Re: [RFC v2 03/10] vfs: add one new mount option '-o hottrack'

[Zhi Yong Wu]

On Tue, Sep 25, 2012 at 5:28 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote:
> On Sun, Sep 23, 2012 at 08:56:28PM +0800, zwu.kernel@xxxxxxxxx wrote:
>> From: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
>>
>>   Introduce one new mount option '-o hottrack',
>> and add its parsing support.
>>   Its usage looks like:
>>    mount -o hottrack
>>    mount -o nouser,hottrack
>>    mount -o nouser,hottrack,loop
>>    mount -o hottrack,nouser
>
> I think that this option parsing should be done by the filesystem,
> even though the tracking functionality is in the VFS. That way ony
> the filesystems that can use the tracking information will turn it
> on, rather than being able to turn it on for everything regardless
> of whether it is useful or not.
>
> Along those lines, just using a normal superblock flag to indicate
> it is active (e.g. MS_HOT_INODE_TRACKING in sb->s_flags) means you
> don't need to allocate the sb->s_hot_info structure just to be able
If we don't allocate one sb->s_hot_info, where will those hash list
head and btree roots locate?

> to check whether we are tracking hot inodes or not.
>
> This then means the hot inode tracking for the superblock can be
> initialised by the filesystem as part of it's fill_super method,
> along with the filesystem specific code that will use the hot
> tracking information the VFS gathers....
>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@xxxxxxxxxxxxx



-- 
Regards,

Zhi Yong Wu
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