linux-kernel - RE: [PATCH V2] arm64: psci: Reduce waiting time of cpu_psci_cpu

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Message-ID: <c97c87b52f474463bc30ff8033a57e0c@AcuMS.aculab.com>
Date:   Thu, 17 Oct 2019 14:00:42 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Yunfeng Ye' <yeyunfeng@...wei.com>,
        Sudeep Holla <sudeep.holla@....com>
CC:     "catalin.marinas@....com" <catalin.marinas@....com>,
        "will@...nel.org" <will@...nel.org>,
        "kstewart@...uxfoundation.org" <kstewart@...uxfoundation.org>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "ard.biesheuvel@...aro.org" <ard.biesheuvel@...aro.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "wuyun.wu@...wei.com" <wuyun.wu@...wei.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "hushiyuan@...wei.com" <hushiyuan@...wei.com>,
        "linfeilong@...wei.com" <linfeilong@...wei.com>
Subject: RE: [PATCH V2] arm64: psci: Reduce waiting time of
 cpu_psci_cpu_kill()

From: Yunfeng Ye
> Sent: 17 October 2019 14:26
...
> >> -	for (i = 0; i < 10; i++) {
> >> +	i = 0;
> >> +	timeout = jiffies + msecs_to_jiffies(100);
> >> +	do {
> >>  		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
> >>  		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
> >>  			pr_info("CPU%d killed.\n", cpu);
> >>  			return 0;
> >>  		}
> >>
> >> -		msleep(10);
> >> -		pr_info("Retrying again to check for CPU kill\n");
> >
> > You dropped this message, any particular reason ?
> >
> When reduce the time interval to 1ms, the print message maybe increase 10 times.
> on the other hand, cpu_psci_cpu_kill() will print message on success or failure, which
> this retry log is not very necessary. of cource, I think use pr_info_once() instead of
> pr_info() is better.

Maybe you should print in on (say) the 10th time around the loop.

	David

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