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Date:   Fri, 11 Sep 2020 01:01:45 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To:     Vijay Balakrishna <vijayb@linux.microsoft.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Song Liu <songliubraving@fb.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Pavel Tatashin <pasha.tatashin@soleen.com>,
        Allen Pais <apais@microsoft.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [[PATCH]] mm: khugepaged: recalculate min_free_kbytes after
 memory hotplug as expected by khugepaged
Message-ID: <20200910220145.5j7iogqulmvg5vr6@black.fi.intel.com>
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On Thu, Sep 10, 2020 at 01:47:39PM -0700, Vijay Balakrishna wrote:
> When memory is hotplug added or removed the min_free_kbytes must be
> recalculated based on what is expected by khugepaged.  Currently
> after hotplug, min_free_kbytes will be set to a lower default and higher
> default set when THP enabled is lost. This leaves the system with small
> min_free_kbytes which isn't suitable for systems especially with network
> intensive loads.  Typical failure symptoms include HW WATCHDOG reset,
> soft lockup hang notices, NETDEVICE WATCHDOG timeouts, and OOM process
> kills.
> 
> Fixes: f000565adb77 ("thp: set recommended min free kbytes")
> 
> Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
> Cc: stable@vger.kernel.org

NAK. It would override min_free_kbytes set by user.

-- 
 Kirill A. Shutemov