Memory eviction in ttm

[Maarten Lankhorst]

Hey Thomas,

I'm playing around with moving reservations from ttm to global, but how ttm
ttm is handling reservations is getting in the way.  The code wants to move
the bo from the lru lock at the same time a reservation is made, but that
seems to be slightly too strict. It would really help me if that guarantee
is removed.

Is it true that only the ttm_mem_evict code depends on it? And in that case
wouldn't it be better to attempt to free any buffer that can be reserved
without blocking first, instead of blocking on the first entry in the list?

This would make integration a lot easier, since I could wait with taking the
lru lock until after reservation is complete, or any time before unreserving.

~Maarten