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

From: Mark Millard <>
Date: Sun, 18 Mar 2018 17:54:30 -0700
bob prohaska fbsd at 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:

Author: jeff
Date: Tue Feb  6 22:10:07 2018
New Revision: 328954

  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

  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 .

Mark Millard
marklmi at
( went
away in early 2018-Mar)
Received on Mon Mar 19 2018 - 01:15:30 UTC

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