Am 11.09.2017 um 11:02 schrieb Monk Liu:
> need to unreserve ttm bo before "cs_add_fence" and "entity_push_job"
> otherwise there will be deadlock between "recover_vram_from_shadow"
> and previous two routines on the ttm bo's resv lock.
>
> Change-Id: I9c18b677e474ce5b45a9cc24da3fa255d77b3d44
> Signed-off-by: Monk Liu <Monk.Liu at amd.com>
Yeah, I was thinking about this as well. Problem is this won't work
without further changes.
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 35 ++++++++++++++++++----------------
> 1 file changed, 19 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index c1f1ae9..823ac12 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -736,26 +736,12 @@ static int amdgpu_cs_sync_rings(struct amdgpu_cs_parser *p)
> /**
> * cs_parser_fini() - clean parser states
> * @parser: parser structure holding parsing context.
> - * @error: error number
> - *
> - * If error is set than unvalidate buffer, otherwise just free memory
> - * used by parsing context.
> **/
> -static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser, int error, bool backoff)
> +static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser)
> {
> struct amdgpu_fpriv *fpriv = parser->filp->driver_priv;
> unsigned i;
>
> - if (!error) {
> - amdgpu_vm_move_pt_bos_in_lru(parser->adev, &fpriv->vm);
> -
> - ttm_eu_fence_buffer_objects(&parser->ticket,
> - &parser->validated,
> - parser->fence);
> - } else if (backoff) {
> - ttm_eu_backoff_reservation(&parser->ticket,
> - &parser->validated);
> - }
> fence_put(parser->fence);
>
> if (parser->ctx)
> @@ -1075,6 +1061,16 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
> job->owner = p->filp;
> job->fence_ctx = entity->fence_context;
> p->fence = fence_get(&job->base.s_fence->finished);
> +
> + /* hook sched fence to all BOs' reservation in validated list
> + * and unreserve them.
> + *
> + * we unreserve at here is because otherwise
> + * there'll be deadlock between ctx_add_fence/sched_entity_push_job
> + * and gpu_reset routine's recover_bo_from_shadow on PD/PTEs' ttm bo lock
> + */
> + ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
The order of job->base.s_fence and preventing concurrent CS was
guaranteed by the VM PD being reserved, that is now no longer the case
and we need a new lock for protection.
I suggest to add another lock to the context which we grab in
amdgpu_ctx_get() and release in amdgpu_ctx_put().
Regards,
Christian.
> +
> r = amdgpu_ctx_add_fence(p->ctx, ring, p->fence, &seq);
> if (r) {
> fence_put(p->fence);
> @@ -1095,6 +1091,7 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
> {
> struct amdgpu_device *adev = dev->dev_private;
> union drm_amdgpu_cs *cs = data;
> + struct amdgpu_fpriv *fpriv;
> struct amdgpu_cs_parser parser = {};
> bool reserved_buffers = false;
> int i, r;
> @@ -1104,6 +1101,7 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
>
> parser.adev = adev;
> parser.filp = filp;
> + fpriv = filp->driver_priv;
>
> r = amdgpu_cs_parser_init(&parser, data);
> if (r) {
> @@ -1141,7 +1139,12 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
> r = amdgpu_cs_submit(&parser, cs);
>
> out:
> - amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
> + if (!r)
> + amdgpu_vm_move_pt_bos_in_lru(parser.adev, &fpriv->vm);
> + else if (reserved_buffers)
> + ttm_eu_backoff_reservation(&parser.ticket, &parser.validated);
> +
> + amdgpu_cs_parser_fini(&parser);
> return r;
> }
>
