Re: [PATCH v4 04/38] drm/i915: Split i915_dem_do_execbuffer() in half

Jesse Barnes
2016-02-04T17:09:08Z

On 01/11/2016 10:42 AM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> Split the execbuffer() function in half. The first half collects and
> validates all the information required to process the batch buffer. It
> also does all the object pinning, relocations, active list management,
> etc - basically anything that must be done upfront before the IOCTL
> returns and allows the user land side to start changing/freeing
> things. The second half does the actual ring submission.
>
> This change implements the split but leaves the back half being called
> directly from the end of the front half.
>
> v2: Updated due to changes in underlying tree - addition of sync fence
> support and removal of cliprects.
>
> v3: Moved local 'ringbuf' variable to make later patches in the
> series a bit neater.
>
> v4: Corrected a typo in the commit message and downgraded a BUG_ON to
> a WARN_ON as the latter is preferred. Also removed all the external
> sync/fence support as that will now be a separate patch series.
>
> For: VIZ-1587
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 11 ++++
> drivers/gpu/drm/i915/i915_gem.c | 2 +
> drivers/gpu/drm/i915/i915_gem_execbuffer.c | 101 ++++++++++++++++++++++-------
> drivers/gpu/drm/i915/intel_lrc.c | 57 +++++++++++-----
> drivers/gpu/drm/i915/intel_lrc.h | 1 +
> 5 files changed, 130 insertions(+), 42 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index acfe25f..2520459 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1679,10 +1679,18 @@ struct i915_execbuffer_params {
> struct drm_device *dev;
> struct drm_file *file;
> uint32_t dispatch_flags;
> + uint32_t args_flags;
> uint32_t args_batch_start_offset;
> + uint32_t args_batch_len;
> + uint32_t args_num_cliprects;
> + uint32_t args_DR1;
> + uint32_t args_DR4;
> uint64_t batch_obj_vm_offset;
> struct intel_engine_cs *ring;
> struct drm_i915_gem_object *batch_obj;
> + struct drm_clip_rect *cliprects;
> + uint32_t instp_mask;
> + int instp_mode;
> struct intel_context *ctx;
> struct drm_i915_gem_request *request;
> };
> @@ -1944,6 +1952,7 @@ struct drm_i915_private {
> int (*execbuf_submit)(struct i915_execbuffer_params *params,
> struct drm_i915_gem_execbuffer2 *args,
> struct list_head *vmas);
> + int (*execbuf_final)(struct i915_execbuffer_params *params);
> int (*init_rings)(struct drm_device *dev);
> void (*cleanup_ring)(struct intel_engine_cs *ring);
> void (*stop_ring)(struct intel_engine_cs *ring);
> @@ -2790,9 +2799,11 @@ int i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
> void i915_gem_execbuffer_move_to_active(struct list_head *vmas,
> struct drm_i915_gem_request *req);
> void i915_gem_execbuffer_retire_commands(struct i915_execbuffer_params *params);
> +void i915_gem_execbuff_release_batch_obj(struct drm_i915_gem_object *batch_obj);
> int i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
> struct drm_i915_gem_execbuffer2 *args,
> struct list_head *vmas);
> +int i915_gem_ringbuffer_submission_final(struct i915_execbuffer_params *params);
> int i915_gem_execbuffer(struct drm_device *dev, void *data,
> struct drm_file *file_priv);
> int i915_gem_execbuffer2(struct drm_device *dev, void *data,
