[PATCH 1/6] drm/ttm: add on_alloc_stage and reservation into ttm_operation_ctx

Thomas Hellstrom thomas at shipmail.org
Thu Dec 14 08:55:28 UTC 2017

Hi, Christian,

On 12/14/2017 09:40 AM, Christian K├Ânig wrote:
> Hi Thomas,
> sorry for that. Noted on the rest of that series as well that we need 
> to improve the commit messages. But this one somehow slipped through 
> because I discussed this change previously internally with Roger.
> That made the change completely logical for me, but without this 
> context everybody else just thinks "Hui what?". Going to keep that in 
> mind the next time.
> But back to topic: This series allows BOs which share the same 
> reservation object as the BO currently allocated/validated to be 
> evicted even when they are reserved.
> This is useful because amdgpu wants to use a single reservation object 
> for almost all BOs of a process.

Yes, that indeed makes the whole thing more clear, and makes sense.

Out of interest, is the shared reservation object usage a speed 
optimization (avoiding the ww_mutex_locks at reservation time?)
or something else?

I guess that even if LRU lists might get crowded with unevictable BOs, 
iterating through those lists isn't really part of the fast path.

> Regards,
> Christian. 

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