[v8 10/11] drm/amdgpu: Switch user queues to use preempt/restore for eviction

[Jesse.Zhang]

This patch modifies the user queue management to use preempt/restore
operations instead of full map/unmap for queue eviction scenarios where
applicable. The changes include:

1. Introduces new helper functions:
   - amdgpu_userqueue_preempt_helper()
   - amdgpu_userqueue_restore_helper()

2. Updates queue state management to track PREEMPTED state

3. Modifies eviction handling to use preempt instead of unmap:
   - amdgpu_userq_evict_all() now uses preempt_helper
   - amdgpu_userq_restore_all() now uses restore_helper

The preempt/restore approach provides better performance during queue
eviction by avoiding the overhead of full queue teardown and setup.
Full map/unmap operations are still used for initial setup/teardown
and system suspend scenarios.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Jesse Zhang <Jesse.Zhang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 49 +++++++++++++++++++++--
 1 file changed, 46 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
index aac0de86f3e8..decedf8057ac 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
@@ -45,7 +45,7 @@ u32 amdgpu_userq_get_supported_ip_mask(struct amdgpu_device *adev)
 }
 
 static int
-amdgpu_userq_unmap_helper(struct amdgpu_userq_mgr *uq_mgr,
+amdgpu_userqueue_preempt_helper(struct amdgpu_userq_mgr *uq_mgr,
 			  struct amdgpu_usermode_queue *queue)
 {
 	struct amdgpu_device *adev = uq_mgr->adev;
@@ -54,6 +54,49 @@ amdgpu_userq_unmap_helper(struct amdgpu_userq_mgr *uq_mgr,
 	int r = 0;
 
 	if (queue->state == AMDGPU_USERQ_STATE_MAPPED) {
+		r = userq_funcs->preempt(uq_mgr, queue);
+		if (r) {
+			queue->state = AMDGPU_USERQ_STATE_HUNG;
+		} else {
+			queue->state = AMDGPU_USERQ_STATE_PREEMPTED;
+		}
+	}
+
+	return r;
+}
+
+static int
+amdgpu_userqueue_restore_helper(struct amdgpu_userq_mgr *uq_mgr,
+			struct amdgpu_usermode_queue *queue)
+{
+	struct amdgpu_device *adev = uq_mgr->adev;
+	const struct amdgpu_userq_funcs *userq_funcs =
+		adev->userq_funcs[queue->queue_type];
+	int r = 0;
+
+	if (queue->state == AMDGPU_USERQ_STATE_PREEMPTED) {
+		r = userq_funcs->restore(uq_mgr, queue);
+		if (r) {
+			queue->state = AMDGPU_USERQ_STATE_HUNG;
+		} else {
+			queue->state = AMDGPU_USERQ_STATE_MAPPED;
+		}
+	}
+
+	return r;
+}
+
+static int
+amdgpu_userq_unmap_helper(struct amdgpu_userq_mgr *uq_mgr,
+			  struct amdgpu_usermode_queue *queue)
+{
+	struct amdgpu_device *adev = uq_mgr->adev;
+	const struct amdgpu_userq_funcs *userq_funcs =
+		adev->userq_funcs[queue->queue_type];
+	int r = 0;
+
+	if ((queue->state == AMDGPU_USERQ_STATE_MAPPED) ||
+		(queue->state == AMDGPU_USERQ_STATE_PREEMPTED)) {
 		r = userq_funcs->unmap(uq_mgr, queue);
 		if (r)
 			queue->state = AMDGPU_USERQ_STATE_HUNG;
@@ -536,7 +579,7 @@ amdgpu_userq_restore_all(struct amdgpu_userq_mgr *uq_mgr)
 
 	/* Resume all the queues for this process */
 	idr_for_each_entry(&uq_mgr->userq_idr, queue, queue_id) {
-		r = amdgpu_userq_map_helper(uq_mgr, queue);
+		r = amdgpu_userqueue_restore_helper(uq_mgr, queue);
 		if (r)
 			ret = r;
 	}
@@ -693,7 +736,7 @@ amdgpu_userq_evict_all(struct amdgpu_userq_mgr *uq_mgr)
 
 	/* Try to unmap all the queues in this process ctx */
 	idr_for_each_entry(&uq_mgr->userq_idr, queue, queue_id) {
-		r = amdgpu_userq_unmap_helper(uq_mgr, queue);
+		r = amdgpu_userqueue_preempt_helper(uq_mgr, queue);
 		if (r)
 			ret = r;
 	}
-- 
2.49.0