Re: [PATCH v5 2/3] drm/xe/ufence: Flush xe ordered_wq in case of ufence timeout

[John Harrison <john.c.harrison@intel.com>]

On 10/29/2024 05:01, Nirmoy Das wrote:
> Flush xe ordered_wq in case of ufence timeout which is observed
> on LNL and that points to recent scheduling issue with E-cores.
>
> This is similar to the recent fix:
> commit e51527233804 ("drm/xe/guc/ct: Flush g2h worker in case of g2h
> response timeout") and should be removed once there is a E-core
> scheduling fix for LNL.
>
> v2: Add platform check(Himal)
>      s/__flush_workqueue/flush_workqueue(Jani)
> v3: Remove gfx platform check as the issue related to cpu
>      platform(John)
> v4: Use the Common macro(John) and print when the flush resolves
>      timeout(Matt B)
>
> Cc: Badal Nilawar <badal.nilawar@intel.com>
> Cc: Matthew Auld <matthew.auld@intel.com>
> Cc: John Harrison <John.C.Harrison@Intel.com>
> Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Cc: <stable@vger.kernel.org> # v6.11+
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2754
> Suggested-by: Matthew Brost <matthew.brost@intel.com>
> Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_wait_user_fence.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_wait_user_fence.c b/drivers/gpu/drm/xe/xe_wait_user_fence.c
> index f5deb81eba01..5b4264ea38bd 100644
> --- a/drivers/gpu/drm/xe/xe_wait_user_fence.c
> +++ b/drivers/gpu/drm/xe/xe_wait_user_fence.c
> @@ -155,6 +155,13 @@ int xe_wait_user_fence_ioctl(struct drm_device *dev, void *data,
>   		}
>   
>   		if (!timeout) {
> +			LNL_FLUSH_WORKQUEUE(xe->ordered_wq);
> +			err = do_compare(addr, args->value, args->mask,
> +					 args->op);
> +			if (err <= 0) {
> +				drm_dbg(&xe->drm, "LNL_FLUSH_WORKQUEUE resolved ufence timeout\n");
Should this not be a warning as well? To match the one in the G2H code, 
with the reason being that we want CI to track how often this is occurring.

John.

> +				break;
> +			}
>   			err = -ETIME;
>   			break;
>   		}