From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx102.postini.com [74.125.245.102]) by kanga.kvack.org (Postfix) with SMTP id 3CE336B002C for ; Wed, 1 Feb 2012 03:59:40 -0500 (EST) Message-ID: <4F28FEB6.4040905@parallels.com> Date: Wed, 1 Feb 2012 12:58:30 +0400 From: Glauber Costa MIME-Version: 1.0 Subject: Re: [LSF/MM TOPIC] memcg topics. References: <20120201095556.812db19c.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20120201095556.812db19c.kamezawa.hiroyu@jp.fujitsu.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, "hannes@cmpxchg.org" , Michal Hocko , "bsingharora@gmail.com" , Hugh Dickins , Ying Han , Mel Gorman On 02/01/2012 04:55 AM, KAMEZAWA Hiroyuki wrote: > Hi, I guess we have some topics on memory cgroups. > > 1-4 : someone has an implemanation > 5 : no implemenation. > > 1. page_cgroup diet > memory cgroup uses 'struct page_cgroup', it was 40bytes per 4096bytes in past. > Johannes removed ->page and ->lru from page_cgroup, then now, > sizeof(page_cgroup)==16. Now, I'm working on removing ->flags to make > sizeof(page_cgroup)==8. > > Then, finally, page_cgroup can be moved into struct page on 64bit system ? > How 32bit system will be ? > > 2. memory reclaim > Johannes, Michal and Ying, ant others, are now working on memory reclaim problem > with new LRU. Under it, LRU is per-memcg-per-zone. > Following topics are discussed now. > > - simplificaiton/re-implemenation of softlimit > - isolation of workload (by softlimit) > - when we should stop memory reclaim, especially under direct-reclaim. > (Now, we scan all zonelist..) > > 3. per-memcg-lru-zone-lru-lock > I hear Hugh Dickins have some patches and are testing it. > It will be good to discuss this if it has Pros. and Cons or implemenation issue. > > 4. dirty ratio > In the last year, patches were posted but not merged. I'd like to hear > works on this area. > > 5. accounting other than user pages. > Last year, tcp buffer limiting was added to "memcg". I was about to correct you about "last year", when suddenly my mind went "oh god, this is 2012!" > If someone has other plans, I'd like to hear. > I myself don't think 'generic kernel memory limitation' is a good thing.... > admins can't predict performance. > > Can we make accounting on dentry/inode into memcg and call shrink_slab() ? > But I guess per-zone-shrink-slab() should go 1st... Well, I have work in progress to continue that. There are a couple of slabs I'd like to track. I am convinced that a generic framework is a good thing, but indeed, I am still not sure if a generic interface is. The advantage of keeping it unified, is that it prevents the number of knobs from exploding. For us, this is not that much of a problem, because there are only a couple of ones we are interested in. dcache and inode is an example of that: when we sent out some proposals (that didn't use memcg), some people wanted to see inode, not dcache being tracked. We disagreed. But yet, the truth remains that only *one* of them needs to be tracked, because they live in a close relation to each other. So if we manage to find a couple of slabs that are key to that, we can limit only those. Well, that was food for thought only. I do think this is a nice topic. Also, there is no serious implementation for that, as you mentioned, but a series of patches were sent out for appreciation last year. So there is at least a basis for starting -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org