From: Chris Down <chris@chrisdown.name>
To: yulei zhang <yulei.kernel@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>, Tejun Heo <tj@kernel.org>,
Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Christian Brauner <christian@brauner.io>,
Cgroups <cgroups@vger.kernel.org>,
benbjiang@tencent.com, Wanpeng Li <kernellwp@gmail.com>,
Yulei Zhang <yuleixzhang@tencent.com>,
Linux MM <linux-mm@kvack.org>, Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <guro@fb.com>
Subject: Re: [RFC 0/7] Introduce memory allocation speed throttle in memcg
Date: Thu, 3 Jun 2021 12:38:57 +0100 [thread overview]
Message-ID: <YLi/UeS71mk12VZ3@chrisdown.name> (raw)
In-Reply-To: <CACZOiM3g6GhJgXurMPeE3A7zO8eUhoUPyUvyT3p2Kw98WkX8+g@mail.gmail.com>
yulei zhang writes:
>Thanks. IMHO, there are differences between these two throttlings.
>memory.high is a per-memcg throttle which targets to limit the memory
>usage of the tasks in the cgroup. For the memory allocation speed throttle(MST),
>the purpose is to avoid the memory burst in cgroup which would trigger
>the global reclaim and affects the timing sensitive workloads in other cgroup.
>For example, we have two pods with memory overcommit enabled, one includes
>online tasks and the other has offline tasks, if we restrict the memory usage of
>the offline pod with memory.high, it will lose the benefit of memory overcommit
>when the other workloads are idle. On the other hand, if we don't
>limit the memory
>usage, it will easily break the system watermark when there suddenly has massive
>memory operations. If enable MST in this case, we will be able to
>avoid the direct
>reclaim and leverage the overcommit.
Having a speed throttle is a very primitive knob: it's hard to know what the
correct values are for a user. That's one of the reasons why we've moved away
from that kind of tunable for blkio.
Ultimately, if you want work-conserving behaviour, why not use memory.low?
next prev parent reply other threads:[~2021-06-03 11:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1622043596.git.yuleixzhang@tencent.com>
2021-05-26 20:52 ` [RFC 0/7] Introduce memory allocation speed throttle in memcg Shakeel Butt
2021-05-31 12:11 ` yulei zhang
2021-05-31 18:20 ` Shakeel Butt
2021-06-01 14:45 ` Chris Down
2021-06-02 9:11 ` yulei zhang
2021-06-02 15:39 ` Shakeel Butt
2021-06-03 10:19 ` yulei zhang
2021-06-03 11:38 ` Chris Down [this message]
2021-06-04 10:15 ` yulei zhang
2021-06-04 11:51 ` Chris Down
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