Re: [PATCH] drm/xe: Skip media GT TLB invalidation when VM has no queues mapped

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On Wed, 2026-03-04 at 15:37 -0800, Matthew Brost wrote:
> If no exec queues from a VM are mapped on the media GT, issuing a
> PPGTT TLB invalidation for that GT requires an rc6 wake which is
> expensive.
> 
> Skip the media GT TLB invalidation when the VM has no exec queues
> mapped on it. If TLB invalidations are already in-flight on that GT
> we can't break fence ordering, so issue a dummy GGTT invalidation
> instead to maintain seqno ordering.
> 
> This optimization is particularly impactful for SVM workloads which
> may or may not use the media GT. Average TLB invalidation time drops
> from ~75us to ~18us in such benchmarks.
> 
> Assisted-by: GitHub Copilot:claude-sonnet-4.6 # Documentation only.
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>

Can we make this gt type agnostic so that regardless of gt type,
we skip tlb invalidations if there are no active exec-queues?

/Thomas



> ---
>  drivers/gpu/drm/xe/xe_guc_tlb_inval.c | 43
> +++++++++++++++++++++++++--
>  1 file changed, 41 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc_tlb_inval.c
> b/drivers/gpu/drm/xe/xe_guc_tlb_inval.c
> index ced58f46f846..20c34469d9a5 100644
> --- a/drivers/gpu/drm/xe/xe_guc_tlb_inval.c
> +++ b/drivers/gpu/drm/xe/xe_guc_tlb_inval.c
> @@ -205,14 +205,53 @@ static int send_tlb_inval_asid_ppgtt(struct
> xe_tlb_inval *tlb_inval, u32 seqno,
>  				     struct drm_suballoc *prl_sa)
>  {
>  	struct xe_guc *guc = tlb_inval->private;
> +	struct xe_device *xe = guc_to_xe(guc);
> +	struct xe_gt *gt = guc_to_gt(guc);
> +	struct xe_vm *vm;
> +	int err = 0, id = guc_to_gt(guc)->info.id;
>  
>  	lockdep_assert_held(&tlb_inval->seqno_lock);
>  
>  	if (guc_to_xe(guc)->info.force_execlist)
>  		return -ECANCELED;
>  
> -	return send_tlb_inval_ppgtt(guc, seqno, start, end, asid,
> -				    XE_GUC_TLB_INVAL_PAGE_SELECTIVE,
> prl_sa);
> +	if (!xe_gt_is_media_type(gt))
> +		return send_tlb_inval_ppgtt(guc, seqno, start, end,
> asid,
> +					   
> XE_GUC_TLB_INVAL_PAGE_SELECTIVE,
> +					    prl_sa);
> +
> +	/* Try to skip media GT TLB invalidations */
> +
> +	vm = xe_device_asid_to_vm(xe, asid);
> +	if (IS_ERR(vm))
> +		return PTR_ERR(vm);
> +
> +	down_read(&vm->exec_queues.lock);
> +
> +	if (!vm->exec_queues.count[id]) {
> +		/*
> +		 * We can't break fence ordering for TLB
> invalidation jobs, if
> +		 * TLB invalidations are inflight issue a dummy
> invalidation to
> +		 * maintain ordering. Nor can we move safely the
> seqno_recv when
> +		 * returning -ECANCELED if TLB invalidations are in
> flight. Use
> +		 * GGTT invalidation as dummy invalidation given
> ASID
> +		 * invalidations are unsupported here.
> +		 */
> +		if (xe_tlb_inval_idle(tlb_inval))
> +			err = -ECANCELED;
> +		else
> +			err = send_tlb_inval_ggtt(tlb_inval, seqno);
> +		goto err_unlock;
> +	}
> +
> +	err = send_tlb_inval_ppgtt(guc, seqno, start, end, asid,
> +				   XE_GUC_TLB_INVAL_PAGE_SELECTIVE,
> prl_sa);
> +
> +err_unlock:
> +	up_read(&vm->exec_queues.lock);
> +	xe_vm_put(vm);
> +
> +	return err;
>  }
>  
>  static int send_tlb_inval_ctx_ppgtt(struct xe_tlb_inval *tlb_inval,
> u32 seqno,