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References: <20190401222635.25013-1-eric@anholt.net> <20190401222635.25013-8-eric@anholt.net>
In-Reply-To: <20190401222635.25013-8-eric@anholt.net>
From:   Qiang Yu <yuq825@gmail.com>
Date:   Tue, 2 Apr 2019 18:22:07 +0800
Message-ID: <CAKGbVbvfXmwKcLX=OwKRjDNBg8d9uK8yLQUUG6KsmdMyW5zxGA@mail.gmail.com>
Subject: Re: [PATCH 7/7] drm/lima: Use the drm_gem_fence_array_add helpers for
 our deps.
To:     Eric Anholt <eric@anholt.net>
Cc:     dri-devel <dri-devel@lists.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        david.emett@broadcom.com, thomas.spurden@broadcom.com,
        Rob Herring <robh@kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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On Tue, Apr 2, 2019 at 6:26 AM Eric Anholt <eric@anholt.net> wrote:
>
> I haven't tested this, but it's a pretty direct port of what I did for
> v3d.
>
> Signed-off-by: Eric Anholt <eric@anholt.net>
> ---
>  drivers/gpu/drm/lima/lima_gem.c   | 37 +----------------
>  drivers/gpu/drm/lima/lima_sched.c | 66 ++++++-------------------------
>  drivers/gpu/drm/lima/lima_sched.h |  6 +--
>  3 files changed, 16 insertions(+), 93 deletions(-)
>
> diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
> index 2d3cf96f6c58..8f80286c80b4 100644
> --- a/drivers/gpu/drm/lima/lima_gem.c
> +++ b/drivers/gpu/drm/lima/lima_gem.c
> @@ -144,40 +144,7 @@ static int lima_gem_sync_bo(struct lima_sched_task *task, struct lima_bo *bo,
>         if (explicit)
>                 return 0;
>
> -       /* implicit sync use bo fence in resv obj */
> -       if (write) {
> -               unsigned nr_fences;
> -               struct dma_fence **fences;
> -               int i;
> -
> -               err = reservation_object_get_fences_rcu(
> -                       bo->gem.resv, NULL, &nr_fences, &fences);
> -               if (err || !nr_fences)
> -                       return err;
> -
> -               for (i = 0; i < nr_fences; i++) {
> -                       err = lima_sched_task_add_dep(task, fences[i]);
> -                       if (err)
> -                               break;
> -               }
> -
> -               /* for error case free remaining fences */
> -               for ( ; i < nr_fences; i++)
> -                       dma_fence_put(fences[i]);
> -
> -               kfree(fences);
> -       } else {
> -               struct dma_fence *fence;
> -
> -               fence = reservation_object_get_excl_rcu(bo->gem.resv);
> -               if (fence) {
> -                       err = lima_sched_task_add_dep(task, fence);
> -                       if (err)
> -                               dma_fence_put(fence);
> -               }
> -       }
> -
> -       return err;
> +       return drm_gem_fence_array_add_implicit(&task->deps, &bo->gem, write);
>  }
>
>  static int lima_gem_lock_bos(struct lima_bo **bos, u32 nr_bos,
> @@ -250,7 +217,7 @@ static int lima_gem_add_deps(struct drm_file *file, struct lima_submit *submit)
>                 if (err)
>                         return err;
>
> -               err = lima_sched_task_add_dep(submit->task, fence);
> +               err = drm_gem_fence_array_add(&submit->task->deps, fence);
>                 if (err) {
>                         dma_fence_put(fence);
>                         return err;
> diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
> index 97bd9c1deb87..e253d031fb3d 100644
> --- a/drivers/gpu/drm/lima/lima_sched.c
> +++ b/drivers/gpu/drm/lima/lima_sched.c
> @@ -3,6 +3,7 @@
>
>  #include <linux/kthread.h>
>  #include <linux/slab.h>
> +#include <linux/xarray.h>
>
>  #include "lima_drv.h"
>  #include "lima_sched.h"
> @@ -126,19 +127,24 @@ int lima_sched_task_init(struct lima_sched_task *task,
>
>         task->num_bos = num_bos;
>         task->vm = lima_vm_get(vm);
> +
> +       xa_init_flags(&task->deps, XA_FLAGS_ALLOC);
> +
>         return 0;
>  }
>
>  void lima_sched_task_fini(struct lima_sched_task *task)
>  {
> +       struct dma_fence *fence;
> +       unsigned long index;
>         int i;
>
>         drm_sched_job_cleanup(&task->base);
>
> -       for (i = 0; i < task->num_dep; i++)
> -               dma_fence_put(task->dep[i]);
> -
> -       kfree(task->dep);
> +       xa_for_each(&task->deps, index, fence) {
> +               dma_fence_put(fence);
> +       }
> +       xa_destroy(&task->deps);
>
>         if (task->bos) {
>                 for (i = 0; i < task->num_bos; i++)
> @@ -149,42 +155,6 @@ void lima_sched_task_fini(struct lima_sched_task *task)
>         lima_vm_put(task->vm);
>  }
>
> -int lima_sched_task_add_dep(struct lima_sched_task *task, struct dma_fence *fence)
> -{
> -       int i, new_dep = 4;
> -
> -       /* same context's fence is definitly earlier then this task */
> -       if (fence->context == task->base.s_fence->finished.context) {
> -               dma_fence_put(fence);
> -               return 0;
> -       }

