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Date: Wed, 1 Jun 2011 17:35:37 -0700 From: Greg Thelen <gthelen@...gle.com> To: Hiroyuki Kamezawa <kamezawa.hiroyuki@...il.com> Cc: Johannes Weiner <hannes@...xchg.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>, Daisuke Nishimura <nishimura@....nes.nec.co.jp>, Balbir Singh <balbir@...ux.vnet.ibm.com>, Ying Han <yinghan@...gle.com>, Michal Hocko <mhocko@...e.cz>, Andrew Morton <akpm@...ux-foundation.org>, Rik van Riel <riel@...hat.com>, Minchan Kim <minchan.kim@...il.com>, KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>, Mel Gorman <mgorman@...e.de>, Michel Lespinasse <walken@...gle.com>, "linux-mm@...ck.org" <linux-mm@...ck.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [patch 0/8] mm: memcg naturalization -rc2 On Wed, Jun 1, 2011 at 4:52 PM, Hiroyuki Kamezawa <kamezawa.hiroyuki@...il.com> wrote: > 2011/6/1 Johannes Weiner <hannes@...xchg.org>: >> Hi, >> >> this is the second version of the memcg naturalization series. The >> notable changes since the first submission are: >> >> o the hierarchy walk is now intermittent and will abort and >> remember the last scanned child after sc->nr_to_reclaim pages >> have been reclaimed during the walk in one zone (Rik) >> >> o the global lru lists are never scanned when memcg is enabled >> after #2 'memcg-aware global reclaim', which makes this patch >> self-sufficient and complete without requiring the per-memcg lru >> lists to be exclusive (Michal) >> >> o renamed sc->memcg and sc->current_memcg to sc->target_mem_cgroup >> and sc->mem_cgroup and fixed their documentation, I hope this is >> better understandable now (Rik) >> >> o the reclaim statistic counters have been renamed. there is no >> more distinction between 'pgfree' and 'pgsteal', it is now >> 'pgreclaim' in both cases; 'kswapd' has been replaced by >> 'background' >> >> o fixed a nasty crash in the hierarchical soft limit check that >> happened during global reclaim in memcgs that are hierarchical >> but have no hierarchical parents themselves >> >> o properly implemented the memcg-aware unevictable page rescue >> scanner, there were several blatant bugs in there >> >> o documentation on new public interfaces >> >> Thanks for your input on the first version. >> >> I ran microbenchmarks (sparse file catting, essentially) to stress >> reclaim and LRU operations. There is no measurable overhead for >> !CONFIG_MEMCG, memcg disabled during boot, memcg enabled but no >> configured groups, and hard limit reclaim. >> >> I also ran single-threaded kernbenchs in four unlimited memcgs in >> parallel, contained in a hard-limited hierarchical parent that put >> constant pressure on the workload. There is no measurable difference >> in runtime, the pgpgin/pgpgout counters, and fairness among memcgs in >> this test compared to an unpatched kernel. Needs more evaluation, >> especially with a higher number of memcgs. >> >> The soft limit changes are also proven to work in so far that it is >> possible to prioritize between children in a hierarchy under pressure >> and that runtime differences corresponded directly to the soft limit >> settings in the previously described kernbench setup with staggered >> soft limits on the groups, but this needs quantification. >> >> Based on v2.6.39. >> > > Hmm, I welcome and will review this patches but.....some points I want to say. > > 1. No more conflict with Ying's work ? > Could you explain what she has and what you don't in this v2 ? > If Ying's one has something good to be merged to your set, please > include it. > > 2. it's required to see performance score in commit log. > > 3. I think dirty_ratio as 1st big patch to be merged. (But...hmm..Greg ? > My patches for asynchronous reclaim is not very important. I can rework it. I am testing the next version (v8) of the memcg dirty ratio patches. I expect to have it posted for review later this week. > 4. This work can be splitted into some small works. > a) fix for current code and clean ups > a') statistics > b) soft limit rework > c) change global reclaim > > I like (a)->(b)->(c) order. and while (b) you can merge your work > with Ying's one. > And for a') , I'd like to add a new file memory.reclaim_stat as I've > already shown. > and allow resetting. > > Hmm, how about splitting patch 2/8 into small patches and see what happens in > 3.2 or 3.3 ? While that, we can make softlimit works better. > (and once we do 2/8, our direction will be fixed to the direction to > remove global LRU.) > > 5. please write documentation to explain what new LRU do. > > BTW, after this work, lists of ROOT cgroup comes again. I may need to check > codes which see memcg is ROOT or not. Because we removed many atomic > ops in memcg, I wonder ROOT cgroup can be accounted again.. > > Thanks, > -Kame > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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