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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Glauber Costa <glommer@parallels.com>,
	kvm@vger.kernel.org, johnstul@us.ibm.com, zamsden@gmail.com,
	gleb@redhat.com, avi@redhat.com, pbonzini@redhat.com
Subject: Re: [patch 08/18] x86: pvclock: generic pvclock vsyscall initialization
Date: Mon, 29 Oct 2012 10:46:35 -0700	[thread overview]
Message-ID: <508EC0FB.3050401@goop.org> (raw)
In-Reply-To: <20121029145419.GB13104@amt.cnet>

On 10/29/2012 07:54 AM, Marcelo Tosatti wrote:
> On Mon, Oct 29, 2012 at 06:18:20PM +0400, Glauber Costa wrote:
>> On 10/24/2012 05:13 PM, Marcelo Tosatti wrote:
>>> Index: vsyscall/arch/x86/Kconfig
>>> ===================================================================
>>> --- vsyscall.orig/arch/x86/Kconfig
>>> +++ vsyscall/arch/x86/Kconfig
>>> @@ -632,6 +632,13 @@ config PARAVIRT_SPINLOCKS
>>>  
>>>  config PARAVIRT_CLOCK
>>>  	bool
>>> +config PARAVIRT_CLOCK_VSYSCALL
>>> +	bool "Paravirt clock vsyscall support"
>>> +	depends on PARAVIRT_CLOCK && GENERIC_TIME_VSYSCALL
>>> +	---help---
>>> +	  Enable performance critical clock related system calls to
>>> +	  be executed in userspace, provided that the hypervisor
>>> +	  supports it.
>>>  
>>>  endif
>> Besides debugging, what is the point in having this as an
>> extra-selectable? Is there any case in which a virtual machine has code
>> for this, but may decide to run without it ?
> Don't think so (its pretty small anyway, the code).
>
>> I believe all this code in vsyscall should be wrapped in PARAVIRT_CLOCK
>> only.
> Unless Jeremy has a reason, i'm fine with that.

I often set up blind config variables for dependency management; I'm
guessing the "GENERIC_TIME_VSYSCALL" dependency is important.  I think
the problem is that this exists, but that it's a user-selectable
option.  Removing the prompt should fix that.

    J


  reply	other threads:[~2012-10-29 17:56 UTC|newest]

