[PATCH 2/2] drm/xe/guc: Don't allocate managed BO for each policy change

[Matthew Brost]

On Tue, May 13, 2025 at 12:00:18AM +0200, Michal Wajdeczko wrote:
> We shouldn't use xe_managed_bo_create_from_data() to allocate
> temporary BO, as it will be released only on unload and every
> change in wedge_mode policy will consume resources (including
> precious GGTT). Instead just switchover to GuC buffer cache.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: John Harrison <John.C.Harrison at Intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>

Same as previous patch - do you want fixes here for backporting?

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

> ---
>  drivers/gpu/drm/xe/xe_guc_ads.c | 27 +++++++++++++--------------
>  1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc_ads.c b/drivers/gpu/drm/xe/xe_guc_ads.c
> index 44c1fa2fe7c8..07a027755627 100644
> --- a/drivers/gpu/drm/xe/xe_guc_ads.c
> +++ b/drivers/gpu/drm/xe/xe_guc_ads.c
> @@ -20,6 +20,7 @@
>  #include "xe_gt_ccs_mode.h"
>  #include "xe_gt_printk.h"
>  #include "xe_guc.h"
> +#include "xe_guc_buf.h"
>  #include "xe_guc_capture.h"
>  #include "xe_guc_ct.h"
>  #include "xe_hw_engine.h"
> @@ -994,6 +995,16 @@ static int guc_ads_action_update_policies(struct xe_guc_ads *ads, u32 policy_off
>  	return xe_guc_ct_send(ct, action, ARRAY_SIZE(action), 0, 0);
>  }
>  
> +static int guc_ads_update_policies(struct xe_guc_ads *ads, const struct guc_policies *policies)
> +{
> +	CLASS(xe_guc_buf_from_data, buf)(&ads_to_guc(ads)->buf, policies, sizeof(*policies));
> +
> +	if (!xe_guc_buf_is_valid(buf))
> +		return -ENOBUFS;
> +
> +	return guc_ads_action_update_policies(ads, xe_guc_buf_flush(buf));
> +}
> +
>  /**
>   * xe_guc_ads_scheduler_policy_toggle_reset - Toggle reset policy
>   * @ads: Additional data structures object
> @@ -1005,11 +1016,8 @@ static int guc_ads_action_update_policies(struct xe_guc_ads *ads, u32 policy_off
>  int xe_guc_ads_scheduler_policy_toggle_reset(struct xe_guc_ads *ads)
>  {
>  	struct xe_device *xe = ads_to_xe(ads);
> -	struct xe_gt *gt = ads_to_gt(ads);
> -	struct xe_tile *tile = gt_to_tile(gt);
>  	struct guc_policies *policies;
> -	struct xe_bo *bo;
> -	int ret = 0;
> +	int ret;
>  
>  	policies = kmalloc(sizeof(*policies), GFP_KERNEL);
>  	if (!policies)
> @@ -1023,16 +1031,7 @@ int xe_guc_ads_scheduler_policy_toggle_reset(struct xe_guc_ads *ads)
>  	else
>  		policies->global_flags &= ~GLOBAL_POLICY_DISABLE_ENGINE_RESET;
>  
> -	bo = xe_managed_bo_create_from_data(xe, tile, policies, sizeof(struct guc_policies),
> -					    XE_BO_FLAG_VRAM_IF_DGFX(tile) |
> -					    XE_BO_FLAG_GGTT);
> -	if (IS_ERR(bo)) {
> -		ret = PTR_ERR(bo);
> -		goto out;
> -	}
> -
> -	ret = guc_ads_action_update_policies(ads, xe_bo_ggtt_addr(bo));
> -out:
> +	ret = guc_ads_update_policies(ads, policies);
>  	kfree(policies);
>  	return ret;
>  }
> -- 
> 2.47.1
>