From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1758315AbdKGRKH (ORCPT <rfc822;w@1wt.eu>);
        Tue, 7 Nov 2017 12:10:07 -0500
Received: from resqmta-ch2-01v.sys.comcast.net ([69.252.207.33]:56066 "EHLO
        resqmta-ch2-01v.sys.comcast.net" rhost-flags-OK-OK-OK-OK)
        by vger.kernel.org with ESMTP id S1751079AbdKGRKF (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 7 Nov 2017 12:10:05 -0500
Date: Tue, 7 Nov 2017 11:10:02 -0600 (CST)
From: Christopher Lameter <cl@linux.com>
X-X-Sender: cl@nuc-kabylake
To: Chris Metcalf <cmetcalf@mellanox.com>
cc: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Rik van Riel <riel@redhat.com>, Tejun Heo <tj@kernel.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Francis Giraldeau <francis.giraldeau@gmail.com>,
        linux-mm@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-api@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v16 00/13] support "task_isolation" mode
In-Reply-To: <bd5526d4-7b6e-3b3d-79d0-5d6567c0bdf8@mellanox.com>
Message-ID: <alpine.DEB.2.20.1711071109090.19523@nuc-kabylake>
References: <1509728692-10460-1-git-send-email-cmetcalf@mellanox.com> <alpine.DEB.2.20.1711060932520.9015@nuc-kabylake> <bd5526d4-7b6e-3b3d-79d0-5d6567c0bdf8@mellanox.com>
User-Agent: Alpine 2.20 (DEB 67 2015-01-07)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
X-CMAE-Envelope: MS4wfI4SsJIHvE6sxZHjC/J17AanGfcwfQvCQls+JtT/Nn0rECsbh/Ja8Nahbu8408qXTTKbNrrMYemBqv43aKsdEHRkW+HYQYtTKioq/JYgJ5hSxtxoYUH/
 6eU28o/xd+KRjN2JeXF+9WmNnXqCvXcWtwVxZa5+QUwr9kBQx0K+FQTOERifwLeXNWhIEHMzPjoDQvryKWMrWngv7JKDGU9NpBgGGykJ8t8V54hky6iEYWZ8
 7AwicT01VLuyzDnTjhB8BqXlZTKUd9dDXADI63SyGZoxwB15G1Ddt/LefDQnwMwBZ/CPna2bFV8WK6FdY8I1U/vUBOb9ofKFbPXRzlrUzGDdOGKNrY32IUe3
 kHx8Ukf9VOgD5NKHDvmmNiobqJHK7coCvAd32XcmhnWcuDZ+9l8sWylx5a5vgqryM+2zNWfqxaOD67NjQa0UK+/CdMg9GBswH90k0s6lXG8u619i+wAZqPb3
 lg4Fhr8F90XBDAGGR0QtU4t7/pKFPE0zwZtcXIWO1RXi7S/Q5GlUODkvzdF4E2tJQUr4RrTHl+97U5JVJ9cnblw8QdZX6xMei6Nybm8cNt/WGRB9dxf6fC3o
 kFMUk+dXmOgqo60ZMhwSB131NurK4GKyaGFjr0+lTvm+zyD9h/sSGTGp0Vd/OaznlEkihEDR65k+76gxa0m0HMDoqpl2gwsI6bj6qrdt6ji+R3gI0lhlydA0
 W961gdnyqJPL03Yfgw8z4CVWJrZUSz865dWGyo6i9FXPlq+SUR2XmWN2nCSJIs/hjxxU2lCapE4MTVNWLE9t7fe/R8/pKl6K
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, 6 Nov 2017, Chris Metcalf wrote:

> On 11/6/2017 10:38 AM, Christopher Lameter wrote:
> > > What about that d*mn 1 Hz clock?
> > >
> > > It's still there, so this code still requires some further work before
> > > it can actually get a process into long-term task isolation (without
> > > the obvious one-line kernel hack).  Frederic suggested a while ago
> > > forcing updates on cpustats was required as the last gating factor; do
> > > we think that is still true?  Christoph was working on this at one
> > > point - any progress from your point of view?
> > Well if you still have the 1 HZ clock then you can simply defer the numa
> > remote page cleanup of the page allocator to that the time you execute
> > that tick.
>
> We have to get rid of the 1 Hz tick, so we don't want to tie anything
> else to it...

Yes we want to get rid of the 1 HZ tick but the work on that could also
include dealing with the remove page cleanup issue that we have deferred.

Presumably we have another context there were we may be able to call into
the cleanup code with interrupts enabled.