On Tue, Jul 09, 2013 at 09:45:09AM +0200, Daniel Vetter wrote:
> On Mon, Jul 08, 2013 at 11:08:42PM -0700, Ben Widawsky wrote:
> > Probably need to squash whole thing, or just the inactive part, tbd...
> >
> > Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
>
> I agree that we need vma->active, but I'm not sold on removing
> obj->active. Atm we have to use-cases for checking obj->active:
> - In the evict/unbind code to check whether the gpu is still using this
> specific mapping. This use-case nicely fits into checking vma->active.
> - In the shrinker code and everywhere we want to do cpu access we only
> care about whether the gpu is accessing the object, not at all through
> which mapping precisely. There a vma-independant obj->active sounds much
> saner.
>
> Note though that just keeping track of vma->active isn't too useful, since
> if some other vma is keeping the object busy we'll still stall on that one
> for eviction. So we'd need a vma->ring and vma->last_rendering_seqno, too.
>
> At that point I wonder a bit whether all this complexity is worth it ...
>
> I need to ponder this some more.
> -Daniel
I think eventually the complexity might prove worthwhile, it might not.
In the meanwhile, I see vma->active as just a bookkeeping thing, and not
really useful in determining what we actually care about. As you mention
obj->active is really what we care about, and I used the getter
i915_gem_object_is_active() as a way to avoid the confusion of having
two active members.
I think we're in the same state of mind on this, and I've picked what I
consider to be a less offensive solution which is easy to clean up
later.
Let me know when you make a decision.
>
> > ---
> > drivers/gpu/drm/i915/i915_drv.h | 14 ++++++------
> > drivers/gpu/drm/i915/i915_gem.c | 47 ++++++++++++++++++++++++-----------------
> > 2 files changed, 35 insertions(+), 26 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> > index 38d07f2..e6694ae 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -541,6 +541,13 @@ struct i915_vma {
> > struct drm_i915_gem_object *obj;
> > struct i915_address_space *vm;
> >
> > + /**
> > + * This is set if the object is on the active lists (has pending
> > + * rendering and so a non-zero seqno), and is not set if it i s on
> > + * inactive (ready to be unbound) list.
> > + */
> > + unsigned int active:1;
> > +
> > /** This object's place on the active/inactive lists */
> > struct list_head mm_list;
> >
> > @@ -1250,13 +1257,6 @@ struct drm_i915_gem_object {
> > struct list_head exec_list;
> >
> > /**
> > - * This is set if the object is on the active lists (has pending
> > - * rendering and so a non-zero seqno), and is not set if it i s on
> > - * inactive (ready to be unbound) list.
> > - */
> > - unsigned int active:1;
> > -
> > - /**
> > * This is set if the object has been written to since last bound
> > * to the GTT
> > */
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index c2ecb78..b87073b 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -137,7 +137,13 @@ int i915_mutex_lock_interruptible(struct drm_device *dev)
> > /* NB: Not the same as !i915_gem_object_is_inactive */
> > bool i915_gem_object_is_active(struct drm_i915_gem_object *obj)
> > {
> > - return obj->active;
> > + struct i915_vma *vma;
> > +
> > + list_for_each_entry(vma, &obj->vma_list, vma_link)
> > + if (vma->active)
> > + return true;
> > +
> > + return false;
> > }
> >
> > static inline bool
> > @@ -1899,14 +1905,14 @@ i915_gem_object_move_to_active(struct drm_i915_gem_object *obj,
