Skip to content

RFC Ocfs2 allocation reservations

Joel Becker ocfs2-devel 1 version New

Get series with b4
b4 am [email protected]

Versions newest first

  1. v1 RFC Latest0 of 4 patches 0 repliesNew

Patches in v1 No applies recorded yet

None of the 4 patches the cover letter announces are in this archive.

Reviews trailers per patch

No Reviewed-by, Acked-by or Tested-by trailers for v1 yet.

Read the v1 thread

Cover letter [Ocfs2-devel] [RFC 0/4] Ocfs2 allocation reservations
Quoted 7 lines · Mark Fasheh

Hi, the following patches implement allocation reservations for Ocfs2. Right now I'd consider them to be beta quality - simple operations work but the code likely won't survive a kernel build. As it is implemented, the code only takes reservations on the local alloc bitmap. I've divorced the structures from any bitmap type however, so we can extend this to the chain allocators with only a small amount of code. Also, there's nothing in reservations.c which depends on a struct inode.

It looks nice and simple. As I read it, when you get some space
from the localalloc, you try to reserve the next space. Simple chaining of requests. It's efficacy obviously depends on how much you reserve for the next cycle.

Quoted 5 lines

This version of the reservations code shows the following improvements:

Inode: 66007 % fragmented: 50.00 clusters: 32 extents: 16
Inode: 66009 % fragmented: 68.75 clusters: 32 extents: 22
Inode: 66008 % fragmented: 43.75 clusters: 32 extents: 14

This is probably plenty good. Here's hoping the knob allows us
to tune it. We can probably run with different tunings to see where we come out best.
Have you seen any deleterious effects from very aggressive
reservations?

Joel

Signature · 8 lines
"Time is an illusion, lunchtime doubly so."
        -Douglas Adams

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127