[Intel-gfx] [PATCH 4/5] drm/i915: Implement GGTT update method with MI_UPDATE_GTT

[Nirmoy Das]

On 9/7/2023 3:48 PM, Andi Shyti wrote:
> Hi Nirmoy,
>
> On Wed, Sep 06, 2023 at 01:31:20PM +0200, Nirmoy Das wrote:
>> Implement GGTT update method with blitter command, MI_UPDATE_GTT
>> and install those handlers if a platform requires that.
>>
>> v2: Make sure we hold the GT wakeref and Blitter engine wakeref before
>> we call mutex_lock/intel_context_enter below. When GT/engine are not
>> awake, the intel_context_enter calls into some runtime pm function which
>> can end up with kmalloc/fs_reclaim. But trigger fs_reclaim holding a
>> mutex lock is not allowed because shrinker can also try to hold the same
>> mutex lock. It is a circular lock. So hold the GT/blitter engine wakeref
>> before calling mutex_lock, to fix the circular lock.
> Thanks for the explanation here.
>
>> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
>> Signed-off-by: Oak Zeng <oak.zeng at intel.com>
> [...]
>
> all looks good
>
> [...]
>
>> +#define for_each_sgt_daddr_next(__dp, __iter) \
>> +	__for_each_daddr_next(__dp, __iter, I915_GTT_PAGE_SIZE)
>> +
> should this go in the previous patch?
Yes, I think so too. Will move it to the previous one.
>
> Andi