[Intel-gfx] [PATCH v2 6/6] drm/i915/ttm: Update i915_gem_obj_copy_ttm() to be asynchronous

Thomas Hellström
2021-11-11T12:50:52Z

Update the copy function i915_gem_obj_copy_ttm() to be asynchronous for
future users and update the only current user to sync the objects
as needed after this function.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c | 40 ++++++++++++++------
drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c | 2 +
2 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
index ae2c49fc3500..53ed3972c7be 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
@@ -811,33 +811,49 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
.interruptible = intr,
};
struct i915_refct_sgt *dst_rsgt;
- struct dma_fence *copy_fence;
- int ret;
+ struct dma_fence *copy_fence, *dep_fence;
+ struct i915_deps deps;
+ int ret, shared_err;

assert_object_held(dst);
assert_object_held(src);
+ i915_deps_init(&deps, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);

/*
- * Sync for now. This will change with async moves.
+ * We plan to add a shared fence only for the source. If that
+ * fails, we await all source fences before commencing
+ * the copy instead of only the exclusive.
*/
- ret = ttm_bo_wait_ctx(dst_bo, &ctx);
+ shared_err = dma_resv_reserve_shared(src_bo->base.resv, 1);
+ ret = i915_deps_add_resv(&deps, dst_bo->base.resv, true, false, &ctx);
if (!ret)
- ret = ttm_bo_wait_ctx(src_bo, &ctx);
+ ret = i915_deps_add_resv(&deps, src_bo->base.resv,
+ !!shared_err, false, &ctx);
if (ret)
return ret;

+ dep_fence = i915_deps_to_fence(&deps, &ctx);
+ if (IS_ERR(dep_fence))
+ return PTR_ERR(dep_fence);
+
dst_rsgt = i915_ttm_resource_get_st(dst, dst_bo->resource);
copy_fence = __i915_ttm_move(src_bo, false, dst_bo->resource,
- dst_bo->ttm, dst_rsgt, allow_accel, NULL);
+ dst_bo->ttm, dst_rsgt, allow_accel,
+ dep_fence);

i915_refct_sgt_put(dst_rsgt);
- if (IS_ERR(copy_fence))
- return PTR_ERR(copy_fence);
+ if (IS_ERR_OR_NULL(copy_fence))
+ return PTR_ERR_OR_ZERO(copy_fence);

- if (copy_fence) {
- dma_fence_wait(copy_fence, false);
- dma_fence_put(copy_fence);
- }
+ dma_resv_add_excl_fence(dst_bo->base.resv, copy_fence);
+
+ /* If we failed to reserve a shared slot, add an exclusive fence */
+ if (shared_err)
+ dma_resv_add_excl_fence(src_bo->base.resv, copy_fence);
+ else
+ dma_resv_add_shared_fence(src_bo->base.resv, copy_fence);
+
+ dma_fence_put(copy_fence);

return 0;
}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
index 60d10ab55d1e..9aad84059d56 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
@@ -80,6 +80,7 @@ static int i915_ttm_backup(struct i915_gem_apply_to_region *apply,

err = i915_gem_obj_copy_ttm(backup, obj, pm_apply->allow_gpu, false);
GEM_WARN_ON(err);
+ ttm_bo_wait_ctx(backup_bo, &ctx);

obj->ttm.backup = backup;
return 0;
@@ -170,6 +171,7 @@ static int i915_ttm_restore(struct i915_gem_apply_to_region *apply,
err = i915_gem_obj_copy_ttm(obj, backup, pm_apply->allow_gpu,
false);
GEM_WARN_ON(err);
+ ttm_bo_wait_ctx(backup_bo, &ctx);

obj->ttm.backup = NULL;
err = 0;
--
2.31.1