Re: [PATCH v2] drm/sched: Mark scheduler work queues with WQ_MEM_RECLAIM

[Nirmoy Das <nirmoy.das@linux.intel.com>]

On 10/24/2024 1:59 AM, Matthew Brost wrote:
> drm_gpu_scheduler.submit_wq is used to submit jobs, jobs are in the path
> of dma-fences, and dma-fences are in the path of reclaim. Mark scheduler
> work queue with WQ_MEM_RECLAIM to ensure forward progress during
> reclaim; without WQ_MEM_RECLAIM, work queues cannot make forward
> progress during reclaim.
>
> v2:
>  - Fixes tags (Philipp)
>  - Reword commit message (Philipp)
>
> Cc: Luben Tuikov <ltuikov89@gmail.com>
> Cc: Danilo Krummrich <dakr@kernel.org>
> Cc: Philipp Stanner <pstanner@redhat.com>
> Cc: stable@vger.kernel.org
> Fixes: 34f50cc6441b ("drm/sched: Use drm sched lockdep map for submit_wq")
> Fixes: a6149f039369 ("drm/sched: Convert drm scheduler to use a work queue rather than kthread")
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>

Acked-by: Nirmoy Das <nirmoy.das@intel.com>

Looks like Xe has a dependency on this now that xe->ordered_wq is allocated with  WQ_MEM_RECLAIM flag:

https://intel-gfx-ci.01.org/tree/intel-xe/xe-pw-140135v2/bat-lnl-1/igt@xe_exec_fault_mode@twice-invalid-fault.html

> ---
>  drivers/gpu/drm/scheduler/sched_main.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 540231e6bac6..df0a5abb1400 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -1283,10 +1283,11 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
>  		sched->own_submit_wq = false;
>  	} else {
>  #ifdef CONFIG_LOCKDEP
> -		sched->submit_wq = alloc_ordered_workqueue_lockdep_map(name, 0,
> +		sched->submit_wq = alloc_ordered_workqueue_lockdep_map(name,
> +								       WQ_MEM_RECLAIM,
>  								       &drm_sched_lockdep_map);
>  #else
> -		sched->submit_wq = alloc_ordered_workqueue(name, 0);
> +		sched->submit_wq = alloc_ordered_workqueue(name, WQ_MEM_RECLAIM);
>  #endif
>  		if (!sched->submit_wq)
>  			return -ENOMEM;