[Intel-gfx] [PATCH] drm/i915: Split alloc from init for lrc

Daniel, Thomas thomas.daniel at intel.com
Wed Sep 9 06:54:20 PDT 2015


This needs a rebase as a new GuC TLB invalidation call has been added when the context objects are pinned.  Your patch misses this for the default context.  In fact I reckon there's a case to consolidate the two (default / non-default) object pinning sequence into a single function to avoid further duplication or missing bits in future.

Also, as you're rebasing, see my nit-picks below.

> -----Original Message-----
> From: Intel-gfx [mailto:intel-gfx-bounces at lists.freedesktop.org] On Behalf Of
> Nick Hoath
> Sent: Friday, September 4, 2015 2:49 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Daniel Vetter
> Subject: [Intel-gfx] [PATCH] drm/i915: Split alloc from init for lrc
> 
> Extend init/init_hw split to context init.
>    - Move context initialisation in to i915_gem_init_hw
>    - Move one off initialisation for render ring to
>         i915_gem_validate_context
>    - Move default context initialisation to logical_ring_init
> 
> Rename intel_lr_context_deferred_create to
> intel_lr_context_deferred_alloc, to reflect reduced functionality &
> alloc/init split.
> 
> This patch is intended to split out the allocation of resources &
> initialisation to allow easier reuse of code for resume/gpu reset.
> 
> v2: Removed function ptr wrapping of do_switch_context (Daniel Vetter)
>     Left ->init_context int intel_lr_context_deferred_alloc
>     (Daniel Vetter)
>     Remove unnecessary init flag & ring type test. (Daniel Vetter)
>     Improve commit message (Daniel Vetter)
> v3: On init/reinit, set the hw next sequence number to the sw next
>     sequence number. This is set to 1 at driver load time. This prevents
>     the seqno being reset on reinit (Chris Wilson)
> v4: Set seqno back to ~0 - 0x1000 at start-of-day, and increment by 0x100
>     on reset.
>     This makes it obvious which bbs are which after a reset. (David Gordon
>     & John Harrison)
>     Rebase.
> 
> Issue: VIZ-4798
> Signed-off-by: Nick Hoath <nicholas.hoath at intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: John Harrison <john.c.harrison at intel.com>
> Cc: David Gordon <david.s.gordon at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h            |   1 -
>  drivers/gpu/drm/i915/i915_gem.c            |  24 +++--
>  drivers/gpu/drm/i915/i915_gem_execbuffer.c |   3 +-
>  drivers/gpu/drm/i915/intel_lrc.c           | 155 ++++++++++++++---------------
>  drivers/gpu/drm/i915/intel_lrc.h           |   4 +-
>  5 files changed, 93 insertions(+), 94 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 1287007..ded7158 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -888,7 +888,6 @@ struct intel_context {
>  	} legacy_hw_ctx;
> 
>  	/* Execlists */
> -	bool rcs_initialized;
>  	struct {
>  		struct drm_i915_gem_object *state;
>  		struct intel_ringbuffer *ringbuf;
> diff --git a/drivers/gpu/drm/i915/i915_gem.c
> b/drivers/gpu/drm/i915/i915_gem.c
> index 41263cd..c8125a5 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -4613,14 +4613,8 @@ int i915_gem_init_rings(struct drm_device *dev)
>  			goto cleanup_vebox_ring;
>  	}
> 
> -	ret = i915_gem_set_seqno(dev, ((u32)~0 - 0x1000));
> -	if (ret)
> -		goto cleanup_bsd2_ring;
> -
>  	return 0;
> 
> -cleanup_bsd2_ring:
> -	intel_cleanup_ring_buffer(&dev_priv->ring[VCS2]);
>  cleanup_vebox_ring:
>  	intel_cleanup_ring_buffer(&dev_priv->ring[VECS]);
>  cleanup_blt_ring:
> @@ -4639,6 +4633,7 @@ i915_gem_init_hw(struct drm_device *dev)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct intel_engine_cs *ring;
>  	int ret, i, j;
> +	struct drm_i915_gem_request *req;
Please leave req in the loop scope below to avoid unnecessary code churn.

