Good catch and yeah that is actually the real problem why my original
patch didn't worked as expected.
Going to fix this in v2,
Christian.
Am 10.11.2017 um 10:55 schrieb He, Roger:
> static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo,
> bool interruptible, bool no_wait_gpu,
> bool unlock_resv)
> {
> ......
> ttm_bo_del_from_lru(bo);
> list_del_init(&bo->ddestroy);
> kref_put(&bo->list_kref, ttm_bo_ref_bug);
>
> spin_unlock(&glob->lru_lock);
> ttm_bo_cleanup_memtype_use(bo);
>
> if (unlock_resv) //[Roger]: not sure we should add condition here as well. If not, for per-vm-bo, eviction would unlock the VM root BO resv obj which is not we want I think.
> reservation_object_unlock(bo->resv);
>
> return 0;
> }
>
>
> Thanks
> Roger(Hongbo.He)
>
> -----Original Message-----
> From: Christian König [mailto:ckoenig.leichtzumerken at gmail.com]
> Sent: Thursday, November 09, 2017 4:59 PM
> To: dri-devel at lists.freedesktop.org; amd-gfx at lists.freedesktop.org; He, Roger <Hongbo.He at amd.com>; michel at daenzer.net
> Subject: [PATCH 6/7] drm/ttm: make unlocking in ttm_bo_cleanup_refs optional
>
> Needed for the next patch.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 52 ++++++++++++++++++++++++--------------------
> 1 file changed, 28 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 6f5d18366e6e..50a678b504f3 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -486,20 +486,21 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo) }
>
> /**
> - * function ttm_bo_cleanup_refs_and_unlock
> + * function ttm_bo_cleanup_refs
> * If bo idle, remove from delayed- and lru lists, and unref.
> * If not idle, do nothing.
> *
> * Must be called with lru_lock and reservation held, this function
> - * will drop both before returning.
> + * will drop the lru lock and optionally the reservation lock before returning.
> *
> * @interruptible Any sleeps should occur interruptibly.
> * @no_wait_gpu Never wait for gpu. Return -EBUSY instead.
> + * @unlock_resv Unlock the reservation lock as well.
> */
>
> -static int ttm_bo_cleanup_refs_and_unlock(struct ttm_buffer_object *bo,
> - bool interruptible,
> - bool no_wait_gpu)
> +static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo,
> + bool interruptible, bool no_wait_gpu,
> + bool unlock_resv)
> {
> struct ttm_bo_global *glob = bo->glob;
> struct reservation_object *resv;
> @@ -518,7 +519,8 @@ static int ttm_bo_cleanup_refs_and_unlock(struct ttm_buffer_object *bo,
> if (ret && !no_wait_gpu) {
> long lret;
>
> - reservation_object_unlock(bo->resv);
> + if (unlock_resv)
> + reservation_object_unlock(bo->resv);
> spin_unlock(&glob->lru_lock);
>
> lret = reservation_object_wait_timeout_rcu(resv, true, @@ -531,19 +533,22 @@ static int ttm_bo_cleanup_refs_and_unlock(struct ttm_buffer_object *bo,
> return -EBUSY;
>
> spin_lock(&glob->lru_lock);
> - ret = reservation_object_trylock(bo->resv) ? 0 : -EBUSY;
> -
> - /*
> - * We raced, and lost, someone else holds the reservation now,
> - * and is probably busy in ttm_bo_cleanup_memtype_use.
> - *
> - * Even if it's not the case, because we finished waiting any
> - * delayed destruction would succeed, so just return success
> - * here.
> - */
> - if (ret) {
> - spin_unlock(&glob->lru_lock);
> - return 0;
> + if (unlock_resv) {
> + ret = reservation_object_trylock(bo->resv) ? 0 : -EBUSY;
> + /*
> + * We raced, and lost, someone else holds the reservation now,
> + * and is probably busy in ttm_bo_cleanup_memtype_use.
> + *
> + * Even if it's not the case, because we finished waiting any
> + * delayed destruction would succeed, so just return success
> + * here.
> + */
> + if (ret) {
> + spin_unlock(&glob->lru_lock);
> + return 0;
> + }
> + } else {
> + ret = 0;
> }
> }
>
> @@ -600,8 +605,8 @@ static int ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all)
> }
>
> if (!ret)
> - ret = ttm_bo_cleanup_refs_and_unlock(entry, false,
> - !remove_all);
> + ret = ttm_bo_cleanup_refs(entry, false, !remove_all,
> + true);
> else
> spin_unlock(&glob->lru_lock);
>
> @@ -770,8 +775,7 @@ static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
> kref_get(&bo->list_kref);
>
> if (!list_empty(&bo->ddestroy)) {
> - ret = ttm_bo_cleanup_refs_and_unlock(bo, interruptible,
> - no_wait_gpu);
> + ret = ttm_bo_cleanup_refs(bo, interruptible, no_wait_gpu, true);
> kref_put(&bo->list_kref, ttm_bo_release_list);
> return ret;
> }
> @@ -1735,7 +1739,7 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
> kref_get(&bo->list_kref);
>
> if (!list_empty(&bo->ddestroy)) {
> - ret = ttm_bo_cleanup_refs_and_unlock(bo, false, false);
> + ret = ttm_bo_cleanup_refs(bo, false, false, true);
> kref_put(&bo->list_kref, ttm_bo_release_list);
> return ret;
> }
> --
> 2.11.0
>
