On Mon, Oct 5, 2020 at 4:02 PM Daniel Vetter daniel@ffwll.ch wrote:
On Mon, Oct 05, 2020 at 05:24:19PM +0800, Hillf Danton wrote:
On Sun, 4 Oct 2020 12:21:45
From: Rob Clark robdclark@chromium.org
Now that the inactive_list is protected by mm_lock, and everything else on per-obj basis is protected by obj->lock, we no longer depend on struct_mutex.
Signed-off-by: Rob Clark robdclark@chromium.org
drivers/gpu/drm/msm/msm_gem.c | 1 - drivers/gpu/drm/msm/msm_gem_shrinker.c | 54 -------------------------- 2 files changed, 55 deletions(-)
[...]
@@ -71,13 +33,8 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) { struct msm_drm_private *priv = container_of(shrinker, struct msm_drm_private, shrinker);
struct drm_device *dev = priv->dev; struct msm_gem_object *msm_obj; unsigned long freed = 0;
bool unlock;
if (!msm_gem_shrinker_lock(dev, &unlock))
return SHRINK_STOP;mutex_lock(&priv->mm_lock);
Better if the change in behavior is documented that SHRINK_STOP will no longer be needed.
btw I read through this and noticed you have your own obj lock, plus mutex_lock_nested. I strongly recommend to just cut over to dma_resv_lock for all object lock needs (soc drivers have been terrible with this unfortuntaly), and in the shrinker just use dma_resv_trylock instead of trying to play clever games outsmarting lockdep.
I recently wrote an entire blog length rant on why I think mutex_lock_nested is too dangerous to be useful:
https://blog.ffwll.ch/2020/08/lockdep-false-positives.html
Not anything about this here, just general comment. The problem extends to shmem helpers and all that also having their own locks for everything.
This is definitely a tangible improvement though - very happy to see msm_gem_shrinker_lock() go.
Reviewed-by: Kristian H. Kristensen hoegsberg@google.com
-Daniel
Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel