Date: Wed, 3 Jun 2009 12:54:06 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Balbir Singh <balbir@linux.vnet.ibm.com>,
       Li Zefan <lizf@cn.fujitsu.com>, Paul Menage <menage@google.com>
Subject: Re: [PATCH mmotm 1/2] memcg: add interface to reset limits
Message-Id: <20090603125406.fd5a2ef2.kamezawa.hiroyu@jp.fujitsu.com>
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	<20090603114908.52c3aed5.nishimura@mxp.nes.nec.co.jp>
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On Wed, 3 Jun 2009 11:49:08 +0900
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:

> Setting mem.limit or memsw.limit to 0 has no meaning
> in actual use(no process can run in such condition).
> 
> We don't have interface to reset mem.limit or memsw.limit now,
> so let's reset the mem.limit or memsw.limit to default(unlimited)
> when they are being set to 0.
> 
Maybe good. But when I proposed this kind of patch, it was rejected.
(try to add RES_ININITY)

please wait acks from others.
But from me,
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujits.ucom>


> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
> ---
>  Documentation/cgroups/memory.txt |    1 +
>  include/linux/res_counter.h      |    2 ++
>  kernel/res_counter.c             |    2 +-
>  mm/memcontrol.c                  |    2 ++
>  4 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
> index 1a60887..e1c69f3 100644
> --- a/Documentation/cgroups/memory.txt
> +++ b/Documentation/cgroups/memory.txt
> @@ -204,6 +204,7 @@ We can alter the memory limit:
>  
>  NOTE: We can use a suffix (k, K, m, M, g or G) to indicate values in kilo,
>  mega or gigabytes.
> +NOTE: We can write "0" to reset the *.limit_in_bytes(unlimited).
>  
>  # cat /cgroups/0/memory.limit_in_bytes
>  4194304
> diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
> index 4c5bcf6..511f42f 100644
> --- a/include/linux/res_counter.h
> +++ b/include/linux/res_counter.h
> @@ -49,6 +49,8 @@ struct res_counter {
>  	struct res_counter *parent;
>  };
>  
> +#define RESOURCE_MAX (unsigned long long)LLONG_MAX
> +
>  /**
>   * Helpers to interact with userspace
>   * res_counter_read_u64() - returns the value of the specified member.
> diff --git a/kernel/res_counter.c b/kernel/res_counter.c
> index bf8e753..0a45778 100644
> --- a/kernel/res_counter.c
> +++ b/kernel/res_counter.c
> @@ -18,7 +18,7 @@
>  void res_counter_init(struct res_counter *counter, struct res_counter *parent)
>  {
>  	spin_lock_init(&counter->lock);
> -	counter->limit = (unsigned long long)LLONG_MAX;
> +	counter->limit = RESOURCE_MAX;
>  	counter->parent = parent;
>  }
>  
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index a83e039..6629ed2 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2040,6 +2040,8 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
>  		ret = res_counter_memparse_write_strategy(buffer, &val);
>  		if (ret)
>  			break;
> +		if (!val)
> +			val = RESOURCE_MAX;
>  		if (type == _MEM)
>  			ret = mem_cgroup_resize_limit(memcg, val);
>  		else
> 

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