Am 15.08.22 um 13:19 schrieb Dmitry Osipenko:
[SNIP]
I'll try to dig out the older discussions, thank you for the quick
reply!
Are you sure it was really discussed in public previously? All I can
find is yours two answers to a similar patches where you're saying that
this it's a wrong solution without in-depth explanation and further
discussions.
Yeah, that's my problem as well I can't find that of hand.
But yes it certainly was discussed in public.
If it was only CC'd to dri-devel, then could be that emails didn't pass
the spam moderation :/
That might be possible.
Maybe it was discussed privately? In this case I will be happy to get
more info from you about the root of the problem so I could start to
look at how to fix it properly. It's not apparent where the problem is
to a TTM newbie like me.
Well this is completely unfixable. See the whole purpose of TTM is to
allow tracing where what is mapped of a buffer object.
If you circumvent that and increase the page reference yourself than
that whole functionality can't work correctly any more.
Are you suggesting that the problem is that TTM doesn't see the KVM page
faults/mappings?
Yes, and no. It's one of the issues, but there is more behind that (e.g.
what happens when TTM switches from pages to local memory for backing a BO).
Another question is why is KVM accessing the page structure in the first
place? The VMA is mapped with VM_PFNMAP and VM_IO, KVM should never ever
touch any of those pages.
Regards,
Christian.
