Re: [PATCH] drm/i915/ggtt: Move ballooning support to i915_ggtt

[Jani Nikula <jani.nikula@intel.com>]

On Thu, 21 Nov 2019, Michal Wajdeczko <michal.wajdeczko@intel.com> wrote:
> Today VGT implements GGTT ballooning on its own, using some private
> static structure to hold info about reserved GGTT nodes and then
> manually update vm.reserved size owned by i915_ggtt.
>
> As i915_ggtt already manages some custom reserved nodes (like uc_fw)
> move VGT ballooning support to i915_ggtt and make it more generic
> for possible future reuse in other scenarios.
>
> As a bonus we can drop another place in driver that uses static data.
>
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Cc: Xiong Zhang <xiong.y.zhang@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 47 +++++++++++++++++++
>  drivers/gpu/drm/i915/i915_gem_gtt.h | 18 ++++++++

Maybe not part of this patch, but should we start moving this stuff out
of the top level instead of addming more?

BR,
Jani.

>  drivers/gpu/drm/i915/i915_vgpu.c    | 72 ++++++-----------------------
>  3 files changed, 78 insertions(+), 59 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 6239a9adbf14..d8b2084dab7e 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -3827,6 +3827,53 @@ int i915_gem_gtt_insert(struct i915_address_space *vm,
>  					   start, end, DRM_MM_INSERT_EVICT);
>  }
>  
> +int i915_ggtt_balloon_space(struct i915_ggtt *ggtt,
> +			    enum i915_ggtt_balloon_id id,
> +			    u64 start, u64 end)
> +{
> +	struct drm_mm_node *node = &ggtt->balloon[id];
> +	u64 size = end - start;
> +	int ret;
> +
> +	GEM_BUG_ON(id < 0 || id >= ARRAY_SIZE(ggtt->balloon));
> +	GEM_BUG_ON(start >= end);
> +	DRM_DEV_DEBUG_DRIVER(ggtt->vm.i915->drm.dev,
> +			     "%sGGTT [%#llx-%#llx] %lluK\n",
> +			     "ballooning ", start, end, size / SZ_1K);
> +
> +	ret = i915_gem_gtt_reserve(&ggtt->vm, node, size, start,
> +				   I915_COLOR_UNEVICTABLE, PIN_NOEVICT);
> +	if (unlikely(ret)) {
> +		DRM_DEV_ERROR(ggtt->vm.i915->drm.dev,
> +			      "%sGGTT [%#llx-%#llx] %lluK\n",
> +			      "Failed to balloon ", node->start,
> +			      node->start + node->size, node->size / SZ_1K);
> +	} else {
> +		ggtt->vm.reserved += node->size;
> +	}
> +
> +	return ret;
> +}
> +
> +void i915_ggtt_deballoon_space(struct i915_ggtt *ggtt,
> +			       enum i915_ggtt_balloon_id id)
> +{
> +	struct drm_mm_node *node = &ggtt->balloon[id];
> +
> +	GEM_BUG_ON(id < 0 || id >= ARRAY_SIZE(ggtt->balloon));
> +	if (!drm_mm_node_allocated(node))
> +		return;
> +
> +	DRM_DEV_DEBUG_DRIVER(ggtt->vm.i915->drm.dev,
> +			     "%sGGTT [%#llx-%#llx] %lluK\n",
> +			     "deballooning ", node->start,
> +			     node->start + node->size, node->size / SZ_1K);
> +
> +	GEM_BUG_ON(ggtt->vm.reserved < node->size);
> +	ggtt->vm.reserved -= node->size;
> +	drm_mm_remove_node(node);
> +}
> +
>  #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
>  #include "selftests/mock_gtt.c"
>  #include "selftests/i915_gem_gtt.c"
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index 402283ce2864..ba40cae0e97a 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
> @@ -432,6 +432,12 @@ struct i915_ggtt {
>  
>  	struct drm_mm_node error_capture;
>  	struct drm_mm_node uc_fw;
> +
> +	/*
> +	 * There might be up to 4 regions ballooned.
> +	 * (2 for mappable and 2 for unmappable graphic memory)
> +	 */
> +	struct drm_mm_node balloon[4];
>  };
>  
>  struct i915_ppgtt {
> @@ -649,6 +655,18 @@ int i915_gem_gtt_insert(struct i915_address_space *vm,
>  			u64 size, u64 alignment, unsigned long color,
>  			u64 start, u64 end, unsigned int flags);
>  
> +enum i915_ggtt_balloon_id {
> +	I915_GGTT_BALLOON0,
> +	I915_GGTT_BALLOON1,
> +	I915_GGTT_BALLOON2,
> +	I915_GGTT_BALLOON3,
> +};
> +
> +int i915_ggtt_balloon_space(struct i915_ggtt *ggtt,
> +			    enum i915_ggtt_balloon_id id, u64 start, u64 end);
> +void i915_ggtt_deballoon_space(struct i915_ggtt *ggtt,
> +			       enum i915_ggtt_balloon_id id);
> +
>  /* Flags used by pin/bind&friends. */
>  #define PIN_NOEVICT		BIT_ULL(0)
