On Wed, Sep 23, 2020 at 11:28 AM Akhil P Oommen <akhilpo@xxxxxxxxxxxxxx> wrote: > > On 9/23/2020 8:20 PM, Jordan Crouse wrote: > > On Tue, Sep 22, 2020 at 08:25:26PM +0530, Akhil P Oommen wrote: > >> In the case where we have a back-to-back submission that shares the same > >> BO, this BO will be prematurely moved to inactive_list while retiring the > >> first submit. But it will be still part of the second submit which is > >> being processed by the GPU. Now, if the shrinker happens to be triggered at > >> this point, it will result in a premature purging of this BO. > >> > >> To fix this, we need to refcount BO while doing submit and retire. Then, > >> it should be moved to inactive list when this refcount becomes 0. > >> > >> Signed-off-by: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxx> > >> --- > >> Changes in v2: > >> 1. Keep Active List around > >> 2. Put back the deleted WARN_ON > >> > >> drivers/gpu/drm/msm/msm_drv.h | 5 ++--- > >> drivers/gpu/drm/msm/msm_gem.c | 32 ++++++++++++++++---------------- > >> drivers/gpu/drm/msm/msm_gem.h | 4 +++- > >> drivers/gpu/drm/msm/msm_gpu.c | 11 +++++++---- > >> 4 files changed, 28 insertions(+), 24 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h > >> index 3193274..28e3c8d 100644 > >> --- a/drivers/gpu/drm/msm/msm_drv.h > >> +++ b/drivers/gpu/drm/msm/msm_drv.h > >> @@ -309,9 +309,8 @@ void msm_gem_put_vaddr(struct drm_gem_object *obj); > >> int msm_gem_madvise(struct drm_gem_object *obj, unsigned madv); > >> int msm_gem_sync_object(struct drm_gem_object *obj, > >> struct msm_fence_context *fctx, bool exclusive); > >> -void msm_gem_move_to_active(struct drm_gem_object *obj, > >> - struct msm_gpu *gpu, bool exclusive, struct dma_fence *fence); > >> -void msm_gem_move_to_inactive(struct drm_gem_object *obj); > >> +void msm_gem_active_get(struct drm_gem_object *obj, struct msm_gpu *gpu); > >> +void msm_gem_active_put(struct drm_gem_object *obj); > >> int msm_gem_cpu_prep(struct drm_gem_object *obj, uint32_t op, ktime_t *timeout); > >> int msm_gem_cpu_fini(struct drm_gem_object *obj); > >> void msm_gem_free_object(struct drm_gem_object *obj); > >> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c > >> index 76a6c52..14e14ca 100644 > >> --- a/drivers/gpu/drm/msm/msm_gem.c > >> +++ b/drivers/gpu/drm/msm/msm_gem.c > >> @@ -743,31 +743,31 @@ int msm_gem_sync_object(struct drm_gem_object *obj, > >> return 0; > >> } > >> > >> -void msm_gem_move_to_active(struct drm_gem_object *obj, > >> - struct msm_gpu *gpu, bool exclusive, struct dma_fence *fence) > >> +void msm_gem_active_get(struct drm_gem_object *obj, struct msm_gpu *gpu) > >> { > >> struct msm_gem_object *msm_obj = to_msm_bo(obj); > >> + WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex)); > >> WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED); > >> - msm_obj->gpu = gpu; > >> - if (exclusive) > >> - dma_resv_add_excl_fence(obj->resv, fence); > >> - else > >> - dma_resv_add_shared_fence(obj->resv, fence); > >> - list_del_init(&msm_obj->mm_list); > >> - list_add_tail(&msm_obj->mm_list, &gpu->active_list); > >> + > >> + if (!atomic_fetch_inc(&msm_obj->active_count)) { > >> + msm_obj->gpu = gpu; > >> + list_del_init(&msm_obj->mm_list); > >> + list_add_tail(&msm_obj->mm_list, &gpu->active_list); > >> + } > > > > I'm not sure if all the renaming and reorganization are really needed here - > > this is the meat of the change and it would have fit in reasonably well with the > > existing function design. > This happened due to the way I implemented the v1 patch. In the > hindsight, I think you are