On Sun, Jul 25, 2010 at 3:18 PM, KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: >> >> 1. How far does this push pages (in terms of when limit is hit)? >> > >> > 32 pages per mem_cgroup_shrink_node_zone(). >> > >> > That said, the algorithm is here. >> > >> > 1. call mem_cgroup_largest_soft_limit_node() >> > calculate largest cgroup >> > 2. call mem_cgroup_shrink_node_zone() and shrink 32 pages >> > 3. goto 1 if limit is still exceed. >> > >> > If it's not your intention, can you please your intended algorithm? >> >> We set it to 0, since we care only about a single page reclaim on >> hitting the limit. IIRC, in the past we saw an excessive pushback on >> reclaiming SWAP_CLUSTER_MAX pages, just wanted to check if you are >> seeing the same behaviour even now after your changes. > > Actually, we have 32 pages reclaim batch size. (see nr_scan_try_batch() and related functions) > thus <32 value doesn't works as your intended. > > But, If you run your test again, and (if there is) report any bugs. I'm very glad and fix it soon. > I understand that, the point is when to do stop the reclaim (do we really need 32 pages to stop the reclaim, when we hit the limit, something as low as a single page can help). This is quite a subtle thing, I'd mark it as low priority. I'll definitely come back if I see unexpected behaviour. Balbir -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href