Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.36 as permitted sender) client-ip=23.128.96.36;
Message-ID: <db78e251-acd1-496a-bfcd-202ef1d43f31@samsung.com>
Date:   Fri, 6 Oct 2023 22:15:14 +0200
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] sched/fair: fix pick_eevdf to always find the correct
 se
Content-Language: en-US
To:     Peter Zijlstra <peterz@infradead.org>,
        Mike Galbraith <efault@gmx.de>
Cc:     Biju Das <biju.das.jz@bp.renesas.com>,
        "bsegall@google.com" <bsegall@google.com>,
        "bristot@redhat.com" <bristot@redhat.com>,
        "chris.hyser@oracle.com" <chris.hyser@oracle.com>,
        "corbet@lwn.net" <corbet@lwn.net>,
        "dietmar.eggemann@arm.com" <dietmar.eggemann@arm.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "joel@joelfernandes.org" <joel@joelfernandes.org>,
        "joshdon@google.com" <joshdon@google.com>,
        "juri.lelli@redhat.com" <juri.lelli@redhat.com>,
        "kprateek.nayak@amd.com" <kprateek.nayak@amd.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "mingo@kernel.org" <mingo@kernel.org>,
        "patrick.bellasi@matbug.net" <patrick.bellasi@matbug.net>,
        Pavel Machek <pavel@ucw.cz>, "pjt@google.com" <pjt@google.com>,
        "qperret@google.com" <qperret@google.com>,
        "qyousef@layalina.io" <qyousef@layalina.io>,
        "rostedt@goodmis.org" <rostedt@goodmis.org>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "tim.c.chen@linux.intel.com" <tim.c.chen@linux.intel.com>,
        "timj@gnu.org" <timj@gnu.org>,
        "vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
        "youssefesmat@chromium.org" <youssefesmat@chromium.org>,
        "yu.c.chen@intel.com" <yu.c.chen@intel.com>,
        "mgorman@suse.de" <mgorman@suse.de>,
        "linux-renesas-soc@vger.kernel.org" 
        <linux-renesas-soc@vger.kernel.org>
From:   Marek Szyprowski <m.szyprowski@samsung.com>
In-Reply-To: <20231006192445.GE743@noisy.programming.kicks-ass.net>
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 201P
References: <OS0PR01MB59220AF3959BDC5FEFC0340F86CAA@OS0PR01MB5922.jpnprd01.prod.outlook.com>
        <20231005150258.GA36277@noisy.programming.kicks-ass.net>
        <CGME20231005150845eucas1p1ed3aae6b90c411b5c26a5dfadf7e0733@eucas1p1.samsung.com>
        <OS0PR01MB592295E06AD01CAEFBA83BF386CAA@OS0PR01MB5922.jpnprd01.prod.outlook.com>
        <553e2ee4-ab3a-4635-a74f-0ba4cc03f3f9@samsung.com>
        <867f5121d7d010cacf938c293f862b0cea560ec2.camel@gmx.de>
        <20231006140042.GG36277@noisy.programming.kicks-ass.net>
        <e2645a659b6fc1c592e2f2dc45273c361a2d2f47.camel@gmx.de>
        <20231006155501.GH36277@noisy.programming.kicks-ass.net>
        <20231006192445.GE743@noisy.programming.kicks-ass.net>
Precedence: bulk

On 06.10.2023 21:24, Peter Zijlstra wrote:
> On Fri, Oct 06, 2023 at 05:55:01PM +0200, Peter Zijlstra wrote:
>> And yeah, min_deadline is hosed somehow.
>>
>> migration/28-185     [028] d..2.    70.264274: validate_cfs_rq: --- /
>> migration/28-185     [028] d..2.    70.264277: __print_se: ffff88845cf48080 w: 1024 ve: -58857638 lag: 870381 vd: -55861854 vmd: -66302085 E (11372/tr)
>> migration/28-185     [028] d..2.    70.264280: __print_se:   ffff88810d165800 w: 25 ve: -80323686 lag: 22336429 vd: -41496434 vmd: -66302085 E (-1//autogroup-31)
>> migration/28-185     [028] d..2.    70.264282: __print_se:   ffff888108379000 w: 25 ve: 0 lag: -57987257 vd: 114632828 vmd: 114632828 N (-1//autogroup-33)
>> migration/28-185     [028] d..2.    70.264283: validate_cfs_rq: min_deadline: -55861854 avg_vruntime: -62278313462 / 1074 = -57987256
>>
>> I need to go make dinner (kids hungry), but I'll see if I can figure out
>> how this happens...
> *sigh*, does the below help?

It looks that this fixed the issue. At least I was no longer able to 
reproduce it.

Feel free to add:

Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

> ---
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 04fbcbda97d5..6a670f119efa 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3632,6 +3747,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
>   		 */
>   		deadline = div_s64(deadline * old_weight, weight);
>   		se->deadline = se->vruntime + deadline;
> +		min_deadline_cb_propagate(&se->run_node, NULL);
>   	}
>   
>   #ifdef CONFIG_SMP
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland