[PATCH 10/11] drm/amdgpu: use a fence array for VMID management

["Christian König" <deathsimple@vodafone.de>]

From: Christian König <christian.koenig@amd.com>

Just wait for any fence to become available, instead
of waiting for the last entry of the LRU.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h      |  10 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_job.c  |   2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c |  69 +++-----------
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c   | 155 +++++++++++++++++++------------
 4 files changed, 117 insertions(+), 119 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index f154d9f..52326d3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -597,10 +597,8 @@ int amdgpu_sync_resv(struct amdgpu_device *adev,
 		     struct amdgpu_sync *sync,
 		     struct reservation_object *resv,
 		     void *owner);
-bool amdgpu_sync_is_idle(struct amdgpu_sync *sync,
-			 struct amdgpu_ring *ring);
-int amdgpu_sync_cycle_fences(struct amdgpu_sync *dst, struct amdgpu_sync *src,
-			     struct fence *fence);
+struct fence *amdgpu_sync_peek_fence(struct amdgpu_sync *sync,
+				     struct amdgpu_ring *ring);
 struct fence *amdgpu_sync_get_fence(struct amdgpu_sync *sync);
 void amdgpu_sync_free(struct amdgpu_sync *sync);
 int amdgpu_sync_init(void);
@@ -910,6 +908,10 @@ struct amdgpu_vm_manager {
 	struct list_head			ids_lru;
 	struct amdgpu_vm_id			ids[AMDGPU_NUM_VM];
 
+	/* Handling of VM fences */
+	u64					fence_context;
+	unsigned				seqno[AMDGPU_MAX_RINGS];
+
 	uint32_t				max_pfn;
 	/* vram base address for page table entry  */
 	u64					vram_base_offset;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index e395bbe..b50a845 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -166,7 +166,7 @@ static struct fence *amdgpu_job_run(struct amd_sched_job *sched_job)
 	}
 	job = to_amdgpu_job(sched_job);
 
-	BUG_ON(!amdgpu_sync_is_idle(&job->sync, NULL));
+	BUG_ON(amdgpu_sync_peek_fence(&job->sync, NULL));
 
 	trace_amdgpu_sched_run_job(job);
 	r = amdgpu_ib_schedule(job->ring, job->num_ibs, job->ibs,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
index a2766d7..5c8d302 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sync.c
@@ -223,16 +223,16 @@ int amdgpu_sync_resv(struct amdgpu_device *adev,
 }
 
 /**
- * amdgpu_sync_is_idle - test if all fences are signaled
+ * amdgpu_sync_peek_fence - get the next fence not signaled yet
  *
  * @sync: the sync object
  * @ring: optional ring to use for test
  *
- * Returns true if all fences in the sync object are signaled or scheduled to
- * the ring (if provided).
+ * Returns the next fence not signaled yet without removing it from the sync
+ * object.
  */
-bool amdgpu_sync_is_idle(struct amdgpu_sync *sync,
-			 struct amdgpu_ring *ring)
+struct fence *amdgpu_sync_peek_fence(struct amdgpu_sync *sync,
+				     struct amdgpu_ring *ring)
 {
 	struct amdgpu_sync_entry *e;
 	struct hlist_node *tmp;
@@ -246,68 +246,25 @@ bool amdgpu_sync_is_idle(struct amdgpu_sync *sync,
 			/* For fences from the same ring it is sufficient
 			 * when they are scheduled.
 			 */
-			if (s_fence->sched == &ring->sched &&
-			    fence_is_signaled(&s_fence->scheduled))
-				continue;
-		}
+			if (s_fence->sched == &ring->sched) {
+				if (fence_is_signaled(&s_fence->scheduled))
+					continue;
 
-		if (fence_is_signaled(f)) {
-			hash_del(&e->node);
-			fence_put(f);
-			kmem_cache_free(amdgpu_sync_slab, e);
-			continue;
+				return &s_fence->scheduled;
+			}
 		}
 
