linux-kernel - Re: [PATCH 1/2] mm: thp: relax __GFP_THISNODE for MADV

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Message-ID: <20181029105601.GB3823@redhat.com>
Date:   Mon, 29 Oct 2018 06:56:01 -0400
From:   Andrea Arcangeli <aarcange@...hat.com>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     Balbir Singh <bsingharora@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mel Gorman <mgorman@...e.de>, Vlastimil Babka <vbabka@...e.cz>,
        David Rientjes <rientjes@...gle.com>,
        Andrea Argangeli <andrea@...nel.org>,
        Zi Yan <zi.yan@...rutgers.edu>,
        Stefan Priebe - Profihost AG <s.priebe@...fihost.ag>,
        "Kirill A. Shutemov" <kirill@...temov.name>, linux-mm@...ck.org,
        LKML <linux-kernel@...r.kernel.org>,
        Stable tree <stable@...r.kernel.org>
Subject: Re: [PATCH 1/2] mm: thp:  relax __GFP_THISNODE for MADV_HUGEPAGE
 mappings

Hello,

On Mon, Oct 29, 2018 at 11:08:34AM +0100, Michal Hocko wrote:
> This seems like a separate issue which should better be debugged. Please
> open a new thread describing the problem and the state of the node.

Yes, in my view it should be evaluated separately too, because it's
overall less concerning: __GFP_THISNODE there can only be set by the
root user there. So it has a chance to be legitimate behavior
there. Let's focus on solving the __GFP_THISNODE that any user in the
system can set (not only root) and cause severe and unexpected swap
storms or slowdowns to all other processes run by other users.

ls -l /sys/kernel/mm/hugepages/*/nr_hugepages

(and boot command line)

Thanks,
Andrea