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;
Date:   Fri, 30 Oct 2020 09:41:12 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Joel Fernandes <joel@joelfernandes.org>
Cc:     Nishanth Aravamudan <naravamudan@digitalocean.com>,
        Julien Desfossez <jdesfossez@digitalocean.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Vineeth Pillai <viremana@linux.microsoft.com>,
        Aaron Lu <aaron.lwe@gmail.com>,
        Aubrey Li <aubrey.intel@gmail.com>,
        Thomas Glexiner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Greg Kerr <kerrnel@google.com>, Phil Auld <pauld@redhat.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>, vineeth@bitbyteword.org,
        Chen Yu <yu.c.chen@intel.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Agata Gruza <agata.gruza@intel.com>,
        Antonio Gomez Iglesias <antonio.gomez.iglesias@intel.com>,
        graf@amazon.com, konrad.wilk@oracle.com,
        Dario Faggioli <dfaggioli@suse.com>,
        Paul Turner <pjt@google.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Patrick Bellasi <derkling@google.com>,
        =?utf-8?B?YmVuYmppYW5nKOiSi+W9qik=?= <benbjiang@tencent.com>,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        James.Bottomley@hansenpartnership.com, OWeisse@umich.edu,
        Dhaval Giani <dhaval.giani@oracle.com>,
        Junaid Shahid <junaids@google.com>,
        Jesse Barnes <jsbarnes@google.com>,
        "Hyser,Chris" <chris.hyser@oracle.com>,
        Aubrey Li <aubrey.li@linux.intel.com>,
        Tim Chen <tim.c.chen@intel.com>
Subject: Re: [PATCH v8 -tip 08/26] sched/fair: Snapshot the min_vruntime of
 CPUs on force idle
Message-ID: <20201030084112.GX2628@hirez.programming.kicks-ass.net>
References: <20201020014336.2076526-1-joel@joelfernandes.org>
 <20201020014336.2076526-9-joel@joelfernandes.org>
 <20201026124724.GT2611@hirez.programming.kicks-ass.net>
 <20201029182429.GA1844482@google.com>
 <20201029185933.GG2611@hirez.programming.kicks-ass.net>
 <CAEXW_YRtrhhL4Gc8W8_-2CR1CCw6_hhtnwSdQ-dMLYCJ+fP+RA@mail.gmail.com>
 <CAEXW_YTnJWANAZNeR9b=5xUeHu1CAPq9vgYaH8WSHgApJZ21Rw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAEXW_YTnJWANAZNeR9b=5xUeHu1CAPq9vgYaH8WSHgApJZ21Rw@mail.gmail.com>
Precedence: bulk

On Thu, Oct 29, 2020 at 10:42:29PM -0400, Joel Fernandes wrote:

> Forgot to ask, do you also need to do the task_vruntime_update() for
> the unconstrained pick?

Humm.. interesting case.

Yes, however... since in that case the picks aren't synchronized it's a
wee bit dodgy. I'll throw it on the pile together with SMT4.


Also, I'm still hoping you can make this form work:

  https://lkml.kernel.org/r/20201026093131.GF2628@hirez.programming.kicks-ass.net

(note that the put_prev_task() needs an additional rq argument)

That's both simpler code and faster.