-		return false;
-	}
-
-	return true;
-}
-
-/**
- * amdgpu_sync_cycle_fences - move fences from one sync object into another
- *
- * @dst: the destination sync object
- * @src: the source sync object
- * @fence: fence to add to source
- *
- * Remove all fences from source and put them into destination and add
- * fence as new one into source.
- */
-int amdgpu_sync_cycle_fences(struct amdgpu_sync *dst, struct amdgpu_sync *src,
-			     struct fence *fence)
-{
-	struct amdgpu_sync_entry *e, *newone;
-	struct hlist_node *tmp;
-	int i;
-
-	/* Allocate the new entry before moving the old ones */
-	newone = kmem_cache_alloc(amdgpu_sync_slab, GFP_KERNEL);
-	if (!newone)
-		return -ENOMEM;
-
-	hash_for_each_safe(src->fences, i, tmp, e, node) {
-		struct fence *f = e->fence;
-
-		hash_del(&e->node);
 		if (fence_is_signaled(f)) {
+			hash_del(&e->node);
 			fence_put(f);
 			kmem_cache_free(amdgpu_sync_slab, e);
 			continue;
 		}
 
-		if (amdgpu_sync_add_later(dst, f)) {
-			kmem_cache_free(amdgpu_sync_slab, e);
-			continue;
-		}
-
-		hash_add(dst->fences, &e->node, f->context);
+		return f;
 	}
 
-	hash_add(src->fences, &newone->node, fence->context);
-	newone->fence = fence_get(fence);
-
-	return 0;
+	return NULL;
 }
 
 /**
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index f206820..8ea1c73 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -25,6 +25,7 @@
  *          Alex Deucher
  *          Jerome Glisse
  */
+#include <linux/fence-array.h>
 #include <drm/drmP.h>
 #include <drm/amdgpu_drm.h>
 #include "amdgpu.h"
@@ -180,82 +181,116 @@ int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring,
 	struct amdgpu_device *adev = ring->adev;
 	struct fence *updates = sync->last_vm_update;
 	struct amdgpu_vm_id *id, *idle;
-	unsigned i = ring->idx;
-	int r;
+	struct fence **fences;
+	unsigned i;
+	int r = 0;
+
+	fences = kmalloc_array(sizeof(void *), adev->vm_manager.num_ids,
+			       GFP_KERNEL);
+	if (!fences)
+		return -ENOMEM;
 
 	mutex_lock(&adev->vm_manager.lock);
 
 	/* Check if we have an idle VMID */
+	i = 0;
 	list_for_each_entry(idle, &adev->vm_manager.ids_lru, list) {
-		if (amdgpu_sync_is_idle(&idle->active, ring))
+		fences[i] = amdgpu_sync_peek_fence(&idle->active, ring);
+		if (!fences[i])
 			break;
-
+		++i;
 	}
 
-	/* If we can't find a idle VMID to use, just wait for the oldest */
+	/* If we can't find a idle VMID to use, wait till one becomes available */
 	if (&idle->list == &adev->vm_manager.ids_lru) {
-		id = list_first_entry(&adev->vm_manager.ids_lru,
-				      struct amdgpu_vm_id,
-				      list);
-	} else {
-		/* Check if we can use a VMID already assigned to this VM */
-		do {
-			struct fence *flushed;
-
-			id = vm->ids[i++];
-			if (i == AMDGPU_MAX_RINGS)
-				i = 0;
-
-			/* Check all the prerequisites to using this VMID */
-			if (!id)
-				continue;
-
-			if (atomic64_read(&id->owner) != vm->client_id)
-				continue;
-
-			if (pd_addr != id->pd_gpu_addr)
-				continue;
-
-			if (id->last_user != ring && (!id->last_flush ||
-			    !fence_is_signaled(id->last_flush)))
-				continue;
-
-			flushed  = id->flushed_updates;
-			if (updates && (!flushed ||
-			    fence_is_later(updates, flushed)))
-				continue;
-
-			/* Good we can use this VMID */
-			if (id->last_user == ring) {
-				r = amdgpu_sync_fence(ring->adev, sync,
-						      id->first);
-				if (r)
-					goto error;
-			}
+		u64 fence_context = adev->vm_manager.fence_context + ring->idx;
+		unsigned seqno = ++adev->vm_manager.seqno[ring->idx];
+		struct fence_array *array;
+		unsigned j;
+
+		for (j = 0; j < i; ++j)
+			fence_get(fences[j]);
+
+		array = fence_array_create(i, fences, fence_context,
+					   seqno, true);
+		if (!array) {
+			for (j = 0; j < i; ++j)
+				fence_put(fences[j]);
+			kfree(fences);
+			r = -ENOMEM;
+			goto error;
+		}
+
+
+		r = amdgpu_sync_fence(ring->adev, sync, &array->base);
+		fence_put(&array->base);
+		if (r)
+			goto error;
+
+		mutex_unlock(&adev->vm_manager.lock);
+		return 0;
+
+	}
+	kfree(fences);
+
+	/* Check if we can use a VMID already assigned to this VM */
+	i = ring->idx;
+	do {
+		struct fence *flushed;
+
+		id = vm->ids[i++];
+		if (i == AMDGPU_MAX_RINGS)
+			i = 0;
 
