Re: [PATCH 1/2] fs: Do not dispatch FITRIM through separate super_operation

Dave Chinner
2011-06-03T02:06:22Z

On Thu, Jun 02, 2011 at 01:52:12PM +0900, Kyungmin Park wrote:
> On Wed, Dec 8, 2010 at 1:52 AM, Chris Mason <chris.mason@oracle.com> wrote:
> > Excerpts from Christoph Hellwig's message of 2010-12-07 04:27:49 -0500:
> >> On Fri, Nov 19, 2010 at 10:21:35AM -0500, Mark Lord wrote:
> >> > >I really hate to rely on this third party hearsay (from all sides), and
> >> > >have implement TRIM support in qemu now.  I'll soon install win7 and
> >> > >will check out the TRIM patters myself.
> >> >
> >> > Excellent!
> >>
> >> I did a Windows 7 installation under qemu today, and the result is:
> >
> > Great, thanks for testing this.
> >
> >>
> >>  - it TRIMs the whole device early during the installation
> >>  - after that I see a constant stream of small trims during the
> >>    installation.  It's using lots of non-contiguous ranges in a single
> >>    TRIM command, with sizes down to 8 sectors (4k) for a single range.
> >>  - after installation there's is some background-trimming going on
> >>    even when doing no user interaction with the VM at all.
>
> Hi Lukas,
>
> Now FITRIM is based on user interaction. So how about to implement the
> AUTO batched discard at kernel level?
> Idea is same as windows, make a single thread and iterate the
> superblocks and call the trim.

Surely this the responsibility of a userspace daemon and a config
file to decide and implement the background trim policy?

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com