Re: [PATCH 1/2] drm/i915: Extend GET_APERTURE ioctl to report available map space

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 07/08/2015 07:51 AM, ankitprasad.r.sharma@intel.com wrote:
> From: Rodrigo Vivi <rodrigo.vivi at intel.com>
>
> When constructing a batchbuffer, it is sometimes crucial to know the
> largest hole into which we can fit a fenceable buffer (for example when
> handling very large objects on gen2 and gen3). This depends on the
> fragmentation of pinned buffers inside the aperture, a question only the
> kernel can easily answer.
>
> This patch extends the current DRM_I915_GEM_GET_APERTURE ioctl to
> include a couple of new fields in its reply to userspace - the total
> amount of space available in the mappable region of the aperture and
> also the single largest block available.
>
> This is not quite what userspace wants to answer the question of whether
> this batch will fit as fences are also required to meet severe alignment
> constraints within the batch. For this purpose, a third conservative
> estimate of largest fence available is also provided. For when userspace
> needs more than one batch, we also provide the culmulative space
> available for fences such that it has some additional guidance to how
> much space it could allocate to fences. Conservatism still wins.
>
> The patch also adds a debugfs file for convenient testing and reporting.
>
> v2: The first object cannot end at offset 0, so we can use last==0 to
> detect the empty list.
>
> v3: Expand all values to 64bit, just in case.
>      Report total mappable aperture size for userspace that cannot easily
>      determine it by inspecting the PCI device.
>
> v4: (Rodrigo) Fixed rebase conflicts.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_debugfs.c |  27 +++++++++
>   drivers/gpu/drm/i915/i915_gem.c     | 116 ++++++++++++++++++++++++++++++++++--
>   include/uapi/drm/i915_drm.h         |  25 ++++++++
>   3 files changed, 164 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 31d8768..49ec438 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -512,6 +512,32 @@ static int i915_gem_object_info(struct seq_file *m, void* data)
>   	return 0;
>   }
>
> +static int i915_gem_aperture_info(struct seq_file *m, void *data)
> +{
> +	struct drm_info_node *node = m->private;
> +	struct drm_i915_gem_get_aperture arg;
> +	int ret;
> +
> +	ret = i915_gem_get_aperture_ioctl(node->minor->dev, &arg, NULL);
> +	if (ret)
> +		return ret;
> +
> +	seq_printf(m, "Total size of the GTT: %llu bytes\n",
> +		   arg.aper_size);
> +	seq_printf(m, "Available space in the GTT: %llu bytes\n",
> +		   arg.aper_available_size);
> +	seq_printf(m, "Available space in the mappable aperture: %llu bytes\n",
> +		   arg.map_available_size);
> +	seq_printf(m, "Single largest space in the mappable aperture: %llu bytes\n",
> +		   arg.map_largest_size);
> +	seq_printf(m, "Available space for fences: %llu bytes\n",
> +		   arg.fence_available_size);
> +	seq_printf(m, "Single largest fence available: %llu bytes\n",
> +		   arg.fence_largest_size);
> +
> +	return 0;
> +}
> +
>   static int i915_gem_gtt_info(struct seq_file *m, void *data)
>   {
>   	struct drm_info_node *node = m->private;
> @@ -5030,6 +5056,7 @@ static int i915_debugfs_create(struct dentry *root,
>   static const struct drm_info_list i915_debugfs_list[] = {
>   	{"i915_capabilities", i915_capabilities, 0},
>   	{"i915_gem_objects", i915_gem_object_info, 0},
> +	{"i915_gem_aperture", i915_gem_aperture_info, 0},
>   	{"i915_gem_gtt", i915_gem_gtt_info, 0},
>   	{"i915_gem_pinned", i915_gem_gtt_info, 0, (void *) PINNED_LIST},
>   	{"i915_gem_active", i915_gem_object_list_info, 0, (void *) ACTIVE_LIST},
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index a2a4a27..ccfc8d3 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -32,6 +32,7 @@
>   #include "i915_vgpu.h"
>   #include "i915_trace.h"
>   #include "intel_drv.h"
> +#include <linux/list_sort.h>
>   #include <linux/shmem_fs.h>
>   #include <linux/slab.h>
>   #include <linux/swap.h>
> @@ -143,6 +144,55 @@ int i915_mutex_lock_interruptible(struct drm_device *dev)
>   	return 0;
>   }
>
> +static inline bool
> +i915_gem_object_is_inactive(struct drm_i915_gem_object *obj)
> +{
> +	return i915_gem_obj_bound_any(obj) && !obj->active;
> +}

Oh and this function is not used.

Regards,

Tvrtko
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