[Cluster-devel] [GFS2 PATCH] [TRY #2] GFS2: Implement a "bitmap has no extents longer than X" scheme

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
| Hi,
| 
| On Wed, 2013-11-06 at 10:59 -0500, Bob Peterson wrote:
| > Hi,
| > 
| > This is a slightly revised version of a patch I recently sent out:
| > 
| > Before this patch, we used a bit, GBF_FULL, to determine when a bitmap
| > was full. With the preceding patch, we started accepting block
| > reservations smaller than the ideal size, which requires a lot more
| > parsing of the bitmaps. To reduce the amount of bitmap searching, this
| > patch implements a scheme whereby each rgrp keeps track of the point
| > at this multi-block reservations will fail.
| > 
| The first two patches look good. However this one I'm still not so keen
| on. I'd much prefer if we can avoid dropping the GBF_FULL support at
| bitmap level if the new test is at rgrp level. It doesn't look like that
| is too tricky to achieve either - all we need to do is to not remove the
| GBF_FULL support since there doesn't appear to be any conflict between
| the two mechanisms.
| 
| The net result is a diffstat that looks like this:
| 
| [root at chywoon linux-2.6]# diffstat -p1 ./patch3.diff
|  fs/gfs2/incore.h |    1 +
|  fs/gfs2/lops.c   |    1 +
|  fs/gfs2/rgrp.c   |   32 ++++++++++++++++++++++++++------
|  3 files changed, 28 insertions(+), 6 deletions(-)
| 
| as opposed to your patch which looks like:
| 
| [root at chywoon linux-2.6]# diffstat -p1 ../bob-a-3.mbox
|  fs/gfs2/incore.h |    2 +-
|  fs/gfs2/lops.c   |    2 +-
|  fs/gfs2/rgrp.c   |   53
|  ++++++++++++++++++++++++++---------------------------
|  3 files changed, 28 insertions(+), 29 deletions(-)
| 
| So there would be fewer changes overall. I've given this a quick spin,
| and it hasn't broken yet, so let me know what you think,
| 
| Steve.
Hi Steve,

I've done a fair amount of testing on your new patch that does not remove
the GBF_FULL flag, and it seems to work fine. Go ahead and use that one
instead of mine.

IOW: ACK

Regards,

Bob Peterson
Red Hat File Systems