[Intel-gfx] [PATCH v6] drm/i915: Add soft-pinning API for execbuffer
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Wed Dec 2 03:28:52 PST 2015
On 16/10/15 11:59, Thomas Daniel wrote:
> From: Chris Wilson <chris at 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 <chris at 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.
>
> v5: Added I915_PARAM_HAS_EXEC_SOFTPIN parameter for detecting this capability
> (Kristian). Added check for multiple pinnings on eviction (Akash). Made sure
> buffers are not considered misplaced without the user specifying
> EXEC_OBJECT_SUPPORTS_48B_ADDRESS. User must assume responsibility for any
> addressing workarounds. Updated object2.offset field comment again to clarify
> NO_RELOC case (Chris). checkpatch cleanup.
>
> v6: Trivial rebase on latest drm-intel-nightly
>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Akash Goel <akash.goel at intel.com>
> Cc: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
> Cc: Michal Winiarski <michal.winiarski at intel.com>
> Cc: Zou Nanhai <nanhai.zou at intel.com>
> Cc: Kristian Høgsberg <hoegsberg at gmail.com>
> Signed-off-by: Thomas Daniel <thomas.daniel at intel.com>
> ---
> drivers/gpu/drm/i915/i915_dma.c | 3 ++
> drivers/gpu/drm/i915/i915_drv.h | 2 +
> drivers/gpu/drm/i915/i915_gem.c | 64 ++++++++++++++++++++----------
> drivers/gpu/drm/i915/i915_gem_evict.c | 39 ++++++++++++++++++
> drivers/gpu/drm/i915/i915_gem_execbuffer.c | 19 +++++++--
> include/uapi/drm/i915_drm.h | 12 ++++--
> 6 files changed, 113 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 2336af9..824c6c3 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 1396af9..73c3acf 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2816,6 +2816,7 @@ void i915_gem_vma_destroy(struct i915_vma *vma);
> #define PIN_UPDATE (1<<5)
> #define PIN_ZONE_4G (1<<6)
> #define PIN_HIGH (1<<7)
> +#define PIN_OFFSET_FIXED (1<<8)
> #define PIN_OFFSET_MASK (~4095)
> int __must_check
> i915_gem_object_pin(struct drm_i915_gem_object *obj,
> @@ -3163,6 +3164,7 @@ 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 *target);
> 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 1e67484..c3453bd 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3450,30 +3450,50 @@ 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)) {
> + 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);
This will return ENOSPC to userspace when they have passed in an address
outside the (PP)GTT range which is misleading.
I would suggest explicit checking against the 'end' (available a bit
further up in the same function) and returning something more
appropriate. At least EINVAL, although execbuf overloads that one so
much I would even rather steal some other semi-appropriate one like
ENXIO (No such device or _address_) or something.
Regards,
Tvrtko
> + 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_flag = DRM_MM_SEARCH_DEFAULT;
> - alloc_flag = DRM_MM_CREATE_DEFAULT;
> - }
> + 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;
> @@ -4007,6 +4027,10 @@ 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 d71a133..07c6e4d 100644
> --- a/drivers/gpu/drm/i915/i915_gem_evict.c
> +++ b/drivers/gpu/drm/i915/i915_gem_evict.c
> @@ -199,6 +199,45 @@ 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) {
> + if (!vma->exec_entry || (vma->pin_count > 1))
> + /* Object is pinned for some other use */
> + return -EBUSY;
> +
> + /* We need to evict a buffer in the same batch */
> + 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 6ed7d63a..b72ffe6 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -599,6 +599,8 @@ 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;
> if ((flags & PIN_MAPPABLE) == 0)
> flags |= PIN_HIGH;
> }
> @@ -670,6 +672,10 @@ 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;
> @@ -678,7 +684,8 @@ eb_vma_misplaced(struct i915_vma *vma)
> if (entry->flags & __EXEC_OBJECT_NEEDS_MAP && !obj->map_and_fenceable)
> return !only_mappable_for_reloc(entry->flags);
>
> - if ((entry->flags & EXEC_OBJECT_SUPPORTS_48B_ADDRESS) == 0 &&
> + if (!(entry->flags &
> + (EXEC_OBJECT_SUPPORTS_48B_ADDRESS | EXEC_OBJECT_PINNED)) &&
> (vma->node.start + vma->node.size - 1) >> 32)
> return true;
>
> @@ -695,6 +702,7 @@ 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;
>
> @@ -703,6 +711,7 @@ 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;
> @@ -721,7 +730,9 @@ 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
> @@ -731,6 +742,7 @@ 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:
> @@ -1317,7 +1329,8 @@ 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 484a9fb..fc754a3 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;
> @@ -682,8 +683,12 @@ 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.
> + * When the I915_EXEC_NO_RELOC flag is specified this must contain the
> + * presumed_offset of the object.
> + * During execbuffer2 the kernel populates it with the value of the
> + * current GTT offset of the object, for future presumed_offset writes.
> */
> __u64 offset;
>
> @@ -691,7 +696,8 @@ struct drm_i915_gem_exec_object2 {
> #define EXEC_OBJECT_NEEDS_GTT (1<<1)
> #define EXEC_OBJECT_WRITE (1<<2)
> #define EXEC_OBJECT_SUPPORTS_48B_ADDRESS (1<<3)
> -#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_SUPPORTS_48B_ADDRESS<<1)
> +#define EXEC_OBJECT_PINNED (1<<4)
> +#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_PINNED<<1)
> __u64 flags;
>
> __u64 rsvd1;
>
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