From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
kvm-devel <kvm@vger.kernel.org>, stable <stable@vger.kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: x86: kvm: Revert "remove sched notifier for cross-cpu migrations"
Date: Wed, 25 Mar 2015 13:52:15 +0100 [thread overview]
Message-ID: <20150325125212.GC21710@potion.brq.redhat.com> (raw)
In-Reply-To: <20150325110814.GE21522@potion.brq.redhat.com>
2015-03-25 12:08+0100, Radim Krčmář:
> Reverting the patch protects us from any migration, but I don't think we
> need to care about changing VCPUs as long as we read a consistent data
> from kvmclock. (VCPU can change outside of this loop too, so it doesn't
> matter if we return a value not fit for this VCPU.)
>
> I think we could drop the second __getcpu if our kvmclock was being
> handled better; maybe with a patch like the one below:
The second __getcpu is not neccessary, but I forgot about rdtsc.
We need to either use rtdscp, know the host has synchronized tsc, or
monitor VCPU migrations. Only the last one works everywhere.
next prev parent reply other threads:[~2015-03-25 12:52 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-23 23:21 x86: kvm: Revert "remove sched notifier for cross-cpu migrations" Marcelo Tosatti
2015-03-23 23:30 ` Andy Lutomirski
2015-03-24 15:34 ` Radim Krčmář
2015-03-24 22:33 ` Andy Lutomirski
2015-03-25 11:08 ` Radim Krčmář
2015-03-25 12:52 ` Radim Krčmář [this message]
2015-03-25 21:28 ` Marcelo Tosatti
2015-03-25 22:33 ` Andy Lutomirski
2015-03-25 22:41 ` Marcelo Tosatti
2015-03-25 22:48 ` Andy Lutomirski
2015-03-25 23:13 ` Marcelo Tosatti
2015-03-25 23:22 ` Andy Lutomirski
2015-03-26 11:29 ` Marcelo Tosatti
2015-03-26 18:51 ` Andy Lutomirski
2015-03-26 20:31 ` Radim Krcmar
2015-03-26 20:58 ` Andy Lutomirski
2015-03-26 22:22 ` Andy Lutomirski
2015-03-26 22:56 ` Marcelo Tosatti
2015-03-26 23:09 ` Andy Lutomirski
2015-03-26 23:22 ` Marcelo Tosatti
2015-03-26 23:28 ` Andy Lutomirski
2015-03-26 23:38 ` Marcelo Tosatti
2015-03-26 18:47 ` Andy Lutomirski
2015-03-26 20:10 ` Radim Krčmář
2015-03-26 20:52 ` Paolo Bonzini
2015-03-24 22:59 ` Marcelo Tosatti
2015-03-25 11:09 ` Radim Krčmář
2015-03-25 13:06 ` Radim Krčmář
2015-03-26 20:59 ` Radim Krčmář
2015-03-26 22:22 ` Marcelo Tosatti
2015-03-26 22:24 ` Andy Lutomirski
2015-03-26 22:40 ` Marcelo Tosatti
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