Re: [PATCH v4 03/38] drm/i915: Prelude to splitting i915_gem_do_execbuffer in two

Jesse Barnes
2016-02-04T17:01:36Z

On 01/11/2016 10:42 AM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The scheduler decouples the submission of batch buffers to the driver
> with their submission to the hardware. This basically means splitting
> the execbuffer() function in half. This change rearranges some code
> ready for the split to occur.
>
> For: VIZ-1587
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> ---
> drivers/gpu/drm/i915/i915_gem_execbuffer.c | 63 ++++++++++++++++++------------
> drivers/gpu/drm/i915/intel_lrc.c | 18 ++++++---
> 2 files changed, 51 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index bfc4c17..0eca2b6 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -933,10 +933,7 @@ i915_gem_execbuffer_move_to_gpu(struct drm_i915_gem_request *req,
> if (flush_domains & I915_GEM_DOMAIN_GTT)
> wmb();
>
> - /* Unconditionally invalidate gpu caches and ensure that we do flush
> - * any residual writes from the previous batch.
> - */
> - return intel_ring_invalidate_all_caches(req);
> + return 0;
> }
>
> static bool
> @@ -1189,17 +1186,6 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
> u32 instp_mask;
> int ret;
>
> - ret = i915_gem_execbuffer_move_to_gpu(params->request, vmas);
> - if (ret)
> - return ret;
> -
> - ret = i915_switch_context(params->request);
> - if (ret)
> - return ret;
> -
> - WARN(params->ctx->ppgtt && params->ctx->ppgtt->pd_dirty_rings & (1<<ring->id),
> - "%s didn't clear reload\n", ring->name);
> -
> instp_mode = args->flags & I915_EXEC_CONSTANTS_MASK;
> instp_mask = I915_EXEC_CONSTANTS_MASK;
> switch (instp_mode) {
> @@ -1233,11 +1219,37 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
> return -EINVAL;
> }
>
> + ret = i915_gem_execbuffer_move_to_gpu(params->request, vmas);
> + if (ret)
> + return ret;
> +
> + i915_gem_execbuffer_move_to_active(vmas, params->request);
> +
> + /* To be split into two functions here... */
> +
> + intel_runtime_pm_get(dev_priv);
> +
> + /*
> + * Unconditionally invalidate gpu caches and ensure that we do flush
> + * any residual writes from the previous batch.
> + */
> + ret = intel_ring_invalidate_all_caches(params->request);
> + if (ret)
> + goto error;
> +
> + /* Switch to the correct context for the batch */
> + ret = i915_switch_context(params->request);
> + if (ret)
> + goto error;
> +
> + WARN(params->ctx->ppgtt && params->ctx->ppgtt->pd_dirty_rings & (1<<ring->id),
> + "%s didn't clear reload\n", ring->name);
> +
> if (ring == &dev_priv->ring[RCS] &&
> instp_mode != dev_priv->relative_constants_mode) {
> ret = intel_ring_begin(params->request, 4);
> if (ret)
> - return ret;
> + goto error;
>
> intel_ring_emit(ring, MI_NOOP);
> intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
> @@ -1251,7 +1263,7 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
> if (args->flags & I915_EXEC_GEN7_SOL_RESET) {
> ret = i915_reset_gen7_sol_offsets(dev, params->request);
> if (ret)
> - return ret;
> + goto error;
> }
>
> exec_len = args->batch_len;
> @@ -1262,14 +1274,20 @@ i915_gem_ringbuffer_submission(struct i915_execbuffer_params *params,
> exec_start, exec_len,
> params->dispatch_flags);
> if (ret)
> - return ret;
> + goto error;
>
> trace_i915_gem_ring_dispatch(params->request, params->dispatch_flags);
>
> - i915_gem_execbuffer_move_to_active(vmas, params->request);
> i915_gem_execbuffer_retire_commands(params);
>
> - return 0;
> +error:
> + /*
> + * intel_gpu_busy should also get a ref, so it will free when the device
> + * is really idle.
> + */
> + intel_runtime_pm_put(dev_priv);
> +
> + return ret;
> }
>
> /**
> @@ -1424,8 +1442,6 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
> dispatch_flags |= I915_DISPATCH_RS;
> }
>
> - intel_runtime_pm_get(dev_priv);
> -
> ret = i915_mutex_lock_interruptible(dev);
> if (ret)
> goto pre_mutex_err;
> @@ -1599,9 +1615,6 @@ err:
> mutex_unlock(&dev->struct_mutex);
>
> pre_mutex_err:
> - /* intel_gpu_busy should also get a ref, so it will free when the device
> - * is really idle. */
> - intel_runtime_pm_put(dev_priv);
> return ret;
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index e510730..4bf0ee6 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -647,10 +647,7 @@ static int execlists_move_to_gpu(struct drm_i915_gem_request *req,
> if (flush_domains & I915_GEM_DOMAIN_GTT)
> wmb();
>
> - /* Unconditionally invalidate gpu caches and ensure that we do flush
> - * any residual writes from the previous batch.
> - */
> - return logical_ring_invalidate_all_caches(req);
> + return 0;
> }
>
> int intel_logical_ring_alloc_request_extras(struct drm_i915_gem_request *request)
> @@ -913,6 +910,18 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,
> if (ret)
> return ret;
>
> + i915_gem_execbuffer_move_to_active(vmas, params->request);
> +
> + /* To be split into two functions here... */
> +
> + /*
> + * Unconditionally invalidate gpu caches and ensure that we do flush
> + * any residual writes from the previous batch.
> + */
> + ret = logical_ring_invalidate_all_caches(params->request);
> + if (ret)
> + return ret;
> +
> if (ring == &dev_priv->ring[RCS] &&
> instp_mode != dev_priv->relative_constants_mode) {
> ret = intel_logical_ring_begin(params->request, 4);
> @@ -937,7 +946,6 @@ int intel_execlists_submission(struct i915_execbuffer_params *params,
>
> trace_i915_gem_ring_dispatch(params->request, params->dispatch_flags);
>
> - i915_gem_execbuffer_move_to_active(vmas, params->request);
> i915_gem_execbuffer_retire_commands(params);
>
> return 0;
>

Do we need to do anything if the cache invalidation fails like move the buffers back off the active list? The order changed here, so I'm wondering.

If that's not a problem, then:
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>