Re: [PATCH v6 12/24] drm/xe: Don't use migrate exec queue for page fault binds

["Ghimiray, Himal Prasad" <himal.prasad.ghimiray@intel.com>]

On 05-09-2026 02:46, Matthew Brost wrote:
> Now that the CPU is always used for binds even in jobs, CPU bind jobs
> can pass GPU jobs in the same exec queue resulting dma-fences signaling
> out-of-order. Use a dedicated exec queue for binds issued from page
> faults to avoid ordering issues and avoid blocking kernel binds on
> unrelated copies / clears.
> 
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> Link: https://patch.msgid.link/20260228013501.106680-13-matthew.brost@intel.com
> Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
> ---
>   drivers/gpu/drm/xe/xe_migrate.c | 47 ++++++++++++++++++++++++++++++---
>   drivers/gpu/drm/xe/xe_migrate.h |  1 +
>   drivers/gpu/drm/xe/xe_vm.c      | 17 +++++++-----
>   3 files changed, 55 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
> index 53160c2c35a6..ba8e195afcc8 100644
> --- a/drivers/gpu/drm/xe/xe_migrate.c
> +++ b/drivers/gpu/drm/xe/xe_migrate.c
> @@ -51,6 +51,8 @@
>   struct xe_migrate {
>   	/** @q: Default exec queue used for migration */
>   	struct xe_exec_queue *q;
> +	/** @bind_q: Default exec queue used for binds */
> +	struct xe_exec_queue *bind_q;
>   	/** @tile: Backpointer to the tile this struct xe_migrate belongs to. */
>   	struct xe_tile *tile;
>   	/** @job_mutex: Timeline mutex for @eng. */
> @@ -115,6 +117,7 @@ static void xe_migrate_fini(void *arg)
>   	mutex_destroy(&m->job_mutex);
>   	xe_vm_close_and_put(m->q->vm);
>   	xe_exec_queue_put(m->q);
> +	xe_exec_queue_put(m->bind_q);
>   }
>   
>   static inline u16 xe_migrate_pat_index(struct xe_device *xe,
> @@ -504,6 +507,15 @@ int xe_migrate_init(struct xe_migrate *m)
>   			goto err_out;
>   		}
>   
> +		m->bind_q = xe_exec_queue_create(xe, vm, logical_mask, 1, hwe0,
> +						 EXEC_QUEUE_FLAG_KERNEL |
> +						 EXEC_QUEUE_FLAG_HIGH_PRIORITY |
> +						 EXEC_QUEUE_FLAG_MIGRATE, 0);
> +		if (IS_ERR(m->bind_q)) {
> +			err = PTR_ERR(m->bind_q);
> +			goto err_out;
> +		}
> +
>   		/*
>   		 * XXX: Currently only reserving 1 (likely slow) BCS instance on
>   		 * PVC, may want to revisit if performance is needed.
> @@ -514,6 +526,15 @@ int xe_migrate_init(struct xe_migrate *m)
>   					    EXEC_QUEUE_FLAG_MIGRATE |
>   					    EXEC_QUEUE_FLAG_LOW_LATENCY, 0);
>   	} else {
> +		m->bind_q = xe_exec_queue_create_class(xe, primary_gt, vm,
> +						       XE_ENGINE_CLASS_COPY,
> +						       EXEC_QUEUE_FLAG_KERNEL |
> +						       EXEC_QUEUE_FLAG_MIGRATE, 0);
> +		if (IS_ERR(m->bind_q)) {
> +			err = PTR_ERR(m->bind_q);
> +			goto err_out;
> +		}
> +
>   		m->q = xe_exec_queue_create_class(xe, primary_gt, vm,
>   						  XE_ENGINE_CLASS_COPY,
>   						  EXEC_QUEUE_FLAG_KERNEL |
> @@ -549,6 +570,8 @@ int xe_migrate_init(struct xe_migrate *m)
>   	return err;
>   
>   err_out:
> +	if (!IS_ERR_OR_NULL(m->bind_q))
> +		xe_exec_queue_put(m->bind_q);
>   	xe_vm_close_and_put(vm);
>   	return err;
>   
> @@ -1505,6 +1528,17 @@ static u32 blt_mem_set_cmd_len(struct xe_device *xe)
>   	return 7;
>   }
>   
> +/**
> + * xe_get_migrate_bind_queue() - Get the bind queue from migrate context.
> + * @migrate: Migrate context.
> + *
> + * Return: Pointer to bind queue on success, error on failure
> + */
> +struct xe_exec_queue *xe_migrate_bind_queue(struct xe_migrate *migrate)
> +{
> +	return migrate->bind_q;
> +}
> +
>   static void emit_clear_link_copy(struct xe_gt *gt, struct xe_bb *bb, u64 src_ofs,
>   				 u32 size, u32 pitch)
>   {
> @@ -1892,6 +1926,11 @@ xe_migrate_update_pgtables_cpu(struct xe_migrate *m,
>   	return dma_fence_get_stub();
>   }
>   
> +static bool is_migrate_queue(struct xe_migrate *m, struct xe_exec_queue *q)
> +{
> +	return m->bind_q == q;
> +}
> +
>   static struct dma_fence *
>   __xe_migrate_update_pgtables(struct xe_migrate *m,
>   			     struct xe_migrate_pt_update *pt_update,
> @@ -1909,7 +1948,7 @@ __xe_migrate_update_pgtables(struct xe_migrate *m,
>   	u32 num_updates = 0, current_update = 0;
