Re: git: c849eb8f1925 - main - nullfs: Add the vfs.nullfs.cache_nodes sysctl to control nocache default [unknown oid 'vfs.nullfs.cache_nodes']

On Mar 16, 2024, at 21:48, Seigo Tanimura <seigo.tanimura@gmail.com> wrote:

> Hello Mark,

Hello.

> Is the nullfs(5) kernel module loaded?
> 
> vfs.nullfs.cache_nodes is implemented in nullfs(5), which is not in GENERIC.

I had not expected a tunable to require a kernel
module load first. Also, the name was actually
vfs.nullfs.cache_vnodes .

With nullfs.ko loaded:

# sysctl -T vfs.nullfs.cache_vnodes
vfs.nullfs.cache_vnodes: 1

That indicates it is a tunable (so it should be
appropriate for /boot/loader.conf use, as I
understand what tunable refers to). But
vfs.nullfs.cache_vnodes can not be internally
set before nullfs.ko is loaded.

There might need to be notes about the proper
handling for early (tunable) time frames.

Mark

> Best regards,
> 
> --
> Seigo Tanimura <seigo.tanimura@gmail.com>
> 
> 
> On Sun, Mar 17, 2024 at 1:18 PM Mark Millard <marklmi@yahoo.com> wrote:
> Both an official PkgBase install and a personal build do not find the new oid for this for main:
> 
> # uname -apKU
> FreeBSD 7950X3D-ZFS 15.0-CURRENT FreeBSD 15.0-CURRENT main-n268827-75464941dc17 GENERIC-NODEBUG amd64 amd64 1500015 1500015
> 
> # uname -apKU
> FreeBSD 7950X3D-ZFS 15.0-CURRENT FreeBSD 15.0-CURRENT #139 main-n268827-75464941dc17-dirty: Sun Mar 17 03:16:30 UTC 2024     root@7950X3D-ZFS:/usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/sys/GENERIC-NODBG amd64 amd64 1500015 1500015
> 
> The results are:
> 
> # sysctl -d vfs.nullfs.cache_nodes
> sysctl: unknown oid 'vfs.nullfs.cache_nodes'
> 
> # sysctl -a | grep vnode
> kern.maxvnodes: 3224925
> kern.ipc.umtx_vnode_persistent: 0
> vm.vnode_pbufs: 2048
> vm.stats.vm.v_vnodepgsout: 0
> vm.stats.vm.v_vnodepgsin: 4923
> vm.stats.vm.v_vnodeout: 0
> vm.stats.vm.v_vnodein: 662
> vfs.wantfreevnodes: 806231
> vfs.freevnodes: 1323
> vfs.vnodes_created: 3654
> vfs.numvnodes: 1807
> vfs.vnode.vnlru.uma_reclaim_calls: 0
> vfs.vnode.vnlru.kicks: 0
> vfs.vnode.vnlru.max_free_per_call: 10000
> vfs.vnode.vnlru.failed_runs: 0
> vfs.vnode.vnlru.direct_recycles_free: 0
> vfs.vnode.vnlru.recycles_free: 0
> vfs.vnode.vnlru.recycles: 0
> vfs.vnode.stats.alloc_sleeps: 0
> vfs.vnode.stats.free: 1323
> vfs.vnode.stats.skipped_requeues: 0
> vfs.vnode.stats.created: 3654
> vfs.vnode.stats.count: 1807
> vfs.vnode.param.wantfree: 806231
> vfs.vnode.param.limit: 3224925
> vfs.cache.debug.vnodes_cel_3_failures: 0
> vfs.cache.stats.heldvnodes: 119
> debug.vnode_domainset: <NULL>
> debug.sizeof.vnode: 448
> debug.fail_point.status_fill_kinfo_vnode__random_path: off
> debug.fail_point.fill_kinfo_vnode__random_path: off
> 
> Note: The mount_nullfs man page does have:
> 
> QUOTE
>              cache    Force enable metadata caching.
> 
>      The vfs.nullfs.cache_vnodes sysctl specifies global default for mount-
>      specific cache/nocache option.
> END QUOTE
> 
> That is evidence of the vintage of materials.




===
Mark Millard
marklmi at yahoo.com