[PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[Zhang, Xiantao]

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>From 2c14c54eed790553fddbcb3970f0967a4aa79dca Mon Sep 17 00:00:00 2001
From: Xiantao Zhang <xiantao.zhang@intel.com>
Date: Sat, 23 Aug 2008 10:21:06 +0800
Subject: [PATCH] KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS,
once
virtualization configured.

Once virtulization configured, make PREEMPT_NOTIFIERS, ANON_INODES
selected by default.
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
---
 arch/ia64/kvm/Kconfig |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/kvm/Kconfig b/arch/ia64/kvm/Kconfig
index 7914e48..07f6b69 100644
--- a/arch/ia64/kvm/Kconfig
+++ b/arch/ia64/kvm/Kconfig
@@ -7,6 +7,8 @@ config HAVE_KVM
 menuconfig VIRTUALIZATION
 	bool "Virtualization"
 	depends on HAVE_KVM || IA64
+	select PREEMPT_NOTIFIERS
+	select ANON_INODES
 	default y
 	---help---
 	  Say Y here to get to see options for using your Linux host to
run other
@@ -20,8 +22,6 @@ if VIRTUALIZATION
 config KVM
 	tristate "Kernel-based Virtual Machine (KVM) support"
 	depends on HAVE_KVM && EXPERIMENTAL
-	select PREEMPT_NOTIFIERS
-	select ANON_INODES
 	---help---
 	  Support hosting fully virtualized guest machines using
hardware
 	  virtualization extensions.  You will need a fairly recent
-- 
1.5.1

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From 2c14c54eed790553fddbcb3970f0967a4aa79dca Mon Sep 17 00:00:00 2001
From: Xiantao Zhang <xiantao.zhang@intel.com>
Date: Sat, 23 Aug 2008 10:21:06 +0800
Subject: [PATCH] KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once
virtualization configured.

Once virtulization configured, make PREEMPT_NOTIFIERS, ANON_INODES
selected by default.
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
---
 arch/ia64/kvm/Kconfig |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/kvm/Kconfig b/arch/ia64/kvm/Kconfig
index 7914e48..07f6b69 100644
--- a/arch/ia64/kvm/Kconfig
+++ b/arch/ia64/kvm/Kconfig
@@ -7,6 +7,8 @@ config HAVE_KVM
 menuconfig VIRTUALIZATION
 	bool "Virtualization"
 	depends on HAVE_KVM || IA64
+	select PREEMPT_NOTIFIERS
+	select ANON_INODES
 	default y
 	---help---
 	  Say Y here to get to see options for using your Linux host to run other
@@ -20,8 +22,6 @@ if VIRTUALIZATION
 config KVM
 	tristate "Kernel-based Virtual Machine (KVM) support"
 	depends on HAVE_KVM && EXPERIMENTAL
-	select PREEMPT_NOTIFIERS
-	select ANON_INODES
 	---help---
 	  Support hosting fully virtualized guest machines using hardware
 	  virtualization extensions.  You will need a fairly recent
-- 
1.5.1

Re: [PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[Jes Sorensen]

>>>>> "Xiantao" == Zhang, Xiantao <xiantao.zhang@intel.com> writes:

Xiantao> From 2c14c54eed790553fddbcb3970f0967a4aa79dca Mon Sep 17
Xiantao> 00:00:00 2001 From: Xiantao Zhang <xiantao.zhang@intel.com>
Xiantao> Date: Sat, 23 Aug 2008 10:21:06 +0800 Subject: [PATCH] KVM:
Xiantao> kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once
Xiantao> virtualization configured.

Hi Xiantao,

I think this patch should be sent to Tony and
linux-ia64@vger.kernel.org as well.

Cheers,
Jes

Re: [PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[Avi Kivity]

Zhang, Xiantao wrote:
> From 2c14c54eed790553fddbcb3970f0967a4aa79dca Mon Sep 17 00:00:00 2001
> From: Xiantao Zhang <xiantao.zhang@intel.com>
> Date: Sat, 23 Aug 2008 10:21:06 +0800
> Subject: [PATCH] KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS,
> once
> virtualization configured.
>
> Once virtulization configured, make PREEMPT_NOTIFIERS, ANON_INODES
> selected by default.
>   

What is the motivation for this?  Don't things work as is?

> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
> ---
>  arch/ia64/kvm/Kconfig |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/ia64/kvm/Kconfig b/arch/ia64/kvm/Kconfig
> index 7914e48..07f6b69 100644
> --- a/arch/ia64/kvm/Kconfig
> +++ b/arch/ia64/kvm/Kconfig
> @@ -7,6 +7,8 @@ config HAVE_KVM
>  menuconfig VIRTUALIZATION
>  	bool "Virtualization"
>  	depends on HAVE_KVM || IA64
> +	select PREEMPT_NOTIFIERS
> +	select ANON_INODES
>  	default y
>   

Suppose VIRTUALIZATION is selected but KVM is not.  Why select 
ANON_INODES and PREEMPT_NOTIFIERS?

>  	---help---
>  	  Say Y here to get to see options for using your Linux host to
> run other
> @@ -20,8 +22,6 @@ if VIRTUALIZATION
>  config KVM
>  	tristate "Kernel-based Virtual Machine (KVM) support"
>  	depends on HAVE_KVM && EXPERIMENTAL
> -	select PREEMPT_NOTIFIERS
> -	select ANON_INODES
>  	---help---
>  	  Support hosting fully virtualized guest machines using
> hardware
>  	  virtualization extensions.  You will need a fairly recent
>   


-- 
error compiling committee.c: too many arguments to function

RE: [PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[Zhang, Xiantao]

Avi Kivity wrote:
> Zhang, Xiantao wrote:
>> From 2c14c54eed790553fddbcb3970f0967a4aa79dca Mon Sep 17 00:00:00
>> 2001 From: Xiantao Zhang <xiantao.zhang@intel.com>
>> Date: Sat, 23 Aug 2008 10:21:06 +0800
>> Subject: [PATCH] KVM: kvm/ia64: select ANON_INODES
>> PREEMPT_NOTIFIERS, once virtualization configured.
>> 
>> Once virtulization configured, make PREEMPT_NOTIFIERS, ANON_INODES
>> selected by default. 
>> 
> 
> What is the motivation for this?  Don't things work as is

You know, kvm depends on these two configrations.  If user doesn't
configure KVM when building host kernel, then PREEMPT_NOTIFIERS and
ANON_INODES shouldn't be selected .  In this case, once user wants to
exercise KVM later, he has to replace the host kernel again. To some
high-end servers, it maybe infeasible to replace kernel and get a
restart.  So I want to get them selected once users doesn't disable
virtulization explictly. 
 
Thanks
Xiantao

Re: [PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[Avi Kivity]

Zhang, Xiantao wrote:
> Avi Kivity wrote:
>   
>> Zhang, Xiantao wrote:
>>     
>>> From 2c14c54eed790553fddbcb3970f0967a4aa79dca Mon Sep 17 00:00:00
>>> 2001 From: Xiantao Zhang <xiantao.zhang@intel.com>
>>> Date: Sat, 23 Aug 2008 10:21:06 +0800
>>> Subject: [PATCH] KVM: kvm/ia64: select ANON_INODES
>>> PREEMPT_NOTIFIERS, once virtualization configured.
>>>
>>> Once virtulization configured, make PREEMPT_NOTIFIERS, ANON_INODES
>>> selected by default. 
>>>
>>>       
>> What is the motivation for this?  Don't things work as is
>>     
>
> You know, kvm depends on these two configrations.  If user doesn't
> configure KVM when building host kernel, then PREEMPT_NOTIFIERS and
> ANON_INODES shouldn't be selected .  In this case, once user wants to
> exercise KVM later, he has to replace the host kernel again. To some
> high-end servers, it maybe infeasible to replace kernel and get a
> restart.  So I want to get them selected once users doesn't disable
> virtulization explictly.

But it also means the user will have these features enabled needlessly.  
Right now when KVM is the only option under the virtualization menu, 
this may be okay, but if other features are added, this is not acceptable.

Really, if users want KVM, they should enable it in their kernel 
configuration.