> 
>  	if (INTEL_INFO(dev)->gen < 6 && !intel_enable_gtt())
>  		return -EIO;
> @@ -4706,9 +4701,16 @@ i915_gem_init_hw(struct drm_device *dev)
>  			goto out;
>  	}
> 
> +	/*
> +	 * Increment the next seqno by 0x100 so we have a visible break
> +	 * on re-initialisation
> +	 */
> +	ret = i915_gem_set_seqno(dev, dev_priv->next_seqno+0x100);
> +	if (ret)
> +		goto out;
> +
>  	/* Now it is safe to go back round and do everything else: */
>  	for_each_ring(ring, dev_priv, i) {
> -		struct drm_i915_gem_request *req;
> 
>  		WARN_ON(!ring->default_context);
> 
> @@ -4907,6 +4909,14 @@ i915_gem_load(struct drm_device *dev)
>  		dev_priv->num_fence_regs =
>  				I915_READ(vgtif_reg(avail_rs.fence_num));
> 
> +	/*
> +	 * Set initial sequence number for requests.
> +	 * Using this number allows the wraparound to happen early,
> +	 * catching any obvious problems.
> +	 */
> +	dev_priv->next_seqno = ((u32)~0 - 0x1100);
> +	dev_priv->last_seqno = ((u32)~0 - 0x1101);
> +
>  	/* Initialize fence registers to zero */
>  	INIT_LIST_HEAD(&dev_priv->mm.fence_list);
>  	i915_gem_restore_fences(dev);
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index a953d49..64674dc 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -994,6 +994,7 @@ i915_gem_validate_context(struct drm_device *dev,
> struct drm_file *file,
>  {
>  	struct intel_context *ctx = NULL;
>  	struct i915_ctx_hang_stats *hs;
> +	int ret;
Another strictly unnecessary scope change.  I would normally prefer function-scope ret, but in this case we usually return ctx.

> 
>  	if (ring->id != RCS && ctx_id != DEFAULT_CONTEXT_HANDLE)
>  		return ERR_PTR(-EINVAL);
> @@ -1009,7 +1010,7 @@ i915_gem_validate_context(struct drm_device *dev,
> struct drm_file *file,
>  	}
> 
>  	if (i915.enable_execlists && !ctx->engine[ring->id].state) {
> -		int ret = intel_lr_context_deferred_create(ctx, ring);
> +		ret = intel_lr_context_deferred_alloc(ctx, ring);
>  		if (ret) {
>  			DRM_DEBUG("Could not create LRC %u: %d\n", ctx_id,
> ret);
>  			return ERR_PTR(ret);
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 28a712e..ebe30a9 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -1445,11 +1445,32 @@ out:
>  	return ret;
>  }
> 
> +static void lrc_setup_hardware_status_page(struct intel_engine_cs *ring,
> +		struct drm_i915_gem_object *default_ctx_obj)
> +{
> +	struct drm_i915_private *dev_priv = ring->dev->dev_private;
> +	struct page *page;
> +
> +	/* The HWSP is part of the default context object in LRC mode. */
> +	ring->status_page.gfx_addr =
> i915_gem_obj_ggtt_offset(default_ctx_obj)
> +			+ LRC_PPHWSP_PN * PAGE_SIZE;
> +	page = i915_gem_object_get_page(default_ctx_obj, LRC_PPHWSP_PN);
> +	ring->status_page.page_addr = kmap(page);
> +	ring->status_page.obj = default_ctx_obj;
> +
> +	I915_WRITE(RING_HWS_PGA(ring->mmio_base),
> +			(u32)ring->status_page.gfx_addr);
> +	POSTING_READ(RING_HWS_PGA(ring->mmio_base));
> +}
> +
Moving this function will lead to unnecessary churn, making it difficult to follow history with git blame and to know whether you actually changed the function.  Maybe adding a forward declaration is the better way to go.  Not sure what is preferred generally though...

