From: Paolo Bonzini <pbonzini@redhat.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>,
Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>,
kvm@vger.kernel.org, xiaoguangrong@linux.vnet.ibm.com
Subject: Re: [PATCH] KVM: MMU: Inform users of mmio generation wraparound
Date: Thu, 20 Jun 2013 15:14:42 +0200 [thread overview]
Message-ID: <51C30042.5030505@redhat.com> (raw)
In-Reply-To: <20130620125438.GM5832@redhat.com>
Il 20/06/2013 14:54, Gleb Natapov ha scritto:
>> If they see mysterious peformance problems induced by this wraparound, the only
>> way to know the cause later is by this kind of information in the syslog.
>> So even the first wraparound may better be printed out IMO.
> Think about starting hundreds VMs on a freshly booted host. You will see
> hundreds of those pretty quickly.
With the change I made to Xiao's patch (changing -13 to -150) you won't
see it immediately after startup, but the first wraparound may still
come very soon with a loop that reads the ROM. (The second takes 5
minutes).
>> I want to let administrators know the cause if possible, any better way?
>>
> Not that I can think of. Paolo what about print_once() and ignore first
> wraparound?
printk_ratelimited is enough, even without ignoring the first
wraparound. It will handle the case of multiple VMs too.
Paolo
next prev parent reply other threads:[~2013-06-20 13:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-20 8:59 [PATCH] KVM: MMU: Inform users of mmio generation wraparound Takuya Yoshikawa
2013-06-20 10:59 ` Paolo Bonzini
2013-06-20 11:45 ` Gleb Natapov
2013-06-20 12:28 ` Takuya Yoshikawa
2013-06-20 12:54 ` Gleb Natapov
2013-06-20 13:14 ` Paolo Bonzini [this message]
2013-06-20 14:26 ` Takuya Yoshikawa
2013-06-20 13:17 ` Takuya Yoshikawa
2013-06-20 12:35 ` Paolo Bonzini
2013-06-20 12:46 ` Gleb Natapov
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