Re: mm, vmscan: commit makes PAE kernel crash nightly (bisected)

[Michal Hocko]

On Fri 03-02-17 18:36:54, Trevor Cordes wrote:
> On 2017-02-01 Michal Hocko wrote:
> > On Wed 01-02-17 03:29:28, Trevor Cordes wrote:
> > > On 2017-01-30 Michal Hocko wrote:  
> > [...]
> > > > Testing with Valinall rc6 released just yesterday would be a good
> > > > fit. There are some more fixes sitting on mmotm on top and maybe
> > > > we want some of them in finall 4.10. Anyway all those pending
> > > > changes should be merged in the next merge window - aka 4.11  
> > > 
> > > After 30 hours of running vanilla 4.10.0-rc6, the box started to go
> > > bonkers at 3am, so vanilla does not fix the bug :-(  But, the bug
> > > hit differently this time, the box just bogged down like crazy and
> > > gave really weird top output.  Starting nano would take 10s, then
> > > would run full speed, then when saving a file would take 5s.
> > > Starting any prog not in cache took equally as long.  
> > 
> > Could you try with to_test/linus-tree/oom_hickups branch on the same
> > git tree? I have cherry-picked "mm, vmscan: consider eligible zones in
> > get_scan_count" which might be the missing part.
> 
> I ran to_test/linus-tree/oom_hickups branch (4.10.0-rc6+) for 50 hours
> and it does NOT have the bug!  No problems at all so far.

OK, that is definitely good to know. My other fix ("mm, vmscan: consider
eligible zones in get_scan_count") was more theoretical than bug driven.
I would add your
Tested-by: Trevor Cordes <trevor@xxxxxxxxxxxxx>

unless you have anything against that.

> So I think whatever to_test/linus-tree/oom_hickups has that since-4.9
> has that vanilla 4.10-rc6 does *not* have is indeed the fix.
> 
> For my reference, and I know you guys aren't distro-specific, what is
> the best way to get this fix into Fedora 24 (currently 4.9)?

I will send this patch to 4.9+ stable as soon as it hits Linus tree.

-- 
Michal Hocko
SUSE Labs