right. > fwiw, I'd already pushed v2 to msm-next.. I guess it could have been a smaller diff-stat, but I don't really object to the other changes (which were replacing things that were already a result of how things had previously evolved) BR, -R > Akhil. > > > >> } > >> > >> -void msm_gem_move_to_inactive(struct drm_gem_object *obj) > >> +void msm_gem_active_put(struct drm_gem_object *obj) > >> { > >> - struct drm_device *dev = obj->dev; > >> - struct msm_drm_private *priv = dev->dev_private; > >> struct msm_gem_object *msm_obj = to_msm_bo(obj); > >> + struct msm_drm_private *priv = obj->dev->dev_private; > >> > >> - WARN_ON(!mutex_is_locked(&dev->struct_mutex)); > >> + WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex)); > >> > >> - msm_obj->gpu = NULL; > >> - list_del_init(&msm_obj->mm_list); > >> - list_add_tail(&msm_obj->mm_list, &priv->inactive_list); > >> + if (!atomic_dec_return(&msm_obj->active_count)) { > >> + msm_obj->gpu = NULL; > >> + list_del_init(&msm_obj->mm_list); > >> + list_add_tail(&msm_obj->mm_list, &priv->inactive_list); > >> + } > > > > Same. > > > > Jordan > >> } > >> > >> int msm_gem_cpu_prep(struct drm_gem_object *obj, uint32_t op, ktime_t *timeout) > >> diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h > >> index 7b1c7a5..a1bf741 100644 > >> --- a/drivers/gpu/drm/msm/msm_gem.h > >> +++ b/drivers/gpu/drm/msm/msm_gem.h > >> @@ -88,12 +88,14 @@ struct msm_gem_object { > >> struct mutex lock; /* Protects resources associated with bo */ > >> > >> char name[32]; /* Identifier to print for the debugfs files */ > >> + > >> + atomic_t active_count; > >> }; > >> #define to_msm_bo(x) container_of(x, struct msm_gem_object, base) > >> > >> static inline bool is_active(struct msm_gem_object *msm_obj) > >> { > >> - return msm_obj->gpu != NULL; > >> + return atomic_read(&msm_obj->active_count); > >> } > >> > >> static inline bool is_purgeable(struct msm_gem_object *msm_obj) > >> diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c > >> index 29c8d73c..55d1648 100644 > >> --- a/drivers/gpu/drm/msm/msm_gpu.c > >> +++ b/drivers/gpu/drm/msm/msm_gpu.c > >> @@ -698,8 +698,8 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring, > >> > >> for (i = 0; i < submit->nr_bos; i++) { > >> struct msm_gem_object *msm_obj = submit->bos[i].obj; > >> - /* move to inactive: */ > >> - msm_gem_move_to_inactive(&msm_obj->base); > >> + > >> + msm_gem_active_put(&msm_obj->base); > >> msm_gem_unpin_iova(&msm_obj->base, submit->aspace); > >> drm_gem_object_put_locked(&msm_obj->base); > >> } > >> @@ -774,6 +774,7 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit) > >> > >> for (i = 0; i < submit->nr_bos; i++) { > >> struct msm_gem_object *msm_obj = submit->bos[i].obj; > >> + struct drm_gem_object *drm_obj = &msm_obj->base; > >> uint64_t iova; > >> > >> /* can't happen yet.. but when we add 2d support we'll have > >> @@ -786,9 +787,11 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit) > >> msm_gem_get_and_pin_iova(&msm_obj->base, submit->aspace, &iova); > >> > >> if (submit->bos[i].flags & MSM_SUBMIT_BO_WRITE) > >> - msm_gem_move_to_active(&msm_obj->base, gpu, true, submit->fence); > >> + dma_resv_add_excl_fence(drm_obj->resv, submit->fence); > >> else if (submit->bos[i].flags & MSM_SUBMIT_BO_READ) > >> - msm_gem_move_to_active(&msm_obj->base, gpu, false, submit->fence); > >> + dma_resv_add_shared_fence(drm_obj->resv, submit->fence); > >> + > >> + msm_gem_active_get(drm_obj, gpu); > >> } > >> > >> gpu->funcs->submit(gpu, submit); > >> -- > >> 2.7.4 > >> > > > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel