zfs: drop duplicate vfs.zfs.metaslab.condense_pct sysctl

[chris.longros_gmail.com]

Summary

metaslab.c already registers this tunable via ZFS_MODULE_PARAM, so the SYSCTL_UINT here is a second registration of the same leaf:

sysctl_register_oid: can't re-use a leaf (vfs.zfs.metaslab.condense_pct)

Remove it, as OpenZFS upstream did.

Signed-off-by: Christos Longros <[e-mail]>

Test Plan

Tested on FreeBSD 16.0-CURRENT: the warning is gone and vfs.zfs.metaslab.condense_pct still reads and writes.

[dim]

Hm, I thought this was fixed by @mm's rGb1b4871f373e9f2a5defdc1242543be291f5e9d9, but apparently not:

sysctl_register_oid: can't re-use a leaf (vfs.zfs.metaslab.condense_pct)!

It looks good to me, but I'm not an OpenZFS expert, so probably better wait for an OK from @mm :)

[markmi_dsl-only.net]

In the kind of context that I originally reported based on:

I patched the /usr/main-src/ tree that I use for personal kernel and world builds, built the kernels (debug and non-debug), installed them, and boot tested them, and, finally, tested causing zfs.ko to load and tried reading and writing vfs.zfs.metaslab.condense_pct . It all seemed to work just fine, with no complaints being output. That included kldunload of zfs.ko .

(My non-personal kernels and worlds are from upstream pkgbase distributions. Not really a natural context for patch testing.)

[chris.longros_gmail.com]

So will this commit land to main ? :)

[markmi_dsl-only.net]

In D57721#1333711, @chris.longros_gmail.com wrote:

So will this commit land to main ? :)

I do not know if testing is ever considered sufficient for an approval. That is all I reported up to now.

My code-level FreeBSD specific knowledge should normally be considered too weak to be reasonable for code review based overall approval --and I'm not a comitter. But this looks to be a very simple redundancy and the related code looks to be otherwise centralized in sys/contrib/openzfs/module/zfs/metaslab.c (making that likely the right one to preserve). It sure looks to me like it should be approved.

[chris.longros_gmail.com]

@mm