From 7e0cf7e9936c4358b0863357b90aa12afe6489da Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Fri, 29 Nov 2019 14:59:08 +0100 Subject: [PATCH] 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: 013b65101315 ("drm/panfrost: Add madvise and shrinker support") Cc: Signed-off-by: Boris Brezillon Reviewed-by: Steven Price Signed-off-by: Rob Herring Link: https://patchwork.freedesktop.org/patch/msgid/20191129135908.2439529-9-boris.brezillon@collabora.com --- drivers/gpu/drm/panfrost/panfrost_drv.c | 1 + drivers/gpu/drm/panfrost/panfrost_gem.h | 6 ++++++ drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c | 3 +++ drivers/gpu/drm/panfrost/panfrost_job.c | 7 ++++++- 4 files changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c index 88b431a267af..273d67e251c2 100644 --- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -166,6 +166,7 @@ panfrost_lookup_bos(struct drm_device *dev, break; } + atomic_inc(&bo->gpu_usecount); job->mappings[i] = mapping; } diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h index ca1bc9019600..b3517ff9630c 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.h +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h @@ -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; }; diff --git a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c index f5dd7b29bc95..288e46c40673 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c @@ -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; diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c index e364ee00f3d0..4d383831c1fc 100644 --- a/drivers/gpu/drm/panfrost/panfrost_job.c +++ b/drivers/gpu/drm/panfrost/panfrost_job.c @@ -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); } -- 2.11.4.GIT