Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <cover.1583332764.git.vpillai@digitalocean.com>
 <2f83d888890cec14be3a7aead0859dceebb4012f.1583332765.git.vpillai@digitalocean.com>
 <20200414135624.GU20730@hirez.programming.kicks-ass.net> <20200415033408.GA168322@ziqianlu-desktop.localdomain>
 <20200415040741.GA169001@ziqianlu-desktop.localdomain> <CANaguZAXsjD=X-bB7dvQZ3FSqLioiZU=YREHH_7JqiFsZCTxHA@mail.gmail.com>
 <20200417094045.GA197704@ziqianlu-desktop.localdomain> <20200420080759.GA224731@ziqianlu-desktop.localdomain>
In-Reply-To: <20200420080759.GA224731@ziqianlu-desktop.localdomain>
From:   Vineeth Remanan Pillai <vpillai@digitalocean.com>
Date:   Mon, 20 Apr 2020 18:26:34 -0400
Message-ID: <CANaguZDP3nyBdjLeeCZGoUoYk6Lf0HUv19N2Qxo4CpZfrjPZHA@mail.gmail.com>
Subject: Re: [PATCH updated] sched/fair: core wide cfs task priority comparison
To:     Aaron Lu <aaron.lwe@gmail.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Nishanth Aravamudan <naravamudan@digitalocean.com>,
        Julien Desfossez <jdesfossez@digitalocean.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Paul Turner <pjt@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Aaron Lu <aaron.lu@linux.alibaba.com>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        =?UTF-8?B?RnLDqWTDqXJpYyBXZWlzYmVja2Vy?= <fweisbec@gmail.com>,
        Kees Cook <keescook@chromium.org>,
        Greg Kerr <kerrnel@google.com>, Phil Auld <pauld@redhat.com>,
        Aubrey Li <aubrey.intel@gmail.com>,
        "Li, Aubrey" <aubrey.li@linux.intel.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Joel Fernandes <joelaf@google.com>,
        Joel Fernandes <joel@joelfernandes.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Apr 20, 2020 at 4:08 AM Aaron Lu <aaron.lwe@gmail.com> wrote:
>
> On Fri, Apr 17, 2020 at 05:40:45PM +0800, Aaron Lu wrote:

> The adjust is only needed when core scheduling is enabled while I
> mistakenly called it on both enable and disable. And I come to think
> normalize is a better name than adjust.
>
I guess we would also need to update the min_vruntime of the sibling
to match the rq->core->min_vruntime on coresched disable. Otherwise
a new enqueue on root cfs of the sibling would inherit the very old
min_vruntime before coresched enable and thus would starve all the
already queued tasks until the newly enqueued se's vruntime catches up.

Other than that, I think the patch looks good. We haven't tested it
yet. Will do a round of testing and let you know soon.

Thanks,
Vineeth