Deadlocks / hangs in ZFS

[Slawa Olhovchenkov]

On Tue, May 22, 2018 at 04:16:32PM +0200, Alexander Leidinger wrote:

> 
> Quoting Slawa Olhovchenkov <slw at zxy.spb.ru> (from Tue, 22 May 2018  
> 15:29:24 +0300):
> 
> > On Tue, May 22, 2018 at 08:17:00AM -0400, Steve Wills wrote:
> >
> >> I may be seeing similar issues. Have you tried leaving top -SHa running
> >> and seeing what threads are using CPU when it hangs? I did and saw pid
> >> 17 [zfskern{txg_thread_enter}] using lots of CPU but no disk activity
> >> happening. Do you see similar?
> 
> I will try and report back.
> 
> > Can you try https://reviews.freebsd.org/D7538 and report?
> 
> The patch tells it is against -STABLE, we're talking -current here.

ZFS don't changes this.

> It has been a while since I tried Karl's patch the last time, and I  
> stopped because it didn't apply to -current anymore at some point.
> Will what is provided right now in the patch work on -current?

I am mean yes, after s/vm_cnt.v_free_count/vm_free_count()/g
I am don't know how to have two distinct patch (for stable and current) in one review.

> As a data point, the system I talk about in the start of the thread  
> has 64 GB RAM and the ARC is not limited via sysctl.

Currently vanlia ARC poorly limited via sysctl. After abd extra.
May be interesting test

./sys/cddl/contrib/opensolaris/uts/common/fs/zfs/abd.c:boolean_t zfs_abd_scatter_enabled = B_FALSE;

(no sysctl for change this exist)