[PATCH v7 20/20] drm/i915/vm_bind: Async vm_unbind support
Niranjana Vishwanathapura
niranjana.vishwanathapura at intel.com
Thu Dec 1 15:11:35 UTC 2022
On Thu, Dec 01, 2022 at 10:10:14AM +0000, Matthew Auld wrote:
>On 29/11/2022 23:26, Niranjana Vishwanathapura wrote:
>>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.
>
>Ok, maybe make that a seperate patch, since it seems to change the
>behaviour for more than just persisent mappings, AFAICT.
>
Ok, will do.
Niranjana
>>
>>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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