Many apologies to Michal for incorrectly spelling his name in the CC list.
Thomas.
> -----Original Message-----
> From: Daniel, Thomas
> Sent: Tuesday, June 30, 2015 3:13 PM
> To: intel-gfx@lists.freedesktop.org
> Cc: Chris Wilson; Goel, Akash; Belgaumkar, Vinay; Michal Winiarsky; Zou,
> Nanhai; Daniel, Thomas
> Subject: [PATCH v4] drm/i915: Add soft-pinning API for execbuffer
>
> From: Chris Wilson <ch...@chris-wilson.co.uk>
>
> 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.
>
> Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
>
> v2: Fixed incorrect eviction found by Michal Winiarski - fix suggested by
> Chris
> Wilson. Fixed incorrect error paths causing crash found by Michal Winiarski.
> (Not published externally)
>
> v3: Rebased because of trivial conflict in object_bind_to_vm. Fixed eviction
> to allow eviction of soft-pinned objects when another soft-pinned object used
> by a subsequent execbuffer overlaps reported by Michal Winiarski.
> (Not published externally)
>
> v4: Moved soft-pinned objects to the front of ordered_vmas so that they are
> pinned first after an address conflict happens to avoid repeated conflicts in
> rare cases (Suggested by Chris Wilson). Expanded comment on
> drm_i915_gem_exec_object2.offset to cover this new API.
>
> Cc: Chris Wilson <ch...@chris-wilson.co.uk>
> Cc: Akash Goel <akash.g...@intel.com>
> Cc: Vinay Belgaumkar <vinay.belgaum...@intel.com>
> Cc: Michal Winiarsky <michal.winiar...@intel.com>
> Cc: Zou Nanhai <nanhai....@intel.com>
> Signed-off-by: Thomas Daniel <thomas.dan...@intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 4 +++
> drivers/gpu/drm/i915/i915_gem.c | 51
> ++++++++++++++++++++--------
> drivers/gpu/drm/i915/i915_gem_evict.c | 38 +++++++++++++++++++++
> drivers/gpu/drm/i915/i915_gem_execbuffer.c | 16 +++++++--
> include/uapi/drm/i915_drm.h | 9 +++--
> 5 files changed, 99 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index d90a782..e96c101 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2747,7 +2747,9 @@ void i915_gem_vma_destroy(struct i915_vma *vma);
> #define PIN_USER (1<<4)
> #define PIN_UPDATE (1<<5)
> #define PIN_FULL_RANGE (1<<6)
> +#define PIN_OFFSET_FIXED (1<<7)
> #define PIN_OFFSET_MASK (~4095)
> +
> int __must_check
> i915_gem_object_pin(struct drm_i915_gem_object *obj,
> struct i915_address_space *vm,
> @@ -3085,6 +3087,8 @@ 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 *target);
> int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle);
> int i915_gem_evict_everything(struct drm_device *dev);
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c
> b/drivers/gpu/drm/i915/i915_gem.c
> index f170da6..a7e5ff2 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3806,22 +3806,41 @@ i915_gem_object_bind_to_vm(struct
> drm_i915_gem_object *obj,
> if (IS_ERR(vma))
> goto err_unpin;
>
> + if (flags & PIN_OFFSET_FIXED) {
> + uint64_t offset = flags & PIN_OFFSET_MASK;
> + if (offset & (alignment - 1)) {
> + ret = -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);
> + if (ret == 0)
> + ret = drm_mm_reserve_node(&vm->mm,
> &vma->node);
> + }
> + if (ret)
> + goto err_free_vma;
> + } else {
> 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;
> @@ -4357,6 +4376,10 @@ i915_vma_misplaced(struct i915_vma *vma,
> uint32_t alignment, uint64_t flags)
> 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 d09e35e..6098e2f 100644
> --- a/drivers/gpu/drm/i915/i915_gem_evict.c
> +++ b/drivers/gpu/drm/i915/i915_gem_evict.c
> @@ -199,6 +199,44 @@ found:
> return ret;
> }
>
> +int
> +i915_gem_evict_for_vma(struct i915_vma *target)
> +{
> + struct drm_mm_node *node, *next;
> +
> + list_for_each_entry_safe(node, next,
> + &target->vm->mm.head_node.node_list,
> + node_list) {
