Commit 7e0cf7e9 authored by Boris Brezillon's avatar Boris Brezillon Committed by Rob Herring
Browse files

drm/panfrost: Make sure the shrinker does not reclaim referenced BOs 



Userspace might tag a BO purgeable while it's still referenced by GPU
jobs. We need to make sure the shrinker does not purge such BOs until
all jobs referencing it are finished.

Fixes: 013b6510 ("drm/panfrost: Add madvise and shrinker support")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: default avatarSteven Price <steven.price@arm.com>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191129135908.2439529-9-boris.brezillon@collabora.com
parent 8ccb5bf7

drivers/gpu/drm/panfrost/panfrost_drv.c

+1 −0
Original line number Diff line number Diff line
@@ -166,6 +166,7 @@ panfrost_lookup_bos(struct drm_device *dev, 
			break;

		}



		atomic_inc(&bo->gpu_usecount);

		job->mappings[i] = mapping;

	}

drivers/gpu/drm/panfrost/panfrost_gem.h

+6 −0
Original line number Diff line number Diff line
@@ -30,6 +30,12 @@ struct panfrost_gem_object { 
		struct mutex lock;

	} mappings;



	/*

	 * Count the number of jobs referencing this BO so we don't let the

	 * shrinker reclaim this object prematurely.

	 */

	atomic_t gpu_usecount;



	bool noexec		:1;

	bool is_heap		:1;

};

drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c

+3 −0
Original line number Diff line number Diff line
@@ -41,6 +41,9 @@ static bool panfrost_gem_purge(struct drm_gem_object *obj) 
	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);

	struct panfrost_gem_object *bo = to_panfrost_bo(obj);



	if (atomic_read(&bo->gpu_usecount))

		return false;



	if (!mutex_trylock(&shmem->pages_lock))

		return false;

drivers/gpu/drm/panfrost/panfrost_job.c

+6 −1
Original line number Diff line number Diff line
@@ -269,8 +269,13 @@ static void panfrost_job_cleanup(struct kref *ref) 
	dma_fence_put(job->render_done_fence);



	if (job->mappings) {

		for (i = 0; i < job->bo_count; i++)

		for (i = 0; i < job->bo_count; i++) {

			if (!job->mappings[i])

				break;



			atomic_dec(&job->mappings[i]->obj->gpu_usecount);

			panfrost_gem_mapping_put(job->mappings[i]);

		}

		kvfree(job->mappings);

	}

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