Re: [PATCH] drm/v3d: clean caches at the end of render jobs on request from user space

Iago Toral Quiroga itoral@igalia.com writes:

Extends the user space ioctl for CL submissions so it can include a request to flush the cache once the CL execution has completed. Fixes memory write violation messages reported by the kernel in workloads involving shader memory writes (SSBOs, shader images, scratch, etc) which sometimes also lead to GPU resets during Piglit and CTS workloads.

Some context for any other reviewers: This patch is the interface change necessary to expose GLES 3.1 on V3D. It turns out the HW packets for flushing the caches were broken in multiple ways.

Signed-off-by: Iago Toral Quiroga itoral@igalia.com

drivers/gpu/drm/v3d/v3d_gem.c | 51 +++++++++++++++++++++++++++++------ include/uapi/drm/v3d_drm.h | 7 ++--- 2 files changed, 47 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c index 5d80507b539b..530fe9d9d5bd 100644 --- a/drivers/gpu/drm/v3d/v3d_gem.c +++ b/drivers/gpu/drm/v3d/v3d_gem.c @@ -530,13 +530,16 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, struct drm_v3d_submit_cl *args = data; struct v3d_bin_job *bin = NULL; struct v3d_render_job *render;

• struct v3d_job *clean_job = NULL;

• struct v3d_job *last_job; struct ww_acquire_ctx acquire_ctx; int ret = 0;

  trace_v3d_submit_cl_ioctl(&v3d->drm, args->rcl_start, args->rcl_end);

• if (args->pad != 0) {

• DRM_INFO("pad must be zero: %d\n", args->pad);
  

• if (args->flags != 0 &&

•    args->flags != DRM_V3D_SUBMIT_CL_FLUSH_CACHE_FLAG) {
  

• DRM_INFO("invalid flags: %d\n", args->flags);
  

  return -EINVAL; }

@@ -575,12 +578,28 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, bin->render = render; }

• ret = v3d_lookup_bos(dev, file_priv, &render->base,

• if (args->flags & DRM_V3D_SUBMIT_CL_FLUSH_CACHE_FLAG) {

• clean_job = kcalloc(1, sizeof(*clean_job), GFP_KERNEL);
  

• if (!clean_job) {
  

• 	ret = -ENOMEM;
  

• 	goto fail;
  

• }
  

• ret = v3d_job_init(v3d, file_priv, clean_job, v3d_job_free, 0);
  

• if (ret)
  

• 	goto fail;
  

Only issue I see: If v3d_job_init() fails, we need to not v3d_job_put() it. I'm fine with either kfree() it and NULL the ptr before jumping to fail, or open code the bin/render puts.

With that,

Reviewed-by: Eric Anholt eric@anholt.net

• last_job = clean_job;
  

• } else {

• last_job = &render->base;
  

• }
• ret = v3d_lookup_bos(dev, file_priv, last_job, args->bo_handles, args->bo_handle_count); if (ret) goto fail;

• ret = v3d_lock_bo_reservations(&render->base, &acquire_ctx);

• ret = v3d_lock_bo_reservations(last_job, &acquire_ctx); if (ret) goto fail;

@@ -599,28 +618,44 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, ret = v3d_push_job(v3d_priv, &render->base, V3D_RENDER); if (ret) goto fail_unreserve;

• if (clean_job) {

• struct dma_fence *render_fence =
  

• 	dma_fence_get(render->base.done_fence);
  

• ret = drm_gem_fence_array_add(&clean_job->deps, render_fence);
  

• if (ret)
  

• 	goto fail_unreserve;
  

• ret = v3d_push_job(v3d_priv, clean_job, V3D_CACHE_CLEAN);
  

• if (ret)
  

• 	goto fail_unreserve;
  

• }

• mutex_unlock(&v3d->sched_lock);

  v3d_attach_fences_and_unlock_reservation(file_priv,

• 				 &render->base,
  

• 				 last_job,
  			 &acquire_ctx,
  			 args->out_sync,
  

• 				 render->base.done_fence);
  

• 				 last_job->done_fence);
  
  

  if (bin) v3d_job_put(&bin->base); v3d_job_put(&render->base);

• if (clean_job)

• v3d_job_put(clean_job);
  
  

  return 0;

fail_unreserve: mutex_unlock(&v3d->sched_lock);

• drm_gem_unlock_reservations(render->base.bo,

• 		    render->base.bo_count, &acquire_ctx);
  

• drm_gem_unlock_reservations(last_job->bo,

• 		    last_job->bo_count, &acquire_ctx);
  

fail: if (bin) v3d_job_put(&bin->base); v3d_job_put(&render->base);

• if (clean_job)

• v3d_job_put(clean_job);
  
  

  return ret;

} diff --git a/include/uapi/drm/v3d_drm.h b/include/uapi/drm/v3d_drm.h index 58fbe48c91e9..58d2040ea48c 100644 --- a/include/uapi/drm/v3d_drm.h +++ b/include/uapi/drm/v3d_drm.h @@ -48,6 +48,8 @@ extern "C" { #define DRM_IOCTL_V3D_SUBMIT_TFU DRM_IOW(DRM_COMMAND_BASE + DRM_V3D_SUBMIT_TFU, struct drm_v3d_submit_tfu) #define DRM_IOCTL_V3D_SUBMIT_CSD DRM_IOW(DRM_COMMAND_BASE + DRM_V3D_SUBMIT_CSD, struct drm_v3d_submit_csd)

+#define DRM_V3D_SUBMIT_CL_FLUSH_CACHE_FLAG 0x01

/**

• struct drm_v3d_submit_cl - ioctl argument for submitting commands to the 3D
• engine.

@@ -61,7 +63,7 @@ extern "C" {

• flushed by the time the render done IRQ happens, which is the
• trigger for out_sync. Any dirtying of cachelines by the job (only
• possible using TMU writes) must be flushed by the caller using the

• • CL's cache flush commands.

• • DRM_V3D_SUBMIT_CL_FLUSH_CACHE_FLAG flag.
  */

struct drm_v3d_submit_cl { /* Pointer to the binner command list. @@ -124,8 +126,7 @@ struct drm_v3d_submit_cl { /* Number of BO handles passed in (size is that times 4). */ __u32 bo_handle_count;

• /* Pad, must be zero-filled. */
• __u32 pad;

• __u32 flags;

};

/**

2.17.1