So it seems there was several issue with the various ttm pool. The obvious one is fixed in patch 2 where the always empty pool syndrom is addressed. However the pool size are kind of crazy and because before some pool were never actualy fill we might never have experience the hill effect of the crazy maximum limit. This is what is addressed by first patch.
Last patch cook it up further so that under memory pressure the pool size is divided by 2 each time a shrinker is run on a pool. There is a timeout to restore the pool size on next allocation. Idea here is that memory should not last and if it last then shrinker will keep minimize the pool size and anyway thing are probably already sluggish once we it the shrinker path.
Of course because this fix thing in ttm memory allocation this need careful testing. So before pushing anything i would like to see more people testing this.
Cheers, Jérôme