On Fri, Jul 08, 2022 at 03:20:01PM +0000, Hellstrom, Thomas wrote:
On Fri, 2022-07-08 at 07:51 -0700, Niranjana Vishwanathapura wrote:
> Since we don't loop over the vm_bound_list, there is a need to
> check
> whether the rebind_list is empty here under the notifier_lock in
> read
> mode, and in that case, restart from eb_lookup_vmas(). That might
> also
> eliminate the need for the __EXEC3_USERPTR_USED flag?
>
> That will also catch any objects that were evicted between
> eb_lookup_vmas() where the rebind_list was last checked, and
> i915_gem_vm_priv_lock(), which prohibits further eviction, but if
> we
> want to catch these earlier (which I think is a good idea), we
> could
> check that the rebind_list is indeed empty just after taking the
> vm_priv_lock(), and if not, restart from eb_lookup_vmas().
Yah, right, we need to check rebind_list here and if not empty,
restart
from lookup phase.
It is bit tricky with userptr here as the unbind happens during
submit_init() call after we scoop unbound vmas here, the vmas gets
re-added to rebind_list :(.
Ugh.
I think we need a separate 'invalidated_userptr_list' here and we
iterate through it for submit_init() and submit_done() calls (yes,
__EXEC3_USERPTR_USED flag won't be needed then).
And, we call, eb_scoop_unbound_vmas() after calling
eb_lookup_persistent_userptr_vmas(), so that we scoop all unbound
vmas properly.
I'm not sure that will help much, because we'd also need to recheck the
rebind_list and possibly restart after taking the vm_priv_lock, since
objects can be evicted between the scooping and taking the
vm_priv_lock. So then the userptrs will be caught by that check.
Yah, what I mentioned above is in addition to rechecking rebind_list and
restarting.
Niranjana
/Thomas
