Re: [PATCH v2 2/6] drm/xe: Move exponential sleep logic to helper

[Matthew Brost <matthew.brost@intel.com>]

On Tue, Jan 27, 2026 at 08:37:22PM +0100, Michal Wajdeczko wrote:
> We want to reuse the same increased sleep logic in other places.
> To avoid code duplication, move it to the helper.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>

Reviewed-by: Matthew Brost <matthew.brost@intel.com>

> ---
>  drivers/gpu/drm/xe/xe_guc_submit.c |  5 +----
>  drivers/gpu/drm/xe/xe_sleep.h      | 21 +++++++++++++++++++++
>  2 files changed, 22 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 4ea14f2794f4..66dffa13553e 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -1045,10 +1045,7 @@ static int wq_wait_for_space(struct xe_exec_queue *q, u32 wqi_size)
>  				return -ENODEV;
>  			}
>  
> -			msleep(sleep_period_ms);
> -			sleep_total_ms += sleep_period_ms;
> -			if (sleep_period_ms < 64)
> -				sleep_period_ms <<= 1;
> +			sleep_total_ms += xe_sleep_exponential_ms(&sleep_period_ms, 64);
>  			goto try_again;
>  		}
>  	}
> diff --git a/drivers/gpu/drm/xe/xe_sleep.h b/drivers/gpu/drm/xe/xe_sleep.h
> index a772f1a37395..2bc3f4c0ee0b 100644
> --- a/drivers/gpu/drm/xe/xe_sleep.h
> +++ b/drivers/gpu/drm/xe/xe_sleep.h
> @@ -33,4 +33,25 @@ static inline void xe_sleep_relaxed_ms(unsigned int delay_ms)
>  	usleep_range(min_us, max_us);
>  }
>  
> +/**
> + * xe_sleep_exponential_ms() - Sleep for a exponentially increased time.
> + * @sleep_period_ms: current time in msec to sleep
> + * @max_sleep_ms: maximum time in msec to sleep
> + *
> + * Sleep for the @sleep_period_ms and exponentially increase this time for the
> + * next loop, unless reaching the @max_sleep_ms limit.
> + *
> + * Return: approximate time in msec the task was delayed.
> + */
> +static inline unsigned int xe_sleep_exponential_ms(unsigned int *sleep_period_ms,
> +						   unsigned int max_sleep_ms)
> +{
> +	unsigned int delay_ms = *sleep_period_ms;
> +	unsigned int next_delay_ms = 2 * delay_ms;
> +
> +	xe_sleep_relaxed_ms(delay_ms);
> +	*sleep_period_ms = min(next_delay_ms, max_sleep_ms);
> +	return delay_ms;
> +}
> +
>  #endif
> -- 
> 2.47.1
>