[Intel-xe] [PATCH v3 2/6] drm/xe/vm: Simplify and document xe_vm_lock()

Matthew Brost matthew.brost at intel.com
Thu Aug 31 17:06:22 UTC 2023


On Thu, Aug 31, 2023 at 11:29:33AM +0200, Thomas Hellström wrote:
> The xe_vm_lock() function was unnecessarily using ttm_eu_reserve_buffers().
> Simplify and document the interface.
> 
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> ---
>  drivers/gpu/drm/xe/tests/xe_bo.c      |  9 +++--
>  drivers/gpu/drm/xe/tests/xe_migrate.c |  5 ++-
>  drivers/gpu/drm/xe/xe_bo.c            |  5 ++-
>  drivers/gpu/drm/xe/xe_exec_queue.c    |  5 ++-
>  drivers/gpu/drm/xe/xe_lrc.c           |  6 ++--
>  drivers/gpu/drm/xe/xe_migrate.c       | 10 +++---
>  drivers/gpu/drm/xe/xe_vm.c            | 50 +++++++++++++--------------
>  drivers/gpu/drm/xe/xe_vm.h            |  5 ++-
>  8 files changed, 42 insertions(+), 53 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/tests/xe_bo.c b/drivers/gpu/drm/xe/tests/xe_bo.c
> index 31fd4f9b2d5b..c6025404042d 100644
> --- a/drivers/gpu/drm/xe/tests/xe_bo.c
> +++ b/drivers/gpu/drm/xe/tests/xe_bo.c
> @@ -180,17 +180,16 @@ static int evict_test_run_gt(struct xe_device *xe, struct xe_gt *gt, struct kuni
>  	unsigned int bo_flags = XE_BO_CREATE_USER_BIT |
>  		XE_BO_CREATE_VRAM_IF_DGFX(gt_to_tile(gt));
>  	struct xe_vm *vm = xe_migrate_get_vm(xe_device_get_root_tile(xe)->migrate);
> -	struct ww_acquire_ctx ww;
>  	int err, i;
>  
>  	kunit_info(test, "Testing device %s gt id %u vram id %u\n",
>  		   dev_name(xe->drm.dev), gt->info.id, gt_to_tile(gt)->id);
>  
>  	for (i = 0; i < 2; ++i) {
> -		xe_vm_lock(vm, &ww, 0, false);
> +		xe_vm_lock(vm, false);
>  		bo = xe_bo_create(xe, NULL, vm, 0x10000, ttm_bo_type_device,
>  				  bo_flags);
> -		xe_vm_unlock(vm, &ww);
> +		xe_vm_unlock(vm);
>  		if (IS_ERR(bo)) {
>  			KUNIT_FAIL(test, "bo create err=%pe\n", bo);
>  			break;
> @@ -259,9 +258,9 @@ static int evict_test_run_gt(struct xe_device *xe, struct xe_gt *gt, struct kuni
>  
>  		if (i) {
>  			down_read(&vm->lock);
> -			xe_vm_lock(vm, &ww, 0, false);
> +			xe_vm_lock(vm, false);
>  			err = xe_bo_validate(bo, bo->vm, false);
> -			xe_vm_unlock(vm, &ww);
> +			xe_vm_unlock(vm);
>  			up_read(&vm->lock);
>  			if (err) {
>  				KUNIT_FAIL(test, "bo valid err=%pe\n",
> diff --git a/drivers/gpu/drm/xe/tests/xe_migrate.c b/drivers/gpu/drm/xe/tests/xe_migrate.c
> index 5c8d5e78d9bc..8bb081086ca2 100644
> --- a/drivers/gpu/drm/xe/tests/xe_migrate.c
> +++ b/drivers/gpu/drm/xe/tests/xe_migrate.c
> @@ -396,14 +396,13 @@ static int migrate_test_run_device(struct xe_device *xe)
>  
>  	for_each_tile(tile, xe, id) {
>  		struct xe_migrate *m = tile->migrate;
> -		struct ww_acquire_ctx ww;
>  
>  		kunit_info(test, "Testing tile id %d.\n", id);
> -		xe_vm_lock(m->q->vm, &ww, 0, true);
> +		xe_vm_lock(m->q->vm, true);
>  		xe_device_mem_access_get(xe);
>  		xe_migrate_sanity_test(m, test);
>  		xe_device_mem_access_put(xe);
> -		xe_vm_unlock(m->q->vm, &ww);
> +		xe_vm_unlock(m->q->vm);
>  	}
>  
>  	return 0;
> diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> index 9d70d12e79b1..f329fe798394 100644
> --- a/drivers/gpu/drm/xe/xe_bo.c
> +++ b/drivers/gpu/drm/xe/xe_bo.c
> @@ -1749,7 +1749,6 @@ int xe_gem_create_ioctl(struct drm_device *dev, void *data,
