PHP-FPM processes hang in UFS-state

[Konstantin Belousov]

On Sat, Oct 24, 2020 at 10:25:33PM +0300, Christos Chatzaras wrote:
> 
> 
> > On 24 Oct 2020, at 22:16, Konstantin Belousov <kostikbel at gmail.com> wrote:
> > 
> >   30 100097 syncer              -                   mi_switch+0xe2 sleepq_wait+0x2c sleeplk+0x185 lockmgr_xlock_hard+0x1f5 __lockmgr_args+0x2bf ffs_lock+0xa5 VOP_LOCK1_APV+0x7c _vn_lock+0x44 vget+0x4a qsync+0x99 ffs_sync+0x7d5 sync_fsync+0x10f VOP_FSYNC_APV+0x7c sched_sync+0x379 fork_exit+0x83 fork_trampoline+0xe
> > 
> 
> In another system that has no stuck processes it shows:
> 
> procstat -kk 33
>   PID    TID COMM                TDNAME              KSTACK
>    33 100100 syncer              -                   mi_switch+0xe2 sleepq_timedwait+0x2f _cv_timedwait_sbt+0x17a sched_sync+0x714 fork_exit+0x83 fork_trampoline+0xe 
> 
> But how we know that syncer lock it's related to quota?
Because of qsync().