* backport Rewrite sync_core() to use IRET-to-self to stable kernels?
@ 2018-01-23 2:59 Zhang, Ning A
2018-01-23 3:06 ` Andy Lutomirski
0 siblings, 1 reply; 8+ messages in thread
From: Zhang, Ning A @ 2018-01-23 2:59 UTC (permalink / raw)
To: gregkh@linuxfoundation.org, luto@kernel.org, tglx@linutronix.de
Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org
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hello, Greg, Andy, Thomas
would you like to backport these two patches to LTS kernel?
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=1c52d859cb2d417e7216d3e56bb7fea88444cec9
x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit kernels
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=c198b121b1a1d7a7171770c634cd49191bac4477
x86/asm: Rewrite sync_core() to use IRET-to-self
BR.
Ning.
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: backport Rewrite sync_core() to use IRET-to-self to stable kernels?
2018-01-23 2:59 backport Rewrite sync_core() to use IRET-to-self to stable kernels? Zhang, Ning A
@ 2018-01-23 3:06 ` Andy Lutomirski
2018-01-23 7:25 ` gregkh
0 siblings, 1 reply; 8+ messages in thread
From: Andy Lutomirski @ 2018-01-23 3:06 UTC (permalink / raw)
To: Zhang, Ning A
Cc: gregkh@linuxfoundation.org, luto@kernel.org, tglx@linutronix.de,
stable@vger.kernel.org, linux-kernel@vger.kernel.org
On Mon, Jan 22, 2018 at 6:59 PM, Zhang, Ning A <ning.a.zhang@intel.com> wrote:
> hello, Greg, Andy, Thomas
>
> would you like to backport these two patches to LTS kernel?
>
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=1c52d859cb2d417e7216d3e56bb7fea88444cec9
>
> x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit kernels
>
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=c198b121b1a1d7a7171770c634cd49191bac4477
>
> x86/asm: Rewrite sync_core() to use IRET-to-self
>
I'd be in favor of backporting
1c52d859cb2d417e7216d3e56bb7fea88444cec9. I see no compelling reason
to backport the other one, since it doesn't fix a bug. Greg, can you
do this?
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: backport Rewrite sync_core() to use IRET-to-self to stable kernels?
2018-01-23 3:06 ` Andy Lutomirski
@ 2018-01-23 7:25 ` gregkh
2018-01-24 8:19 ` Zhang, Ning A
2018-01-24 9:00 ` gregkh
0 siblings, 2 replies; 8+ messages in thread
From: gregkh @ 2018-01-23 7:25 UTC (permalink / raw)
To: Andy Lutomirski
Cc: Zhang, Ning A, tglx@linutronix.de, stable@vger.kernel.org,
linux-kernel@vger.kernel.org
On Mon, Jan 22, 2018 at 07:06:29PM -0800, Andy Lutomirski wrote:
> On Mon, Jan 22, 2018 at 6:59 PM, Zhang, Ning A <ning.a.zhang@intel.com> wrote:
> > hello, Greg, Andy, Thomas
> >
> > would you like to backport these two patches to LTS kernel?
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=1c52d859cb2d417e7216d3e56bb7fea88444cec9
> >
> > x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit kernels
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=c198b121b1a1d7a7171770c634cd49191bac4477
> >
> > x86/asm: Rewrite sync_core() to use IRET-to-self
> >
>
> I'd be in favor of backporting
> 1c52d859cb2d417e7216d3e56bb7fea88444cec9. I see no compelling reason
> to backport the other one, since it doesn't fix a bug. Greg, can you
> do this?
I'll work on this after this round of stable kernels are released.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread
* RE: backport Rewrite sync_core() to use IRET-to-self to stable kernels?
2018-01-23 7:25 ` gregkh
@ 2018-01-24 8:19 ` Zhang, Ning A
2018-01-24 9:01 ` gregkh
2018-01-24 9:00 ` gregkh
1 sibling, 1 reply; 8+ messages in thread
From: Zhang, Ning A @ 2018-01-24 8:19 UTC (permalink / raw)
To: gregkh@linuxfoundation.org, Andy Lutomirski
Cc: tglx@linutronix.de, stable@vger.kernel.org,
linux-kernel@vger.kernel.org
Thanks Greg, Andy
How about c198b121b1a1d7a7171770c634cd49191bac4477?
Will both patches go to stable kernel?
BR.
Ning.
-----Original Message-----
From: gregkh@linuxfoundation.org [mailto:gregkh@linuxfoundation.org]
Sent: Tuesday, January 23, 2018 3:26 PM
To: Andy Lutomirski <luto@kernel.org>
Cc: Zhang, Ning A <ning.a.zhang@intel.com>; tglx@linutronix.de; stable@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: backport Rewrite sync_core() to use IRET-to-self to stable kernels?
On Mon, Jan 22, 2018 at 07:06:29PM -0800, Andy Lutomirski wrote:
> On Mon, Jan 22, 2018 at 6:59 PM, Zhang, Ning A <ning.a.zhang@intel.com> wrote:
> > hello, Greg, Andy, Thomas
> >
> > would you like to backport these two patches to LTS kernel?
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.
> > git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=1c52d859cb
> > 2d417e7216d3e56bb7fea88444cec9
> >
> > x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit
> > kernels
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.
> > git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=c198b121b1
> > a1d7a7171770c634cd49191bac4477
> >
> > x86/asm: Rewrite sync_core() to use IRET-to-self
> >
>
> I'd be in favor of backporting
> 1c52d859cb2d417e7216d3e56bb7fea88444cec9. I see no compelling reason
> to backport the other one, since it doesn't fix a bug. Greg, can you
> do this?