>   	u64 addr;
>   	int err = 0;
> -	bool is_migrate = pt_update_ops->q == m->q;
> +	bool is_migrate = is_migrate_queue(m, pt_update_ops->q);
>   	bool usm = is_migrate && xe->info.has_usm;
>   
>   	for (i = 0; i < pt_update_ops->num_ops; ++i) {
> @@ -2631,7 +2670,7 @@ int xe_migrate_access_memory(struct xe_migrate *m, struct xe_bo *bo,
>    */
>   void xe_migrate_job_lock(struct xe_migrate *m, struct xe_exec_queue *q)
>   {
> -	bool is_migrate = q == m->q;
> +	bool is_migrate = is_migrate_queue(m, q);
>   
>   	if (is_migrate)
>   		mutex_lock(&m->job_mutex);
> @@ -2649,7 +2688,7 @@ void xe_migrate_job_lock(struct xe_migrate *m, struct xe_exec_queue *q)
>    */
>   void xe_migrate_job_unlock(struct xe_migrate *m, struct xe_exec_queue *q)
>   {
> -	bool is_migrate = q == m->q;
> +	bool is_migrate = is_migrate_queue(m, q);
>   
>   	if (is_migrate)
>   		mutex_unlock(&m->job_mutex);
> @@ -2666,7 +2705,7 @@ void xe_migrate_job_lock_assert(struct xe_exec_queue *q)
>   {
>   	struct xe_migrate *m = gt_to_tile(q->gt)->migrate;
>   
> -	xe_gt_assert(q->gt, q == m->q);
> +	xe_gt_assert(q->gt, q == m->bind_q);
>   	lockdep_assert_held(&m->job_mutex);
>   }
>   #endif
> diff --git a/drivers/gpu/drm/xe/xe_migrate.h b/drivers/gpu/drm/xe/xe_migrate.h
> index 04ef20692b6a..7a824654cb72 100644
> --- a/drivers/gpu/drm/xe/xe_migrate.h
> +++ b/drivers/gpu/drm/xe/xe_migrate.h
> @@ -146,6 +146,7 @@ void xe_migrate_ccs_rw_copy_clear(struct xe_bo *src_bo,
>   
>   struct xe_lrc *xe_migrate_lrc(struct xe_migrate *migrate);
>   struct xe_exec_queue *xe_migrate_exec_queue(struct xe_migrate *migrate);
> +struct xe_exec_queue *xe_migrate_bind_queue(struct xe_migrate *migrate);
>   struct dma_fence *xe_migrate_vram_copy_chunk(struct xe_bo *vram_bo, u64 vram_offset,
>   					     struct xe_bo *sysmem_bo, u64 sysmem_offset,
>   					     u64 size, enum xe_migrate_copy_dir dir);
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index 2737bd25f39a..13e984ac4e4f 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -795,7 +795,9 @@ int xe_vm_rebind(struct xe_vm *vm, bool rebind_worker)
>   	struct xe_vma *vma, *next;
>   	struct xe_vma_ops vops;
>   	struct xe_vma_op *op, *next_op;
> -	int err, i;
> +	struct xe_tile *tile;
> +	u8 id;
> +	int err;
>   
>   	lockdep_assert_held(&vm->lock);
>   	if ((xe_vm_in_lr_mode(vm) && !rebind_worker) ||
> @@ -803,8 +805,11 @@ int xe_vm_rebind(struct xe_vm *vm, bool rebind_worker)
>   		return 0;
>   
>   	xe_vma_ops_init(&vops, vm, NULL, NULL, 0);
> -	for (i = 0; i < XE_MAX_TILES_PER_DEVICE; ++i)
> -		vops.pt_update_ops[i].wait_vm_bookkeep = true;
> +	for_each_tile(tile, vm->xe, id) {
> +		vops.pt_update_ops[id].wait_vm_bookkeep = true;
> +		vops.pt_update_ops[id].q =
> +			xe_migrate_bind_queue(tile->migrate);
> +	}
>   
>   	xe_vm_assert_held(vm);
>   	list_for_each_entry(vma, &vm->rebind_list, combined_links.rebind) {
> @@ -862,7 +867,7 @@ struct dma_fence *xe_vma_rebind(struct xe_vm *vm, struct xe_vma *vma, u8 tile_ma
>   	for_each_tile(tile, vm->xe, id) {
>   		vops.pt_update_ops[id].wait_vm_bookkeep = true;
>   		vops.pt_update_ops[tile->id].q =
> -			xe_migrate_exec_queue(tile->migrate);
> +			xe_migrate_bind_queue(tile->migrate);
>   	}
>   
>   	err = xe_vm_ops_add_rebind(&vops, vma, tile_mask);
> @@ -954,7 +959,7 @@ struct dma_fence *xe_vm_range_rebind(struct xe_vm *vm,
>   	for_each_tile(tile, vm->xe, id) {
>   		vops.pt_update_ops[id].wait_vm_bookkeep = true;
>   		vops.pt_update_ops[tile->id].q =
> -			xe_migrate_exec_queue(tile->migrate);
> +			xe_migrate_bind_queue(tile->migrate);
>   	}
>   
>   	err = xe_vm_ops_add_range_rebind(&vops, vma, range, tile_mask);
> @@ -1038,7 +1043,7 @@ struct dma_fence *xe_vm_range_unbind(struct xe_vm *vm,
>   	for_each_tile(tile, vm->xe, id) {
>   		vops.pt_update_ops[id].wait_vm_bookkeep = true;
>   		vops.pt_update_ops[tile->id].q =
> -			xe_migrate_exec_queue(tile->migrate);
> +			xe_migrate_bind_queue(tile->migrate);
>   	}

LGTM
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>


>   
>   	err = xe_vm_ops_add_range_unbind(&vops, range);