Re: [PATCH v21 00/19] per memcg lru lock

[Hugh Dickins]

On Tue, 5 Jan 2021, Qian Cai wrote:
> On Tue, 2021-01-05 at 11:42 -0800, Shakeel Butt wrote:
> > On Tue, Jan 5, 2021 at 11:30 AM Qian Cai <qcai@xxxxxxxxxx> wrote:
> > > On Thu, 2020-11-05 at 16:55 +0800, Alex Shi wrote:
> > > > This version rebase on next/master 20201104, with much of Johannes's
> > > > Acks and some changes according to Johannes comments. And add a new patch
> > > > v21-0006-mm-rmap-stop-store-reordering-issue-on-page-mapp.patch to support
> > > > v21-0007.
> > > > 
> > > > This patchset followed 2 memcg VM_WARN_ON_ONCE_PAGE patches which were
> > > > added to -mm tree yesterday.
> > > > 
> > > > Many thanks for line by line review by Hugh Dickins, Alexander Duyck and
> > > > Johannes Weiner.
> > > 
> > > Given the troublesome history of this patchset, and had been put into linux-
> > > next
> > > recently, as well as it touched both THP and mlock. Is it a good idea to
> > > suspect
> > > this patchset introducing some races and a spontaneous crash with some mlock
> > > memory presume?
> > 
> > This has already been merged into the linus tree. Were you able to get
> > a similar crash on the latest upstream kernel as well?
> 
> No, I seldom test the mainline those days. Before the vacations, I have tested
> linux-next up to something like 12/10 which did not include this patchset IIRC
> and never saw any crash like this. I am still trying to figure out how to
> reproduce it fast, so I can try a revert to confirm.

This patchset went into mmotm 2020-11-16-16-23, so probably linux-next
on 2020-11-17: you'll have had three trouble-free weeks testing with it
in, so it's not a likely suspect.  I haven't looked yet at your report,
to think of a more likely suspect: will do.

Hugh