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index e8ec49e..5bf7da6 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -5220,11 +5220,13 @@ int i915_gem_init(struct drm_device *dev)
>
> if (!i915.enable_execlists) {
> dev_priv->gt.execbuf_submit = i915_gem_ringbuffer_submission;
> + dev_priv->gt.execbuf_final = i915_gem_ringbuffer_submission_final;
> dev_priv->gt.init_rings = i915_gem_init_rings;
> dev_priv->gt.cleanup_ring = intel_cleanup_ring_buffer;
> dev_priv->gt.stop_ring = intel_stop_ring_buffer;
> } else {
> dev_priv->gt.execbuf_submit = intel_execlists_submission;
> + dev_priv->gt.execbuf_final = intel_execlists_submission_final;
> dev_priv->gt.init_rings = intel_logical_rings_init;
> dev_priv->gt.cleanup_ring = intel_logical_ring_cleanup;
> dev_priv->gt.stop_ring = intel_logical_ring_stop;
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 0eca2b6..eff171d 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -1181,41 +1181,38 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
> struct drm_device *dev = params->dev;
> struct intel_engine_cs *ring = params->ring;
> struct drm_i915_private *dev_priv = dev->dev_private;
> - u64 exec_start, exec_len;
> - int instp_mode;
> - u32 instp_mask;
> int ret;
>
> - instp_mode = args->flags & I915_EXEC_CONSTANTS_MASK;
> - instp_mask = I915_EXEC_CONSTANTS_MASK;
> - switch (instp_mode) {
> + params->instp_mode = args->flags & I915_EXEC_CONSTANTS_MASK;
> + params->instp_mask = I915_EXEC_CONSTANTS_MASK;
> + switch (params->instp_mode) {
> case I915_EXEC_CONSTANTS_REL_GENERAL:
> case I915_EXEC_CONSTANTS_ABSOLUTE:
> case I915_EXEC_CONSTANTS_REL_SURFACE:
> - if (instp_mode != 0 && ring != &dev_priv->ring[RCS]) {
> + if (params->instp_mode != 0 && ring != &dev_priv->ring[RCS]) {
> DRM_DEBUG("non-0 rel constants mode on non-RCS\n");
> return -EINVAL;
> }
>
> - if (instp_mode != dev_priv->relative_constants_mode) {
> + if (params->instp_mode != dev_priv->relative_constants_mode) {
> if (INTEL_INFO(dev)->gen < 4) {
> DRM_DEBUG("no rel constants on pre-gen4\n");
> return -EINVAL;
> }
>
> if (INTEL_INFO(dev)->gen > 5 &&
> - instp_mode == I915_EXEC_CONSTANTS_REL_SURFACE) {
> + params->instp_mode == I915_EXEC_CONSTANTS_REL_SURFACE) {
> DRM_DEBUG("rel surface constants mode invalid on gen5+\n");
> return -EINVAL;
> }
>
> /* The HW changed the meaning on this bit on gen6 */
> if (INTEL_INFO(dev)->gen >= 6)
> - instp_mask &= ~I915_EXEC_CONSTANTS_REL_SURFACE;
> + params->instp_mask &= ~I915_EXEC_CONSTANTS_REL_SURFACE;
> }
> break;
> default:
> - DRM_DEBUG("execbuf with unknown constants: %d\n", instp_mode);
> + DRM_DEBUG("execbuf with unknown constants: %d\n", params->instp_mode);
> return -EINVAL;
> }
>
> @@ -1225,7 +1222,33 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
>
> i915_gem_execbuffer_move_to_active(vmas, params->request);
>
> - /* To be split into two functions here... */
> + ret = dev_priv->gt.execbuf_final(params);
> + if (ret)
> + return ret;
> +
> + /*
> + * Free everything that was stored in the QE structure (until the
> + * scheduler arrives and does it instead):
> + */
> + if (params->dispatch_flags & I915_DISPATCH_SECURE)
> + i915_gem_execbuff_release_batch_obj(params->batch_obj);
> +
> + return 0;
> +}
> +
> +/*
> + * This is the main function for adding a batch to the ring.
> + * It is called from the scheduler, with the struct_mutex already held.
