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Date:   Fri, 25 Oct 2019 16:27:37 +0100
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Yunfeng Ye <yeyunfeng@huawei.com>
Cc:     will@kernel.org, kstewart@linuxfoundation.org,
        sudeep.holla@arm.com, gregkh@linuxfoundation.org,
        lorenzo.pieralisi@arm.com, tglx@linutronix.de,
        David.Laight@ACULAB.COM, mark.rutland@arm.com,
        linux-arm-kernel@lists.infradead.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        hushiyuan@huawei.com, wuyun.wu@huawei.com, linfeilong@huawei.com
Subject: Re: [PATCH v6] arm64: psci: Reduce the waiting time for
 cpu_psci_cpu_kill()
Message-ID: <20191025152737.GN3328@arrakis.emea.arm.com>
References: <0842431c-fa15-2ba1-ae6d-c1fea157941f@huawei.com>
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On Mon, Oct 21, 2019 at 07:31:21PM +0800, Yunfeng Ye wrote:
> In cases like suspend-to-disk and suspend-to-ram, a large number of CPU
> cores need to be shut down. At present, the CPU hotplug operation is
> serialised, and the CPU cores can only be shut down one by one. In this
> process, if PSCI affinity_info() does not return LEVEL_OFF quickly,
> cpu_psci_cpu_kill() needs to wait for 10ms. If hundreds of CPU cores
> need to be shut down, it will take a long time.
> 
> Normally, there is no need to wait 10ms in cpu_psci_cpu_kill(). So
> change the wait interval from 10 ms to max 1 ms and use usleep_range()
> instead of msleep() for more accurate timer.
> 
> In addition, reducing the time interval will increase the messages
> output, so remove the "Retry ..." message, instead, track time and
> output to the the sucessful message.
> 
> Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>

Queued for 5.5. Thanks.

-- 
Catalin