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

[Zhi Yong Wu]

On Thu, Sep 27, 2012 at 3:05 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote:
> On Thu, Sep 27, 2012 at 01:25:34PM +0800, Zhi Yong Wu wrote:
>> 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?
>
> I wrote that thinking (mistakenly) that s-hot)info was dynamically
> allocated rather than being embedded in the struct super_block.
>
> Indeed, if the mount option is held in s_flags, then it could be
> dynamically allocated, but I don't think that's really necessary...
ah, you prefer allocating it, OK, let me try. thanks for your explaination.

>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@xxxxxxxxxxxxx



-- 
Regards,

Zhi Yong Wu
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