Thread overview: 94+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-24 13:13 [patch 00/18] pvclock vsyscall support + KVM hypervisor support (v2) Marcelo Tosatti
2012-10-24 13:13 ` [patch 01/18] KVM: x86: retain pvclock guest stopped bit in guest memory Marcelo Tosatti
2012-10-24 13:13 ` [patch 02/18] x86: pvclock: make sure rdtsc doesnt speculate out of region Marcelo Tosatti
2012-10-24 13:13 ` [patch 03/18] x86: pvclock: remove pvclock_shadow_time Marcelo Tosatti
2012-10-30  9:23   ` Avi Kivity
2012-10-30  9:24     ` Avi Kivity
2012-10-24 13:13 ` [patch 04/18] x86: pvclock: create helper for pvclock data retrieval Marcelo Tosatti
2012-10-24 13:13 ` [patch 05/18] x86: pvclock: fix flags usage race Marcelo Tosatti
2012-10-24 13:13 ` [patch 06/18] x86: pvclock: introduce helper to read flags Marcelo Tosatti
2012-10-24 13:13 ` [patch 07/18] sched: add notifier for cross-cpu migrations Marcelo Tosatti
2012-10-24 13:13 ` [patch 08/18] x86: pvclock: generic pvclock vsyscall initialization Marcelo Tosatti
2012-10-29 14:18   ` Glauber Costa
2012-10-29 14:54     ` Marcelo Tosatti
2012-10-29 17:46       ` Jeremy Fitzhardinge [this message]
2012-10-29 14:39   ` Glauber Costa
2012-10-24 13:13 ` [patch 09/18] KVM: x86: introduce facility to support vsyscall pvclock, via MSR Marcelo Tosatti
2012-10-29 14:45   ` Glauber Costa
2012-10-29 17:44     ` Jeremy Fitzhardinge
2012-10-29 18:40       ` Marcelo Tosatti
2012-10-30  7:41         ` Glauber Costa
2012-10-30  9:39         ` Avi Kivity
2012-10-31  3:12           ` Marcelo Tosatti
2012-11-02 10:21             ` Glauber Costa
2012-10-30  7:38       ` Glauber Costa
2012-10-24 13:13 ` [patch 10/18] x86: kvm guest: pvclock vsyscall support Marcelo Tosatti
2012-10-24 13:13 ` [patch 11/18] x86: vsyscall: pass mode to gettime backend Marcelo Tosatti
2012-10-29 14:47   ` Glauber Costa
2012-10-29 18:41     ` Marcelo Tosatti
2012-10-30  7:42       ` Glauber Costa
2012-10-24 13:13 ` [patch 12/18] x86: vdso: pvclock gettime support Marcelo Tosatti
2012-10-29 14:59   ` Glauber Costa
2012-10-29 18:42     ` Marcelo Tosatti
2012-10-30  7:49       ` Glauber Costa
2012-10-31  3:16         ` Marcelo Tosatti
2012-10-24 13:13 ` [patch 13/18] KVM: x86: pass host_tsc to read_l1_tsc Marcelo Tosatti
2012-10-29 15:04   ` Glauber Costa
2012-10-29 18:45     ` Marcelo Tosatti
2012-10-30  7:55       ` Glauber Costa
2012-10-24 13:13 ` [patch 14/18] time: export time information for KVM pvclock Marcelo Tosatti
2012-11-10  1:02   ` John Stultz
2012-11-13 21:07     ` Marcelo Tosatti
2012-10-24 13:13 ` [patch 15/18] KVM: x86: implement PVCLOCK_TSC_STABLE_BIT pvclock flag Marcelo Tosatti
2012-10-30  8:34   ` Glauber Costa
2012-10-31  3:19     ` [patch 15/18] KVM: x86: implement PVCLOCK_TSC_STABLE_BIT pvclock flag\ Marcelo Tosatti
2012-10-24 13:13 ` [patch 16/18] KVM: x86: notifier for clocksource changes Marcelo Tosatti
2012-10-24 13:13 ` [patch 17/18] KVM: x86: add kvm_arch_vcpu_postcreate callback, move TSC initialization Marcelo Tosatti
2012-10-24 13:13 ` [patch 18/18] KVM: x86: require matched TSC offsets for master clock Marcelo Tosatti
2012-10-31 22:46 ` [patch 00/16] pvclock vsyscall support + KVM hypervisor support (v3) Marcelo Tosatti
2012-10-31 22:46   ` [patch 01/16] KVM: x86: retain pvclock guest stopped bit in guest memory Marcelo Tosatti
2012-11-01 10:39     ` Gleb Natapov
2012-11-01 20:51       ` Marcelo Tosatti
2012-11-01 13:44     ` Glauber Costa
2012-10-31 22:46   ` [patch 02/16] x86: pvclock: make sure rdtsc doesnt speculate out of region Marcelo Tosatti
2012-11-01 11:48     ` Gleb Natapov
2012-11-01 13:49       ` Glauber Costa
2012-11-01 13:51         ` Gleb Natapov
2012-11-01 20:56         ` Marcelo Tosatti
2012-11-01 22:13           ` Gleb Natapov
2012-11-01 22:21             ` Marcelo Tosatti
2012-11-02  6:02               ` Gleb Natapov
2012-10-31 22:46   ` [patch 03/16] x86: pvclock: remove pvclock_shadow_time Marcelo Tosatti
2012-11-01 13:52     ` Glauber Costa
2012-10-31 22:47   ` [patch 04/16] x86: pvclock: create helper for pvclock data retrieval Marcelo Tosatti
2012-11-01 14:04     ` Glauber Costa
2012-11-01 20:57       ` Marcelo Tosatti
2012-10-31 22:47   ` [patch 05/16] x86: pvclock: introduce helper to read flags Marcelo Tosatti
2012-11-01 14:07     ` Glauber Costa
2012-11-01 21:08       ` Marcelo Tosatti
2012-10-31 22:47   ` [patch 06/16] sched: add notifier for cross-cpu migrations Marcelo Tosatti
2012-11-01 14:08     ` Glauber Costa
2012-10-31 22:47   ` [patch 07/16] x86: pvclock: generic pvclock vsyscall initialization Marcelo Tosatti
2012-11-01 14:19     ` Glauber Costa
2012-10-31 22:47   ` [patch 08/16] KVM: x86: introduce facility to support vsyscall pvclock, via MSR Marcelo Tosatti
2012-11-01 14:28     ` Glauber Costa
2012-11-01 21:39       ` Marcelo Tosatti
2012-11-02 10:23         ` Glauber Costa
2012-11-02 13:00           ` Marcelo Tosatti
2012-11-05  8:03             ` Glauber Costa
2012-10-31 22:47   ` [patch 09/16] x86: kvm guest: pvclock vsyscall support Marcelo Tosatti
2012-11-02  9:42     ` Glauber Costa
2012-11-05  8:35       ` Marcelo Tosatti
2012-10-31 22:47   ` [patch 10/16] x86: vdso: pvclock gettime support Marcelo Tosatti
2012-11-01 14:41     ` Glauber Costa
2012-11-01 21:42       ` Marcelo Tosatti
2012-11-02  0:33         ` Marcelo Tosatti
2012-11-02 10:25           ` Glauber Costa
2012-11-14 10:42     ` Gleb Natapov
2012-11-14 22:42       ` Marcelo Tosatti
2012-10-31 22:47   ` [patch 11/16] KVM: x86: pass host_tsc to read_l1_tsc Marcelo Tosatti
2012-10-31 22:47   ` [patch 12/16] time: export time information for KVM pvclock Marcelo Tosatti
2012-10-31 22:47   ` [patch 13/16] KVM: x86: implement PVCLOCK_TSC_STABLE_BIT pvclock flag Marcelo Tosatti
2012-10-31 22:47   ` [patch 14/16] KVM: x86: notifier for clocksource changes Marcelo Tosatti
2012-10-31 22:47   ` [patch 15/16] KVM: x86: add kvm_arch_vcpu_postcreate callback, move TSC initialization Marcelo Tosatti
2012-10-31 22:47   ` [patch 16/16] KVM: x86: require matched TSC offsets for master clock Marcelo Tosatti

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