page allocator bug in 3.16?

[Thomas Hellstrom]

On 09/26/2014 12:40 PM, Chuck Ebbert wrote:
> On Fri, 26 Sep 2014 09:15:57 +0200
> Thomas Hellstrom <thellstrom at vmware.com> wrote:
>
>> On 09/26/2014 01:52 AM, Peter Hurley wrote:
>>> On 09/25/2014 03:35 PM, Chuck Ebbert wrote:
>>>> There are six ttm patches queued for 3.16.4:
>>>>
>>>> drm-ttm-choose-a-pool-to-shrink-correctly-in-ttm_dma_pool_shrink_scan.patch
>>>> drm-ttm-fix-handling-of-ttm_pl_flag_topdown-v2.patch
>>>> drm-ttm-fix-possible-division-by-0-in-ttm_dma_pool_shrink_scan.patch
>>>> drm-ttm-fix-possible-stack-overflow-by-recursive-shrinker-calls.patch
>>>> drm-ttm-pass-gfp-flags-in-order-to-avoid-deadlock.patch
>>>> drm-ttm-use-mutex_trylock-to-avoid-deadlock-inside-shrinker-functions.patch
>>> Thanks for info, Chuck.
>>>
>>> Unfortunately, none of these fix TTM dma allocation doing CMA dma allocation,
>>> which is the root problem.
>>>
>>> Regards,
>>> Peter Hurley
>> The problem is not really in TTM but in CMA, There was a guy offering to
>> fix this in the CMA code but I guess he didn't probably because he
>> didn't receive any feedback.
>>
> Yeah, the "solution" to this problem seems to be "don't enable CMA on
> x86". Maybe it should even be disabled in the config system.
Or, as previously suggested, don't use CMA for order 0 (single page)
allocations....

/Thomas