>  static int gen8_init_common_ring(struct intel_engine_cs *ring)
>  {
>  	struct drm_device *dev = ring->dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> 
> +	lrc_setup_hardware_status_page(ring,
> +				ring->default_context->engine[ring->id].state);
> +
>  	I915_WRITE_IMR(ring, ~(ring->irq_enable_mask | ring-
> >irq_keep_mask));
>  	I915_WRITE(RING_HWSTAM(ring->mmio_base), 0xffffffff);
> 
> @@ -1889,8 +1910,33 @@ static int logical_ring_init(struct drm_device *dev,
> struct intel_engine_cs *rin
>  	if (ret)
>  		return ret;
> 
> -	ret = intel_lr_context_deferred_create(ring->default_context, ring);
> +	ret = intel_lr_context_deferred_alloc(ring->default_context, ring);
> +	if (ret)
> +		return ret;
> +
> +	ret = i915_gem_obj_ggtt_pin(
> +		ring->default_context->engine[ring->id].state,
> +		GEN8_LR_CONTEXT_ALIGN, 0);
> +	if (ret) {
> +		DRM_DEBUG_DRIVER("Pin LRC backing obj failed: %d\n",
> +				ret);
> +		return ret;
> +	}
> +
> +	ret = intel_pin_and_map_ringbuffer_obj(dev,
> +		ring->default_context->engine[ring->id].ringbuf);
> +	if (ret) {
> +		DRM_ERROR(
> +			"Failed to pin and map ringbuffer %s: %d\n",
> +			ring->name, ret);
> +		goto error_unpin_ggtt;
> +	}
> +
> +	return ret;
> 
> +error_unpin_ggtt:
> +	i915_gem_object_ggtt_unpin(
> +		ring->default_context->engine[ring->id].state);
>  	return ret;
>  }
> 
> @@ -2112,14 +2158,8 @@ int intel_logical_rings_init(struct drm_device *dev)
>  			goto cleanup_vebox_ring;
>  	}
> 
> -	ret = i915_gem_set_seqno(dev, ((u32)~0 - 0x1000));
> -	if (ret)
> -		goto cleanup_bsd2_ring;
> -
>  	return 0;
> 
> -cleanup_bsd2_ring:
> -	intel_logical_ring_cleanup(&dev_priv->ring[VCS2]);
>  cleanup_vebox_ring:
>  	intel_logical_ring_cleanup(&dev_priv->ring[VECS]);
>  cleanup_blt_ring:
> @@ -2370,26 +2410,8 @@ static uint32_t get_lr_context_size(struct
> intel_engine_cs *ring)
>  	return ret;
>  }
> 
> -static void lrc_setup_hardware_status_page(struct intel_engine_cs *ring,
> -		struct drm_i915_gem_object *default_ctx_obj)
> -{
> -	struct drm_i915_private *dev_priv = ring->dev->dev_private;
> -	struct page *page;
> -
> -	/* The HWSP is part of the default context object in LRC mode. */
> -	ring->status_page.gfx_addr =
> i915_gem_obj_ggtt_offset(default_ctx_obj)
> -			+ LRC_PPHWSP_PN * PAGE_SIZE;
> -	page = i915_gem_object_get_page(default_ctx_obj, LRC_PPHWSP_PN);
> -	ring->status_page.page_addr = kmap(page);
> -	ring->status_page.obj = default_ctx_obj;
> -
> -	I915_WRITE(RING_HWS_PGA(ring->mmio_base),
> -			(u32)ring->status_page.gfx_addr);
> -	POSTING_READ(RING_HWS_PGA(ring->mmio_base));
> -}
> -
>  /**
> - * intel_lr_context_deferred_create() - create the LRC specific bits of a context
> + * intel_lr_context_deferred_alloc() - create the LRC specific bits of a context
>   * @ctx: LR context to create.
>   * @ring: engine to be used with the context.
>   *
> @@ -2401,12 +2423,11 @@ static void lrc_setup_hardware_status_page(struct
> intel_engine_cs *ring,
>   *
>   * Return: non-zero on error.
>   */
> -int intel_lr_context_deferred_create(struct intel_context *ctx,
> +
> +int intel_lr_context_deferred_alloc(struct intel_context *ctx,
>  				     struct intel_engine_cs *ring)
>  {
> -	const bool is_global_default_ctx = (ctx == ring->default_context);
>  	struct drm_device *dev = ring->dev;
> -	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct drm_i915_gem_object *ctx_obj;
>  	uint32_t context_size;
>  	struct intel_ringbuffer *ringbuf;
> @@ -2426,82 +2447,50 @@ int intel_lr_context_deferred_create(struct
> intel_context *ctx,
>  		return -ENOMEM;
>  	}
> 
