[dm-devel] [PATCHv2 00/15] dm-zoned: multi-device support

[Damien Le Moal]

On Wed, 2020-05-27 at 09:41 -0400, Mike Snitzer wrote:
> On Wed, May 27 2020 at  2:22am -0400,
> Hannes Reinecke <hare at suse.de> wrote:
> 
> > Hi all,
> > 
> > here's the second version of my patchset to support multiple zoned
> > drives with dm-zoned.
> > This patchset:
> > - Converts the zone array to using xarray for better scalability
> > - Separates out shared structures into per-device structure
> > - Enforce drive-locality for allocating and reclaiming zones
> > - Lifts the restriction of 2 devices to handle an arbitrary number
> >   of drives.
> > 
> > This gives me a near-perfect scalability by increasing the write
> > speed from 150MB/s (for a cache and one zoned drive) to 300MB/s
> > (for a cache and two zoned drives).
> > 
> > Changes to v1:
> > - Include reviews from Damien
> > - Reshuffle patches
> > 
> > Hannes Reinecke (15):
> >   dm-zoned: add debugging message for reading superblocks
> >   dm-zoned: secondary superblock must reside on the same devices than
> >     primary superblock
> >   dm-zoned: improve logging messages for reclaim
> >   dm-zoned: add a 'reserved' zone flag
> >   dm-zoned: convert to xarray
> >   dm-zoned: temporary superblock for tertiary devices
> >   dm-zoned: add device pointer to struct dm_zone
> >   dm-zoned: add metadata pointer to struct dmz_dev
> >   dm-zoned: allocate dm devices dynamically
> >   dm-zoned: per-device reclaim
> >   dm-zoned: move random and sequential zones into struct dmz_dev
> >   dm-zoned: support arbitrary number of devices
> >   dm-zoned: allocate zone by device index
> >   dm-zoned: select reclaim zone based on device index
> >   dm-zoned: prefer full zones for reclaim
> > 
> >  drivers/md/dm-zoned-metadata.c | 448 ++++++++++++++++++++++++-----------------
> >  drivers/md/dm-zoned-reclaim.c  |  95 +++++----
> >  drivers/md/dm-zoned-target.c   | 169 ++++++++++------
> >  drivers/md/dm-zoned.h          |  77 ++++---
> >  4 files changed, 481 insertions(+), 308 deletions(-)
> 
> Would you still like to wait until the 5.9 merge window?
> 
> Or would you prefer to see these changes land for 5.8 so as to limit the
> variants of related code that needs to be supported?
> 
> If you and Damien are OK with 5.8 (and testing backs that up) then I
> should be able to get it to land.

Yes, it would be nice to have all the recent changes under dm-zoned V2.
I just reviewed Hannes V2 series and I am running tests right now. So
far so good. Will send results by the end of my day.

What is your deadline for a final series to make it to 5.8 ? This end
of week ? If Hannes has time to rework another round, we should be good
then.

Thanks.

> 
> Let me know, thanks.
> Mike
> 

-- 
Damien Le Moal
Western Digital Research