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From:   Wanpeng Li <kernellwp@gmail.com>
Date:   Mon, 6 Nov 2017 18:06:47 +0800
Message-ID: <CANRm+CwUOGTHQc+VYfQbUZCFGscyyoqqxBqq-NFLdPP7dTUm6A@mail.gmail.com>
Subject: Re: [PATCH] KVM: X86: Fix softlockup when get the current kvmclock timestamp
To:     Paolo Bonzini <pbonzini@redhat.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        kvm <kvm@vger.kernel.org>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Wanpeng Li <wanpeng.li@hotmail.com>
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2017-11-06 17:29 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>:
> On 06/11/2017 01:55, Wanpeng Li wrote:
>> This can be reproduced when running kvm-unit-tests/hyperv_stimer.flat and
>> cpu-hotplug stress simultaneously. kvm_get_time_scale() takes too long which
>> results in softlockup.
>
> Apart from the pr_debug, kvm_get_time_scale should take less than a
> microsecond.  The patch is fine, but can you confirm that pr_debug is
> the culprit?

I can still encounter softlockup after removing the pr_debug.

Regards,
Wanpeng Li

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