On Mon, Jun 21, 2021 at 1:43 PM Yang Shi <shy828301@xxxxxxxxx> wrote: > > On Thu, Jun 17, 2021 at 11:49 AM Shakeel Butt <shakeelb@xxxxxxxxxx> wrote: [...] > > > > IMHO we should focus more on the "aging" of the application memory and > > "migration/balance" between the tiers. I don't think the memory > > reclaim infrastructure is the right place for these operations > > (unevictable pages are ignored and not accurate ages). What we need is > > Why is unevictable pages a problem? I don't get why you have to demote > unevictable pages. If you do care what nodes the memory will be > mlock'ed on, don't you have to move the memory to the target nodes > before mlock them? > I think we want the ability to balance the memory (hot in higher tier and cold in lower tier) irrespective if it is evictable or not. Similarly we want aging information of both evictable and unevictable memory. If we depend on the reclaim infrastructure for demotion then cold unevictable memory may get stuck in the higher tier and have no aging information of unevictable memory. > > proactive continuous aging and balancing. We need something like, with > > additions, Multi-gen LRUs or DAMON or page idle tracking for aging and > > a new mechanism for balancing which takes ages into account. > > I agree the better balance could be reached by more accurate aging. It > is a more general problem than tier'ed memory specific. > I agree and proactive reclaim is the other use-case.