>  #define PIN_NOSEARCH		BIT_ULL(1)
> diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c
> index 968be26735c5..195c27725cbb 100644
> --- a/drivers/gpu/drm/i915/i915_vgpu.c
> +++ b/drivers/gpu/drm/i915/i915_vgpu.c
> @@ -106,32 +106,6 @@ bool intel_vgpu_has_full_ppgtt(struct drm_i915_private *dev_priv)
>  	return dev_priv->vgpu.caps & VGT_CAPS_FULL_PPGTT;
>  }
>  
> -struct _balloon_info_ {
> -	/*
> -	 * There are up to 2 regions per mappable/unmappable graphic
> -	 * memory that might be ballooned. Here, index 0/1 is for mappable
> -	 * graphic memory, 2/3 for unmappable graphic memory.
> -	 */
> -	struct drm_mm_node space[4];
> -};
> -
> -static struct _balloon_info_ bl_info;
> -
> -static void vgt_deballoon_space(struct i915_ggtt *ggtt,
> -				struct drm_mm_node *node)
> -{
> -	if (!drm_mm_node_allocated(node))
> -		return;
> -
> -	DRM_DEBUG_DRIVER("deballoon space: range [0x%llx - 0x%llx] %llu KiB.\n",
> -			 node->start,
> -			 node->start + node->size,
> -			 node->size / 1024);
> -
> -	ggtt->vm.reserved -= node->size;
> -	drm_mm_remove_node(node);
> -}
> -
>  /**
>   * intel_vgt_deballoon - deballoon reserved graphics address trunks
>   * @ggtt: the global GGTT from which we reserved earlier
> @@ -149,28 +123,7 @@ void intel_vgt_deballoon(struct i915_ggtt *ggtt)
>  	DRM_DEBUG("VGT deballoon.\n");
>  
>  	for (i = 0; i < 4; i++)
> -		vgt_deballoon_space(ggtt, &bl_info.space[i]);
> -}
> -
> -static int vgt_balloon_space(struct i915_ggtt *ggtt,
> -			     struct drm_mm_node *node,
> -			     unsigned long start, unsigned long end)
> -{
> -	unsigned long size = end - start;
> -	int ret;
> -
> -	if (start >= end)
> -		return -EINVAL;
> -
> -	DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n",
> -		 start, end, size / 1024);
> -	ret = i915_gem_gtt_reserve(&ggtt->vm, node,
> -				   size, start, I915_COLOR_UNEVICTABLE,
> -				   0);
> -	if (!ret)
> -		ggtt->vm.reserved += size;
> -
> -	return ret;
> +		i915_ggtt_deballoon_space(ggtt, I915_GGTT_BALLOON0 + i);
>  }
>  
>  /**
> @@ -256,32 +209,33 @@ int intel_vgt_balloon(struct i915_ggtt *ggtt)
>  
>  	/* Unmappable graphic memory ballooning */
>  	if (unmappable_base > ggtt->mappable_end) {
> -		ret = vgt_balloon_space(ggtt, &bl_info.space[2],
> -					ggtt->mappable_end, unmappable_base);
> +		ret = i915_ggtt_balloon_space(ggtt, I915_GGTT_BALLOON2,
> +					      ggtt->mappable_end,
> +					      unmappable_base);
>  
>  		if (ret)
>  			goto err;
>  	}
>  
>  	if (unmappable_end < ggtt_end) {
> -		ret = vgt_balloon_space(ggtt, &bl_info.space[3],
> -					unmappable_end, ggtt_end);
> +		ret = i915_ggtt_balloon_space(ggtt, I915_GGTT_BALLOON3,
> +					      unmappable_end, ggtt_end);
>  		if (ret)
>  			goto err_upon_mappable;
>  	}
>  
>  	/* Mappable graphic memory ballooning */
>  	if (mappable_base) {
> -		ret = vgt_balloon_space(ggtt, &bl_info.space[0],
> -					0, mappable_base);
> +		ret = i915_ggtt_balloon_space(ggtt, I915_GGTT_BALLOON0,
> +					      0, mappable_base);
>  
>  		if (ret)
>  			goto err_upon_unmappable;
>  	}
>  
>  	if (mappable_end < ggtt->mappable_end) {
> -		ret = vgt_balloon_space(ggtt, &bl_info.space[1],
> -					mappable_end, ggtt->mappable_end);
> +		ret = i915_ggtt_balloon_space(ggtt, I915_GGTT_BALLOON1,
> +					      mappable_end, ggtt->mappable_end);
>  
>  		if (ret)
>  			goto err_below_mappable;
> @@ -291,11 +245,11 @@ int intel_vgt_balloon(struct i915_ggtt *ggtt)
>  	return 0;
>  
>  err_below_mappable:
> -	vgt_deballoon_space(ggtt, &bl_info.space[0]);
> +	i915_ggtt_deballoon_space(ggtt, I915_GGTT_BALLOON0);
>  err_upon_unmappable:
> -	vgt_deballoon_space(ggtt, &bl_info.space[3]);
> +	i915_ggtt_deballoon_space(ggtt, I915_GGTT_BALLOON3);
>  err_upon_mappable:
> -	vgt_deballoon_space(ggtt, &bl_info.space[2]);
> +	i915_ggtt_deballoon_space(ggtt, I915_GGTT_BALLOON2);
>  err:
>  	DRM_ERROR("VGT balloon fail\n");
>  	return ret;

-- 
Jani Nikula, Intel Open Source Graphics Center
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