Re: [RFC v1 00/11] vfs: hot data tracking

[Dave Chinner <david@fromorbit.com>]

On Mon, Sep 17, 2012 at 03:18:34PM +0800, zwu.kernel@gmail.com wrote:
> From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> 
> NOTE:
> 
>   The patchset is currently post out mainly to make sure
> it is going in the correct direction and hope to get some
> helpful comments from other guys.
> 
> TODO List:
> 
>  1.) Need to do scalability or performance tests.
>  2.) Turn some Micro into tunables
>        TIME_TO_KICK, and HEAT_UPDATE_DELAY
>  3.) Rafactor hot_hash_is_aging()
>        If you just made the timeout value a timespec and compared
>      the _timespecs_, you would be doing a lot fewer conversions.
>  4.) Cleanup some unnecessary lock protect
>  5.) Add more comments to explain how to calc temperature

0) Documentation.

> Zhi Yong Wu (11):
>   vfs: introduce one structure hot_info
>   vfs: introduce one rb tree - hot_inode_tree
>   vfs: introduce 2 rb tree items - inode and range

These three patches can probably just be flattened into one.
Splitting out the first two doesn't add to the clarity of the
series - add the structures in the patch that actually uses them
so we don't ahve to jump between patches to see how they are used.

>   vfs: add support for updating access frequency
>   vfs: add one new mount option '-o hottrack'
>   vfs: add init and exit support
>   vfs: introduce one hash table
>   vfs: enable hot data tracking
>   vfs: fork one private kthread to update temperature info
>   vfs: add 3 new ioctl interfaces
>   vfs: add debugfs support
> 
>  fs/Makefile               |    3 +-
>  fs/compat_ioctl.c         |    8 +
>  fs/dcache.c               |    2 +
>  fs/direct-io.c            |   10 +
>  fs/hot_debugfs.c          |  487 ++++++++++++++++++++++++++++++++++
>  fs/hot_debugfs.h          |   60 +++++
>  fs/hot_hash.c             |  369 ++++++++++++++++++++++++++
>  fs/hot_hash.h             |  108 ++++++++
>  fs/hot_rb.c               |  648 +++++++++++++++++++++++++++++++++++++++++++++
>  fs/hot_rb.h               |   70 +++++
>  fs/hot_track.c            |  113 ++++++++
>  fs/hot_track.h            |   23 ++
>  fs/ioctl.c                |  132 +++++++++
>  fs/namespace.c            |   10 +
>  fs/super.c                |   11 +
>  include/linux/fs.h        |   15 +
>  include/linux/hot_track.h |  169 ++++++++++++
>  mm/filemap.c              |    8 +
>  mm/page-writeback.c       |   21 ++
>  mm/readahead.c            |    9 +
>  20 files changed, 2275 insertions(+), 1 deletions(-)
>  create mode 100644 fs/hot_debugfs.c
>  create mode 100644 fs/hot_debugfs.h
>  create mode 100644 fs/hot_hash.c
>  create mode 100644 fs/hot_hash.h
>  create mode 100644 fs/hot_rb.c
>  create mode 100644 fs/hot_rb.h
>  create mode 100644 fs/hot_track.c
>  create mode 100644 fs/hot_track.h
>  create mode 100644 include/linux/hot_track.h

So, 9 new files for tracking all of this? I'm not sure that so
many new files are needed - putting it all in fs/hot_tracking.[ch]
might make more sense, or if all 8 fs/hot* files remain, putting
them in their own subdirectory might be an idea (like quota).

I'll comment on the code when I get a bit of time to look at it.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com