From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vijay Balakrishna <vijayb@linux.microsoft.com>,
Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>, Song Liu <songliubraving@fb.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Allen Pais <apais@microsoft.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>
Subject: Re: [[PATCH]] mm: khugepaged: recalculate min_free_kbytes after memory hotplug as expected by khugepaged
Date: Thu, 10 Sep 2020 18:28:29 -0400 [thread overview]
Message-ID: <CA+CK2bACLNVqKP9Mgr37HQKOY=7+-PwuLCtqN6+saW7uuiMCfw@mail.gmail.com> (raw)
In-Reply-To: <20200910220145.5j7iogqulmvg5vr6@black.fi.intel.com>
Hi Kirill,
On Thu, Sep 10, 2020 at 6:01 PM Kirill A. Shutemov
<kirill.shutemov@linux.intel.com> wrote:
>
> 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.
Hi Kirill,
Thank you for looking into this. How is this different from when
khugepaged modifies it?
echo always >/sys/kernel/mm/transparent_hugepage/enabled
Which results in:
start_stop_khugepaged
set_recommended_min_free_kbytes
Which will also adjust min_free_kbytes according to hugepaged requirement?
This bug that Vijay described is another hot-plug related issue that
we have found on our system where we perform memory hot add and hot
remove on every reboot.
Thank you,
Pasha
next prev parent reply other threads:[~2020-09-10 22:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-10 20:47 [[PATCH]] mm: khugepaged: recalculate min_free_kbytes after memory hotplug as expected by khugepaged Vijay Balakrishna
2020-09-10 22:01 ` Kirill A. Shutemov
2020-09-10 22:28 ` Pavel Tatashin [this message]
2020-09-10 22:56 ` Vijay Balakrishna
2020-09-15 5:04 ` Vijay Balakrishna
2020-09-14 14:33 ` Michal Hocko
2020-09-14 16:57 ` Vijay Balakrishna
2020-09-15 8:18 ` Michal Hocko
2020-09-15 15:48 ` Vijay Balakrishna
2020-09-16 6:53 ` Michal Hocko
2020-09-16 18:28 ` Vijay Balakrishna
2020-09-17 12:12 ` Michal Hocko
2020-09-17 18:03 ` Vijay Balakrishna
2020-09-18 5:45 ` Michal Hocko
2020-09-18 15:32 ` Vijay Balakrishna
2020-09-21 7:00 ` Michal Hocko
2020-09-15 18:22 ` Pavel Tatashin
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