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From: Michal Hocko <mhocko@suse.cz>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>,
	"bsingharora@gmail.com" <bsingharora@gmail.com>,
	Ying Han <yinghan@google.com>
Subject: Re: [PATCH] [Cleanup] memcg: export memory cgroup's swappiness v2
Date: Thu, 30 Jun 2011 09:33:00 +0200	[thread overview]
Message-ID: <20110630073300.GA13560@tiehlicka.suse.cz> (raw)
In-Reply-To: <20110630161039.604f91b9.kamezawa.hiroyu@jp.fujitsu.com>

On Thu 30-06-11 16:10:39, KAMEZAWA Hiroyuki wrote:
> On Thu, 30 Jun 2011 08:32:32 +0200
> Michal Hocko <mhocko@suse.cz> wrote:
> 
> > On Thu 30-06-11 12:32:29, KAMEZAWA Hiroyuki wrote:
> > [...]
> > > @@ -4288,7 +4287,7 @@ static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
> > >  {
> > >  	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> > >  
> > > -	return get_swappiness(memcg);
> > > +	return mem_cgroup_swappiness(memcg);
> > >  }
> > 
> > If you want to be type clean you should change this one as well. I
> > think it is worth it, though. The function is called only to return the
> > current value to userspace and mem_cgroup_swappiness_write guaranties
> > that it falls down into <0,100> interval. Additionally, cftype doesn't
> > have any read specialization for int values so you would need to use a
> > generic one. Finally if you changed read part you should change also
> > write part and add > 0 check which is a lot of code for not that good
> > reason.
> 
> I don't want to make this type-clean. 

Agreed.

> Should I add type casting as
> ==
>  return (u64) mem_cgroup_swappiness(memcg);
> ==
> ?

I do not think it is necessary. The value is promoted to u64
automatically.

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@suse.cz>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>,
	"bsingharora@gmail.com" <bsingharora@gmail.com>,
	Ying Han <yinghan@google.com>
Subject: Re: [PATCH] [Cleanup] memcg: export memory cgroup's swappiness v2
Date: Thu, 30 Jun 2011 09:33:00 +0200	[thread overview]
Message-ID: <20110630073300.GA13560@tiehlicka.suse.cz> (raw)
In-Reply-To: <20110630161039.604f91b9.kamezawa.hiroyu@jp.fujitsu.com>

On Thu 30-06-11 16:10:39, KAMEZAWA Hiroyuki wrote:
> On Thu, 30 Jun 2011 08:32:32 +0200
> Michal Hocko <mhocko@suse.cz> wrote:
> 
> > On Thu 30-06-11 12:32:29, KAMEZAWA Hiroyuki wrote:
> > [...]
> > > @@ -4288,7 +4287,7 @@ static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
> > >  {
> > >  	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> > >  
> > > -	return get_swappiness(memcg);
> > > +	return mem_cgroup_swappiness(memcg);
> > >  }
> > 
> > If you want to be type clean you should change this one as well. I
> > think it is worth it, though. The function is called only to return the
> > current value to userspace and mem_cgroup_swappiness_write guaranties
> > that it falls down into <0,100> interval. Additionally, cftype doesn't
> > have any read specialization for int values so you would need to use a
> > generic one. Finally if you changed read part you should change also
> > write part and add > 0 check which is a lot of code for not that good
> > reason.
> 
> I don't want to make this type-clean. 

Agreed.

> Should I add type casting as
> ==
>  return (u64) mem_cgroup_swappiness(memcg);
> ==
> ?

I do not think it is necessary. The value is promoted to u64
automatically.

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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  reply	other threads:[~2011-06-30  7:33 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-29 10:03 [PATCH] [Cleanup] memcg: export memory cgroup's swappiness v2 KAMEZAWA Hiroyuki
2011-06-29 10:03 ` KAMEZAWA Hiroyuki
2011-06-29 12:20 ` Michal Hocko
2011-06-29 12:20   ` Michal Hocko
2011-06-29 13:00 ` Balbir Singh
2011-06-29 13:00   ` Balbir Singh
2011-06-29 20:00 ` Andrew Morton
2011-06-29 20:00   ` Andrew Morton
2011-06-30  3:32   ` KAMEZAWA Hiroyuki
2011-06-30  3:32     ` KAMEZAWA Hiroyuki
2011-06-30  6:32     ` Michal Hocko
2011-06-30  6:32       ` Michal Hocko
2011-06-30  7:10       ` KAMEZAWA Hiroyuki
2011-06-30  7:10         ` KAMEZAWA Hiroyuki
2011-06-30  7:33         ` Michal Hocko [this message]
2011-06-30  7:33           ` Michal Hocko
2011-06-30 20:01 ` Andrew Morton
2011-06-30 20:01   ` Andrew Morton
2011-06-30 23:50   ` KAMEZAWA Hiroyuki
2011-06-30 23:50     ` KAMEZAWA Hiroyuki
2011-07-01  0:20     ` KAMEZAWA Hiroyuki
2011-07-01  0:20       ` KAMEZAWA Hiroyuki
2011-07-01  1:06       ` Andrew Morton
2011-07-01  1:06         ` Andrew Morton
2011-07-01  1:16         ` KAMEZAWA Hiroyuki
2011-07-01  1:16           ` KAMEZAWA Hiroyuki
2011-07-01  1:30           ` KAMEZAWA Hiroyuki
2011-07-01  1:30             ` KAMEZAWA Hiroyuki
2011-07-01  7:10             ` KAMEZAWA Hiroyuki
2011-07-01  7:10               ` KAMEZAWA Hiroyuki
2011-07-06  5:18               ` [PATCH] [Cleanup] memcg: export memory cgroup's swappiness v5 KAMEZAWA Hiroyuki
2011-07-06  5:18                 ` KAMEZAWA Hiroyuki

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