From: Hillf Danton <hdanton@sina.com>
To: Tejun Heo <tj@kernel.org>
Cc: "Shakeel Butt" <shakeelb@google.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Muchun Song" <songmuchun@bytedance.com>,
"Michal Hocko" <mhocko@kernel.org>,
"Roman Gushchin" <guro@fb.com>,
"Michal Koutný" <mkoutny@suse.com>,
"Huang Ying" <ying.huang@intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] memcg: periodically flush the memcg stats
Date: Sat, 5 Jun 2021 15:43:30 +0800 [thread overview]
Message-ID: <20210605074331.6952-1-hdanton@sina.com> (raw)
In-Reply-To: <YLriZxiWo+2hMI7g@slm.duckdns.org>
On Fri, 4 Jun 2021 22:33:11 -0400 Tejun Heo wrote:
>On Sat, Jun 05, 2021 at 09:54:21AM +0800, Hillf Danton wrote:
>> The cond_resched() in cgroup_rstat_flush_locked() matches its appearence in
>> your post [1]. So does unbound IMHO.
>
>Ah yeah, this either needs CPU_INTENSIVE or UNBOUND, prolly the latter is
>better.
>
>> And the short stuff [2] looks to me like it is incorrect to queue a work
>> acquiring mutex lock on to the system_wq. IOW the unbound wq is the right
>> thing for any work that might sleep.
>
>This part doesn't make sense. Blocking from per-cpu workqueue is completely
>fine. What's not fine is consuming a lot of CPU cycles.
Thanks for the light on the per-cpu workqueue - it is difficult to understand
that short stuff without it.
Hillf
prev parent reply other threads:[~2021-06-05 7:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-04 1:56 [PATCH 1/2] memcg: switch lruvec stats to rstat Shakeel Butt
2021-06-04 1:56 ` [PATCH 2/2] memcg: periodically flush the memcg stats Shakeel Butt
2021-06-04 6:18 ` Hillf Danton
2021-06-04 12:45 ` Tejun Heo
[not found] ` <20210605015421.5096-1-hdanton@sina.com>
2021-06-05 2:33 ` Tejun Heo
2021-06-05 4:45 ` Shakeel Butt
2021-06-05 7:43 ` Hillf Danton [this message]
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