From: Johannes Weiner <hannes@cmpxchg.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Balbir Singh <bsingharora@gmail.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] mm/cgroup: delay soft limit data allocation
Date: Thu, 23 Feb 2017 14:03:13 -0500 [thread overview]
Message-ID: <20170223190313.GB6088@cmpxchg.org> (raw)
In-Reply-To: <20170223153107.GD29056@dhcp22.suse.cz>
On Thu, Feb 23, 2017 at 04:31:07PM +0100, Michal Hocko wrote:
> On Thu 23-02-17 14:36:39, Laurent Dufour wrote:
> > Until a soft limit is set to a cgroup, the soft limit data are useless
> > so delay this allocation when a limit is set.
>
> Hmm, I am still undecided whether this is actually worth it. On one hand
> distribution kernels tend to have quite large NUMA_SHIFT (e.g. SLES has
> NUMA_SHIFT=10 and then we will save 8kB+12kB which is not hell of a lot
> but always good if we can save that, especially for a rarely used
> feature. The code grown on the other hand (it was in __init section
> previously) which is a minus, on the other hand.
>
> What do you think Johannes?
Hohumm, saving 5 pages on a NUMA machine vs. the additional complexity
and the increased risk of memory problems when somebody sets up a soft
limit after some uptime... I don't think I can give a strong yes or no
on this one, so inertia wins for me; I'd just leave it alone.
prev parent reply other threads:[~2017-02-23 19:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-23 13:36 [PATCH v2 0/2] mm/cgroup soft limit data allocation Laurent Dufour
2017-02-23 13:36 ` [PATCH v2 1/2] mm/cgroup: avoid panic when init with low memory Laurent Dufour
2017-02-23 15:12 ` Michal Hocko
2017-02-23 18:39 ` Johannes Weiner
2017-02-24 11:10 ` Michal Hocko
2017-02-24 13:42 ` Balbir Singh
2017-02-23 13:36 ` [PATCH v2 2/2] mm/cgroup: delay soft limit data allocation Laurent Dufour
2017-02-23 15:31 ` Michal Hocko
2017-02-23 19:03 ` Johannes Weiner [this message]
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