Seems you dropped this check in the drm_gem_fence_array_add, no bug if we
don't have this, but redundant fence will be added in the deps array. Maybe we
can add a context parameter to drm_gem_fence_array_add and
drm_gem_fence_array_add_implicit to filter out fences from same
drm_sched_entity.

Regards,
Qiang


> -
> -       if (task->dep && task->num_dep == task->max_dep)
> -               new_dep = task->max_dep * 2;
> -
> -       if (task->max_dep < new_dep) {
> -               void *dep = krealloc(task->dep, sizeof(*task->dep) * new_dep, GFP_KERNEL);
> -
> -               if (!dep)
> -                       return -ENOMEM;
> -
> -               task->max_dep = new_dep;
> -               task->dep = dep;
> -       }
> -
> -       for (i = 0; i < task->num_dep; i++) {
> -               if (task->dep[i]->context == fence->context &&
> -                   dma_fence_is_later(fence, task->dep[i])) {
> -                       dma_fence_put(task->dep[i]);
> -                       task->dep[i] = fence;
> -                       return 0;
> -               }
> -       }
> -
> -       task->dep[task->num_dep++] = fence;
> -       return 0;
> -}
> -
>  int lima_sched_context_init(struct lima_sched_pipe *pipe,
>                             struct lima_sched_context *context,
>                             atomic_t *guilty)
> @@ -213,21 +183,9 @@ static struct dma_fence *lima_sched_dependency(struct drm_sched_job *job,
>                                                struct drm_sched_entity *entity)
>  {
>         struct lima_sched_task *task = to_lima_task(job);
> -       int i;
> -
> -       for (i = 0; i < task->num_dep; i++) {
> -               struct dma_fence *fence = task->dep[i];
> -
> -               if (!task->dep[i])
> -                       continue;
> -
> -               task->dep[i] = NULL;
>
> -               if (!dma_fence_is_signaled(fence))
> -                       return fence;
> -
> -               dma_fence_put(fence);
> -       }
> +       if (!xa_empty(&task->deps))
> +               return xa_erase(&task->deps, task->last_dep++);
>
>         return NULL;
>  }
> diff --git a/drivers/gpu/drm/lima/lima_sched.h b/drivers/gpu/drm/lima/lima_sched.h
> index b017cfa7e327..928af91c1118 100644
> --- a/drivers/gpu/drm/lima/lima_sched.h
> +++ b/drivers/gpu/drm/lima/lima_sched.h
> @@ -14,9 +14,8 @@ struct lima_sched_task {
>         struct lima_vm *vm;
>         void *frame;
>
> -       struct dma_fence **dep;
> -       int num_dep;
> -       int max_dep;
> +       struct xarray deps;
> +       unsigned long last_dep;
>
>         struct lima_bo **bos;
>         int num_bos;
> @@ -78,7 +77,6 @@ int lima_sched_task_init(struct lima_sched_task *task,
>                          struct lima_bo **bos, int num_bos,
>                          struct lima_vm *vm);
>  void lima_sched_task_fini(struct lima_sched_task *task);
> -int lima_sched_task_add_dep(struct lima_sched_task *task, struct dma_fence *fence);
>
>  int lima_sched_context_init(struct lima_sched_pipe *pipe,
>                             struct lima_sched_context *context,
> --
> 2.20.1
>