>  	struct xe_device *xe = to_xe_device(dev);
>  	struct xe_file *xef = to_xe_file(file);
>  	struct drm_xe_gem_create *args = data;
> -	struct ww_acquire_ctx ww;
>  	struct xe_vm *vm = NULL;
>  	struct xe_bo *bo;
>  	unsigned int bo_flags = XE_BO_CREATE_USER_BIT;
> @@ -1802,7 +1801,7 @@ int xe_gem_create_ioctl(struct drm_device *dev, void *data,
>  		vm = xe_vm_lookup(xef, args->vm_id);
>  		if (XE_IOCTL_DBG(xe, !vm))
>  			return -ENOENT;
> -		err = xe_vm_lock(vm, &ww, 0, true);
> +		err = xe_vm_lock(vm, true);
>  		if (err) {
>  			xe_vm_put(vm);
>  			return err;
> @@ -1830,7 +1829,7 @@ int xe_gem_create_ioctl(struct drm_device *dev, void *data,
>  	xe_bo_put(bo);
>  out_vm:
>  	if (vm) {
> -		xe_vm_unlock(vm, &ww);
> +		xe_vm_unlock(vm);
>  		xe_vm_put(vm);
>  	}
>  	return err;
> diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c b/drivers/gpu/drm/xe/xe_exec_queue.c
> index e44d71c679cc..6725157d8c1d 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue.c
> +++ b/drivers/gpu/drm/xe/xe_exec_queue.c
> @@ -111,18 +111,17 @@ struct xe_exec_queue *xe_exec_queue_create(struct xe_device *xe, struct xe_vm *v
>  					   u32 logical_mask, u16 width,
>  					   struct xe_hw_engine *hwe, u32 flags)
>  {
> -	struct ww_acquire_ctx ww;
>  	struct xe_exec_queue *q;
>  	int err;
>  
>  	if (vm) {
> -		err = xe_vm_lock(vm, &ww, 0, true);
> +		err = xe_vm_lock(vm, true);
>  		if (err)
>  			return ERR_PTR(err);
>  	}
>  	q = __xe_exec_queue_create(xe, vm, logical_mask, width, hwe, flags);
>  	if (vm)
> -		xe_vm_unlock(vm, &ww);
> +		xe_vm_unlock(vm);
>  
>  	return q;
>  }
> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
> index 2b4219c38359..434fbb364b4b 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.c
> +++ b/drivers/gpu/drm/xe/xe_lrc.c
> @@ -789,16 +789,14 @@ int xe_lrc_init(struct xe_lrc *lrc, struct xe_hw_engine *hwe,
>  
>  void xe_lrc_finish(struct xe_lrc *lrc)
>  {
> -	struct ww_acquire_ctx ww;
> -
>  	xe_hw_fence_ctx_finish(&lrc->fence_ctx);
>  	if (lrc->bo->vm)
> -		xe_vm_lock(lrc->bo->vm, &ww, 0, false);
> +		xe_vm_lock(lrc->bo->vm, false);
>  	else
>  		xe_bo_lock_no_vm(lrc->bo, NULL);
>  	xe_bo_unpin(lrc->bo);
>  	if (lrc->bo->vm)
> -		xe_vm_unlock(lrc->bo->vm, &ww);
> +		xe_vm_unlock(lrc->bo->vm);
>  	else
>  		xe_bo_unlock_no_vm(lrc->bo);
>  	xe_bo_put(lrc->bo);
> diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
> index a782ea282cb6..ee8bc5f3ba3d 100644
> --- a/drivers/gpu/drm/xe/xe_migrate.c
> +++ b/drivers/gpu/drm/xe/xe_migrate.c
> @@ -88,13 +88,12 @@ struct xe_exec_queue *xe_tile_migrate_engine(struct xe_tile *tile)
>  static void xe_migrate_fini(struct drm_device *dev, void *arg)
>  {
>  	struct xe_migrate *m = arg;
> -	struct ww_acquire_ctx ww;
>  
> -	xe_vm_lock(m->q->vm, &ww, 0, false);
> +	xe_vm_lock(m->q->vm, false);
>  	xe_bo_unpin(m->pt_bo);
>  	if (m->cleared_bo)
>  		xe_bo_unpin(m->cleared_bo);
> -	xe_vm_unlock(m->q->vm, &ww);
> +	xe_vm_unlock(m->q->vm);
>  
>  	dma_fence_put(m->fence);
>  	if (m->cleared_bo)
> @@ -338,7 +337,6 @@ struct xe_migrate *xe_migrate_init(struct xe_tile *tile)
>  	struct xe_gt *primary_gt = tile->primary_gt;
>  	struct xe_migrate *m;
>  	struct xe_vm *vm;
> -	struct ww_acquire_ctx ww;
