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 [off-list ref] wrote:

quoted

On Sun, Sep 23, 2012 at 08:56:28PM +0800, zwu.kernel@gmail.com wrote:

quoted

From: Zhi Yong Wu <redacted>

  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...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com