From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
Received: from mail-yw0-f197.google.com (mail-yw0-f197.google.com [209.85.161.197])
	by kanga.kvack.org (Postfix) with ESMTP id E6A986B0038
	for <linux-mm@kvack.org>; Thu,  1 Sep 2016 06:06:40 -0400 (EDT)
Received: by mail-yw0-f197.google.com with SMTP id f123so160668560ywd.2
        for <linux-mm@kvack.org>; Thu, 01 Sep 2016 03:06:40 -0700 (PDT)
Received: from merlin.infradead.org (merlin.infradead.org. [2001:4978:20e::2])
        by mx.google.com with ESMTPS id n2si34274750itn.36.2016.09.01.03.06.39
        for <linux-mm@kvack.org>
        (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
        Thu, 01 Sep 2016 03:06:39 -0700 (PDT)
Date: Thu, 1 Sep 2016 12:06:31 +0200
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v15 04/13] task_isolation: add initial support
Message-ID: <20160901100631.GQ10153@twins.programming.kicks-ass.net>
References: <1471382376-5443-1-git-send-email-cmetcalf@mellanox.com>
 <1471382376-5443-5-git-send-email-cmetcalf@mellanox.com>
 <20160829163352.GV10153@twins.programming.kicks-ass.net>
 <fe4b8667-57d5-7767-657a-d89c8b62f8e3@mellanox.com>
 <20160830075854.GZ10153@twins.programming.kicks-ass.net>
 <a321c8a7-fa9c-21f7-61f8-54a8f80763fe@mellanox.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <a321c8a7-fa9c-21f7-61f8-54a8f80763fe@mellanox.com>
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Gilad Ben Yossef <giladb@mellanox.com>, Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@kernel.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>, Christoph Lameter <cl@linux.com>, Viresh Kumar <viresh.kumar@linaro.org>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, Andy Lutomirski <luto@amacapital.net>, Michal Hocko <mhocko@suse.com>, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org

On Tue, Aug 30, 2016 at 11:32:16AM -0400, Chris Metcalf wrote:
> On 8/30/2016 3:58 AM, Peter Zijlstra wrote:

> >What !? I really don't get this, what are you waiting for? Why is
> >rescheduling making things better.
> 
> We need to wait for the last dyntick to fire before we can return to
> userspace.  There are plenty of options as to what we can do in the
> meanwhile.

Why not keep your _TIF_TASK_ISOLATION_FOO flag set and re-enter the
loop?

I really don't see how setting TIF_NEED_RESCHED is helping anything.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>