[Intel-gfx] [PATCH 3/3] drm/i915: Add soft-pinning API for execbuffer

Kristian Høgsberg krh at bitplanet.net
Thu Nov 5 09:51:48 PST 2015


On Tue, Oct 6, 2015 at 3:53 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> Userspace can pass in an offset that it presumes the object is located
> at. The kernel will then do its utmost to fit the object into that
> location. The assumption is that userspace is handling its own object
> locations (for example along with full-ppgtt) and that the kernel will
> rarely have to make space for the user's requests.

I know the commit message isn't documentation, but the phrase "do its
utmost" makes me uncomfortable. I'd like to be explicit about what
might make it fail (should only be pinned fbs in case of aliased ppgtt
or userspace errors such as overlapping placements), or conversely,
spell out when the flag can be expected to work (full ppgtt).

Kristian

> v2: Fix i915_gem_evict_range() (now evict_for_vma) to handle ordinary
> and fixed objects within the same batch
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: "Daniel, Thomas" <thomas.daniel at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_dma.c            |  3 ++
>  drivers/gpu/drm/i915/i915_drv.h            | 10 +++--
>  drivers/gpu/drm/i915/i915_gem.c            | 68 +++++++++++++++++++++---------
>  drivers/gpu/drm/i915/i915_gem_evict.c      | 61 +++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/i915_gem_execbuffer.c |  9 +++-
>  drivers/gpu/drm/i915/i915_trace.h          | 23 ++++++++++
>  include/uapi/drm/i915_drm.h                |  4 +-
>  7 files changed, 151 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index ab37d1121be8..cd79ef114b8e 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -170,6 +170,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
>         case I915_PARAM_HAS_RESOURCE_STREAMER:
>                 value = HAS_RESOURCE_STREAMER(dev);
>                 break;
> +       case I915_PARAM_HAS_EXEC_SOFTPIN:
> +               value = 1;
> +               break;
>         default:
>                 DRM_DEBUG("Unknown parameter %d\n", param->param);
>                 return -EINVAL;
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index a0ce011a5dc0..7d351d991022 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2778,10 +2778,11 @@ void i915_gem_vma_destroy(struct i915_vma *vma);
>  #define PIN_NONBLOCK   (1<<1)
>  #define PIN_GLOBAL     (1<<2)
>  #define PIN_OFFSET_BIAS        (1<<3)
> -#define PIN_USER       (1<<4)
> -#define PIN_UPDATE     (1<<5)
> -#define PIN_ZONE_4G    (1<<6)
> -#define PIN_HIGH       (1<<7)
> +#define PIN_OFFSET_FIXED (1<<4)
> +#define PIN_USER       (1<<5)
> +#define PIN_UPDATE     (1<<6)
> +#define PIN_ZONE_4G    (1<<7)
> +#define PIN_HIGH       (1<<8)
>  #define PIN_OFFSET_MASK (~4095)
>  int __must_check
>  i915_gem_object_pin(struct drm_i915_gem_object *obj,
> @@ -3127,6 +3128,7 @@ int __must_check i915_gem_evict_something(struct drm_device *dev,
>                                           unsigned long start,
>                                           unsigned long end,
>                                           unsigned flags);
> +int __must_check i915_gem_evict_for_vma(struct i915_vma *vma, unsigned flags);
>  int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle);
>
>  /* belongs in i915_gem_gtt.h */
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 8fe3df0cdcb8..82efd6a6dee0 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3334,7 +3334,6 @@ i915_gem_object_bind_to_vm(struct drm_i915_gem_object *obj,
>         struct drm_device *dev = obj->base.dev;
>         struct drm_i915_private *dev_priv = dev->dev_private;
>         u64 start, end;
> -       u32 search_flag, alloc_flag;
>         struct i915_vma *vma;
>         int ret;
>
> @@ -3409,30 +3408,53 @@ i915_gem_object_bind_to_vm(struct drm_i915_gem_object *obj,
>         if (IS_ERR(vma))
>                 goto err_unpin;
>
> -       if (flags & PIN_HIGH) {
> -               search_flag = DRM_MM_SEARCH_BELOW;
> -               alloc_flag = DRM_MM_CREATE_TOP;
> +       if (flags & PIN_OFFSET_FIXED) {
> +               uint64_t offset = flags & PIN_OFFSET_MASK;
> +               if (offset & (alignment - 1) || offset + size > end) {
> +                       vma = ERR_PTR(-EINVAL);
> +                       goto err_free_vma;
> +               }
> +               vma->node.start = offset;
> +               vma->node.size = size;
> +               vma->node.color = obj->cache_level;
> +               ret = drm_mm_reserve_node(&vm->mm, &vma->node);
> +               if (ret) {
> +                       ret = i915_gem_evict_for_vma(vma, flags);
> +                       if (ret == 0)
