[PATCH v7 20/20] drm/i915/vm_bind: Async vm_unbind support
Niranjana Vishwanathapura
niranjana.vishwanathapura at intel.com
Tue Nov 29 23:26:34 UTC 2022
On Wed, Nov 23, 2022 at 11:42:58AM +0000, Matthew Auld wrote:
>On 16/11/2022 00:37, Niranjana Vishwanathapura wrote:
>>On Tue, Nov 15, 2022 at 03:15:03PM -0800, Niranjana Vishwanathapura wrote:
>>>On Tue, Nov 15, 2022 at 08:33:47AM -0800, Niranjana
>>>Vishwanathapura wrote:
>>>>On Tue, Nov 15, 2022 at 04:20:54PM +0000, Matthew Auld wrote:
>>>>>On 15/11/2022 16:15, Niranjana Vishwanathapura wrote:
>>>>>>On Tue, Nov 15, 2022 at 11:05:21AM +0000, Matthew Auld wrote:
>>>>>>>On 13/11/2022 07:57, Niranjana Vishwanathapura wrote:
>>>>>>>>Asynchronously unbind the vma upon vm_unbind call.
>>>>>>>>Fall back to synchronous unbind if backend doesn't support
>>>>>>>>async unbind or if async unbind fails.
>>>>>>>>
>>>>>>>>No need for vm_unbind out fence support as i915 will internally
>>>>>>>>handle all sequencing and user need not try to sequence any
>>>>>>>>operation with the unbind completion.
>>>>>>>>
>>>>>>>>v2: use i915_vma_destroy_async in vm_unbind ioctl
>>>>>>>>
>>>>>>>>Signed-off-by: Niranjana Vishwanathapura
>>>>>>>><niranjana.vishwanathapura at intel.com>
>>>>>>>
>>>>>>>This only does it for non-partial vma, right? Or was that
>>>>>>>changed somewhere?
>>>>>>>
>>>>>>
>>>>>>No, it applies to any vma (partial or non-partial).
>>>>>>It was so from the beginning.
>>>>>
>>>>>Doesn't __i915_vma_unbind_async() return an error when
>>>>>mm.pages != vma->pages? IIRC this was discussed before. Just
>>>>>trying to think about the consequences of this change.
>>>>
>>>>I am not seeing any such restriction. Let me probe and check if there
>>>>is any such restriction anywhere in the call chain.
>>>
>>>I checked and I am not seeing any restriction anywher in the call chain.
>>>
>>
>>Note that just like binding case, unbinding is also synchronous unless
>>there is a pending activity, in which case, it will be asynchronous.
>
>In __i915_vma_unbind_async() there is:
>
>if (i915_vma_is_pinned(vma) ||
> &vma->obj->mm.rsgt->table != vma->resource->bi.pages)
> return ERR_PTR(-EAGAIN);
>
>AFAICT we then also don't get any pipelined moves with such an object,
>if there is such a binding present.
I had to remove this check as otherwise for VM_BIND (persistent) mappings,
it will alwasy be true and we will always endup with -EAGAIN.
Persistent mappings, as they support partial binding, can't have an sg
table which is just a pointer to object's sg table.