> -	if (is_global_default_ctx) {
> -		ret = i915_gem_obj_ggtt_pin(ctx_obj,
> GEN8_LR_CONTEXT_ALIGN,
> -				PIN_OFFSET_BIAS | GUC_WOPCM_TOP);
> -		if (ret) {
> -			DRM_DEBUG_DRIVER("Pin LRC backing obj failed:
> %d\n",
> -					ret);
> -			drm_gem_object_unreference(&ctx_obj->base);
> -			return ret;
> -		}
> -
> -		/* Invalidate GuC TLB. */
> -		if (i915.enable_guc_submission)
> -			I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
> -	}
> -
>  	ringbuf = intel_engine_create_ringbuffer(ring, 4 * PAGE_SIZE);
>  	if (IS_ERR(ringbuf)) {
>  		ret = PTR_ERR(ringbuf);
> -		goto error_unpin_ctx;
> -	}
> -
> -	if (is_global_default_ctx) {
> -		ret = intel_pin_and_map_ringbuffer_obj(dev, ringbuf);
> -		if (ret) {
> -			DRM_ERROR(
> -				  "Failed to pin and map ringbuffer %s: %d\n",
> -				  ring->name, ret);
> -			goto error_ringbuf;
> -		}
> +		goto error_deref_obj;
>  	}
> 
>  	ret = populate_lr_context(ctx, ctx_obj, ring, ringbuf);
>  	if (ret) {
>  		DRM_DEBUG_DRIVER("Failed to populate LRC: %d\n", ret);
> -		goto error;
> +		goto error_ringbuf;
>  	}
> 
>  	ctx->engine[ring->id].ringbuf = ringbuf;
>  	ctx->engine[ring->id].state = ctx_obj;
> 
> -	if (ctx == ring->default_context)
> -		lrc_setup_hardware_status_page(ring, ctx_obj);
> -	else if (ring->id == RCS && !ctx->rcs_initialized) {
> -		if (ring->init_context) {
> -			struct drm_i915_gem_request *req;
> -
> -			ret = i915_gem_request_alloc(ring, ctx, &req);
> -			if (ret)
> -				return ret;
> +	if (ctx != ring->default_context && ring->init_context) {
> +		struct drm_i915_gem_request *req;
> 
> -			ret = ring->init_context(req);
> -			if (ret) {
> -				DRM_ERROR("ring init context: %d\n", ret);
> -				i915_gem_request_cancel(req);
> -				ctx->engine[ring->id].ringbuf = NULL;
> -				ctx->engine[ring->id].state = NULL;
> -				goto error;
> -			}
> -
> -			i915_add_request_no_flush(req);
> +		ret = i915_gem_request_alloc(ring,
> +			ring->default_context, &req);
> +		if (ret) {
> +			DRM_ERROR("ring create req: %d\n",
> +				ret);
> +			i915_gem_request_cancel(req);
> +			goto error_ringbuf;
>  		}
> 
> -		ctx->rcs_initialized = true;
> +		ret = ring->init_context(req);
> +		if (ret) {
> +			DRM_ERROR("ring init context: %d\n",
> +				ret);
> +			i915_gem_request_cancel(req);
> +			goto error_ringbuf;
> +		}
> +		i915_add_request_no_flush(req);
>  	}
> -
>  	return 0;
> 
> -error:
> -	if (is_global_default_ctx)
> -		intel_unpin_ringbuffer_obj(ringbuf);
>  error_ringbuf:
>  	intel_ringbuffer_free(ringbuf);
> -error_unpin_ctx:
> -	if (is_global_default_ctx)
> -		i915_gem_object_ggtt_unpin(ctx_obj);
> +error_deref_obj:
>  	drm_gem_object_unreference(&ctx_obj->base);
> +	ctx->engine[ring->id].ringbuf = NULL;
> +	ctx->engine[ring->id].state = NULL;
>  	return ret;
>  }
> 
> diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
> index 4cc54b3..69d99f0 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.h
> +++ b/drivers/gpu/drm/i915/intel_lrc.h
> @@ -75,8 +75,8 @@ static inline void intel_logical_ring_emit(struct
> intel_ringbuffer *ringbuf,
>  #define LRC_STATE_PN	(LRC_PPHWSP_PN + 1)
> 
>  void intel_lr_context_free(struct intel_context *ctx);
> -int intel_lr_context_deferred_create(struct intel_context *ctx,
> -				     struct intel_engine_cs *ring);
> +int intel_lr_context_deferred_alloc(struct intel_context *ctx,
> +				    struct intel_engine_cs *ring);
>  void intel_lr_context_unpin(struct drm_i915_gem_request *req);
>  void intel_lr_context_reset(struct drm_device *dev,
>  			struct intel_context *ctx);
> --
> 2.1.1
> 
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