-- 
error compiling committee.c: too many arguments to function

RE: [PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[Zhang, Xiantao]

Avi Kivity wrote:
> Zhang, Xiantao wrote:
>> Avi Kivity wrote:
>> 
>>> Zhang, Xiantao wrote:
>>> 
>>>> From 2c14c54eed790553fddbcb3970f0967a4aa79dca Mon Sep 17 00:00:00
>>>> 2001 From: Xiantao Zhang <xiantao.zhang@intel.com>
>>>> Date: Sat, 23 Aug 2008 10:21:06 +0800
>>>> Subject: [PATCH] KVM: kvm/ia64: select ANON_INODES
>>>> PREEMPT_NOTIFIERS, once virtualization configured.
>>>> 
>>>> Once virtulization configured, make PREEMPT_NOTIFIERS, ANON_INODES
>>>> selected by default. 
>>>> 
>>>> 
>>> What is the motivation for this?  Don't things work as is
>>> 
>> 
>> You know, kvm depends on these two configrations.  If user doesn't
>> configure KVM when building host kernel, then PREEMPT_NOTIFIERS and
>> ANON_INODES shouldn't be selected .  In this case, once user wants to
>> exercise KVM later, he has to replace the host kernel again. To some
>> high-end servers, it maybe infeasible to replace kernel and get a
>> restart.  So I want to get them selected once users doesn't disable
>> virtulization explictly.
> 
> But it also means the user will have these features enabled
> needlessly. Right now when KVM is the only option under the
> virtualization menu, 
> this may be okay, but if other features are added, this is not
> acceptable. 
> 
> Really, if users want KVM, they should enable it in their kernel
> configuration.

But if users don't configure it @ building kernel, they can't exercise
kvm unless re-configure and re-build the host kernel.  Generally, we
should allow users to build kvm in the form of modules, and insert to
host kernels without other dependcies.   BTW, we often meet such fails
and have to do rebuild.  :(
Thanks
Xiantao

Re: [PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[Avi Kivity]

Zhang, Xiantao wrote:
> But if users don't configure it @ building kernel, they can't exercise
> kvm unless re-configure and re-build the host kernel.  Generally, we
> should allow users to build kvm in the form of modules, and insert to
> host kernels without other dependcies.   BTW, we often meet such fails
> and have to do rebuild.  :(


If users don't configure networking, they can't compile any drivers.

Sorry, that's how the kernel works.  btw, on x86 we manage to run even 
without preempt notifiers, but a lot of pain is involved.

In practice, I don't expect a problem.  Most users get their kernels 
from a distribution.  You should talk to ia64 distribution vendors to 
make sure they enable kvm in their ia64 2.6.26+ kernels.

-- 
error compiling committee.c: too many arguments to function

RE: [PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[Zhang, Xiantao]

Avi Kivity wrote:
> Zhang, Xiantao wrote:
>> But if users don't configure it @ building kernel, they can't
>> exercise kvm unless re-configure and re-build the host kernel. 
>> Generally, we should allow users to build kvm in the form of
>> modules, and insert to host kernels without other dependcies.   BTW,
>> we often meet such fails and have to do rebuild.  :(
> 
> 
> If users don't configure networking, they can't compile any drivers.
> 
> Sorry, that's how the kernel works.  btw, on x86 we manage to run even
> without preempt notifiers, but a lot of pain is involved.

Yes, we  have to do a lot of work to make it work. 

> In practice, I don't expect a problem.  Most users get their kernels
> from a distribution.  You should talk to ia64 distribution vendors to
> make sure they enable kvm in their ia64 2.6.26+ kernels.

Agree.  Could we change default configration to make preempt_notifier
configured if no more overhead introduced ?  I noticed kvm/s390 has did
in this way.   

> error compiling committee.c: too many arguments to function

Re: [PATCH]KVM: kvm/ia64: select ANON_INODES PREEMPT_NOTIFIERS, once

[Avi Kivity]

Zhang, Xiantao wrote:
>> In practice, I don't expect a problem.  Most users get their kernels
>> from a distribution.  You should talk to ia64 distribution vendors to
>> make sure they enable kvm in their ia64 2.6.26+ kernels.
>>     
>
> Agree.  Could we change default configration to make preempt_notifier
> configured if no more overhead introduced ?  I noticed kvm/s390 has did
> in this way.   
>   

That's up to your arch maintainer.  I don't recommend it though.  I 
guess ia64 priorities are different, but for x86 we disable anything 
that isn't strictly required.

-- 
error compiling committee.c: too many arguments to function