Re: [PATCH 1/2] drm/amdgpu: unwrap fence chains in the explicit sync fence

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Jun 17, 2021 at 07:30:24PM +0200, Daniel Vetter wrote:
> On Thu, Jun 17, 2021 at 09:44:25AM +0200, Christian König wrote:
> > Alex do want to review those so that we can close the ticket?
> 
> Maybe I'm behind on mails, but 2nd patch still has the issues I think I'm
> seeing ...

Ok with temperatures getting colder towards the night the 2nd patch looks
much better now :-) I replied there.
-Daniel

> -Daniel
> 
> > 
> > Thanks,
> > Christian.
> > 
> > Am 14.06.21 um 19:45 schrieb Christian König:
> > > Unwrap the explicit fence if it is a dma_fence_chain and
> > > sync to the first fence not matching the owner rules.
> > > 
> > > Signed-off-by: Christian König <christian.koenig@amd.com>
> > > Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > > ---
> > >   drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c | 118 +++++++++++++----------
> > >   1 file changed, 68 insertions(+), 50 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
> > > index 1b2ceccaf5b0..862eb3c1c4c5 100644
> > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
> > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
> > > @@ -28,6 +28,8 @@
> > >    *    Christian König <christian.koenig@amd.com>
> > >    */
> > > +#include <linux/dma-fence-chain.h>
> > > +
> > >   #include "amdgpu.h"
> > >   #include "amdgpu_trace.h"
> > >   #include "amdgpu_amdkfd.h"
> > > @@ -186,6 +188,55 @@ int amdgpu_sync_vm_fence(struct amdgpu_sync *sync, struct dma_fence *fence)
> > >   	return amdgpu_sync_fence(sync, fence);
> > >   }
> > > +/* Determine based on the owner and mode if we should sync to a fence or not */
> > > +static bool amdgpu_sync_test_fence(struct amdgpu_device *adev,
> > > +				   enum amdgpu_sync_mode mode,
> > > +				   void *owner, struct dma_fence *f)
> > > +{
> > > +	void *fence_owner = amdgpu_sync_get_owner(f);
> > > +
> > > +	/* Always sync to moves, no matter what */
> > > +	if (fence_owner == AMDGPU_FENCE_OWNER_UNDEFINED)
> > > +		return true;
> > > +
> > > +	/* We only want to trigger KFD eviction fences on
> > > +	 * evict or move jobs. Skip KFD fences otherwise.
> > > +	 */
> > > +	if (fence_owner == AMDGPU_FENCE_OWNER_KFD &&
> > > +	    owner != AMDGPU_FENCE_OWNER_UNDEFINED)
> > > +		return false;
> > > +
> > > +	/* Never sync to VM updates either. */
> > > +	if (fence_owner == AMDGPU_FENCE_OWNER_VM &&
> > > +	    owner != AMDGPU_FENCE_OWNER_UNDEFINED)
> > > +		return false;
> > > +
> > > +	/* Ignore fences depending on the sync mode */
> > > +	switch (mode) {
> > > +	case AMDGPU_SYNC_ALWAYS:
> > > +		return true;
> > > +
> > > +	case AMDGPU_SYNC_NE_OWNER:
> > > +		if (amdgpu_sync_same_dev(adev, f) &&
> > > +		    fence_owner == owner)
> > > +			return false;
> > > +		break;
> > > +
> > > +	case AMDGPU_SYNC_EQ_OWNER:
> > > +		if (amdgpu_sync_same_dev(adev, f) &&
> > > +		    fence_owner != owner)
> > > +			return false;
> > > +		break;
> > > +
> > > +	case AMDGPU_SYNC_EXPLICIT:
> > > +		return false;
> > > +	}
> > > +
> > > +	WARN(debug_evictions && fence_owner == AMDGPU_FENCE_OWNER_KFD,
> > > +	     "Adding eviction fence to sync obj");
> > > +	return true;
> > > +}
> > > +
> > >   /**
> > >    * amdgpu_sync_resv - sync to a reservation object
> > >    *
> > > @@ -211,67 +262,34 @@ int amdgpu_sync_resv(struct amdgpu_device *adev, struct amdgpu_sync *sync,
> > >   	/* always sync to the exclusive fence */
> > >   	f = dma_resv_excl_fence(resv);
> > > -	r = amdgpu_sync_fence(sync, f);
> > > +	dma_fence_chain_for_each(f, f) {
> > > +		struct dma_fence_chain *chain = to_dma_fence_chain(f);
> > > +
> > > +		if (amdgpu_sync_test_fence(adev, mode, owner, chain ?
> > > +					   chain->fence : f)) {
> > > +			r = amdgpu_sync_fence(sync, f);
> > > +			dma_fence_put(f);
> > > +			if (r)
> > > +				return r;
> > > +			break;
> > > +		}
> > > +	}
> > >   	flist = dma_resv_shared_list(resv);
> > > -	if (!flist || r)
> > > -		return r;
> > > +	if (!flist)
> > > +		return 0;
> > >   	for (i = 0; i < flist->shared_count; ++i) {
> > > -		void *fence_owner;
> > > -
> > >   		f = rcu_dereference_protected(flist->shared[i],
> > >   					      dma_resv_held(resv));
> > > -		fence_owner = amdgpu_sync_get_owner(f);
> > > -
> > > -		/* Always sync to moves, no matter what */
> > > -		if (fence_owner == AMDGPU_FENCE_OWNER_UNDEFINED) {
> > > +		if (amdgpu_sync_test_fence(adev, mode, owner, f)) {
> > >   			r = amdgpu_sync_fence(sync, f);
> > >   			if (r)
> > > -				break;
> > > -		}
> > > -
> > > -		/* We only want to trigger KFD eviction fences on
> > > -		 * evict or move jobs. Skip KFD fences otherwise.
> > > -		 */
> > > -		if (fence_owner == AMDGPU_FENCE_OWNER_KFD &&
> > > -		    owner != AMDGPU_FENCE_OWNER_UNDEFINED)
> > > -			continue;
> > > -
> > > -		/* Never sync to VM updates either. */
> > > -		if (fence_owner == AMDGPU_FENCE_OWNER_VM &&
> > > -		    owner != AMDGPU_FENCE_OWNER_UNDEFINED)
> > > -			continue;
> > > -
> > > -		/* Ignore fences depending on the sync mode */
> > > -		switch (mode) {
> > > -		case AMDGPU_SYNC_ALWAYS:
> > > -			break;
> > > -
> > > -		case AMDGPU_SYNC_NE_OWNER:
> > > -			if (amdgpu_sync_same_dev(adev, f) &&
> > > -			    fence_owner == owner)
> > > -				continue;
> > > -			break;
> > > -
> > > -		case AMDGPU_SYNC_EQ_OWNER:
> > > -			if (amdgpu_sync_same_dev(adev, f) &&
> > > -			    fence_owner != owner)
> > > -				continue;
> > > -			break;
> > > -
> > > -		case AMDGPU_SYNC_EXPLICIT:
> > > -			continue;
> > > +				return r;
> > >   		}
> > > -
> > > -		WARN(debug_evictions && fence_owner == AMDGPU_FENCE_OWNER_KFD,
> > > -		     "Adding eviction fence to sync obj");
> > > -		r = amdgpu_sync_fence(sync, f);
> > > -		if (r)
> > > -			break;
> > >   	}
> > > -	return r;
> > > +	return 0;
> > >   }
> > >   /**
> > 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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