Re: [PATCH] drm/i915: Split alloc from init for lrc

Daniel, Thomas
2015-09-09T13:54:24Z

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@lists.freedesktop.org] On Behalf Of
> Nick Hoath
> Sent: Friday, September 4, 2015 2:49 PM
> To: intel-gfx@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@intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: John Harrison <john.c.harrison@intel.com>
> Cc: David Gordon <david.s.gordon@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
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx