Re: [PATCH 10/14] Add /sys trigger for per-node memory compaction

From: KAMEZAWA Hiroyuki
Date: Tue Apr 06 2010 - 20:35:52 EST


On Tue, 6 Apr 2010 17:05:59 -0700
Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Fri, 2 Apr 2010 17:02:44 +0100
> Mel Gorman <mel@xxxxxxxxx> wrote:
>
> > This patch adds a per-node sysfs file called compact. When the file is
> > written to, each zone in that node is compacted. The intention that this
> > would be used by something like a job scheduler in a batch system before
> > a job starts so that the job can allocate the maximum number of
> > hugepages without significant start-up cost.
>
> Would it make more sense if this was a per-memcg thing rather than a
> per-node thing?

memcg doesn't have any relationship with placement of memory (now).
It's just controls the amount of memory.
So, memcg has no relationship with compaction.

A cgroup which controls placement of memory is cpuset.
One idea is per cpuset. But per-node seems ok.

Thanks,
-Kame

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