linux-kernel - Re: [PATCH v3] xen: add steal

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Date:	Thu, 19 May 2016 09:43:22 -0400
From:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:	Juergen Gross <jgross@...e.com>, xen-devel@...ts.xenproject.org,
	linux-kernel@...r.kernel.org
Cc:	sstabellini@...nel.org, david.vrabel@...rix.com
Subject: Re: [PATCH v3] xen: add steal_clock support on x86

On 05/19/2016 09:26 AM, Juergen Gross wrote:
> The pv_time_ops structure contains a function pointer for the
> "steal_clock" functionality used only by KVM and Xen on ARM. Xen on x86
> uses its own mechanism to account for the "stolen" time a thread wasn't
> able to run due to hypervisor scheduling.
>
> Add support in Xen arch independent time handling for this feature by
> moving it out of the arm arch into drivers/xen and remove the x86 Xen
> hack.
>
> Signed-off-by: Juergen Gross <jgross@...e.com>

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>

I think this also needs to be acked by (or at least copied to) generic
Linux maintainers.

> ---
>  arch/arm/xen/enlighten.c    | 17 ++---------------
>  arch/x86/xen/time.c         | 44 ++------------------------------------------
>  drivers/xen/time.c          | 20 ++++++++++++++++++++
>  include/linux/kernel_stat.h |  1 -
>  include/xen/xen-ops.h       |  1 +
>  kernel/sched/cputime.c      | 10 ----------
>  6 files changed, 25 insertions(+), 68 deletions(-)

...

>  }
> diff --git a/drivers/xen/time.c b/drivers/xen/time.c
> index 7107842..2257b66 100644
> --- a/drivers/xen/time.c
> +++ b/drivers/xen/time.c
> @@ -6,6 +6,7 @@
>  #include <linux/math64.h>
>  #include <linux/gfp.h>
>  
> +#include <asm/paravirt.h>
>  #include <asm/xen/hypervisor.h>
>  #include <asm/xen/hypercall.h>
>  
> @@ -75,6 +76,15 @@ bool xen_vcpu_stolen(int vcpu)
>  	return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
>  }

(Unrelated to this patch.) Should this include RUNSTATE_offline as well?

-boris