linux-kernel - Re: [PATCH v2 2/3] mm: Force update of mem cgroup soft limit tree on usage excess

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <781634ee-ffb9-598d-fdb6-0ae6067448b7@linux.intel.com>
Date:   Fri, 26 Feb 2021 16:56:28 -0800
From:   Tim Chen <tim.c.chen@...ux.intel.com>
To:     Michal Hocko <mhocko@...e.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Johannes Weiner <hannes@...xchg.org>,
        Vladimir Davydov <vdavydov.dev@...il.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Ying Huang <ying.huang@...el.com>, linux-mm@...ck.org,
        cgroups@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/3] mm: Force update of mem cgroup soft limit tree on
 usage excess



On 2/26/21 12:52 AM, Michal Hocko wrote:

>>
>> Michal,
>>
>> Let's take an extreme case where memcg 1 always generate the
>> first event and memcg 2 generates the rest of 128*8-1 events
>> and the pattern repeat.
> 
> I do not follow. Events are per-memcg, aren't they?
> 	__this_cpu_read(memcg->vmstats_percpu->targets[target]);
> 	[...]
> 	__this_cpu_write(memcg->vmstats_percpu->targets[target], next);
> 

You are right. My previous reasoning is incorrect as the sampling is done per memcg.
I'll do some additional debugging on why memcg is not on the tree.

Tim