> +                               ret = drm_mm_reserve_node(&vm->mm, &vma->node);
> +               }
> +               if (ret) {
> +                       vma = ERR_PTR(ret);
> +                       goto err_free_vma;
> +               }
>         } else {
> -               search_flag = DRM_MM_SEARCH_DEFAULT;
> -               alloc_flag = DRM_MM_CREATE_DEFAULT;
> -       }
> +               u32 search_flag, alloc_flag;
> +
> +               if (flags & PIN_HIGH) {
> +                       search_flag = DRM_MM_SEARCH_BELOW;
> +                       alloc_flag = DRM_MM_CREATE_TOP;
> +               } else {
> +                       search_flag = DRM_MM_SEARCH_DEFAULT;
> +                       alloc_flag = DRM_MM_CREATE_DEFAULT;
> +               }
>
>  search_free:
> -       ret = drm_mm_insert_node_in_range_generic(&vm->mm, &vma->node,
> -                                                 size, alignment,
> -                                                 obj->cache_level,
> -                                                 start, end,
> -                                                 search_flag,
> -                                                 alloc_flag);
> -       if (ret) {
> -               ret = i915_gem_evict_something(dev, vm, size, alignment,
> -                                              obj->cache_level,
> -                                              start, end,
> -                                              flags);
> -               if (ret == 0)
> -                       goto search_free;
> +               ret = drm_mm_insert_node_in_range_generic(&vm->mm, &vma->node,
> +                                                         size, alignment,
> +                                                         obj->cache_level,
> +                                                         start, end,
> +                                                         search_flag,
> +                                                         alloc_flag);
> +               if (ret) {
> +                       ret = i915_gem_evict_something(dev, vm, size, alignment,
> +                                                      obj->cache_level,
> +                                                      start, end,
> +                                                      flags);
> +                       if (ret == 0)
> +                               goto search_free;
>
> -               goto err_free_vma;
> +                       goto err_free_vma;
> +               }
>         }
>         if (WARN_ON(!i915_gem_valid_gtt_space(vma, obj->cache_level))) {
>                 ret = -EINVAL;
> @@ -3970,6 +3992,10 @@ i915_vma_misplaced(struct i915_vma *vma,
>             vma->node.start < (flags & PIN_OFFSET_MASK))
>                 return true;
>
> +       if (flags & PIN_OFFSET_FIXED &&
> +           vma->node.start != (flags & PIN_OFFSET_MASK))
> +               return true;
> +
>         return false;
>  }
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
> index d71a133ceff5..60450a95a491 100644
> --- a/drivers/gpu/drm/i915/i915_gem_evict.c
> +++ b/drivers/gpu/drm/i915/i915_gem_evict.c
> @@ -199,6 +199,67 @@ found:
>         return ret;
>  }
>
> +int
> +i915_gem_evict_for_vma(struct i915_vma *target, unsigned flags)
> +{
> +       struct list_head eviction_list;
> +       struct interval_tree_node *it;
> +       u64 end = target->node.start + target->node.size;
> +       struct drm_mm_node *node;
> +       struct i915_vma *vma, *next;
> +       int ret;
> +
> +       trace_i915_gem_evict_vma(target, flags);
> +
> +       it = interval_tree_iter_first(&target->vm->mm.interval_tree,
> +                                     target->node.start, end -1);
> +       if (it == NULL)
> +               return 0;
> +
> +       INIT_LIST_HEAD(&eviction_list);
> +       node = container_of(it, typeof(*node), it);
> +       list_for_each_entry_from(node,
> +                                &target->vm->mm.head_node.node_list,
> +                                node_list) {
> +               if (node->start >= end)
> +                       break;
> +
> +               vma = container_of(node, typeof(*vma), node);
> +               if (flags & PIN_NONBLOCK &&
> +                   (vma->pin_count || vma->obj->active)) {
> +                       ret = -ENOSPC;
> +                       break;
> +               }
> +
> +               if (vma->exec_entry &&
> +                   vma->exec_entry->flags & EXEC_OBJECT_PINNED) {
> +                       /* Overlapping pinned objects in the same batch */
> +                       ret = -EINVAL;
> +                       break;
> +               }
> +
