-next only ttm_place patch also goes to
>>>> stable (else replace ttm_place with ttm_placements in the patch for
>>>> stable)?
>>>
>>> Right, I guess I should drop the Cc: stable then and submit a manual
>>> backport of it to the stable list once it has landed in Linus' tree.
>>
>> I've thought it's ok to cc: stable a patch - Greg's scripts will send you
>> a mail as a nice reminder if the patch fails to apply. At least we
>> regularly pull this stunt with i915 patches. Cc'ing Greg for
>> clarification.
>
> Yup, that's fine to do, it's what the scripts are for :)

Okay, thanks guys for the clarification.


-- 
Earthling Michel Dänzer            |                  http://www.amd.com
Libre software enthusiast          |                Mesa and X developer