swapping is completely broken in -CURRENT r334649?

[Kevin Lo]

On Fri, Jun 15, 2018 at 04:40:22AM -0400, Mark Johnston wrote:
> 
> On Fri, Jun 15, 2018 at 01:10:25PM +0800, Kevin Lo wrote:
> > On Tue, Jun 05, 2018 at 05:48:08PM -0400, Mark Johnston wrote:
> > > 
> > > On Wed, Jun 06, 2018 at 12:22:08AM +0300, Lev Serebryakov wrote:
> > > > On 05.06.2018 19:17, Gary Jennejohn wrote:
> > > > 
> > > > 
> > > > > I complained about this also and alc@ gave me this hint:
> > > > > 	sysctl vm.pageout_update_period=0
> > > > 
> > > >  Really, situation is worse than stated in subject, because processes
> > > > are being killed AFTER memory pressure, when here are a lot of free
> > > > memory already!
> > > > 
> > > >  It looks like very serious bug.
> > > 
> > > The issue was identified earlier this week and is being worked on. It's
> > > a regression from r329882 which appears only on certain hardware. You
> > > can probably work around it by setting vm.pageout_oom_seq to a large
> > > value (try 1000 for instance), though this will make the "true" OOM
> > > killer take longer to kick in. The problem is unrelated to the
> > > pageout_update_period.
> > 
> > I have a large swap space and I've encountered this issue as well
> > 
> > pid 90707 (getty), uid 0, was killed: out of swap space
> > pid 90709 (getty), uid 0, was killed: out of swap space
> > pid 90709 (getty), uid 0, was killed: out of swap space
> > ...
> > 
> > Setting vm.pageout_oom_seq to 1000 doesn't help.  If you have a patch I'll be
> > happy to test it, thanks.
> 
> The change was committed as r334752.  Are you seeing unexpected OOM
> kills on or after that revision?

The box is running -CURRENT r334983.  I'll investigate further, thanks.