From: Jaegeuk Kim <jaegeuk.kim@samsung.com>
To: "'Arnd Bergmann'" <arnd@arndb.de>
Cc: "'Vyacheslav Dubeyko'" <slava@dubeyko.com>, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org,
        viro@zeniv.linux.org.uk, tytso@mit.edu, chur.lee@samsung.com,
        cm224.lee@samsung.com, jooyoung.hwang@samsung.com
References: <001001cdb0c5$2ac96520$805c2f60$%kim@samsung.com>
 <1351077945.2097.9.camel@slavad-ubuntu>
 <00e601cdb32a$59fbe090$0df3a1b0$%kim@samsung.com>
 <201210260818.18155.arnd@arndb.de>
In-reply-to: <201210260818.18155.arnd@arndb.de>
Subject: RE: [PATCH 02/16 v2] f2fs: add on-disk layout
Date: Fri, 26 Oct 2012 17:31:46 +0900
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> On Friday 26 October 2012, Jaegeuk Kim wrote:
> 
> > > > +
> > > > +#define F2FS_ROOT_INO(sbi)	(sbi->root_ino_num)
> > > > +#define F2FS_NODE_INO(sbi)	(sbi->node_ino_num)
> > > > +#define F2FS_META_INO(sbi)	(sbi->meta_ino_num)
> > > > +
> > > > +#define GFP_F2FS_MOVABLE	(__GFP_WAIT | __GFP_IO | __GFP_ZERO)
> > > > +
> > > > +#define MAX_ACTIVE_LOGS	16
> > > > +#define MAX_ACTIVE_NODE_LOGS	8
> > > > +#define MAX_ACTIVE_DATA_LOGS	8
> > >
> > > I think that it makes sense to comment the reasons of such limitations
> > > in MAX_ACTIVE_LOGS, MAX_ACTIVE_NODE_LOGS, MAX_ACTIVE_DATA_LOGS.
> >
> > The maximum number of logs is suggested by arnd before.
> > As I understood, why he suggested such a quite large number is for further
> > optimization of multiple logs without any on-disk layout changes.
> > And, I think it is quite enough.
> 
> I agree. I think Vyacheslav was just asking you to add a comment
> explaining how we got to these numbers, like
> 
> /*
>  * The file format supports up to 16 active logs, which should be
>  * more than enough for future optimizations. The implementation
>  * currently uses no more than 6 logs.
>  * Half the logs are used for nodes, the other half are used for data.
>  */
> 

Right. I added like that.
Thank you for explanation, and it'd better add additional words described by you.

> 
> 	Arnd


---
Jaegeuk Kim
Samsung

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