Re: [Intel-gfx] [PATCH 1/2] drm/i915: Split gt cache flushing and gt idling functions

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

On 9/5/2023 9:36 PM, Andi Shyti wrote:
> In preparation for multi-gt cache flushing debugfs interface,
> split the cache dropping function and gt idling.
>
> Based on a patch by Tvrtko.
>
> Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
>   drivers/gpu/drm/i915/i915_debugfs.c | 32 +++++++++++++++++++++--------
>   1 file changed, 24 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 7a90a2e32c9f1..3dfe8a8b7cdfe 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -703,11 +703,25 @@ i915_drop_caches_get(void *data, u64 *val)
>   	return 0;
>   }
>   
> +static int gt_idle(struct intel_gt *gt, u64 val)
> +{
> +	if (val & (DROP_RETIRE | DROP_IDLE))
> +		intel_gt_retire_requests(gt);
> +
> +	if (val & DROP_IDLE) {
> +		int ret;
> +
> +		ret = intel_gt_pm_wait_for_idle(gt);
return intel_gt_pm_wait_for_idle(gt) should work fine.
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
>   static int
>   gt_drop_caches(struct intel_gt *gt, u64 val)
>   {
> -	int ret;
> -
>   	if (val & DROP_RESET_ACTIVE &&
>   	    wait_for(intel_engines_are_idle(gt), 200))
>   		intel_gt_set_wedged(gt);
> @@ -716,13 +730,9 @@ gt_drop_caches(struct intel_gt *gt, u64 val)
>   		intel_gt_retire_requests(gt);
>   
>   	if (val & (DROP_IDLE | DROP_ACTIVE)) {
> -		ret = intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT);
> -		if (ret)
> -			return ret;
> -	}
> +		int ret;
>   
> -	if (val & DROP_IDLE) {
> -		ret = intel_gt_pm_wait_for_idle(gt);
> +		ret = intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT);
>   		if (ret)
>   			return ret;
>   	}
> @@ -746,10 +756,16 @@ i915_drop_caches_set(void *data, u64 val)
>   	drm_dbg(&i915->drm, "Dropping caches: 0x%08llx [0x%08llx]\n",
>   		val, val & DROP_ALL);
>   
> +	/* Flush all the active requests across both GT ... */
For now it is just GT0 so this comment should be in next patch ?
>   	ret = gt_drop_caches(to_gt(i915), val);
>   	if (ret)
>   		return ret;
>   
> +	/* ... then wait for idle as there may be cross-gt wakerefs. */

same as above.

Regards,

Nirmoy

> +	ret = gt_idle(to_gt(i915), val);
> +	if (ret)
> +		return ret;
> +
>   	fs_reclaim_acquire(GFP_KERNEL);
>   	flags = memalloc_noreclaim_save();
>   	if (val & DROP_BOUND)