>  	int err;
>  
>  	m = drmm_kzalloc(&xe->drm, sizeof(*m), GFP_KERNEL);
> @@ -353,9 +351,9 @@ struct xe_migrate *xe_migrate_init(struct xe_tile *tile)
>  	if (IS_ERR(vm))
>  		return ERR_CAST(vm);
>  
> -	xe_vm_lock(vm, &ww, 0, false);
> +	xe_vm_lock(vm, false);
>  	err = xe_migrate_prepare_vm(tile, m, vm);
> -	xe_vm_unlock(vm, &ww);
> +	xe_vm_unlock(vm);
>  	if (err) {
>  		xe_vm_close_and_put(vm);
>  		return ERR_PTR(err);
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index 5679c47f47ca..ac222cbe78f0 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -518,18 +518,17 @@ void xe_vm_unlock_dma_resv(struct xe_vm *vm,
>  
>  static void xe_vm_kill(struct xe_vm *vm)
>  {
> -	struct ww_acquire_ctx ww;
>  	struct xe_exec_queue *q;
>  
>  	lockdep_assert_held(&vm->lock);
>  
> -	xe_vm_lock(vm, &ww, 0, false);
> +	xe_vm_lock(vm, false);
>  	vm->flags |= XE_VM_FLAG_BANNED;
>  	trace_xe_vm_kill(vm);
>  
>  	list_for_each_entry(q, &vm->preempt.exec_queues, compute.link)
>  		q->ops->kill(q);
> -	xe_vm_unlock(vm, &ww);
> +	xe_vm_unlock(vm);
>  
>  	/* TODO: Inform user the VM is banned */
>  }
> @@ -1407,7 +1406,6 @@ static void xe_vm_close(struct xe_vm *vm)
>  void xe_vm_close_and_put(struct xe_vm *vm)
>  {
>  	LIST_HEAD(contested);
> -	struct ww_acquire_ctx ww;
>  	struct xe_device *xe = vm->xe;
>  	struct xe_tile *tile;
>  	struct xe_vma *vma, *next_vma;
> @@ -1430,7 +1428,7 @@ void xe_vm_close_and_put(struct xe_vm *vm)
>  	}
>  
>  	down_write(&vm->lock);
> -	xe_vm_lock(vm, &ww, 0, false);
> +	xe_vm_lock(vm, false);
>  	drm_gpuva_for_each_va_safe(gpuva, next, &vm->mgr) {
>  		vma = gpuva_to_vma(gpuva);
>  
> @@ -1471,7 +1469,7 @@ void xe_vm_close_and_put(struct xe_vm *vm)
>  					      NULL);
>  		}
>  	}
> -	xe_vm_unlock(vm, &ww);
> +	xe_vm_unlock(vm);
>  
>  	/*
>  	 * VM is now dead, cannot re-add nodes to vm->vmas if it's NULL
> @@ -1509,7 +1507,6 @@ static void vm_destroy_work_func(struct work_struct *w)
>  {
>  	struct xe_vm *vm =
>  		container_of(w, struct xe_vm, destroy_work);
> -	struct ww_acquire_ctx ww;
>  	struct xe_device *xe = vm->xe;
>  	struct xe_tile *tile;
>  	u8 id;
> @@ -1534,14 +1531,14 @@ static void vm_destroy_work_func(struct work_struct *w)
>  	 * is needed for xe_vm_lock to work. If we remove that dependency this
>  	 * can be moved to xe_vm_close_and_put.
>  	 */
> -	xe_vm_lock(vm, &ww, 0, false);
> +	xe_vm_lock(vm, false);
>  	for_each_tile(tile, xe, id) {
>  		if (vm->pt_root[id]) {
>  			xe_pt_destroy(vm->pt_root[id], vm->flags, NULL);
>  			vm->pt_root[id] = NULL;
>  		}
>  	}
> -	xe_vm_unlock(vm, &ww);
> +	xe_vm_unlock(vm);
>  
>  	trace_xe_vm_free(vm);
>  	dma_fence_put(vm->rebind_fence);
> @@ -3417,30 +3414,31 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
>  	return err == -ENODATA ? 0 : err;
>  }
>  
> -/*
> - * XXX: Using the TTM wrappers for now, likely can call into dma-resv code
> - * directly to optimize. Also this likely should be an inline function.
> +/**
> + * xe_vm_lock() - Lock the vm's dma_resv object
> + * @vm: The struct xe_vm whose lock is to be locked
> + * @intr: Whether to perform any wait interruptible
> + *
> + * Return: 0 on success, -EINTR if @intr is true and the wait for a
> + * contended lock was interrupted.

