Kernel modules not compiled (Stats, NFS, AFS, etc)

I don't know if this is related but I thought I would add more information. I am pretty sure cachefs is working for me:

jorge@bojack:~$ time cp /home/jorge/Backup/ISO/ubuntu/lucid-alternate-amd64.iso .
real 2m24.703s
user 0m0.000s
sys 0m1.260s
jorge@bojack:~$ cd Desktop/
jorge@bojack:~/Desktop$ time cp /home/jorge/Backup/ISO/ubuntu/lucid-alternate-amd64.iso .

real 0m0.796s
user 0m0.000s
sys 0m0.770s

however there doesn't appear to be anything in the cache directory which is specified in /var/cache/fscache:

root@bojack:~/Desktop# du -h /var/cache/fscache/
4.0K /var/cache/fscache/graveyard
4.0K /var/cache/fscache/cache
12K /var/cache/fscache/

are you sure this is going through the on disk cache and not the in memory cache?

@Jorge: no, this has nothing to do with cachefilesd, this is your "normal" filesystem cache.

The issue Wido raised is that the *_FSCACHE modules are not compiled into the kernel and hence cachefilesd is not working.

Indeed you are correct. Someone posted about this on the kernel list: https://lists.ubuntu.com/archives/kernel-team/2009-September/007263.html

and it looks like it was not reviewed during the UDS kernel config review: https://wiki.ubuntu.com/specs/KernelLucidKernelConfigReview

I am unsure if the module is still considered experimental in the upstream .32 kernel, but grepping my config in Lucid shows it as disabled like Wido's config.

Leann maybe you can point us to the right person on the kernel team?

First, I'm reassigning this to the linux kernel package.

Next, I've examined the Lucid kernel configs and this is still noted as EXPERIMENTAL. As Tim noted in the kernel team mailing list, we do not typically enable experimental config options. Setting this to wishlist for now. Will try to bring this up for discussion with the team. Thanks.

config NFS_FSCACHE
        bool "Provide NFS client caching support (EXPERIMENTAL)"
        depends on EXPERIMENTAL
        depends on NFS_FS=m && FSCACHE || NFS_FS=y && FSCACHE=y
        help
          Say Y here if you want NFS data to be cached locally on disc through
          the general filesystem cache manager

Ah, sounds great!

And since i am not that into compilen modules myself, how could i compile the .ko files myself so i can load them manually?

I should be able to build these files against the source without rebuilding my whole kernel, right?

@Leann: Perhaps it's too late now, I should've double checked the moment you were replying: you're saying that the *_FSCACHE modules cannot be enabled in an Ubuntu kernel, because they depend on EXPERIMENTAL. While I'm currently trying to convince[0] upstream to remove the EXPERIMENTAL flag from NFS_FSCACHE, I just noticed that both CONFIG_FSCACHE and CONFIG_CACHEFILES is already enabled in Karmic - which are both marked EXPERIMENTAL (since CACHEFILES depends on FSCACHE).

So, I just have to ask: how comes?

From looking at a Karmic config (2.6.31-20-server) I can see that there are other options, which are enabled as well, despite the fact that they depend on EXPERIMENTAL.

Also, Ubuntu is currently shipping the userspace cachefilesd daemon - which is unusable, without the proper kernel support.

So, if anyone from the kernel team reads this - please reconsider and enable the missing *_FSCACHE options.

Thanks,
Christian.

[0] http://marc.info/?l=linux-nfs&m=126684776217594&w=2

+1 (fscache works flawlessy in Debian Squeeze)

FWIW, the experimemental tag has been removed in mainline: http://tinyurl.com/y8h8yq6

@Pete: please elaborate if you're changing bugs to WONTFIX.

In the latest Lucid kernel these modules aren't compiled as we speak, is there any change that they will make it into the final release?

@Leann: can you change the importance from wishlist back to something more serious? Without the *_FSCACHE options, the cachefilesd package is pretty much useless :-\

This bug was fixed in the package linux - 2.6.35-4.5

---------------
linux (2.6.35-4.5) maverick; urgency=low

  [ Leann Ogasawara ]

  * Revert "[Upstream] (evdev) Use driver hint to compute the evdev buffer
    size (rev2)"
  * Revert "[Upstream] (evdev) Convert to dynamic event buffer (rev4)"
  * Revert "[Upstream] (evdev) Use multi-reader buffer to save space
    (rev4)"
  * Revert "SAUCE: drivers: Remove some duplicate device entries in various
    modules"
  * [Upstream] USB: option: Remove duplicate AMOI_VENDOR_ID
  * [Upstream] Revert "USB: Adding support for HTC Smartphones to ipaq"
  * [Upstream] p54usb: Comment out duplicate Medion MD40900 device id

  [ Tim Gardner ]

  * [Config] CONFIG_NFS_FSCACHE=y
    - LP: #440522
  * [Config] CONFIG_FSCACHE_STATS=y, CONFIG_FSCACHE_HISTOGRAM=y
    - LP: #440522
 -- Leann Ogasawara <email address hidden> Wed, 16 Jun 2010 08:43:07 -0700

Since Lucid is a LTS version, please consider backporting the fix.

I agree, this would really be a nice feature for Lucid. Can a backport be considered?

Oh yes, please backport it, this is a too interesting feature to leave it away from the recent LTS Release. Thanks!

Backport would be awesome.

You can always use the LTS backport kernel from http://ppa.launchpad.net/kernel-ppa/ppa/ubuntu. Choose your favorite meta package from linux-meta-lts-backport-maverick.