I'll work on this after this round of stable kernels are released.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: backport Rewrite sync_core() to use IRET-to-self to stable kernels?
2018-01-24 8:19 ` Zhang, Ning A
@ 2018-01-24 9:01 ` gregkh
2018-01-25 2:22 ` Zhang, Ning A
0 siblings, 1 reply; 8+ messages in thread
From: gregkh @ 2018-01-24 9:01 UTC (permalink / raw)
To: Zhang, Ning A
Cc: Andy Lutomirski, tglx@linutronix.de, stable@vger.kernel.org,
linux-kernel@vger.kernel.org
On Wed, Jan 24, 2018 at 08:19:44AM +0000, Zhang, Ning A wrote:
> Thanks Greg, Andy
>
> How about c198b121b1a1d7a7171770c634cd49191bac4477?
Why do you think that is needed in the older stable kernels? What
problem does it solve? Do any distros have this patch in their kernels?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread
* RE: backport Rewrite sync_core() to use IRET-to-self to stable kernels?
2018-01-24 9:01 ` gregkh
@ 2018-01-25 2:22 ` Zhang, Ning A
2018-01-25 6:50 ` gregkh
0 siblings, 1 reply; 8+ messages in thread
From: Zhang, Ning A @ 2018-01-25 2:22 UTC (permalink / raw)
To: gregkh@linuxfoundation.org
Cc: Andy Lutomirski, tglx@linutronix.de, stable@vger.kernel.org,
linux-kernel@vger.kernel.org
When Linux runs as a guest OS, CPUID is privileged instruction, sync_core() will be very slow.
If apply this patch, 200ms will be saved for kernel initial, when Linux runs as a guest OS.
BR.
Ning.
-----Original Message-----
From: gregkh@linuxfoundation.org [mailto:gregkh@linuxfoundation.org]
Sent: Wednesday, January 24, 2018 5:01 PM
To: Zhang, Ning A <ning.a.zhang@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>; tglx@linutronix.de; stable@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: backport Rewrite sync_core() to use IRET-to-self to stable kernels?
On Wed, Jan 24, 2018 at 08:19:44AM +0000, Zhang, Ning A wrote:
> Thanks Greg, Andy
>
> How about c198b121b1a1d7a7171770c634cd49191bac4477?
Why do you think that is needed in the older stable kernels? What problem does it solve? Do any distros have this patch in their kernels?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: backport Rewrite sync_core() to use IRET-to-self to stable kernels?
2018-01-25 2:22 ` Zhang, Ning A
@ 2018-01-25 6:50 ` gregkh
0 siblings, 0 replies; 8+ messages in thread
From: gregkh @ 2018-01-25 6:50 UTC (permalink / raw)
To: Zhang, Ning A
Cc: Andy Lutomirski, tglx@linutronix.de, stable@vger.kernel.org,
linux-kernel@vger.kernel.org
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
A: No.
Q: Should I include quotations after my reply?
http://daringfireball.net/2007/07/on_top
On Thu, Jan 25, 2018 at 02:22:57AM +0000, Zhang, Ning A wrote:
> When Linux runs as a guest OS, CPUID is privileged instruction, sync_core() will be very slow.
>
> If apply this patch, 200ms will be saved for kernel initial, when Linux runs as a guest OS.
That's not a regression. Why not just use a newer kernel release if you
want to get the feature of "faster boot"? :)
thanks,
greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: backport Rewrite sync_core() to use IRET-to-self to stable kernels?
2018-01-23 7:25 ` gregkh
2018-01-24 8:19 ` Zhang, Ning A
@ 2018-01-24 9:00 ` gregkh
1 sibling, 0 replies; 8+ messages in thread
From: gregkh @ 2018-01-24 9:00 UTC (permalink / raw)
To: Andy Lutomirski
Cc: Zhang, Ning A, tglx@linutronix.de, stable@vger.kernel.org,
linux-kernel@vger.kernel.org
On Tue, Jan 23, 2018 at 08:25:33AM +0100, gregkh@linuxfoundation.org wrote:
> On Mon, Jan 22, 2018 at 07:06:29PM -0800, Andy Lutomirski wrote:
> > On Mon, Jan 22, 2018 at 6:59 PM, Zhang, Ning A <ning.a.zhang@intel.com> wrote:
> > > hello, Greg, Andy, Thomas
> > >
> > > would you like to backport these two patches to LTS kernel?
> > >
> > > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=1c52d859cb2d417e7216d3e56bb7fea88444cec9
> > >
> > > x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit kernels
> > >
> > > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/arch/x86/include/asm/processor.h?h=v4.14.14&id=c198b121b1a1d7a7171770c634cd49191bac4477
> > >
> > > x86/asm: Rewrite sync_core() to use IRET-to-self
> > >
> >
> > I'd be in favor of backporting
> > 1c52d859cb2d417e7216d3e56bb7fea88444cec9. I see no compelling reason
> > to backport the other one, since it doesn't fix a bug. Greg, can you
> > do this?
>
> I'll work on this after this round of stable kernels are released.
Now applied, thanks.
greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread
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2018-01-23 2:59 backport Rewrite sync_core() to use IRET-to-self to stable kernels? Zhang, Ning A
2018-01-23 3:06 ` Andy Lutomirski
2018-01-23 7:25 ` gregkh
2018-01-24 8:19 ` Zhang, Ning A
2018-01-24 9:01 ` gregkh
2018-01-25 2:22 ` Zhang, Ning A
2018-01-25 6:50 ` gregkh
2018-01-24 9:00 ` gregkh
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