Same as previous patch [1] add a comment on checking the return value.
[1] https://patchwork.freedesktop.org/patch/555184/?series=123100&rev=2

>   */
> -int xe_vm_lock(struct xe_vm *vm, struct ww_acquire_ctx *ww,
> -	       int num_resv, bool intr)
> +int xe_vm_lock(struct xe_vm *vm, bool intr)

Even though it isn't used, to be uniform I'm wondering if we should
include an argument to reserve fence slots like xe_bo_lock()? Just a
thought, up to you.

Other than the NITs LGTM.

Matt

>  {
> -	struct ttm_validate_buffer tv_vm;
> -	LIST_HEAD(objs);
> -	LIST_HEAD(dups);
> -
> -	XE_WARN_ON(!ww);
> -
> -	tv_vm.num_shared = num_resv;
> -	tv_vm.bo = xe_vm_ttm_bo(vm);
> -	list_add_tail(&tv_vm.head, &objs);
> +	if (intr)
> +		return dma_resv_lock_interruptible(&vm->resv, NULL);
>  
> -	return ttm_eu_reserve_buffers(ww, &objs, intr, &dups);
> +	return dma_resv_lock(&vm->resv, NULL);
>  }
>  
> -void xe_vm_unlock(struct xe_vm *vm, struct ww_acquire_ctx *ww)
> +/**
> + * xe_vm_unlock() - Unlock the vm's dma_resv object
> + * @vm: The struct xe_vm whose lock is to be released.
> + *
> + * Unlock a buffer object lock that was locked by xe_vm_lock().
> + */
> +void xe_vm_unlock(struct xe_vm *vm)
>  {
>  	dma_resv_unlock(&vm->resv);
> -	ww_acquire_fini(ww);
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/xe/xe_vm.h b/drivers/gpu/drm/xe/xe_vm.h
> index 6de6e3edb24a..d7d8fd7bd8da 100644
> --- a/drivers/gpu/drm/xe/xe_vm.h
> +++ b/drivers/gpu/drm/xe/xe_vm.h
> @@ -39,10 +39,9 @@ static inline void xe_vm_put(struct xe_vm *vm)
>  	kref_put(&vm->refcount, xe_vm_free);
>  }
>  
> -int xe_vm_lock(struct xe_vm *vm, struct ww_acquire_ctx *ww,
> -	       int num_resv, bool intr);
> +int xe_vm_lock(struct xe_vm *vm, bool intr);
>  
> -void xe_vm_unlock(struct xe_vm *vm, struct ww_acquire_ctx *ww);
> +void xe_vm_unlock(struct xe_vm *vm);
>  
>  static inline bool xe_vm_is_closed(struct xe_vm *vm)
>  {
> -- 
> 2.41.0
> 


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