On Tue, Jan 15, 2019 at 06:40:36PM +0100, Michal Hocko wrote:
> On Tue 15-01-19 16:51:31, Greg KH wrote:
> > On Tue, Jan 15, 2019 at 04:34:44PM +0100, Michal Hocko wrote:
> > > I do not see a straightforward backport of this patch without pulling
> > > more changes in. Do we have anybody to actually hit the issue on those
> > > older kernels? While the issue is possible in principle I do not
> > > remember anybody complaining.
> >
> > If no one is complaining, that's fine, you just got this message because
> > you put this in the commit:
> >
> > > > Fixes: c3b94f44fcb0 ("memcg: further prevent OOM with too many dirty pages")
> >
> > Which means any kernel newer than 4.2 (and some older stable releases)
> > has the issue that this patch is trying to fix. If it doesn't need to
> > be backported that far, wonderful!
>
> After a second thought, we are not really affected all the way down to
> c3b94f44fcb0. We do account page tables to memcgs only since
> 3e79ec7ddc33 ("arch: x86: charge page tables to kmemcg") 4.8+. Without
> that there is no realy memcg reclaim and thus not wait_on_page_writeback.
>
> So my Fixes is a bit misleading. Sorry about that.
Not a problem, thanks for looking into it. As you say 4.8+, this didn't
apply to 4.9 either, so do I need to look into doing a manual backport
there?
thanks,
greg k-h
