Re: VFS hot tracking: How to calculate data temperature?

[Zhi Yong Wu <zwu.kernel@gmail.com>]

On Mon, Nov 5, 2012 at 4:28 PM, Dave Chinner <david@fromorbit.com> wrote:
> On Mon, Nov 05, 2012 at 10:35:50AM +0800, Zhi Yong Wu wrote:
>> On Sat, Nov 3, 2012 at 5:27 AM, Mingming.cao <cmm@us.ibm.com> wrote:
>> > 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.
>> It seems that only ext4 has the concept of extended attributes.
>
> All major filesystems have xattr support. They are used extensively
> by the security and integrity subsystems, for example.
got it, thanks.
>
> Saving the information might be something that is useful to certian
> applications, but lets have the people that need that functionality
> spell out their requirements before discussing how or what to
> implement.  Indeed, discussion shoul dreally focus on getting the
> core, in-memory infrastructure sorted out first before trying to
> expand the functionality further...
ah, but the latest patchset need some love from experienced FS guys:).......
>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@fromorbit.com



-- 
Regards,

Zhi Yong Wu