From: Arnd Bergmann <arnd@arndb.de>
To: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Subject: Re: [PATCH 02/16 v2] f2fs: add on-disk layout
Date: Fri, 26 Oct 2012 08:18:17 +0000
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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
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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.
 */


	Arnd
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