[Intel-gfx] [PATCH 2/2] drm/i915/gvt: Stop waiting whilst holding struct_mutex

[Zhenyu Wang]

On 2016.10.19 09:12:28 +0100, Chris Wilson wrote:
> For whatever reason, the gvt scheduler runs synchronously. At the very
> least, lets run synchronously without holding the struct_mutex.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

This will break current device model which assume to serve one VM context
on hw at each time but can't switch to another one between for emulation
issue.

This is not good but its current implementation limit we'll address later.

> ---
>  drivers/gpu/drm/i915/gvt/scheduler.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
> index 4cedd3274da7..aa83dd3381a3 100644
> --- a/drivers/gpu/drm/i915/gvt/scheduler.c
> +++ b/drivers/gpu/drm/i915/gvt/scheduler.c
> @@ -420,10 +420,6 @@ static int workload_thread(void *priv)
>  
>  		intel_runtime_pm_get(gvt->dev_priv);
>  
> -		/*
> -		 * Always take i915 big lock first
> -		 */
> -		mutex_lock(&gvt->dev_priv->drm.struct_mutex);
>  
>  		gvt_dbg_sched("ring id %d will dispatch workload %p\n",
>  				workload->ring_id, workload);
> @@ -432,7 +428,10 @@ static int workload_thread(void *priv)
>  			intel_uncore_forcewake_get(gvt->dev_priv,
>  					FORCEWAKE_ALL);
>  
> +		mutex_lock(&gvt->dev_priv->drm.struct_mutex);
>  		ret = dispatch_workload(workload);
> +		mutex_lock(&gvt->dev_priv->drm.struct_mutex);
> +
>  		if (ret) {
>  			gvt_err("fail to dispatch workload, skip\n");
>  			goto complete;
> @@ -442,8 +441,7 @@ static int workload_thread(void *priv)
>  				workload->ring_id, workload);
>  
>  		workload->status = i915_wait_request(workload->req,
> -						     I915_WAIT_LOCKED,
> -						     NULL, NULL);
> +						     0, NULL, NULL);
>  		if (workload->status != 0)
>  			gvt_err("fail to wait workload, skip\n");
>  
> @@ -451,13 +449,14 @@ static int workload_thread(void *priv)
>  		gvt_dbg_sched("will complete workload %p\n, status: %d\n",
>  				workload, workload->status);
>  
> +		mutex_lock(&gvt->dev_priv->drm.struct_mutex);
>  		complete_current_workload(gvt, ring_id);
> +		mutex_unlock(&gvt->dev_priv->drm.struct_mutex);
>  
>  		if (need_force_wake)
>  			intel_uncore_forcewake_put(gvt->dev_priv,
>  					FORCEWAKE_ALL);
>  
> -		mutex_unlock(&gvt->dev_priv->drm.struct_mutex);
>  
>  		intel_runtime_pm_put(gvt->dev_priv);
>  	}
> -- 
> 2.9.3
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Open Source Technology Center, Intel ltd.

$gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 163 bytes
Desc: not available
URL: <https://lists.freedesktop.org/archives/intel-gfx/attachments/20161019/8752cff0/attachment.sig>