> + */
> +int i915_gem_ringbuffer_submission_final(struct i915_execbuffer_params *params)
> +{
> + struct drm_i915_private *dev_priv = params->dev->dev_private;
> + struct intel_engine_cs *ring = params->ring;
> + u64 exec_start, exec_len;
> + int ret;
> +
> + /* The mutex must be acquired before calling this function */
> + WARN_ON(!mutex_is_locked(&params->dev->struct_mutex));
>
> intel_runtime_pm_get(dev_priv);
>
> @@ -1246,7 +1269,7 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
> "%s didn't clear reload\n", ring->name);
>
> if (ring == &dev_priv->ring[RCS] &&
> - instp_mode != dev_priv->relative_constants_mode) {
> + params->instp_mode != dev_priv->relative_constants_mode) {
> ret = intel_ring_begin(params->request, 4);
> if (ret)
> goto error;
> @@ -1254,19 +1277,19 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
> intel_ring_emit(ring, MI_NOOP);
> intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
> intel_ring_emit(ring, INSTPM);
> - intel_ring_emit(ring, instp_mask << 16 | instp_mode);
> + intel_ring_emit(ring, params->instp_mask << 16 | params->instp_mode);
> intel_ring_advance(ring);
>
> - dev_priv->relative_constants_mode = instp_mode;
> + dev_priv->relative_constants_mode = params->instp_mode;
> }
>
> - if (args->flags & I915_EXEC_GEN7_SOL_RESET) {
> - ret = i915_reset_gen7_sol_offsets(dev, params->request);
> + if (params->args_flags & I915_EXEC_GEN7_SOL_RESET) {
> + ret = i915_reset_gen7_sol_offsets(params->dev, params->request);
> if (ret)
> goto error;
> }
>
> - exec_len = args->batch_len;
> + exec_len = params->args_batch_len;
> exec_start = params->batch_obj_vm_offset +
> params->args_batch_start_offset;
>
> @@ -1584,23 +1607,40 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
> params->file = file;
> params->ring = ring;
> params->dispatch_flags = dispatch_flags;
> + params->args_flags = args->flags;
> + params->args_batch_len = args->batch_len;
> + params->args_num_cliprects = args->num_cliprects;
> + params->args_DR1 = args->DR1;
> + params->args_DR4 = args->DR4;
> params->batch_obj = batch_obj;
> params->ctx = ctx;
>
> ret = dev_priv->gt.execbuf_submit(params, args, &eb->vmas);
> + if (ret)
> + goto err_batch_unpin;
> +
> + /* the request owns the ref now */
> + i915_gem_context_unreference(ctx);
>
> -err_batch_unpin:
> /*
> - * FIXME: We crucially rely upon the active tracking for the (ppgtt)
> - * batch vma for correctness. For less ugly and less fragility this
> - * needs to be adjusted to also track the ggtt batch vma properly as
> - * active.
> + * The eb list is no longer required. The scheduler has extracted all
> + * the information than needs to persist.
> */
> + eb_destroy(eb);
> +
> + /*
> + * Don't clean up everything that is now saved away in the queue.
> + * Just unlock and return immediately.
> + */
> + mutex_unlock(&dev->struct_mutex);
> +
> + return 0;
> +
> +err_batch_unpin:
> if (dispatch_flags & I915_DISPATCH_SECURE)
> - i915_gem_object_ggtt_unpin(batch_obj);
> + i915_gem_execbuff_release_batch_obj(batch_obj);
>
> err:
> - /* the request owns the ref now */
> i915_gem_context_unreference(ctx);
> eb_destroy(eb);
>
> @@ -1618,6 +1658,17 @@ pre_mutex_err:
> return ret;
> }
>
> +void i915_gem_execbuff_release_batch_obj(struct drm_i915_gem_object *batch_obj)
> +{
> + /*
> + * FIXME: We crucially rely upon the active tracking for the (ppgtt)
> + * batch vma for correctness. For less ugly and less fragility this
> + * needs to be adjusted to also track the ggtt batch vma properly as
> + * active.
> + */
> + i915_gem_object_ggtt_unpin(batch_obj);
> +}
> +
> /*
> * Legacy execbuffer just creates an exec2 list from the original exec object
> * list array and passes it to the real function.
