From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx152.postini.com [74.125.245.152]) by kanga.kvack.org (Postfix) with SMTP id 8CE116B0037 for ; Wed, 13 Mar 2013 05:16:25 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp (unknown [10.0.50.73]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 61DB43EE0C3 for ; Wed, 13 Mar 2013 18:16:23 +0900 (JST) Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 4300345DEBC for ; Wed, 13 Mar 2013 18:16:23 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id CFC9245DEC0 for ; Wed, 13 Mar 2013 18:16:22 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id A31E4E0800F for ; Wed, 13 Mar 2013 18:16:22 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 3CACDE08007 for ; Wed, 13 Mar 2013 18:16:22 +0900 (JST) Message-ID: <514043B5.1090205@jp.fujitsu.com> Date: Wed, 13 Mar 2013 18:15:33 +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> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit 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 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 is the number we whant for memsw.usage_in_bytes. Thanks, -Kame -- 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/ . Don't email: email@kvack.org