Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756055Ab2HOSD4 (ORCPT ); Wed, 15 Aug 2012 14:03:56 -0400 Received: from mx2.parallels.com ([64.131.90.16]:35828 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751918Ab2HOSDz (ORCPT ); Wed, 15 Aug 2012 14:03:55 -0400 Message-ID: <502BE3CB.2070306@parallels.com> Date: Wed, 15 Aug 2012 22:00:43 +0400 From: Glauber Costa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 MIME-Version: 1.0 To: Ying Han CC: Michal Hocko , , , , , "Johannes Weiner" , Andrew Morton , , Christoph Lameter , "David Rientjes" , Pekka Enberg Subject: Re: [PATCH v2 04/11] kmem accounting basic infrastructure References: <1344517279-30646-1-git-send-email-glommer@parallels.com> <1344517279-30646-5-git-send-email-glommer@parallels.com> <20120814162144.GC6905@dhcp22.suse.cz> <502B6D03.1080804@parallels.com> <20120815123931.GF23985@dhcp22.suse.cz> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [109.173.1.99] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2786 Lines: 60 On 08/15/2012 10:01 PM, Ying Han wrote: > On Wed, Aug 15, 2012 at 5:39 AM, Michal Hocko wrote: >> On Wed 15-08-12 13:33:55, Glauber Costa wrote: >> [...] >>>> This can >>>> be quite confusing. I am still not sure whether we should mix the two >>>> things together. If somebody wants to limit the kernel memory he has to >>>> touch the other limit anyway. Do you have a strong reason to mix the >>>> user and kernel counters? >>> >>> This is funny, because the first opposition I found to this work was >>> "Why would anyone want to limit it separately?" =p >>> >>> It seems that a quite common use case is to have a container with a >>> unified view of "memory" that it can use the way he likes, be it with >>> kernel memory, or user memory. I believe those people would be happy to >>> just silently account kernel memory to user memory, or at the most have >>> a switch to enable it. >>> >>> What gets clear from this back and forth, is that there are people >>> interested in both use cases. >> >> I am still not 100% sure myself. It is just clear that the reclaim would >> need some work in order to do accounting like this. >> >>>> My impression was that kernel allocation should simply fail while user >>>> allocations might reclaim as well. Why should we reclaim just because of >>>> the kernel allocation (which is unreclaimable from hard limit reclaim >>>> point of view)? >>> >>> That is not what the kernel does, in general. We assume that if he wants >>> that memory and we can serve it, we should. Also, not all kernel memory >>> is unreclaimable. We can shrink the slabs, for instance. Ying Han >>> claims she has patches for that already... >> >> Are those patches somewhere around? > > Yes, I am working on it to post it sometime *this week*. My last > rebase is based on v3.3 and now I am trying to get it rebased to > github-memcg. The patch itself has a functional dependency on kernel > slab accounting, and I am trying to get that rebased on Glauber's tree > but has some difficulty now. What I am planning to do is post the RFC > w/ only complied version by far. That would be great, so we can start looking at its design, at least. > The patch handles dentry cache shrinker only at this moment. That is > what we discussed last time as well, where dentry contributes most of > the reclaimable objects. (it pins inode, so we leave inode behind) > This will mark the inodes as reclaimable, but will leave them in memory. If we are assuming memory pressure, it would be good to shrink them too. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/