Re: Strange ARC/Swap/CPU on yesterday's -CURRENT

On Sun, Mar 18, 2018 at 05:54:30PM -0700, Mark Millard wrote:
> bob prohaska fbsd at www.zefox.net wrote on
> Sun Mar 18 21:09:42 UTC 2018 :
> 
> > On Sun, Mar 11, 2018 at 10:43:58AM -1000, Jeff Roberson wrote:
> > 
> > > Also, if you could try going back to r328953 or r326346 and let me know if 
> > > the problem exists in either.  That would be very helpful.  If anyone is 
> > 
> > Not sure this is relevant, but r326343 is able to run a j4 buildworld
> > to completion on an RPi3 with 3 gigs of microSD-based swap. There are
> > periods of seeming distress at times (lots of swread, pfault state
> > in top along with high %idle) in top, but the compilation completes.
> > 
> > In contrast, r328953 could not complete buildworld using -j4. Buildworld
> > would stop, usually reporting c++ killed, apparently for want of swap,
> > even though swap usage never exceeded about 30% accoring to top.
> > 
> > The machine employs UFS filesystems, . . .
> 
> 
> Sounds like -r326346 would be an interesting kernel to test (the
> next check-in on head after -r326343, one of Jeff's check-ins).
> 
> -r328953 was just before Jeff's:
> 

My intent was to try 326346. Somehow 326343 arrived in its place. 
Do architectures affect revision numbers? I thought not, but... 


> Author: jeff
> Date: Tue Feb  6 22:10:07 2018
> New Revision: 328954
> URL: 
> https://svnweb.freebsd.org/changeset/base/328954
> 
> 
> Log:
>   Use per-domain locks for vm page queue free.  Move paging control from
>   global to per-domain state.  Protect reservations with the free lock
>   from the domain that they belong to.  Refactor to make vm domains more
>   of a first class object.
> 
> 
> 
> So, if -r328953 behaves oddly and -r326343 does not, then the
> question is if -r326346 makes the difference:
> 
> Author: jeff
> Date: Tue Nov 28 23:18:35 2017
> New Revision: 326346
> URL: 
> https://svnweb.freebsd.org/changeset/base/326346
> 
> 
> Log:
>   Move domain iterators into the page layer where domain selection should take
>   place.  This makes the majority of the phys layer explicitly domain specific.
> 
> 
> (Unfortunately my FreeBSD time is currently greatly limited.)
> 
> It is also interesting that your test context is UFS. O. Hartmann
> has reported problems for UFS in a more modern version: -r330608 .
> 

When "out of swap" problems appeared I cobbled up a custom kernel,
in the hope that a smaller kernel might help. It has since developed
that the custom kernel can't boot, but GENERIC still boots. The system 
is now running a j4 buildworld on r331153 with a GENERIC kernel
to see if maybe the problem has already been fixed in a way that
was obscured by the customization. The kernel config is at
http://www.zefox.net/~fbsd/rpi3/kernel_config/ZEFOX

Thanks for reading,

bob prohaska