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 4bf0ee6..014180c 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -869,35 +869,31 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,
> struct drm_device *dev = params->dev;
> struct intel_engine_cs *ring = params->ring;
> struct drm_i915_private *dev_priv = dev->dev_private;
> - struct intel_ringbuffer *ringbuf = params->ctx->engine[ring->id].ringbuf;
> - u64 exec_start;
> - int instp_mode;
> - u32 instp_mask;
> int ret;
>
> - instp_mode = args->flags & I915_EXEC_CONSTANTS_MASK;
> - instp_mask = I915_EXEC_CONSTANTS_MASK;
> - switch (instp_mode) {
> + params->instp_mode = args->flags & I915_EXEC_CONSTANTS_MASK;
> + params->instp_mask = I915_EXEC_CONSTANTS_MASK;
> + switch (params->instp_mode) {
> case I915_EXEC_CONSTANTS_REL_GENERAL:
> case I915_EXEC_CONSTANTS_ABSOLUTE:
> case I915_EXEC_CONSTANTS_REL_SURFACE:
> - if (instp_mode != 0 && ring != &dev_priv->ring[RCS]) {
> + if (params->instp_mode != 0 && ring != &dev_priv->ring[RCS]) {
> DRM_DEBUG("non-0 rel constants mode on non-RCS\n");
> return -EINVAL;
> }
>
> - if (instp_mode != dev_priv->relative_constants_mode) {
> - if (instp_mode == I915_EXEC_CONSTANTS_REL_SURFACE) {
> + if (params->instp_mode != dev_priv->relative_constants_mode) {
> + if (params->instp_mode == I915_EXEC_CONSTANTS_REL_SURFACE) {
> DRM_DEBUG("rel surface constants mode invalid on gen5+\n");
> return -EINVAL;
> }
>
> /* The HW changed the meaning on this bit on gen6 */
> - instp_mask &= ~I915_EXEC_CONSTANTS_REL_SURFACE;
> + params->instp_mask &= ~I915_EXEC_CONSTANTS_REL_SURFACE;
> }
> break;
> default:
> - DRM_DEBUG("execbuf with unknown constants: %d\n", instp_mode);
> + DRM_DEBUG("execbuf with unknown constants: %d\n", params->instp_mode);
> return -EINVAL;
> }
>
> @@ -912,7 +908,34 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,
>
> i915_gem_execbuffer_move_to_active(vmas, params->request);
>
> - /* To be split into two functions here... */
> + ret = dev_priv->gt.execbuf_final(params);
> + if (ret)
> + return ret;
> +
> + /*
> + * Free everything that was stored in the QE structure (until the
> + * scheduler arrives and does it instead):
> + */
> + if (params->dispatch_flags & I915_DISPATCH_SECURE)
> + i915_gem_execbuff_release_batch_obj(params->batch_obj);
> +
> + return 0;
> +}
> +
> +/*
> + * This is the main function for adding a batch to the ring.
> + * It is called from the scheduler, with the struct_mutex already held.
> + */
> +int intel_execlists_submission_final(struct i915_execbuffer_params *params)
> +{
> + struct drm_i915_private *dev_priv = params->dev->dev_private;
> + struct intel_ringbuffer *ringbuf = params->request->ringbuf;
> + struct intel_engine_cs *ring = params->ring;
> + u64 exec_start;
> + int ret;
> +
> + /* The mutex must be acquired before calling this function */
> + WARN_ON(!mutex_is_locked(&params->dev->struct_mutex));
>
> /*
> * Unconditionally invalidate gpu caches and ensure that we do flush
> @@ -923,7 +946,7 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,
> return ret;
>
> if (ring == &dev_priv->ring[RCS] &&
> - instp_mode != dev_priv->relative_constants_mode) {
> + params->instp_mode != dev_priv->relative_constants_mode) {
> ret = intel_logical_ring_begin(params->request, 4);
> if (ret)
> return ret;
> @@ -931,14 +954,14 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,
> intel_logical_ring_emit(ringbuf, MI_NOOP);
> intel_logical_ring_emit(ringbuf, MI_LOAD_REGISTER_IMM(1));
> intel_logical_ring_emit(ringbuf, INSTPM);
> - intel_logical_ring_emit(ringbuf, instp_mask << 16 | instp_mode);
> + intel_logical_ring_emit(ringbuf, params->instp_mask << 16 | params->instp_mode);
> intel_logical_ring_advance(ringbuf);
>
> - dev_priv->relative_constants_mode = instp_mode;
> + dev_priv->relative_constants_mode = params->instp_mode;
> }
>
> exec_start = params->batch_obj_vm_offset +
> - args->batch_start_offset;
> + params->args_batch_start_offset;
>
> ret = ring->emit_bb_start(params->request, exec_start, params->dispatch_flags);
> if (ret)
> diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
> index 4e60d54..8d9bad7 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.h
> +++ b/drivers/gpu/drm/i915/intel_lrc.h
> @@ -93,6 +93,7 @@ struct i915_execbuffer_params;
> int intel_execlists_submission(struct i915_execbuffer_params *params,
> struct drm_i915_gem_execbuffer2 *args,
> struct list_head *vmas);
> +int intel_execlists_submission_final(struct i915_execbuffer_params *params);
> u32 intel_execlists_ctx_id(struct drm_i915_gem_object *ctx_obj);
>
> void intel_lrc_irq_handler(struct intel_engine_cs *ring);

Just a nitpick on naming; I think prepare/commit might be better than submit/submit_final. But you don't have to respin just for that.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>