Niranjana
>
>>
>>Niranjana
>>
>>>Niranjana
>>>
>>>>
>>>>Niranjana
>>>>
>>>>>
>>>>>>
>>>>>>Niranjana
>>>>>>
>>>>>>>Reviewed-by: Matthew Auld <matthew.auld at intel.com>
>>>>>>>
>>>>>>>>---
>>>>>>>> .../drm/i915/gem/i915_gem_vm_bind_object.c | 2 +-
>>>>>>>> drivers/gpu/drm/i915/i915_vma.c | 51
>>>>>>>>+++++++++++++++++--
>>>>>>>> drivers/gpu/drm/i915/i915_vma.h | 1 +
>>>>>>>> include/uapi/drm/i915_drm.h | 3 +-
>>>>>>>> 4 files changed, 51 insertions(+), 6 deletions(-)
>>>>>>>>
>>>>>>>>diff --git
>>>>>>>>a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>>>>>>>>b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>>>>>>>>index d87d1210365b..36651b447966 100644
>>>>>>>>--- a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>>>>>>>>+++ b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>>>>>>>>@@ -210,7 +210,7 @@ static int
>>>>>>>>i915_gem_vm_unbind_vma(struct i915_address_space *vm,
>>>>>>>> */
>>>>>>>> obj = vma->obj;
>>>>>>>> i915_gem_object_lock(obj, NULL);
>>>>>>>>- i915_vma_destroy(vma);
>>>>>>>>+ i915_vma_destroy_async(vma);
>>>>>>>> i915_gem_object_unlock(obj);
>>>>>>>> i915_gem_object_put(obj);
>>>>>>>>diff --git a/drivers/gpu/drm/i915/i915_vma.c
>>>>>>>>b/drivers/gpu/drm/i915/i915_vma.c
>>>>>>>>index 7cf77c67d755..483d25f2425c 100644
>>>>>>>>--- a/drivers/gpu/drm/i915/i915_vma.c
>>>>>>>>+++ b/drivers/gpu/drm/i915/i915_vma.c
>>>>>>>>@@ -42,6 +42,8 @@
>>>>>>>> #include "i915_vma.h"
>>>>>>>> #include "i915_vma_resource.h"
>>>>>>>>+static struct dma_fence *__i915_vma_unbind_async(struct
>>>>>>>>i915_vma *vma);
>>>>>>>>+
>>>>>>>> static inline void assert_vma_held_evict(const struct
>>>>>>>>i915_vma *vma)
>>>>>>>> {
>>>>>>>> /*
>>>>>>>>@@ -1713,7 +1715,7 @@ void i915_vma_reopen(struct i915_vma *vma)
>>>>>>>> spin_unlock_irq(>->closed_lock);
>>>>>>>> }
>>>>>>>>-static void force_unbind(struct i915_vma *vma)
>>>>>>>>+static void force_unbind(struct i915_vma *vma, bool async)
>>>>>>>> {
>>>>>>>> if (!drm_mm_node_allocated(&vma->node))
>>>>>>>> return;
>>>>>>>>@@ -1727,7 +1729,21 @@ static void force_unbind(struct
>>>>>>>>i915_vma *vma)
>>>>>>>> i915_vma_set_purged(vma);
>>>>>>>> atomic_and(~I915_VMA_PIN_MASK, &vma->flags);
>>>>>>>>- WARN_ON(__i915_vma_unbind(vma));
>>>>>>>>+ if (async) {
>>>>>>>>+ struct dma_fence *fence;
>>>>>>>>+
>>>>>>>>+ fence = __i915_vma_unbind_async(vma);
>>>>>>>>+ if (IS_ERR_OR_NULL(fence)) {
>>>>>>>>+ async = false;
>>>>>>>>+ } else {
>>>>>>>>+ dma_resv_add_fence(vma->obj->base.resv, fence,
>>>>>>>>+ DMA_RESV_USAGE_READ);
>>>>>>>>+ dma_fence_put(fence);
>>>>>>>>+ }
>>>>>>>>+ }
>>>>>>>>+
>>>>>>>>+ if (!async)
>>>>>>>>+ WARN_ON(__i915_vma_unbind(vma));
>>>>>>>> GEM_BUG_ON(drm_mm_node_allocated(&vma->node));
>>>>>>>> }
>>>>>>>>@@ -1787,7 +1803,7 @@ void
>>>>>>>>i915_vma_destroy_locked(struct i915_vma *vma)
