From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx139.postini.com [74.125.245.139]) by kanga.kvack.org (Postfix) with SMTP id 27A3D6B0006 for ; Wed, 13 Mar 2013 20:04:00 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 386A43EE0C0 for ; Thu, 14 Mar 2013 09:03:58 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 2010045DE59 for ; Thu, 14 Mar 2013 09:03:58 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 0438945DE54 for ; Thu, 14 Mar 2013 09:03:58 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id E81A41DB804E for ; Thu, 14 Mar 2013 09:03:57 +0900 (JST) Received: from m1001.s.css.fujitsu.com (m1001.s.css.fujitsu.com [10.240.81.139]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 8FC761DB8051 for ; Thu, 14 Mar 2013 09:03:57 +0900 (JST) Message-ID: <514113C3.2090505@jp.fujitsu.com> Date: Thu, 14 Mar 2013 09:03:15 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH v2 2/5] memcg: provide root figures from system totals References: <1362489058-3455-1-git-send-email-glommer@parallels.com> <1362489058-3455-3-git-send-email-glommer@parallels.com> <51368D80.20701@jp.fujitsu.com> <5136FEC2.2050004@parallels.com> <51371E4A.7090807@jp.fujitsu.com> <51371FEF.3020507@parallels.com> <513721A5.6080401@jp.fujitsu.com> <514043B5.1090205@jp.fujitsu.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Sha Zhengju Cc: Glauber Costa , linux-mm@kvack.org, cgroups@vger.kernel.org, Tejun Heo , Andrew Morton , Michal Hocko , anton.vorontsov@linaro.org, Johannes Weiner , Mel Gorman (2013/03/13 18:59), Sha Zhengju wrote: > On Wed, Mar 13, 2013 at 5:15 PM, Kamezawa Hiroyuki > wrote: >> (2013/03/13 15:58), Sha Zhengju wrote: >>> >>> On Wed, Mar 6, 2013 at 6:59 PM, Kamezawa Hiroyuki >>> wrote: >>>> >>>> (2013/03/06 19:52), Glauber Costa wrote: >>>>> >>>>> On 03/06/2013 02:45 PM, Kamezawa Hiroyuki wrote: >>>>>> >>>>>> (2013/03/06 17:30), Glauber Costa wrote: >>>>>>> >>>>>>> On 03/06/2013 04:27 AM, Kamezawa Hiroyuki wrote: >>>>>>>> >>>>>>>> (2013/03/05 22:10), Glauber Costa wrote: >>>>>>>>> >>>>>>>>> + case _MEMSWAP: { >>>>>>>>> + struct sysinfo i; >>>>>>>>> + si_swapinfo(&i); >>>>>>>>> + >>>>>>>>> + return ((memcg_read_root_rss() + >>>>>>>>> + atomic_long_read(&vm_stat[NR_FILE_PAGES])) << PAGE_SHIFT) >>>>>>>>> + >>>>>>>>> + i.totalswap - i.freeswap; >>>>>>>> >>>>>>>> >>>>>>>> How swapcache is handled ? ...and How kmem works with this calc ? >>>>>>>> >>>>>>> I am ignoring kmem, because we don't account kmem for the root cgroup >>>>>>> anyway. >>>>>>> >>>>>>> Setting the limit is invalid, and we don't account until the limit is >>>>>>> set. Then it will be 0, always. >>>>>>> >>>>>>> For swapcache, I am hoping that totalswap - freeswap will cover >>>>>>> everything swap related. If you think I am wrong, please enlighten me. >>>>>>> >>>>>> >>>>>> i.totalswap - i.freeswap = # of used swap entries. >>>>>> >>>>>> SwapCache can be rss and used swap entry at the same time. >>>>>> >>>>> >>>>> Well, yes, but the rss entries would be accounted for in get_mm_rss(), >>>>> won't they ? >>>>> >>>>> What am I missing ? >>>> >>>> >>>> >>>> I think the correct caluculation is >>>> >>>> Sum of all RSS + All file caches + (i.total_swap - i.freeswap - # of >>>> mapped SwapCache) >>>> >>>> >>>> In the patch, mapped SwapCache is counted as both of rss and swap. >>>> >>> >>> After a quick look, swapcache is counted as file pages and meanwhile >>> use a swap entry at the same time(__add_to{delete_from}_swap_cache()). >>> Even though, I think we still do not need to exclude swapcache out, >>> because it indeed uses two copy of resource: one is swap entry, one is >>> cache, so the usage should count both of them in. >>> >>> What I think it matters is that swapcache may be counted as both file >>> pages and rss(if it's a process's anonymous page), which we need to >>> subtract # of swapcache to avoid double-counting. But it isn't always >>> so: a shmem/tmpfs page may use swapcache and be counted as file pages >>> but not a rss, then we can not subtract swapcache... Is there anything >>> I lost? >>> >> >> >> Please don't think difficult. All pages for user/caches are counted in >> LRU. All swap-entry usage can be cauht by total_swap_pages - nr_swap_pages. >> We just need to subtract number of swap-cache which is double counted >> as swap-entry and a page in LRU. >> >> NR_ACTIVE_ANON + NR_INACTIVE_ANON + NR_ACTIVE_FILE + NR_INACTIVE_FILE >> + NR_UNEVICTABLE + total_swap_pages - nr_swap_pages - NR_SWAP_CACHE >> > > Using LRU numbers is more suitable. But forgive me, I still doubt > whether we should subtract NR_SWAP_CACHE out because it uses both a > swap entry and a page cache and it isn't a real double counting. > Used swap entry can be reclaimed if there are SwapCache on memory. Thanks, a? 1/4 Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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