From: Jan Kiszka <jan.kiszka@siemens.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
"linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH-next] kvm: don't try to take mmu_lock while holding the main raw kvm_lock
Date: Thu, 27 Jun 2013 14:16:07 +0200 [thread overview]
Message-ID: <51CC2D07.8080105@siemens.com> (raw)
In-Reply-To: <51CC2435.7080204@redhat.com>
On 2013-06-27 13:38, Paolo Bonzini wrote:
> Il 27/06/2013 13:09, Gleb Natapov ha scritto:
>> On Tue, Jun 25, 2013 at 06:34:03PM -0400, Paul Gortmaker wrote:
>>> In commit e935b8372cf8 ("KVM: Convert kvm_lock to raw_spinlock"),
>> I am copying Jan, the author of the patch. Commit message says:
>> "Code under this lock requires non-preemptibility", but which code
>> exactly is this? Is this still true?
>
> hardware_enable_nolock/hardware_disable_nolock does.
IIRC, also the loop in kvmclock_cpufreq_notifier needs it because it
reads the processor ID of the caller. That implies the caller cannot be
preempted, but theses days a migration lock should be fine as well.
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2013-06-27 12:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-25 22:34 [PATCH-next] kvm: don't try to take mmu_lock while holding the main raw kvm_lock Paul Gortmaker
2013-06-26 8:10 ` Paolo Bonzini
2013-06-26 18:11 ` [PATCH-next v2] " Paul Gortmaker
2013-06-26 21:59 ` Paolo Bonzini
2013-06-27 2:56 ` Paul Gortmaker
2013-06-27 10:22 ` Paolo Bonzini
2013-06-27 11:09 ` [PATCH-next] " Gleb Natapov
2013-06-27 11:38 ` Paolo Bonzini
2013-06-27 11:43 ` Gleb Natapov
2013-06-27 11:54 ` Paolo Bonzini
2013-06-27 12:16 ` Jan Kiszka [this message]
2013-06-27 12:32 ` Gleb Natapov
2013-06-27 13:00 ` Paolo Bonzini
2013-06-27 13:01 ` Paolo Bonzini
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