> > BUG_ON(ring == NULL);
> > obj->ring = ring;
> >
> > + /* Move from whatever list we were on to the tail of execution. */
> > + vma = i915_gem_obj_to_vma(obj, vm);
> > /* Add a reference if we're newly entering the active list. */
> > - if (!i915_gem_object_is_active(obj)) {
> > + if (!vma->active) {
> > drm_gem_object_reference(&obj->base);
> > - obj->active = 1;
> > + vma->active = 1;
> > }
> >
> > - /* Move from whatever list we were on to the tail of execution. */
> > - vma = i915_gem_obj_to_vma(obj, vm);
> > list_move_tail(&vma->mm_list, &vm->active_list);
> > list_move_tail(&obj->ring_list, &ring->active_list);
> >
> > @@ -1927,16 +1933,23 @@ i915_gem_object_move_to_active(struct drm_i915_gem_object *obj,
> > }
> >
> > static void
> > -i915_gem_object_move_to_inactive(struct drm_i915_gem_object *obj,
> > - struct i915_address_space *vm)
> > +i915_gem_object_move_to_inactive(struct drm_i915_gem_object *obj)
> > {
> > + struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
> > + struct i915_address_space *vm;
> > struct i915_vma *vma;
> > + int i = 0;
> >
> > BUG_ON(obj->base.write_domain & ~I915_GEM_GPU_DOMAINS);
> > - BUG_ON(!i915_gem_object_is_active(obj));
> >
> > - vma = i915_gem_obj_to_vma(obj, vm);
> > - list_move_tail(&vma->mm_list, &vm->inactive_list);
> > + list_for_each_entry(vm, &dev_priv->vm_list, global_link) {
> > + vma = i915_gem_obj_to_vma(obj, vm);
> For paranoia we might want to track the vm used to run a batch in it
> request struct, then we
>
> > + if (!vma || !vma->active)
> > + continue;
> > + list_move_tail(&vma->mm_list, &vm->inactive_list);
> > + vma->active = 0;
> > + i++;
> > + }
> >
> > list_del_init(&obj->ring_list);
> > obj->ring = NULL;
> > @@ -1948,8 +1961,8 @@ i915_gem_object_move_to_inactive(struct drm_i915_gem_object *obj,
> > obj->last_fenced_seqno = 0;
> > obj->fenced_gpu_access = false;
> >
> > - obj->active = 0;
> > - drm_gem_object_unreference(&obj->base);
> > + while (i--)
> > + drm_gem_object_unreference(&obj->base);
> >
> > WARN_ON(i915_verify_lists(dev));
> > }
> > @@ -2272,15 +2285,13 @@ static void i915_gem_reset_ring_lists(struct drm_i915_private *dev_priv,
> > }
> >
> > while (!list_empty(&ring->active_list)) {
> > - struct i915_address_space *vm;
> > struct drm_i915_gem_object *obj;
> >
> > obj = list_first_entry(&ring->active_list,
> > struct drm_i915_gem_object,
> > ring_list);
> >
> > - list_for_each_entry(vm, &dev_priv->vm_list, global_link)
> > - i915_gem_object_move_to_inactive(obj, vm);
> > + i915_gem_object_move_to_inactive(obj);
> > }
> > }
> >
> > @@ -2356,8 +2367,6 @@ i915_gem_retire_requests_ring(struct intel_ring_buffer *ring)
> > * by the ringbuffer to the flushing/inactive lists as appropriate.
> > */
> > while (!list_empty(&ring->active_list)) {
> > - struct drm_i915_private *dev_priv = ring->dev->dev_private;
> > - struct i915_address_space *vm;
> > struct drm_i915_gem_object *obj;
> >
> > obj = list_first_entry(&ring->active_list,
> > @@ -2367,8 +2376,8 @@ i915_gem_retire_requests_ring(struct intel_ring_buffer *ring)
> > if (!i915_seqno_passed(seqno, obj->last_read_seqno))
> > break;
> >
> > - list_for_each_entry(vm, &dev_priv->vm_list, global_link)
> > - i915_gem_object_move_to_inactive(obj, vm);
> > + BUG_ON(!i915_gem_object_is_active(obj));
> > + i915_gem_object_move_to_inactive(obj);
> > }
> >
> > if (unlikely(ring->trace_irq_seqno &&
> > --
> > 1.8.3.2
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
Ben Widawsky, Intel Open Source Technology Center
