Re: memcg: cat: memory.memsw.* : Operation not supported

From: Michal Hocko
Date: Mon Jan 21 2013 - 08:46:35 EST


On Mon 21-01-13 21:27:33, Zhouping Liu wrote:
> On 01/21/2013 06:56 PM, Michal Hocko wrote:
[...]
> > From 5f8141bf7d27014cfbc7b450f13f6146b5ab099d Mon Sep 17 00:00:00 2001
> >From: Michal Hocko <mhocko@xxxxxxx>
> >Date: Mon, 21 Jan 2013 11:33:26 +0100
> >Subject: [PATCH] memcg: Do not create memsw files if swap accounting is
> > disabled
> >
> >Zhouping Liu has reported that memsw files are exported even though
> >swap accounting is runtime disabled if CONFIG_MEMCG_SWAP is enabled.
> >This behavior has been introduced by af36f906 (memcg: always create
> >memsw files if CONFIG_CGROUP_MEM_RES_CTLR_SWAP) and it causes any
> >attempt to open the file to return EOPNOTSUPP. Although EOPNOTSUPP
> >should say be clear that memsw operations are not supported in the given
> >configuration it is fair to say that this behavior could be quite
> >confusing.
> >
> >Let's tear memsw files out of default cgroup files and add
> >them only if the swap accounting is really enabled (either by
> >CONFIG_MEMCG_SWAP_ENABLED or swapaccount=1 boot parameter). We can
> >hook into mem_cgroup_init which is called when the memcg subsystem is
> >initialized and which happens after boot command line is processed.
>
> Thanks for your quick patch, your patch looks good for me.
>
> I tested it with or without CONFIG_MEMCG_SWAP_ENABLED=y,
> and also tested it with swapaccount=1 kernel parameters, all are okay.
>
> Tested-by: Zhouping Liu <zliu@xxxxxxxxxx>

Thanks for testing!

--
Michal Hocko
SUSE Labs
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