From: Michal Hocko <mhocko@kernel•org>
To: Balbir Singh <bsingharora@gmail•com>
Cc: mpe@ellerman•id.au, hannes@cmpxchg•org, vdavydov.dev@gmail•com,
linuxppc-dev@lists•ozlabs.org, linux-mm@kvack•org,
Tejun Heo <tj@kernel•org>,
Andrew Morton <akpm@linux-foundation•org>
Subject: Re: [RESEND][v1 0/3] Support memory cgroup hotplug
Date: Mon, 21 Nov 2016 15:03:41 +0100 [thread overview]
Message-ID: <20161121140340.GC18112@dhcp22.suse.cz> (raw)
In-Reply-To: <1479253501-26261-1-git-send-email-bsingharora@gmail.com>
On Wed 16-11-16 10:44:58, Balbir Singh wrote:
> In the absence of hotplug we use extra memory proportional to
> (possible_nodes - online_nodes) * number_of_cgroups. PPC64 has a patch
> to disable large consumption with large number of cgroups. This patch
> adds hotplug support to memory cgroups and reverts the commit that
> limited possible nodes to online nodes.
I didn't get to read patches yet (I am currently swamped by emails after
longer vacation so bear with me) but this doesn't tell us _why_ we want
this and how much we can actaully save. In general being dynamic is more
complex and most systems tend to have possible_nodes close to
online_nodes in my experience (well at least on most reasonable
architectures). I would also appreciate some highlevel description of
the implications. E.g. how to we synchronize with the hotplug operations
when iterating node specific data structures.
Thanks!
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-11-21 14:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-15 23:44 [RESEND][v1 0/3] Support memory cgroup hotplug Balbir Singh
2016-11-15 23:44 ` [RESEND] [PATCH v1 1/3] Add basic infrastructure for memcg hotplug support Balbir Singh
2016-11-16 9:01 ` Vladimir Davydov
2016-11-17 0:28 ` Balbir Singh
2016-11-21 8:36 ` Vladimir Davydov
2016-11-22 0:17 ` Balbir Singh
2016-11-15 23:45 ` [RESEND] [PATCH v1 2/3] Move from all possible nodes to online nodes Balbir Singh
2016-11-15 23:45 ` [RESEND] [PATCH v1 3/3] powerpc: fix node_possible_map limitations Balbir Singh
2016-11-16 16:40 ` Reza Arbab
2016-11-16 16:45 ` [PATCH] powerpc/mm: allow memory hotplug into an offline node Reza Arbab
2017-02-01 1:05 ` Michael Ellerman
2016-11-21 14:03 ` Michal Hocko [this message]
2016-11-22 0:16 ` [RESEND][v1 0/3] Support memory cgroup hotplug Balbir Singh
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