[Intel-gfx] [PATCH 1/3] drm/i915: Support for pre-populating the object with system pages
Siluvery, Arun
arun.siluvery at linux.intel.com
Tue Aug 25 03:51:49 PDT 2015
On 24/08/2015 12:58, ankitprasad.r.sharma at intel.com wrote:
> From: Ankitprasad Sharma <ankitprasad.r.sharma at intel.com>
>
> This patch provides support for the User to populate the object
> with system pages at its creation time. Since this can be safely
> performed without holding the 'struct_mutex', it would help to reduce
> the time 'struct_mutex' is kept locked especially during the exec-buffer
> path, where it is generally held for the longest time.
>
> Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma at intel.com>
> ---
> drivers/gpu/drm/i915/i915_dma.c | 2 +-
> drivers/gpu/drm/i915/i915_gem.c | 51 +++++++++++++++++++++++++++++++----------
> include/uapi/drm/i915_drm.h | 11 ++++-----
> 3 files changed, 45 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 8319e07..955aa16 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -171,7 +171,7 @@ static int i915_getparam(struct drm_device *dev, void *data,
> value = HAS_RESOURCE_STREAMER(dev);
> break;
> case I915_PARAM_CREATE_VERSION:
> - value = 2;
> + value = 3;
> break;
> default:
> DRM_DEBUG("Unknown parameter %d\n", param->param);
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index c44bd05..3904feb 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -46,6 +46,7 @@ static void
> i915_gem_object_retire__write(struct drm_i915_gem_object *obj);
> static void
> i915_gem_object_retire__read(struct drm_i915_gem_object *obj, int ring);
> +static int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
>
> static bool cpu_cache_is_coherent(struct drm_device *dev,
> enum i915_cache_level level)
> @@ -414,6 +415,18 @@ i915_gem_create(struct drm_file *file,
> if (obj == NULL)
> return -ENOMEM;
>
> + if (flags & I915_CREATE_POPULATE) {
> + struct drm_i915_private *dev_priv = dev->dev_private;
> +
> + ret = __i915_gem_object_get_pages(obj);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&dev->struct_mutex);
> + list_add_tail(&obj->global_list, &dev_priv->mm.unbound_list);
> + mutex_unlock(&dev->struct_mutex);
> + }
> +
> ret = drm_gem_handle_create(file, &obj->base, &handle);
If I915_CREATE_POPULATE is set, don't we have to release the pages when
this call fails?
regards
Arun
> /* drop reference from allocate - handle holds it now */
> drm_gem_object_unreference_unlocked(&obj->base);
> @@ -2328,6 +2341,31 @@ err_pages:
> return ret;
> }
>
> +static int
> +__i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
> +{
> + const struct drm_i915_gem_object_ops *ops = obj->ops;
> + int ret;
> +
> + WARN_ON(obj->pages);
> +
> + if (obj->madv != I915_MADV_WILLNEED) {
> + DRM_DEBUG("Attempting to obtain a purgeable object\n");
> + return -EFAULT;
> + }
> +
> + BUG_ON(obj->pages_pin_count);
> +
> + ret = ops->get_pages(obj);
> + if (ret)
> + return ret;
> +
> + obj->get_page.sg = obj->pages->sgl;
> + obj->get_page.last = 0;
> +
> + return 0;
> +}
> +
> /* Ensure that the associated pages are gathered from the backing storage
> * and pinned into our object. i915_gem_object_get_pages() may be called
> * multiple times before they are released by a single call to
> @@ -2339,28 +2377,17 @@ int
> i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
> {
> struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
> - const struct drm_i915_gem_object_ops *ops = obj->ops;
> int ret;
>
> if (obj->pages)
> return 0;
>
> - if (obj->madv != I915_MADV_WILLNEED) {
> - DRM_DEBUG("Attempting to obtain a purgeable object\n");
> - return -EFAULT;
> - }
> -
> - BUG_ON(obj->pages_pin_count);
> -
> - ret = ops->get_pages(obj);
> + ret = __i915_gem_object_get_pages(obj);
> if (ret)
> return ret;
>
> list_add_tail(&obj->global_list, &dev_priv->mm.unbound_list);
>
> - obj->get_page.sg = obj->pages->sgl;
> - obj->get_page.last = 0;
> -
> return 0;
> }
>
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index f71f75c..26ea715 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -457,20 +457,19 @@ struct drm_i915_gem_create {
> __u32 handle;
> __u32 pad;
> /**
> - * Requested flags (currently used for placement
> - * (which memory domain))
> + * Requested flags
> *
> * You can request that the object be created from special memory
> * rather than regular system pages using this parameter. Such
> * irregular objects may have certain restrictions (such as CPU
> * access to a stolen object is verboten).
> - *
> - * This can be used in the future for other purposes too
> - * e.g. specifying tiling/caching/madvise
> + * Also using this parameter object can be pre-populated with system
> + * pages.
> */
> __u32 flags;
> #define I915_CREATE_PLACEMENT_STOLEN (1<<0) /* Cannot use CPU mmaps */
> -#define __I915_CREATE_UNKNOWN_FLAGS -(I915_CREATE_PLACEMENT_STOLEN << 1)
> +#define I915_CREATE_POPULATE (1<<1) /* Pre-populate object pages */
> +#define __I915_CREATE_UNKNOWN_FLAGS -(I915_CREATE_POPULATE << 1)
> };
>
> struct drm_i915_gem_pread {
>
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