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From:   Gavin Guo <gavin.guo@canonical.com>
Date:   Thu, 4 Jun 2020 06:09:31 +0800
Message-ID: <CA+eFSM0V6nCHvwy3d5kehA4HpcP7x1zR_C95PnMFGYp9JV36ow@mail.gmail.com>
Subject: Re: [PATCH] mm: thp: Add new kernel parameters transparent_hugepage_defrag/khugepaged_defrag
To:     David Rientjes <rientjes@google.com>
Cc:     Vlastimil Babka <vbabka@suse.cz>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        Kees Cook <keescook@chromium.org>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Christian Brauner <christian.brauner@ubuntu.com>
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On Thu, Jun 4, 2020 at 3:27 AM David Rientjes <rientjes@google.com> wrote:
>
> On Wed, 3 Jun 2020, Vlastimil Babka wrote:
>
> > > There is no way to set up the defrag options in boot time. And it's
> > > useful to set it up by default instead of making it work by a
> > > systemd/upstart service or put the command to set up defrag inside
> > > /etc/rc.local.
> > >
> > > Signed-off-by: Gavin Guo <gavin.guo@canonical.com>
> >
> > Well, maybe isntead of adding these handlers, we could extend the new boot
> > parameter sysctl support (handling procfs /proc/sys/) to sysfs (/sys) as well,
> > as Eric already suggested? [1]
> >
> > [1] https://lore.kernel.org/linux-api/87bloj2skm.fsf@x220.int.ebiederm.org/
> >
>
> Fully agreed, I think the solution needs to be more generic since thp
> defrag isn't special here.  With the generic support to tune sysctls and
> sysfs tunables from the command line it seems like this patch would be
> redundant.

Agreed, I'll try to investigate more on how to do that in a generic way.