| Message ID | 20200529130019.17977-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: Discard a misplaced GGTT vma | expand |
Chris Wilson <chris@chris-wilson.co.uk> writes: > Across the many users of the GGTT vma (internal objects, mmapings, > display etc), we may end up with conflicting requirements for the > placement. Currently, we try to resolve the conflict by unbinding the > vma and rebinding it to match the new constraints; over time we will end > up with a GGTT that matches the most strict constraints over all > concurrent users. However, this causes a problem if the vma is currently > in use as we must wait until it is idle before moving it. But there is > no restriction on the number of views we may (apart from the limited we may...have/impose? -Mika > size of the GGTT itself), and so if the active vma does not meet our > requirements, try and build a new one! > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > --- > drivers/gpu/drm/i915/i915_gem.c | 44 +++++++++++++++++++++++++++++++++ > 1 file changed, 44 insertions(+) > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index 0cbcb9f54e7d..29a4594ddef2 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -933,6 +933,44 @@ void i915_gem_runtime_suspend(struct drm_i915_private *i915) > } > } > > +static bool > +discard_ggtt_vma(struct i915_vma *vma, const struct i915_ggtt_view *view) > +{ > + const struct i915_ggtt_view discard = { > + .type = I915_GGTT_VIEW_PARTIAL, > + }; > + struct drm_i915_gem_object *obj = vma->obj; > + > + spin_lock(&obj->vma.lock); > + if (i915_vma_compare(vma, vma->vm, &discard)) { > + struct rb_node *rb, **p; > + > + rb_erase(&vma->obj_node, &obj->vma.tree); > + vma->ggtt_view = discard; > + > + rb = NULL; > + p = &obj->vma.tree.rb_node; > + while (*p) { > + struct i915_vma *pos; > + long cmp; > + > + rb = *p; > + pos = rb_entry(rb, struct i915_vma, obj_node); > + > + cmp = i915_vma_compare(pos, vma->vm, &discard); > + if (cmp < 0) > + p = &rb->rb_right; > + else > + p = &rb->rb_left; > + } > + rb_link_node(&vma->obj_node, rb, p); > + rb_insert_color(&vma->obj_node, &obj->vma.tree); > + } > + spin_unlock(&obj->vma.lock); > + > + return i915_vma_compare(vma, vma->vm, view); > +} > + > struct i915_vma * > i915_gem_object_ggtt_pin(struct drm_i915_gem_object *obj, > const struct i915_ggtt_view *view, > @@ -979,6 +1017,7 @@ i915_gem_object_ggtt_pin(struct drm_i915_gem_object *obj, > return ERR_PTR(-ENOSPC); > } > > +new_vma: > vma = i915_vma_instance(obj, &ggtt->vm, view); > if (IS_ERR(vma)) > return vma; > @@ -993,6 +1032,11 @@ i915_gem_object_ggtt_pin(struct drm_i915_gem_object *obj, > return ERR_PTR(-ENOSPC); > } > > + if (i915_vma_is_pinned(vma) || i915_vma_is_active(vma)) { > + if (discard_ggtt_vma(vma, view)) > + goto new_vma; > + } > + > ret = i915_vma_unbind(vma); > if (ret) > return ERR_PTR(ret); > -- > 2.20.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Quoting Mika Kuoppala (2020-05-29 15:24:17) > Chris Wilson <chris@chris-wilson.co.uk> writes: > > > Across the many users of the GGTT vma (internal objects, mmapings, > > display etc), we may end up with conflicting requirements for the > > placement. Currently, we try to resolve the conflict by unbinding the > > vma and rebinding it to match the new constraints; over time we will end > > up with a GGTT that matches the most strict constraints over all > > concurrent users. However, this causes a problem if the vma is currently > > in use as we must wait until it is idle before moving it. But there is > > no restriction on the number of views we may (apart from the limited > > we may...have/impose? we may have/create/use From the object point-of-view, there is a presumption that is a single normal view with as many partials as required (one expects up to obj->size/chunk_size). -Chris
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 0cbcb9f54e7d..29a4594ddef2 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -933,6 +933,44 @@ void i915_gem_runtime_suspend(struct drm_i915_private *i915) } } +static bool +discard_ggtt_vma(struct i915_vma *vma, const struct i915_ggtt_view *view) +{ + const struct i915_ggtt_view discard = { + .type = I915_GGTT_VIEW_PARTIAL, + }; + struct drm_i915_gem_object *obj = vma->obj; + + spin_lock(&obj->vma.lock); + if (i915_vma_compare(vma, vma->vm, &discard)) { + struct rb_node *rb, **p; + + rb_erase(&vma->obj_node, &obj->vma.tree); + vma->ggtt_view = discard; + + rb = NULL; + p = &obj->vma.tree.rb_node; + while (*p) { + struct i915_vma *pos; + long cmp; + + rb = *p; + pos = rb_entry(rb, struct i915_vma, obj_node); + + cmp = i915_vma_compare(pos, vma->vm, &discard); + if (cmp < 0) + p = &rb->rb_right; + else + p = &rb->rb_left; + } + rb_link_node(&vma->obj_node, rb, p); + rb_insert_color(&vma->obj_node, &obj->vma.tree); + } + spin_unlock(&obj->vma.lock); + + return i915_vma_compare(vma, vma->vm, view); +} + struct i915_vma * i915_gem_object_ggtt_pin(struct drm_i915_gem_object *obj, const struct i915_ggtt_view *view, @@ -979,6 +1017,7 @@ i915_gem_object_ggtt_pin(struct drm_i915_gem_object *obj, return ERR_PTR(-ENOSPC); } +new_vma: vma = i915_vma_instance(obj, &ggtt->vm, view); if (IS_ERR(vma)) return vma; @@ -993,6 +1032,11 @@ i915_gem_object_ggtt_pin(struct drm_i915_gem_object *obj, return ERR_PTR(-ENOSPC); } + if (i915_vma_is_pinned(vma) || i915_vma_is_active(vma)) { + if (discard_ggtt_vma(vma, view)) + goto new_vma; + } + ret = i915_vma_unbind(vma); if (ret) return ERR_PTR(ret);
Across the many users of the GGTT vma (internal objects, mmapings, display etc), we may end up with conflicting requirements for the placement. Currently, we try to resolve the conflict by unbinding the vma and rebinding it to match the new constraints; over time we will end up with a GGTT that matches the most strict constraints over all concurrent users. However, this causes a problem if the vma is currently in use as we must wait until it is idle before moving it. But there is no restriction on the number of views we may (apart from the limited size of the GGTT itself), and so if the active vma does not meet our requirements, try and build a new one! Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> --- drivers/gpu/drm/i915/i915_gem.c | 44 +++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+)