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

[Zhi Yong Wu]

On Sat, Nov 3, 2012 at 4:10 AM, Darrick J. Wong <darrick.wong@xxxxxxxxxx> wrote:
> On Fri, Nov 02, 2012 at 04:41:09PM +0800, Zheng Liu wrote:
>> On Fri, Nov 02, 2012 at 02:38:29PM +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.
>>
>> Hi Zhiyong,
>>
>> I think that we might define a callback function.  If a filesystem wants
>> to save these data, it can implement a function to save them.  The
>> filesystem can decide whether adding it or not by themselves.
>>
>> BTW, actually I don't really care about how to save these data because I
>> only want to observe which file is accessed in real time, which is very
>> useful for me to track a problem in our product system.
>
> <shrug> I _think_ the vfs quota code simply asks the filesystem for a special
> inode where it save the quota data in whatever (FS-agnostic) format it wants.
> Have you considered something like that?
No, but it is one good hint for my issue. thanks.
>
> (Or, maybe everyone secretly hates doing that?  Secret files, yaaay...)
ah, do you think of doing that?

>
> --D
>>
>> Regards,
>> Zheng
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-- 
Regards,

Zhi Yong Wu
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