On 8/19/21 4:55 AM, Kefeng Wang wrote: > > On 2021/8/19 5:48, Chris Down wrote: >> Vlastimil Babka writes: >> >> I think this is a good idea, thanks for bringing it up :-) >> >> I'm not sure about the bitshift idea, though. It certainly makes sure >> that even large, continuous periods of reclaim eventually terminates, >> but I find it hard to reason about -- for example, if there's a lot of >> parallel activity, that might result in 10 constantly reintroduced >> pages, or 1000 pages, and it's not immediately obvious that we should >> treat those differently. >> >> What about using MAX_RECLAIM_RETRIES? There's already precedent for >> using it in non-OOM scenarios, like mem_cgroup_handle_over_high. It's an option, but then (together with fixed threshold) it ignores how large the 'freed' value is, as long it's above threshold? Although the end result will probably not be much different. > Yes, we meet this issue too, and we add a max loop limit in > drop_slab_node() in our kernel, which also could be reconfigured by > sysctl ;) Sysctl sounds like an overkill. How do you tune the limit? Any experience with what scenarios need what limit?
