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Message-ID: <bb7bac8adfce085cdcc080f8f26cbaae2fe916e0.camel@gmx.de>
Subject: Re: mlockall(MCL_CURRENT) blocking infinitely
From:   Robert Stupp <snazy@gmx.de>
Reply-To: snazy@snazy.de
To:     Jan Kara <jack@suse.cz>
Cc:     Josef Bacik <josef@toxicpanda.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Michal Hocko <mhocko@kernel.org>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Randy Dunlap <rdunlap@infradead.org>,
        linux-kernel@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Potyra, Stefan" <Stefan.Potyra@elektrobit.com>
Date:   Thu, 07 Nov 2019 09:08:04 +0100
In-Reply-To: <20191106172520.GF12685@quack2.suse.cz>
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On Wed, 2019-11-06 at 18:25 +0100, Jan Kara wrote:
> On Wed 06-11-19 18:03:10, Robert Stupp wrote:
> > Oh, and I just realized, that I have two custom settings in my
> > /etc/rc.local - guess, I configured that when I installed that
> > machine
> > years ago. Sorry, that I haven't mentioned that earlier.
> >
> > echo 0 > /sys/block/nvme0n1/queue/read_ahead_kb
> > echo never >
> > /sys/kernel/mm/transparent_hugepage/defrag
> >
> > That setting is probably not quite standard, but I assume there are
> > some database server setups out there, that set RA=3D0 as well.
>
> Ok, yes, that explains ra_pages =3D=3D 0. Thanks for the details.

Ah! And with these settings, a fresh & clean installation of Ubuntu
eoan (5.3.x kernel), hangs during reboot.
And if the VM's booted with these settings in /etc/rc.local, the
mlockall(MCL_CURRENT) is reproducible as well.