> + struct i915_vma *vma;
> + int ret;
> +
> + if (node->start + node->size <= target->node.start)
> + continue;
> + if (node->start >= target->node.start + target->node.size)
> + break;
> +
> + vma = container_of(node, typeof(*vma), node);
> +
> + if (vma->pin_count) {
> + /* We may need to evict a buffer in the same batch */
> + if (!vma->exec_entry)
> + return -EBUSY;
> +
> + if (vma->exec_entry->flags & EXEC_OBJECT_PINNED)
> + /* Overlapping fixed objects in the same batch
> */
> + return -EINVAL;
> +
> + return -ENOSPC;
> + }
> +
> + ret = i915_vma_unbind(vma);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> /**
> * 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 3d94744..4e6955e 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -596,6 +596,8 @@ i915_gem_execbuffer_reserve_vma(struct i915_vma
> *vma,
> flags |= PIN_GLOBAL | PIN_MAPPABLE;
> if (entry->flags & __EXEC_OBJECT_NEEDS_BIAS)
> flags |= BATCH_OFFSET_BIAS | PIN_OFFSET_BIAS;
> + if (entry->flags & EXEC_OBJECT_PINNED)
> + flags |= entry->offset | PIN_OFFSET_FIXED;
> }
>
> ret = i915_gem_object_pin(obj, vma->vm, entry->alignment, flags);
> @@ -665,6 +667,10 @@ eb_vma_misplaced(struct i915_vma *vma)
> vma->node.start & (entry->alignment - 1))
> 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;
> @@ -690,6 +696,7 @@ i915_gem_execbuffer_reserve(struct intel_engine_cs
> *ring,
> struct i915_vma *vma;
> struct i915_address_space *vm;
> struct list_head ordered_vmas;
> + struct list_head pinned_vmas;
> bool has_fenced_gpu_access = INTEL_INFO(ring->dev)->gen < 4;
> int retry;
>
> @@ -698,6 +705,7 @@ i915_gem_execbuffer_reserve(struct intel_engine_cs
> *ring,
> vm = list_first_entry(vmas, struct i915_vma, exec_list)->vm;
>
> INIT_LIST_HEAD(&ordered_vmas);
> + INIT_LIST_HEAD(&pinned_vmas);
> while (!list_empty(vmas)) {
> struct drm_i915_gem_exec_object2 *entry;
> bool need_fence, need_mappable;
> @@ -716,7 +724,9 @@ i915_gem_execbuffer_reserve(struct intel_engine_cs
> *ring,
> obj->tiling_mode != I915_TILING_NONE;
> need_mappable = need_fence || need_reloc_mappable(vma);
>
> - if (need_mappable) {
> + if (entry->flags & EXEC_OBJECT_PINNED)
> + list_move_tail(&vma->exec_list, &pinned_vmas);
> + else if (need_mappable) {
> entry->flags |= __EXEC_OBJECT_NEEDS_MAP;
> list_move(&vma->exec_list, &ordered_vmas);
> } else
> @@ -726,6 +736,7 @@ i915_gem_execbuffer_reserve(struct intel_engine_cs
> *ring,
> obj->base.pending_write_domain = 0;
> }
> list_splice(&ordered_vmas, vmas);
> + list_splice(&pinned_vmas, vmas);
>
> /* Attempt to pin all of the buffers into the GTT.
> * This is done in 3 phases:
> @@ -1404,7 +1415,8 @@ 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/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 55ba527..18f8f99 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -677,8 +677,10 @@ struct drm_i915_gem_exec_object2 {
> __u64 alignment;
>
> /**
> - * Returned value of the updated offset of the object, for future
> - * presumed_offset writes.
> + * When the EXEC_OBJECT_PINNED flag is specified this is populated by
> + * the user with the GTT offset at which this object will be pinned.
> + * Otherwise the kernel populates it with the value of the updated
> + * offset of the object, for future presumed_offset writes.
> */
> __u64 offset;
>
> @@ -686,7 +688,8 @@ struct drm_i915_gem_exec_object2 {
> #define EXEC_OBJECT_NEEDS_GTT (1<<1)
> #define EXEC_OBJECT_WRITE (1<<2)
> #define EXEC_OBJECT_SUPPORTS_48BBADDRESS (1<<3)
> -#define __EXEC_OBJECT_UNKNOWN_FLAGS -
> (EXEC_OBJECT_SUPPORTS_48BBADDRESS<<1)
> +#define EXEC_OBJECT_PINNED (1<<4)
> +#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_PINNED<<1)
> __u64 flags;
>
> __u64 rsvd1;
> --
> 1.7.9.5
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