>>>>>>>> {
>>>>>>>> lockdep_assert_held(&vma->vm->mutex);
>>>>>>>>- force_unbind(vma);
>>>>>>>>+ force_unbind(vma, false);
>>>>>>>> list_del_init(&vma->vm_link);
>>>>>>>> release_references(vma, vma->vm->gt, false);
>>>>>>>> }
>>>>>>>>@@ -1798,7 +1814,34 @@ void i915_vma_destroy(struct i915_vma *vma)
>>>>>>>> bool vm_ddestroy;
>>>>>>>> mutex_lock(&vma->vm->mutex);
>>>>>>>>- force_unbind(vma);
>>>>>>>>+ force_unbind(vma, false);
>>>>>>>>+ list_del_init(&vma->vm_link);
>>>>>>>>+ vm_ddestroy = vma->vm_ddestroy;
>>>>>>>>+ vma->vm_ddestroy = false;
>>>>>>>>+
>>>>>>>>+ /* vma->vm may be freed when releasing vma->vm->mutex. */
>>>>>>>>+ gt = vma->vm->gt;
>>>>>>>>+ mutex_unlock(&vma->vm->mutex);
>>>>>>>>+ release_references(vma, gt, vm_ddestroy);
>>>>>>>>+}
>>>>>>>>+
>>>>>>>>+void i915_vma_destroy_async(struct i915_vma *vma)
>>>>>>>>+{
>>>>>>>>+ bool vm_ddestroy, async = vma->obj->mm.rsgt;
>>>>>>>>+ struct intel_gt *gt;
>>>>>>>>+
>>>>>>>>+ if (dma_resv_reserve_fences(vma->obj->base.resv, 1))
>>>>>>>>+ async = false;
>>>>>>>>+
>>>>>>>>+ mutex_lock(&vma->vm->mutex);
>>>>>>>>+ /*
>>>>>>>>+ * Ensure any asynchronous binding is complete while using
>>>>>>>>+ * async unbind as we will be releasing the vma here.
>>>>>>>>+ */
>>>>>>>>+ if (async && i915_active_wait(&vma->active))
>>>>>>>>+ async = false;
>>>>>>>>+
>>>>>>>>+ force_unbind(vma, async);
>>>>>>>> list_del_init(&vma->vm_link);
>>>>>>>> vm_ddestroy = vma->vm_ddestroy;
>>>>>>>> vma->vm_ddestroy = false;
>>>>>>>>diff --git a/drivers/gpu/drm/i915/i915_vma.h
>>>>>>>>b/drivers/gpu/drm/i915/i915_vma.h
>>>>>>>>index 737ef310d046..25f15965dab8 100644
>>>>>>>>--- a/drivers/gpu/drm/i915/i915_vma.h
>>>>>>>>+++ b/drivers/gpu/drm/i915/i915_vma.h
>>>>>>>>@@ -272,6 +272,7 @@ void i915_vma_reopen(struct i915_vma *vma);
>>>>>>>> void i915_vma_destroy_locked(struct i915_vma *vma);
>>>>>>>> void i915_vma_destroy(struct i915_vma *vma);
>>>>>>>>+void i915_vma_destroy_async(struct i915_vma *vma);
>>>>>>>> #define assert_vma_held(vma)
>>>>>>>>dma_resv_assert_held((vma)->obj->base.resv)
>>>>>>>>diff --git a/include/uapi/drm/i915_drm.h
>>>>>>>>b/include/uapi/drm/i915_drm.h
>>>>>>>>index e5600f358a15..431d40bb1dee 100644
>>>>>>>>--- a/include/uapi/drm/i915_drm.h
>>>>>>>>+++ b/include/uapi/drm/i915_drm.h
>>>>>>>>@@ -3969,7 +3969,8 @@ struct drm_i915_gem_vm_bind {
>>>>>>>> * any error.
>>>>>>>> *
>>>>>>>> * VM_BIND/UNBIND ioctl calls executed on different CPU
>>>>>>>>threads concurrently
>>>>>>>>- * are not ordered.
>>>>>>>>+ * are not ordered. Furthermore, parts of the VM_UNBIND
>>>>>>>>operation can be done
>>>>>>>>+ * asynchronously.
>>>>>>>> */
>>>>>>>> struct drm_i915_gem_vm_unbind {
>>>>>>>> /** @vm_id: VM (address space) id to bind */
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