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charset=us-ascii Content-Disposition: inline In-Reply-To: <20201005092419.15608-1-hdanton@sina.com> X-Operating-System: Linux phenom 5.7.0-1-amd64 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Mon, Oct 05, 2020 at 05:24:19PM +0800, Hillf Danton wrote: > > On Sun, 4 Oct 2020 12:21:45 > > From: Rob Clark > > > > 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 > > --- > > 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. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch