From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Mingming.cao" <cmm@us.ibm.com>
Subject: Re: VFS hot tracking: How to calculate data temperature?
Date: Fri, 02 Nov 2012 14:27:02 -0700
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Cc: linux-fsdevel@vger.kernel.org, linuxram@linux.vnet.ibm.com,
	Dave Chinner <david@fromorbit.com>,
	Ben Chociej <bchociej@gmail.com>,
	James Northrup <northrup.james@gmail.com>
To: Zhi Yong Wu <zwu.kernel@gmail.com>
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On Fri, 2012-11-02 at 14:38 +0800, Zhi Yong Wu wrote:
> Here also has another question.
> 
> How to save the file temperature among the umount to be able to
> preserve the file tempreture after reboot?
> 
> This above is the requirement from DB product.
> I thought that we can save file temperature in its inode struct, that
> is, add one new field in struct inode, then this info will be written
> to disk with inode.
> 
> Any comments or ideas are appreciated, thanks.
> 
> 

Maybe could save the last file temperature with extended attributes.
Just save the per-inode temperature only for now.

Mingming
> On Fri, Nov 2, 2012 at 12:04 PM, Zhi Yong Wu <zwu.kernel@gmail.com> wrote:
> > HI, guys
> >
> >    VFS hot tracking currently show result as below, and it is very
> > strange and not nice.
> >
> > inode #279, reads 0, writes 1, avg read time 18446744073709551615,
> > avg write time 5251566408153596, temp 109
> >
> > Do anyone know if there is one simpler but effective way to calculate
> > data temperature?
> >
> > --
> > Regards,
> >
> > Zhi Yong Wu
> 
> 
>