-			/* And remember this submission as user of the VMID */
-			r = amdgpu_sync_fence(ring->adev, &id->active, fence);
+		/* Check all the prerequisites to using this VMID */
+		if (!id)
+			continue;
+
+		if (atomic64_read(&id->owner) != vm->client_id)
+			continue;
+
+		if (pd_addr != id->pd_gpu_addr)
+			continue;
+
+		if (id->last_user != ring &&
+		    (!id->last_flush || !fence_is_signaled(id->last_flush)))
+			continue;
+
+		flushed  = id->flushed_updates;
+		if (updates &&
+		    (!flushed || fence_is_later(updates, flushed)))
+			continue;
+
+		/* Good we can use this VMID */
+		if (id->last_user == ring) {
+			r = amdgpu_sync_fence(ring->adev, sync,
+					      id->first);
 			if (r)
 				goto error;
+		}
+
+		/* And remember this submission as user of the VMID */
+		r = amdgpu_sync_fence(ring->adev, &id->active, fence);
+		if (r)
+			goto error;
 
-			list_move_tail(&id->list, &adev->vm_manager.ids_lru);
-			vm->ids[ring->idx] = id;
+		list_move_tail(&id->list, &adev->vm_manager.ids_lru);
+		vm->ids[ring->idx] = id;
 
-			*vm_id = id - adev->vm_manager.ids;
-			*vm_pd_addr = AMDGPU_VM_NO_FLUSH;
-			trace_amdgpu_vm_grab_id(vm, ring->idx, *vm_id,
-						*vm_pd_addr);
+		*vm_id = id - adev->vm_manager.ids;
+		*vm_pd_addr = AMDGPU_VM_NO_FLUSH;
+		trace_amdgpu_vm_grab_id(vm, ring->idx, *vm_id, *vm_pd_addr);
 
-			mutex_unlock(&adev->vm_manager.lock);
-			return 0;
+		mutex_unlock(&adev->vm_manager.lock);
+		return 0;
 
-		} while (i != ring->idx);
+	} while (i != ring->idx);
 
-		/* Still no ID to use? Then use the idle one found earlier */
-		id = idle;
-	}
+	/* Still no ID to use? Then use the idle one found earlier */
+	id = idle;
 
-	r = amdgpu_sync_cycle_fences(sync, &id->active, fence);
+	/* Remember this submission as user of the VMID */
+	r = amdgpu_sync_fence(ring->adev, &id->active, fence);
 	if (r)
 		goto error;
 
@@ -1515,6 +1550,10 @@ void amdgpu_vm_manager_init(struct amdgpu_device *adev)
 			      &adev->vm_manager.ids_lru);
 	}
 
+	adev->vm_manager.fence_context = fence_context_alloc(AMDGPU_MAX_RINGS);
+	for (i = 0; i < AMDGPU_MAX_RINGS; ++i)
+		adev->vm_manager.seqno[i] = 0;
+
 	atomic_set(&adev->vm_manager.vm_pte_next_ring, 0);
 	atomic64_set(&adev->vm_manager.client_counter, 0);
 }
-- 
2.5.0