> +               if (vma->pin_count) {
> +                       /* We may need to evict an buffer in the same batch */
> +                       ret = vma->exec_entry ? -ENOSPC : -EBUSY;
> +                       break;
> +               }
> +
> +               list_add(&vma->exec_list, &eviction_list);
> +               drm_gem_object_reference(&vma->obj->base);
> +       }
> +
> +       ret = 0;
> +       list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
> +               struct drm_i915_gem_object *obj = vma->obj;
> +               list_del_init(&vma->exec_list);
> +               if (ret == 0)
> +                       ret = i915_vma_unbind(vma);
> +               drm_gem_object_unreference(&obj->base);
> +       }
> +
> +       return ret;
> +}
> +
>  /**
>   * i915_gem_evict_vm - Evict all idle vmas from a vm
>   * @vm: Address space to cleanse
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 19dd6b05ee1d..c35c9dc526e7 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -603,6 +603,8 @@ i915_gem_execbuffer_reserve_vma(struct i915_vma *vma,
>                         flags |= BATCH_OFFSET_BIAS | PIN_OFFSET_BIAS;
>                 if ((flags & PIN_MAPPABLE) == 0)
>                         flags |= PIN_HIGH;
> +               if (entry->flags & EXEC_OBJECT_PINNED)
> +                       flags |= entry->offset | PIN_OFFSET_FIXED;
>         }
>
>         ret = i915_gem_object_pin(obj, vma->vm,
> @@ -679,6 +681,10 @@ eb_vma_misplaced(struct i915_vma *vma)
>         if (vma->node.size < entry->pad_to_size)
>                 return true;
>
> +       if (entry->flags & EXEC_OBJECT_PINNED &&
> +           vma->node.start != entry->offset)
> +               return true;
> +
>         if (entry->flags & __EXEC_OBJECT_NEEDS_BIAS &&
>             vma->node.start < BATCH_OFFSET_BIAS)
>                 return true;
> @@ -1328,7 +1334,8 @@ eb_get_batch(struct eb_vmas *eb)
>          * Note that actual hangs have only been observed on gen7, but for
>          * paranoia do it everywhere.
>          */
> -       vma->exec_entry->flags |= __EXEC_OBJECT_NEEDS_BIAS;
> +       if ((vma->exec_entry->flags & EXEC_OBJECT_PINNED) == 0)
> +               vma->exec_entry->flags |= __EXEC_OBJECT_NEEDS_BIAS;
>
>         return vma->obj;
>  }
> diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
> index b1dcee718640..ef2387c01fa9 100644
> --- a/drivers/gpu/drm/i915/i915_trace.h
> +++ b/drivers/gpu/drm/i915/i915_trace.h
> @@ -459,6 +459,29 @@ TRACE_EVENT(i915_gem_evict_vm,
>             TP_printk("dev=%d, vm=%p", __entry->dev, __entry->vm)
>  );
>
> +TRACE_EVENT(i915_gem_evict_vma,
> +           TP_PROTO(struct i915_vma *vma, unsigned flags),
> +           TP_ARGS(vma, flags),
> +
> +           TP_STRUCT__entry(
> +                            __field(u32, dev)
> +                            __field(struct i915_address_space *, vm)
> +                            __field(u64, start)
> +                            __field(u64, size)
> +                            __field(unsigned, flags)
> +                           ),
> +
> +           TP_fast_assign(
> +                          __entry->dev = vma->vm->dev->primary->index;
> +                          __entry->vm = vma->vm;
> +                          __entry->start = vma->node.start;
> +                          __entry->size = vma->node.size;
> +                          __entry->flags = flags;
> +                         ),
> +
> +           TP_printk("dev=%d, vm=%p, start=%llx size=%llx, flags=%x", __entry->dev, __entry->vm, (long long)__entry->start, (long long)__entry->size, __entry->flags)
> +);
> +
>  TRACE_EVENT(i915_gem_ring_sync_to,
>             TP_PROTO(struct drm_i915_gem_request *to_req,
>                      struct intel_engine_cs *from,
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 5e2fc61e7d88..766aa4fb8264 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -356,6 +356,7 @@ typedef struct drm_i915_irq_wait {
>  #define I915_PARAM_EU_TOTAL             34
>  #define I915_PARAM_HAS_GPU_RESET        35
>  #define I915_PARAM_HAS_RESOURCE_STREAMER 36
> +#define I915_PARAM_HAS_EXEC_SOFTPIN     37
>
>  typedef struct drm_i915_getparam {
>         s32 param;
> @@ -692,7 +693,8 @@ struct drm_i915_gem_exec_object2 {
>  #define EXEC_OBJECT_WRITE      (1<<2)
>  #define EXEC_OBJECT_SUPPORTS_48B_ADDRESS (1<<3)
>  #define EXEC_OBJECT_PAD_TO_SIZE        (1<<4)
> -#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_PAD_TO_SIZE<<1)
> +#define EXEC_OBJECT_PINNED     (1<<5)
> +#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_PINNED<<1)
>         __u64 flags;
>
>         __u64 pad_to_size;
> --
> 2.6.0
>
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