On 01/10/2021 11:05, Christian König wrote:
This makes the function much simpler since the complex
retry logic is now handled else where.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Sorry I retract until you add the text about the increased cost of the
added atomics. I think the point is important to discuss given proposal
goes from zero atomics to num_fences * 2 (fence get/put unless I am
mistaken) atomics per busy ioctl. That makes me lean towards just
leaving this as is since it is not that complex.
Regards,
Tvrtko
---
drivers/gpu/drm/i915/gem/i915_gem_busy.c | 35 ++++++++++--------------
1 file changed, 14 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_busy.c b/drivers/gpu/drm/i915/gem/i915_gem_busy.c
index 6234e17259c1..dc72b36dae54 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_busy.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_busy.c
@@ -82,8 +82,8 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
{
struct drm_i915_gem_busy *args = data;
struct drm_i915_gem_object *obj;
- struct dma_resv_list *list;
- unsigned int seq;
+ struct dma_resv_iter cursor;
+ struct dma_fence *fence;
int err;
err = -ENOENT;
@@ -109,27 +109,20 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
* to report the overall busyness. This is what the wait-ioctl does.
*
*/
-retry:
- seq = raw_read_seqcount(&obj->base.resv->seq);
-
- /* Translate the exclusive fence to the READ *and* WRITE engine */
- args->busy = busy_check_writer(dma_resv_excl_fence(obj->base.resv));
-
- /* Translate shared fences to READ set of engines */
- list = dma_resv_shared_list(obj->base.resv);
- if (list) {
- unsigned int shared_count = list->shared_count, i;
-
- for (i = 0; i < shared_count; ++i) {
- struct dma_fence *fence =
- rcu_dereference(list->shared[i]);
-
+ args->busy = 0;
+ dma_resv_iter_begin(&cursor, obj->base.resv, true);
+ dma_resv_for_each_fence_unlocked(&cursor, fence) {
+ if (dma_resv_iter_is_restarted(&cursor))
+ args->busy = 0;
+
+ if (dma_resv_iter_is_exclusive(&cursor))
+ /* Translate the exclusive fence to the READ *and* WRITE engine */
+ args->busy |= busy_check_writer(fence);
+ else
+ /* Translate shared fences to READ set of engines */
args->busy |= busy_check_reader(fence);
- }
}
-
- if (args->busy && read_seqcount_retry(&obj->base.resv->seq, seq))
- goto retry;
+ dma_resv_iter_end(&cursor);
err = 0;
out:
