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Date:   Tue, 5 Jan 2021 13:35:20 -0800 (PST)
From:   Hugh Dickins <hughd@google.com>
To:     Qian Cai <qcai@redhat.com>
cc:     Shakeel Butt <shakeelb@google.com>,
        Alex Shi <alex.shi@linux.alibaba.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@techsingularity.net>,
        Tejun Heo <tj@kernel.org>, Hugh Dickins <hughd@google.com>,
        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        Matthew Wilcox <willy@infradead.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        kernel test robot <lkp@intel.com>,
        Linux MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Cgroups <cgroups@vger.kernel.org>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Wei Yang <richard.weiyang@gmail.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        alexander.duyck@gmail.com,
        kernel test robot <rong.a.chen@intel.com>,
        Michal Hocko <mhocko@suse.com>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Yang Shi <shy828301@gmail.com>
Subject: Re: [PATCH v21 00/19] per memcg lru lock
In-Reply-To: <49be27f2652d4658f80c95bea171142c35513761.camel@redhat.com>
Message-ID: <alpine.LSU.2.11.2101051326410.6519@eggly.anvils>
References: <1604566549-62481-1-git-send-email-alex.shi@linux.alibaba.com> <aebcdd933df3abad378aeafc1a07dfe9bbb25548.camel@redhat.com> <CALvZod448Ebw7YE-HVCNXNSbtvTcTvQx+_EqcyxTVd_SZ4ATBA@mail.gmail.com>
 <49be27f2652d4658f80c95bea171142c35513761.camel@redhat.com>
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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@redhat.com> 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