On 8/20/23, Alexander Leidinger <alexan...@leidinger.net> wrote: > Am 2023-08-20 22:02, schrieb Mateusz Guzik: >> On 8/20/23, Alexander Leidinger <alexan...@leidinger.net> wrote: >>> Am 2023-08-20 19:10, schrieb Mateusz Guzik: >>>> On 8/18/23, Alexander Leidinger <alexan...@leidinger.net> wrote: >>> >>>>> I have a 51MB text file, compressed to about 1MB. Are you interested >>>>> to >>>>> get it? >>>>> >>>> >>>> Your problem is not the vnode limit, but nullfs. >>>> >>>> https://people.freebsd.org/~mjg/netchild-periodic-find.svg >>> >>> 122 nullfs mounts on this system. And every jail I setup has several >>> null mounts. One basesystem mounted into every jail, and then shared >>> ports (packages/distfiles/ccache) across all of them. >>> >>>> First, some of the contention is notorious VI_LOCK in order to do >>>> anything. >>>> >>>> But more importantly the mind-boggling off-cpu time comes from >>>> exclusive locking which should not be there to begin with -- as in >>>> that xlock in stat should be a slock. >>>> >>>> Maybe I'm going to look into it later. >>> >>> That would be fantastic. >>> >> >> I did a quick test, things are shared locked as expected. >> >> However, I found the following: >> if ((xmp->nullm_flags & NULLM_CACHE) != 0) { >> mp->mnt_kern_flag |= >> lowerrootvp->v_mount->mnt_kern_flag & >> (MNTK_SHARED_WRITES | MNTK_LOOKUP_SHARED | >> MNTK_EXTENDED_SHARED); >> } >> >> are you using the "nocache" option? it has a side effect of xlocking > > I use noatime, noexec, nosuid, nfsv4acls. I do NOT use nocache. >
If you don't have "nocache" on null mounts, then I don't see how this could happen. -- Mateusz Guzik <mjguzik gmail.com>
